1562 lines
38 KiB
ArmAsm
1562 lines
38 KiB
ArmAsm
/*
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* linux/arch/x86_64/entry.S
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
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* Copyright (C) 2000 Pavel Machek <pavel@suse.cz>
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*/
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/*
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* entry.S contains the system-call and fault low-level handling routines.
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*
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* NOTE: This code handles signal-recognition, which happens every time
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* after an interrupt and after each system call.
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*
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* Normal syscalls and interrupts don't save a full stack frame, this is
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* only done for syscall tracing, signals or fork/exec et.al.
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*
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* A note on terminology:
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* - top of stack: Architecture defined interrupt frame from SS to RIP
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* at the top of the kernel process stack.
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* - partial stack frame: partially saved registers upto R11.
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* - full stack frame: Like partial stack frame, but all register saved.
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*
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* Some macro usage:
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* - CFI macros are used to generate dwarf2 unwind information for better
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* backtraces. They don't change any code.
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* - SAVE_ALL/RESTORE_ALL - Save/restore all registers
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* - SAVE_ARGS/RESTORE_ARGS - Save/restore registers that C functions modify.
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* There are unfortunately lots of special cases where some registers
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* not touched. The macro is a big mess that should be cleaned up.
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* - SAVE_REST/RESTORE_REST - Handle the registers not saved by SAVE_ARGS.
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* Gives a full stack frame.
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* - ENTRY/END Define functions in the symbol table.
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* - FIXUP_TOP_OF_STACK/RESTORE_TOP_OF_STACK - Fix up the hardware stack
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* frame that is otherwise undefined after a SYSCALL
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* - TRACE_IRQ_* - Trace hard interrupt state for lock debugging.
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* - errorentry/paranoidentry/zeroentry - Define exception entry points.
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*/
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#include <linux/linkage.h>
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#include <asm/segment.h>
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#include <asm/cache.h>
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#include <asm/errno.h>
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#include <asm/dwarf2.h>
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#include <asm/calling.h>
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#include <asm/asm-offsets.h>
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#include <asm/msr.h>
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#include <asm/unistd.h>
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#include <asm/thread_info.h>
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#include <asm/hw_irq.h>
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#include <asm/page_types.h>
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#include <asm/irqflags.h>
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#include <asm/paravirt.h>
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#include <asm/ftrace.h>
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#include <asm/percpu.h>
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/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
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#include <linux/elf-em.h>
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#define AUDIT_ARCH_X86_64 (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
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#define __AUDIT_ARCH_64BIT 0x80000000
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#define __AUDIT_ARCH_LE 0x40000000
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.code64
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#ifdef CONFIG_FUNCTION_TRACER
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#ifdef CONFIG_DYNAMIC_FTRACE
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ENTRY(mcount)
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retq
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END(mcount)
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ENTRY(ftrace_caller)
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cmpl $0, function_trace_stop
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jne ftrace_stub
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MCOUNT_SAVE_FRAME
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movq 0x38(%rsp), %rdi
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movq 8(%rbp), %rsi
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subq $MCOUNT_INSN_SIZE, %rdi
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GLOBAL(ftrace_call)
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call ftrace_stub
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MCOUNT_RESTORE_FRAME
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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GLOBAL(ftrace_graph_call)
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jmp ftrace_stub
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#endif
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GLOBAL(ftrace_stub)
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retq
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END(ftrace_caller)
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#else /* ! CONFIG_DYNAMIC_FTRACE */
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ENTRY(mcount)
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cmpl $0, function_trace_stop
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jne ftrace_stub
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cmpq $ftrace_stub, ftrace_trace_function
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jnz trace
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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cmpq $ftrace_stub, ftrace_graph_return
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jnz ftrace_graph_caller
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cmpq $ftrace_graph_entry_stub, ftrace_graph_entry
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jnz ftrace_graph_caller
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#endif
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GLOBAL(ftrace_stub)
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retq
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trace:
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MCOUNT_SAVE_FRAME
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movq 0x38(%rsp), %rdi
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movq 8(%rbp), %rsi
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subq $MCOUNT_INSN_SIZE, %rdi
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call *ftrace_trace_function
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MCOUNT_RESTORE_FRAME
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jmp ftrace_stub
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END(mcount)
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#endif /* CONFIG_DYNAMIC_FTRACE */
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#endif /* CONFIG_FUNCTION_TRACER */
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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ENTRY(ftrace_graph_caller)
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cmpl $0, function_trace_stop
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jne ftrace_stub
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MCOUNT_SAVE_FRAME
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leaq 8(%rbp), %rdi
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movq 0x38(%rsp), %rsi
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movq (%rbp), %rdx
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subq $MCOUNT_INSN_SIZE, %rsi
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call prepare_ftrace_return
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MCOUNT_RESTORE_FRAME
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retq
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END(ftrace_graph_caller)
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GLOBAL(return_to_handler)
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subq $24, %rsp
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/* Save the return values */
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movq %rax, (%rsp)
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movq %rdx, 8(%rsp)
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movq %rbp, %rdi
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call ftrace_return_to_handler
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movq %rax, %rdi
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movq 8(%rsp), %rdx
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movq (%rsp), %rax
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addq $24, %rsp
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jmp *%rdi
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#endif
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#ifndef CONFIG_PREEMPT
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#define retint_kernel retint_restore_args
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#endif
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#ifdef CONFIG_PARAVIRT
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ENTRY(native_usergs_sysret64)
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swapgs
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sysretq
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ENDPROC(native_usergs_sysret64)
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#endif /* CONFIG_PARAVIRT */
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.macro TRACE_IRQS_IRETQ offset=ARGOFFSET
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#ifdef CONFIG_TRACE_IRQFLAGS
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bt $9,EFLAGS-\offset(%rsp) /* interrupts off? */
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jnc 1f
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TRACE_IRQS_ON
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1:
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#endif
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.endm
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/*
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* C code is not supposed to know about undefined top of stack. Every time
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* a C function with an pt_regs argument is called from the SYSCALL based
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* fast path FIXUP_TOP_OF_STACK is needed.
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* RESTORE_TOP_OF_STACK syncs the syscall state after any possible ptregs
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* manipulation.
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*/
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/* %rsp:at FRAMEEND */
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.macro FIXUP_TOP_OF_STACK tmp offset=0
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movq PER_CPU_VAR(old_rsp),\tmp
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movq \tmp,RSP+\offset(%rsp)
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movq $__USER_DS,SS+\offset(%rsp)
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movq $__USER_CS,CS+\offset(%rsp)
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movq $-1,RCX+\offset(%rsp)
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movq R11+\offset(%rsp),\tmp /* get eflags */
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movq \tmp,EFLAGS+\offset(%rsp)
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.endm
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.macro RESTORE_TOP_OF_STACK tmp offset=0
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movq RSP+\offset(%rsp),\tmp
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movq \tmp,PER_CPU_VAR(old_rsp)
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movq EFLAGS+\offset(%rsp),\tmp
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movq \tmp,R11+\offset(%rsp)
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.endm
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.macro FAKE_STACK_FRAME child_rip
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/* push in order ss, rsp, eflags, cs, rip */
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xorl %eax, %eax
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pushq $__KERNEL_DS /* ss */
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CFI_ADJUST_CFA_OFFSET 8
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/*CFI_REL_OFFSET ss,0*/
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pushq %rax /* rsp */
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CFI_ADJUST_CFA_OFFSET 8
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CFI_REL_OFFSET rsp,0
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pushq $X86_EFLAGS_IF /* eflags - interrupts on */
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CFI_ADJUST_CFA_OFFSET 8
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/*CFI_REL_OFFSET rflags,0*/
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pushq $__KERNEL_CS /* cs */
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CFI_ADJUST_CFA_OFFSET 8
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/*CFI_REL_OFFSET cs,0*/
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pushq \child_rip /* rip */
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CFI_ADJUST_CFA_OFFSET 8
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CFI_REL_OFFSET rip,0
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pushq %rax /* orig rax */
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CFI_ADJUST_CFA_OFFSET 8
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.endm
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.macro UNFAKE_STACK_FRAME
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addq $8*6, %rsp
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CFI_ADJUST_CFA_OFFSET -(6*8)
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.endm
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/*
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* initial frame state for interrupts (and exceptions without error code)
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*/
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.macro EMPTY_FRAME start=1 offset=0
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.if \start
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CFI_STARTPROC simple
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CFI_SIGNAL_FRAME
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CFI_DEF_CFA rsp,8+\offset
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.else
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CFI_DEF_CFA_OFFSET 8+\offset
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.endif
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.endm
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/*
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* initial frame state for interrupts (and exceptions without error code)
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*/
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.macro INTR_FRAME start=1 offset=0
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EMPTY_FRAME \start, SS+8+\offset-RIP
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/*CFI_REL_OFFSET ss, SS+\offset-RIP*/
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CFI_REL_OFFSET rsp, RSP+\offset-RIP
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/*CFI_REL_OFFSET rflags, EFLAGS+\offset-RIP*/
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/*CFI_REL_OFFSET cs, CS+\offset-RIP*/
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CFI_REL_OFFSET rip, RIP+\offset-RIP
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.endm
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/*
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* initial frame state for exceptions with error code (and interrupts
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* with vector already pushed)
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*/
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.macro XCPT_FRAME start=1 offset=0
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INTR_FRAME \start, RIP+\offset-ORIG_RAX
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/*CFI_REL_OFFSET orig_rax, ORIG_RAX-ORIG_RAX*/
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.endm
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/*
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* frame that enables calling into C.
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*/
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.macro PARTIAL_FRAME start=1 offset=0
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XCPT_FRAME \start, ORIG_RAX+\offset-ARGOFFSET
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CFI_REL_OFFSET rdi, RDI+\offset-ARGOFFSET
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CFI_REL_OFFSET rsi, RSI+\offset-ARGOFFSET
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CFI_REL_OFFSET rdx, RDX+\offset-ARGOFFSET
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CFI_REL_OFFSET rcx, RCX+\offset-ARGOFFSET
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CFI_REL_OFFSET rax, RAX+\offset-ARGOFFSET
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CFI_REL_OFFSET r8, R8+\offset-ARGOFFSET
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CFI_REL_OFFSET r9, R9+\offset-ARGOFFSET
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CFI_REL_OFFSET r10, R10+\offset-ARGOFFSET
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CFI_REL_OFFSET r11, R11+\offset-ARGOFFSET
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.endm
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/*
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* frame that enables passing a complete pt_regs to a C function.
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*/
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.macro DEFAULT_FRAME start=1 offset=0
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PARTIAL_FRAME \start, R11+\offset-R15
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CFI_REL_OFFSET rbx, RBX+\offset
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CFI_REL_OFFSET rbp, RBP+\offset
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CFI_REL_OFFSET r12, R12+\offset
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CFI_REL_OFFSET r13, R13+\offset
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CFI_REL_OFFSET r14, R14+\offset
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CFI_REL_OFFSET r15, R15+\offset
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.endm
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/* save partial stack frame */
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ENTRY(save_args)
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XCPT_FRAME
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cld
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movq_cfi rdi, RDI+16-ARGOFFSET
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movq_cfi rsi, RSI+16-ARGOFFSET
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movq_cfi rdx, RDX+16-ARGOFFSET
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movq_cfi rcx, RCX+16-ARGOFFSET
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movq_cfi rax, RAX+16-ARGOFFSET
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movq_cfi r8, R8+16-ARGOFFSET
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movq_cfi r9, R9+16-ARGOFFSET
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movq_cfi r10, R10+16-ARGOFFSET
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movq_cfi r11, R11+16-ARGOFFSET
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leaq -ARGOFFSET+16(%rsp),%rdi /* arg1 for handler */
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movq_cfi rbp, 8 /* push %rbp */
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leaq 8(%rsp), %rbp /* mov %rsp, %ebp */
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testl $3, CS(%rdi)
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je 1f
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SWAPGS
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/*
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* irq_count is used to check if a CPU is already on an interrupt stack
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* or not. While this is essentially redundant with preempt_count it is
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* a little cheaper to use a separate counter in the PDA (short of
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* moving irq_enter into assembly, which would be too much work)
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*/
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1: incl PER_CPU_VAR(irq_count)
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jne 2f
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popq_cfi %rax /* move return address... */
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mov PER_CPU_VAR(irq_stack_ptr),%rsp
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EMPTY_FRAME 0
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pushq_cfi %rbp /* backlink for unwinder */
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pushq_cfi %rax /* ... to the new stack */
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/*
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* We entered an interrupt context - irqs are off:
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*/
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2: TRACE_IRQS_OFF
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ret
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CFI_ENDPROC
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END(save_args)
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ENTRY(save_rest)
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PARTIAL_FRAME 1 REST_SKIP+8
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movq 5*8+16(%rsp), %r11 /* save return address */
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movq_cfi rbx, RBX+16
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movq_cfi rbp, RBP+16
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movq_cfi r12, R12+16
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movq_cfi r13, R13+16
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movq_cfi r14, R14+16
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movq_cfi r15, R15+16
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movq %r11, 8(%rsp) /* return address */
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FIXUP_TOP_OF_STACK %r11, 16
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ret
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CFI_ENDPROC
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END(save_rest)
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/* save complete stack frame */
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.pushsection .kprobes.text, "ax"
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ENTRY(save_paranoid)
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XCPT_FRAME 1 RDI+8
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cld
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movq_cfi rdi, RDI+8
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movq_cfi rsi, RSI+8
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movq_cfi rdx, RDX+8
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movq_cfi rcx, RCX+8
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movq_cfi rax, RAX+8
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movq_cfi r8, R8+8
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movq_cfi r9, R9+8
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movq_cfi r10, R10+8
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movq_cfi r11, R11+8
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movq_cfi rbx, RBX+8
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movq_cfi rbp, RBP+8
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movq_cfi r12, R12+8
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movq_cfi r13, R13+8
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movq_cfi r14, R14+8
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movq_cfi r15, R15+8
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movl $1,%ebx
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movl $MSR_GS_BASE,%ecx
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rdmsr
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testl %edx,%edx
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js 1f /* negative -> in kernel */
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SWAPGS
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xorl %ebx,%ebx
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1: ret
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CFI_ENDPROC
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END(save_paranoid)
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.popsection
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/*
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* A newly forked process directly context switches into this address.
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*
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* rdi: prev task we switched from
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*/
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ENTRY(ret_from_fork)
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DEFAULT_FRAME
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LOCK ; btr $TIF_FORK,TI_flags(%r8)
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push kernel_eflags(%rip)
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CFI_ADJUST_CFA_OFFSET 8
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popf # reset kernel eflags
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CFI_ADJUST_CFA_OFFSET -8
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call schedule_tail # rdi: 'prev' task parameter
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GET_THREAD_INFO(%rcx)
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RESTORE_REST
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testl $3, CS-ARGOFFSET(%rsp) # from kernel_thread?
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je int_ret_from_sys_call
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testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET
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jnz int_ret_from_sys_call
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RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET
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jmp ret_from_sys_call # go to the SYSRET fastpath
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CFI_ENDPROC
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END(ret_from_fork)
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/*
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* System call entry. Upto 6 arguments in registers are supported.
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*
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* SYSCALL does not save anything on the stack and does not change the
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* stack pointer.
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*/
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/*
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* Register setup:
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* rax system call number
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* rdi arg0
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* rcx return address for syscall/sysret, C arg3
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* rsi arg1
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* rdx arg2
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* r10 arg3 (--> moved to rcx for C)
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* r8 arg4
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* r9 arg5
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* r11 eflags for syscall/sysret, temporary for C
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* r12-r15,rbp,rbx saved by C code, not touched.
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*
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* Interrupts are off on entry.
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* Only called from user space.
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*
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* XXX if we had a free scratch register we could save the RSP into the stack frame
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* and report it properly in ps. Unfortunately we haven't.
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*
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* When user can change the frames always force IRET. That is because
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* it deals with uncanonical addresses better. SYSRET has trouble
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* with them due to bugs in both AMD and Intel CPUs.
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*/
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ENTRY(system_call)
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CFI_STARTPROC simple
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CFI_SIGNAL_FRAME
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CFI_DEF_CFA rsp,KERNEL_STACK_OFFSET
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CFI_REGISTER rip,rcx
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/*CFI_REGISTER rflags,r11*/
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SWAPGS_UNSAFE_STACK
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/*
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* A hypervisor implementation might want to use a label
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* after the swapgs, so that it can do the swapgs
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* for the guest and jump here on syscall.
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*/
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ENTRY(system_call_after_swapgs)
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movq %rsp,PER_CPU_VAR(old_rsp)
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movq PER_CPU_VAR(kernel_stack),%rsp
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/*
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* No need to follow this irqs off/on section - it's straight
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* and short:
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*/
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ENABLE_INTERRUPTS(CLBR_NONE)
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SAVE_ARGS 8,1
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movq %rax,ORIG_RAX-ARGOFFSET(%rsp)
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movq %rcx,RIP-ARGOFFSET(%rsp)
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CFI_REL_OFFSET rip,RIP-ARGOFFSET
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GET_THREAD_INFO(%rcx)
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testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%rcx)
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jnz tracesys
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system_call_fastpath:
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cmpq $__NR_syscall_max,%rax
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ja badsys
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movq %r10,%rcx
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call *sys_call_table(,%rax,8) # XXX: rip relative
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movq %rax,RAX-ARGOFFSET(%rsp)
|
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/*
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* Syscall return path ending with SYSRET (fast path)
|
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* Has incomplete stack frame and undefined top of stack.
|
|
*/
|
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ret_from_sys_call:
|
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movl $_TIF_ALLWORK_MASK,%edi
|
|
/* edi: flagmask */
|
|
sysret_check:
|
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LOCKDEP_SYS_EXIT
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GET_THREAD_INFO(%rcx)
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
movl TI_flags(%rcx),%edx
|
|
andl %edi,%edx
|
|
jnz sysret_careful
|
|
CFI_REMEMBER_STATE
|
|
/*
|
|
* sysretq will re-enable interrupts:
|
|
*/
|
|
TRACE_IRQS_ON
|
|
movq RIP-ARGOFFSET(%rsp),%rcx
|
|
CFI_REGISTER rip,rcx
|
|
RESTORE_ARGS 0,-ARG_SKIP,1
|
|
/*CFI_REGISTER rflags,r11*/
|
|
movq PER_CPU_VAR(old_rsp), %rsp
|
|
USERGS_SYSRET64
|
|
|
|
CFI_RESTORE_STATE
|
|
/* Handle reschedules */
|
|
/* edx: work, edi: workmask */
|
|
sysret_careful:
|
|
bt $TIF_NEED_RESCHED,%edx
|
|
jnc sysret_signal
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
pushq %rdi
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
call schedule
|
|
popq %rdi
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
jmp sysret_check
|
|
|
|
/* Handle a signal */
|
|
sysret_signal:
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
#ifdef CONFIG_AUDITSYSCALL
|
|
bt $TIF_SYSCALL_AUDIT,%edx
|
|
jc sysret_audit
|
|
#endif
|
|
/*
|
|
* We have a signal, or exit tracing or single-step.
|
|
* These all wind up with the iret return path anyway,
|
|
* so just join that path right now.
|
|
*/
|
|
FIXUP_TOP_OF_STACK %r11, -ARGOFFSET
|
|
jmp int_check_syscall_exit_work
|
|
|
|
badsys:
|
|
movq $-ENOSYS,RAX-ARGOFFSET(%rsp)
|
|
jmp ret_from_sys_call
|
|
|
|
#ifdef CONFIG_AUDITSYSCALL
|
|
/*
|
|
* Fast path for syscall audit without full syscall trace.
|
|
* We just call audit_syscall_entry() directly, and then
|
|
* jump back to the normal fast path.
|
|
*/
|
|
auditsys:
|
|
movq %r10,%r9 /* 6th arg: 4th syscall arg */
|
|
movq %rdx,%r8 /* 5th arg: 3rd syscall arg */
|
|
movq %rsi,%rcx /* 4th arg: 2nd syscall arg */
|
|
movq %rdi,%rdx /* 3rd arg: 1st syscall arg */
|
|
movq %rax,%rsi /* 2nd arg: syscall number */
|
|
movl $AUDIT_ARCH_X86_64,%edi /* 1st arg: audit arch */
|
|
call audit_syscall_entry
|
|
LOAD_ARGS 0 /* reload call-clobbered registers */
|
|
jmp system_call_fastpath
|
|
|
|
/*
|
|
* Return fast path for syscall audit. Call audit_syscall_exit()
|
|
* directly and then jump back to the fast path with TIF_SYSCALL_AUDIT
|
|
* masked off.
|
|
*/
|
|
sysret_audit:
|
|
movq RAX-ARGOFFSET(%rsp),%rsi /* second arg, syscall return value */
|
|
cmpq $0,%rsi /* is it < 0? */
|
|
setl %al /* 1 if so, 0 if not */
|
|
movzbl %al,%edi /* zero-extend that into %edi */
|
|
inc %edi /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */
|
|
call audit_syscall_exit
|
|
movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
|
|
jmp sysret_check
|
|
#endif /* CONFIG_AUDITSYSCALL */
|
|
|
|
/* Do syscall tracing */
|
|
tracesys:
|
|
#ifdef CONFIG_AUDITSYSCALL
|
|
testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%rcx)
|
|
jz auditsys
|
|
#endif
|
|
SAVE_REST
|
|
movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
|
|
FIXUP_TOP_OF_STACK %rdi
|
|
movq %rsp,%rdi
|
|
call syscall_trace_enter
|
|
/*
|
|
* Reload arg registers from stack in case ptrace changed them.
|
|
* We don't reload %rax because syscall_trace_enter() returned
|
|
* the value it wants us to use in the table lookup.
|
|
*/
|
|
LOAD_ARGS ARGOFFSET, 1
|
|
RESTORE_REST
|
|
cmpq $__NR_syscall_max,%rax
|
|
ja int_ret_from_sys_call /* RAX(%rsp) set to -ENOSYS above */
|
|
movq %r10,%rcx /* fixup for C */
|
|
call *sys_call_table(,%rax,8)
|
|
movq %rax,RAX-ARGOFFSET(%rsp)
|
|
/* Use IRET because user could have changed frame */
|
|
|
|
/*
|
|
* Syscall return path ending with IRET.
|
|
* Has correct top of stack, but partial stack frame.
|
|
*/
|
|
GLOBAL(int_ret_from_sys_call)
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
testl $3,CS-ARGOFFSET(%rsp)
|
|
je retint_restore_args
|
|
movl $_TIF_ALLWORK_MASK,%edi
|
|
/* edi: mask to check */
|
|
GLOBAL(int_with_check)
|
|
LOCKDEP_SYS_EXIT_IRQ
|
|
GET_THREAD_INFO(%rcx)
|
|
movl TI_flags(%rcx),%edx
|
|
andl %edi,%edx
|
|
jnz int_careful
|
|
andl $~TS_COMPAT,TI_status(%rcx)
|
|
jmp retint_swapgs
|
|
|
|
/* Either reschedule or signal or syscall exit tracking needed. */
|
|
/* First do a reschedule test. */
|
|
/* edx: work, edi: workmask */
|
|
int_careful:
|
|
bt $TIF_NEED_RESCHED,%edx
|
|
jnc int_very_careful
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
pushq %rdi
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
call schedule
|
|
popq %rdi
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
jmp int_with_check
|
|
|
|
/* handle signals and tracing -- both require a full stack frame */
|
|
int_very_careful:
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
int_check_syscall_exit_work:
|
|
SAVE_REST
|
|
/* Check for syscall exit trace */
|
|
testl $_TIF_WORK_SYSCALL_EXIT,%edx
|
|
jz int_signal
|
|
pushq %rdi
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
leaq 8(%rsp),%rdi # &ptregs -> arg1
|
|
call syscall_trace_leave
|
|
popq %rdi
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
andl $~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU),%edi
|
|
jmp int_restore_rest
|
|
|
|
int_signal:
|
|
testl $_TIF_DO_NOTIFY_MASK,%edx
|
|
jz 1f
|
|
movq %rsp,%rdi # &ptregs -> arg1
|
|
xorl %esi,%esi # oldset -> arg2
|
|
call do_notify_resume
|
|
1: movl $_TIF_WORK_MASK,%edi
|
|
int_restore_rest:
|
|
RESTORE_REST
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
jmp int_with_check
|
|
CFI_ENDPROC
|
|
END(system_call)
|
|
|
|
/*
|
|
* Certain special system calls that need to save a complete full stack frame.
|
|
*/
|
|
.macro PTREGSCALL label,func,arg
|
|
ENTRY(\label)
|
|
PARTIAL_FRAME 1 8 /* offset 8: return address */
|
|
subq $REST_SKIP, %rsp
|
|
CFI_ADJUST_CFA_OFFSET REST_SKIP
|
|
call save_rest
|
|
DEFAULT_FRAME 0 8 /* offset 8: return address */
|
|
leaq 8(%rsp), \arg /* pt_regs pointer */
|
|
call \func
|
|
jmp ptregscall_common
|
|
CFI_ENDPROC
|
|
END(\label)
|
|
.endm
|
|
|
|
PTREGSCALL stub_clone, sys_clone, %r8
|
|
PTREGSCALL stub_fork, sys_fork, %rdi
|
|
PTREGSCALL stub_vfork, sys_vfork, %rdi
|
|
PTREGSCALL stub_sigaltstack, sys_sigaltstack, %rdx
|
|
PTREGSCALL stub_iopl, sys_iopl, %rsi
|
|
|
|
ENTRY(ptregscall_common)
|
|
DEFAULT_FRAME 1 8 /* offset 8: return address */
|
|
RESTORE_TOP_OF_STACK %r11, 8
|
|
movq_cfi_restore R15+8, r15
|
|
movq_cfi_restore R14+8, r14
|
|
movq_cfi_restore R13+8, r13
|
|
movq_cfi_restore R12+8, r12
|
|
movq_cfi_restore RBP+8, rbp
|
|
movq_cfi_restore RBX+8, rbx
|
|
ret $REST_SKIP /* pop extended registers */
|
|
CFI_ENDPROC
|
|
END(ptregscall_common)
|
|
|
|
ENTRY(stub_execve)
|
|
CFI_STARTPROC
|
|
popq %r11
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
CFI_REGISTER rip, r11
|
|
SAVE_REST
|
|
FIXUP_TOP_OF_STACK %r11
|
|
movq %rsp, %rcx
|
|
call sys_execve
|
|
RESTORE_TOP_OF_STACK %r11
|
|
movq %rax,RAX(%rsp)
|
|
RESTORE_REST
|
|
jmp int_ret_from_sys_call
|
|
CFI_ENDPROC
|
|
END(stub_execve)
|
|
|
|
/*
|
|
* sigreturn is special because it needs to restore all registers on return.
|
|
* This cannot be done with SYSRET, so use the IRET return path instead.
|
|
*/
|
|
ENTRY(stub_rt_sigreturn)
|
|
CFI_STARTPROC
|
|
addq $8, %rsp
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
SAVE_REST
|
|
movq %rsp,%rdi
|
|
FIXUP_TOP_OF_STACK %r11
|
|
call sys_rt_sigreturn
|
|
movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer
|
|
RESTORE_REST
|
|
jmp int_ret_from_sys_call
|
|
CFI_ENDPROC
|
|
END(stub_rt_sigreturn)
|
|
|
|
/*
|
|
* Build the entry stubs and pointer table with some assembler magic.
|
|
* We pack 7 stubs into a single 32-byte chunk, which will fit in a
|
|
* single cache line on all modern x86 implementations.
|
|
*/
|
|
.section .init.rodata,"a"
|
|
ENTRY(interrupt)
|
|
.text
|
|
.p2align 5
|
|
.p2align CONFIG_X86_L1_CACHE_SHIFT
|
|
ENTRY(irq_entries_start)
|
|
INTR_FRAME
|
|
vector=FIRST_EXTERNAL_VECTOR
|
|
.rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7
|
|
.balign 32
|
|
.rept 7
|
|
.if vector < NR_VECTORS
|
|
.if vector <> FIRST_EXTERNAL_VECTOR
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
.endif
|
|
1: pushq $(~vector+0x80) /* Note: always in signed byte range */
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
.if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6
|
|
jmp 2f
|
|
.endif
|
|
.previous
|
|
.quad 1b
|
|
.text
|
|
vector=vector+1
|
|
.endif
|
|
.endr
|
|
2: jmp common_interrupt
|
|
.endr
|
|
CFI_ENDPROC
|
|
END(irq_entries_start)
|
|
|
|
.previous
|
|
END(interrupt)
|
|
.previous
|
|
|
|
/*
|
|
* Interrupt entry/exit.
|
|
*
|
|
* Interrupt entry points save only callee clobbered registers in fast path.
|
|
*
|
|
* Entry runs with interrupts off.
|
|
*/
|
|
|
|
/* 0(%rsp): ~(interrupt number) */
|
|
.macro interrupt func
|
|
subq $10*8, %rsp
|
|
CFI_ADJUST_CFA_OFFSET 10*8
|
|
call save_args
|
|
PARTIAL_FRAME 0
|
|
call \func
|
|
.endm
|
|
|
|
/*
|
|
* Interrupt entry/exit should be protected against kprobes
|
|
*/
|
|
.pushsection .kprobes.text, "ax"
|
|
/*
|
|
* The interrupt stubs push (~vector+0x80) onto the stack and
|
|
* then jump to common_interrupt.
|
|
*/
|
|
.p2align CONFIG_X86_L1_CACHE_SHIFT
|
|
common_interrupt:
|
|
XCPT_FRAME
|
|
addq $-0x80,(%rsp) /* Adjust vector to [-256,-1] range */
|
|
interrupt do_IRQ
|
|
/* 0(%rsp): old_rsp-ARGOFFSET */
|
|
ret_from_intr:
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
decl PER_CPU_VAR(irq_count)
|
|
leaveq
|
|
CFI_DEF_CFA_REGISTER rsp
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
exit_intr:
|
|
GET_THREAD_INFO(%rcx)
|
|
testl $3,CS-ARGOFFSET(%rsp)
|
|
je retint_kernel
|
|
|
|
/* Interrupt came from user space */
|
|
/*
|
|
* Has a correct top of stack, but a partial stack frame
|
|
* %rcx: thread info. Interrupts off.
|
|
*/
|
|
retint_with_reschedule:
|
|
movl $_TIF_WORK_MASK,%edi
|
|
retint_check:
|
|
LOCKDEP_SYS_EXIT_IRQ
|
|
movl TI_flags(%rcx),%edx
|
|
andl %edi,%edx
|
|
CFI_REMEMBER_STATE
|
|
jnz retint_careful
|
|
|
|
retint_swapgs: /* return to user-space */
|
|
/*
|
|
* The iretq could re-enable interrupts:
|
|
*/
|
|
DISABLE_INTERRUPTS(CLBR_ANY)
|
|
TRACE_IRQS_IRETQ
|
|
SWAPGS
|
|
jmp restore_args
|
|
|
|
retint_restore_args: /* return to kernel space */
|
|
DISABLE_INTERRUPTS(CLBR_ANY)
|
|
/*
|
|
* The iretq could re-enable interrupts:
|
|
*/
|
|
TRACE_IRQS_IRETQ
|
|
restore_args:
|
|
RESTORE_ARGS 0,8,0
|
|
|
|
irq_return:
|
|
INTERRUPT_RETURN
|
|
|
|
.section __ex_table, "a"
|
|
.quad irq_return, bad_iret
|
|
.previous
|
|
|
|
#ifdef CONFIG_PARAVIRT
|
|
ENTRY(native_iret)
|
|
iretq
|
|
|
|
.section __ex_table,"a"
|
|
.quad native_iret, bad_iret
|
|
.previous
|
|
#endif
|
|
|
|
.section .fixup,"ax"
|
|
bad_iret:
|
|
/*
|
|
* The iret traps when the %cs or %ss being restored is bogus.
|
|
* We've lost the original trap vector and error code.
|
|
* #GPF is the most likely one to get for an invalid selector.
|
|
* So pretend we completed the iret and took the #GPF in user mode.
|
|
*
|
|
* We are now running with the kernel GS after exception recovery.
|
|
* But error_entry expects us to have user GS to match the user %cs,
|
|
* so swap back.
|
|
*/
|
|
pushq $0
|
|
|
|
SWAPGS
|
|
jmp general_protection
|
|
|
|
.previous
|
|
|
|
/* edi: workmask, edx: work */
|
|
retint_careful:
|
|
CFI_RESTORE_STATE
|
|
bt $TIF_NEED_RESCHED,%edx
|
|
jnc retint_signal
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
pushq %rdi
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
call schedule
|
|
popq %rdi
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
GET_THREAD_INFO(%rcx)
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
jmp retint_check
|
|
|
|
retint_signal:
|
|
testl $_TIF_DO_NOTIFY_MASK,%edx
|
|
jz retint_swapgs
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
SAVE_REST
|
|
movq $-1,ORIG_RAX(%rsp)
|
|
xorl %esi,%esi # oldset
|
|
movq %rsp,%rdi # &pt_regs
|
|
call do_notify_resume
|
|
RESTORE_REST
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
GET_THREAD_INFO(%rcx)
|
|
jmp retint_with_reschedule
|
|
|
|
#ifdef CONFIG_PREEMPT
|
|
/* Returning to kernel space. Check if we need preemption */
|
|
/* rcx: threadinfo. interrupts off. */
|
|
ENTRY(retint_kernel)
|
|
cmpl $0,TI_preempt_count(%rcx)
|
|
jnz retint_restore_args
|
|
bt $TIF_NEED_RESCHED,TI_flags(%rcx)
|
|
jnc retint_restore_args
|
|
bt $9,EFLAGS-ARGOFFSET(%rsp) /* interrupts off? */
|
|
jnc retint_restore_args
|
|
call preempt_schedule_irq
|
|
jmp exit_intr
|
|
#endif
|
|
|
|
CFI_ENDPROC
|
|
END(common_interrupt)
|
|
/*
|
|
* End of kprobes section
|
|
*/
|
|
.popsection
|
|
|
|
/*
|
|
* APIC interrupts.
|
|
*/
|
|
.macro apicinterrupt num sym do_sym
|
|
ENTRY(\sym)
|
|
INTR_FRAME
|
|
pushq $~(\num)
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
interrupt \do_sym
|
|
jmp ret_from_intr
|
|
CFI_ENDPROC
|
|
END(\sym)
|
|
.endm
|
|
|
|
#ifdef CONFIG_SMP
|
|
apicinterrupt IRQ_MOVE_CLEANUP_VECTOR \
|
|
irq_move_cleanup_interrupt smp_irq_move_cleanup_interrupt
|
|
apicinterrupt REBOOT_VECTOR \
|
|
reboot_interrupt smp_reboot_interrupt
|
|
#endif
|
|
|
|
#ifdef CONFIG_X86_UV
|
|
apicinterrupt UV_BAU_MESSAGE \
|
|
uv_bau_message_intr1 uv_bau_message_interrupt
|
|
#endif
|
|
apicinterrupt LOCAL_TIMER_VECTOR \
|
|
apic_timer_interrupt smp_apic_timer_interrupt
|
|
apicinterrupt X86_PLATFORM_IPI_VECTOR \
|
|
x86_platform_ipi smp_x86_platform_ipi
|
|
|
|
#ifdef CONFIG_SMP
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+0 \
|
|
invalidate_interrupt0 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+1 \
|
|
invalidate_interrupt1 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+2 \
|
|
invalidate_interrupt2 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+3 \
|
|
invalidate_interrupt3 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+4 \
|
|
invalidate_interrupt4 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+5 \
|
|
invalidate_interrupt5 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+6 \
|
|
invalidate_interrupt6 smp_invalidate_interrupt
|
|
apicinterrupt INVALIDATE_TLB_VECTOR_START+7 \
|
|
invalidate_interrupt7 smp_invalidate_interrupt
|
|
#endif
|
|
|
|
apicinterrupt THRESHOLD_APIC_VECTOR \
|
|
threshold_interrupt smp_threshold_interrupt
|
|
apicinterrupt THERMAL_APIC_VECTOR \
|
|
thermal_interrupt smp_thermal_interrupt
|
|
|
|
#ifdef CONFIG_X86_MCE
|
|
apicinterrupt MCE_SELF_VECTOR \
|
|
mce_self_interrupt smp_mce_self_interrupt
|
|
#endif
|
|
|
|
#ifdef CONFIG_SMP
|
|
apicinterrupt CALL_FUNCTION_SINGLE_VECTOR \
|
|
call_function_single_interrupt smp_call_function_single_interrupt
|
|
apicinterrupt CALL_FUNCTION_VECTOR \
|
|
call_function_interrupt smp_call_function_interrupt
|
|
apicinterrupt RESCHEDULE_VECTOR \
|
|
reschedule_interrupt smp_reschedule_interrupt
|
|
#endif
|
|
|
|
apicinterrupt ERROR_APIC_VECTOR \
|
|
error_interrupt smp_error_interrupt
|
|
apicinterrupt SPURIOUS_APIC_VECTOR \
|
|
spurious_interrupt smp_spurious_interrupt
|
|
|
|
#ifdef CONFIG_PERF_EVENTS
|
|
apicinterrupt LOCAL_PENDING_VECTOR \
|
|
perf_pending_interrupt smp_perf_pending_interrupt
|
|
#endif
|
|
|
|
/*
|
|
* Exception entry points.
|
|
*/
|
|
.macro zeroentry sym do_sym
|
|
ENTRY(\sym)
|
|
INTR_FRAME
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */
|
|
subq $15*8,%rsp
|
|
CFI_ADJUST_CFA_OFFSET 15*8
|
|
call error_entry
|
|
DEFAULT_FRAME 0
|
|
movq %rsp,%rdi /* pt_regs pointer */
|
|
xorl %esi,%esi /* no error code */
|
|
call \do_sym
|
|
jmp error_exit /* %ebx: no swapgs flag */
|
|
CFI_ENDPROC
|
|
END(\sym)
|
|
.endm
|
|
|
|
.macro paranoidzeroentry sym do_sym
|
|
ENTRY(\sym)
|
|
INTR_FRAME
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
pushq $-1 /* ORIG_RAX: no syscall to restart */
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
subq $15*8, %rsp
|
|
call save_paranoid
|
|
TRACE_IRQS_OFF
|
|
movq %rsp,%rdi /* pt_regs pointer */
|
|
xorl %esi,%esi /* no error code */
|
|
call \do_sym
|
|
jmp paranoid_exit /* %ebx: no swapgs flag */
|
|
CFI_ENDPROC
|
|
END(\sym)
|
|
.endm
|
|
|
|
#define INIT_TSS_IST(x) PER_CPU_VAR(init_tss) + (TSS_ist + ((x) - 1) * 8)
|
|
.macro paranoidzeroentry_ist sym do_sym ist
|
|
ENTRY(\sym)
|
|
INTR_FRAME
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
pushq $-1 /* ORIG_RAX: no syscall to restart */
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
subq $15*8, %rsp
|
|
call save_paranoid
|
|
TRACE_IRQS_OFF
|
|
movq %rsp,%rdi /* pt_regs pointer */
|
|
xorl %esi,%esi /* no error code */
|
|
subq $EXCEPTION_STKSZ, INIT_TSS_IST(\ist)
|
|
call \do_sym
|
|
addq $EXCEPTION_STKSZ, INIT_TSS_IST(\ist)
|
|
jmp paranoid_exit /* %ebx: no swapgs flag */
|
|
CFI_ENDPROC
|
|
END(\sym)
|
|
.endm
|
|
|
|
.macro errorentry sym do_sym
|
|
ENTRY(\sym)
|
|
XCPT_FRAME
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
subq $15*8,%rsp
|
|
CFI_ADJUST_CFA_OFFSET 15*8
|
|
call error_entry
|
|
DEFAULT_FRAME 0
|
|
movq %rsp,%rdi /* pt_regs pointer */
|
|
movq ORIG_RAX(%rsp),%rsi /* get error code */
|
|
movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */
|
|
call \do_sym
|
|
jmp error_exit /* %ebx: no swapgs flag */
|
|
CFI_ENDPROC
|
|
END(\sym)
|
|
.endm
|
|
|
|
/* error code is on the stack already */
|
|
.macro paranoiderrorentry sym do_sym
|
|
ENTRY(\sym)
|
|
XCPT_FRAME
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
subq $15*8,%rsp
|
|
CFI_ADJUST_CFA_OFFSET 15*8
|
|
call save_paranoid
|
|
DEFAULT_FRAME 0
|
|
TRACE_IRQS_OFF
|
|
movq %rsp,%rdi /* pt_regs pointer */
|
|
movq ORIG_RAX(%rsp),%rsi /* get error code */
|
|
movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */
|
|
call \do_sym
|
|
jmp paranoid_exit /* %ebx: no swapgs flag */
|
|
CFI_ENDPROC
|
|
END(\sym)
|
|
.endm
|
|
|
|
zeroentry divide_error do_divide_error
|
|
zeroentry overflow do_overflow
|
|
zeroentry bounds do_bounds
|
|
zeroentry invalid_op do_invalid_op
|
|
zeroentry device_not_available do_device_not_available
|
|
paranoiderrorentry double_fault do_double_fault
|
|
zeroentry coprocessor_segment_overrun do_coprocessor_segment_overrun
|
|
errorentry invalid_TSS do_invalid_TSS
|
|
errorentry segment_not_present do_segment_not_present
|
|
zeroentry spurious_interrupt_bug do_spurious_interrupt_bug
|
|
zeroentry coprocessor_error do_coprocessor_error
|
|
errorentry alignment_check do_alignment_check
|
|
zeroentry simd_coprocessor_error do_simd_coprocessor_error
|
|
|
|
/* Reload gs selector with exception handling */
|
|
/* edi: new selector */
|
|
ENTRY(native_load_gs_index)
|
|
CFI_STARTPROC
|
|
pushf
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
|
|
SWAPGS
|
|
gs_change:
|
|
movl %edi,%gs
|
|
2: mfence /* workaround */
|
|
SWAPGS
|
|
popf
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
ret
|
|
CFI_ENDPROC
|
|
END(native_load_gs_index)
|
|
|
|
.section __ex_table,"a"
|
|
.align 8
|
|
.quad gs_change,bad_gs
|
|
.previous
|
|
.section .fixup,"ax"
|
|
/* running with kernelgs */
|
|
bad_gs:
|
|
SWAPGS /* switch back to user gs */
|
|
xorl %eax,%eax
|
|
movl %eax,%gs
|
|
jmp 2b
|
|
.previous
|
|
|
|
ENTRY(kernel_thread_helper)
|
|
pushq $0 # fake return address
|
|
CFI_STARTPROC
|
|
/*
|
|
* Here we are in the child and the registers are set as they were
|
|
* at kernel_thread() invocation in the parent.
|
|
*/
|
|
call *%rsi
|
|
# exit
|
|
mov %eax, %edi
|
|
call do_exit
|
|
ud2 # padding for call trace
|
|
CFI_ENDPROC
|
|
END(kernel_thread_helper)
|
|
|
|
/*
|
|
* execve(). This function needs to use IRET, not SYSRET, to set up all state properly.
|
|
*
|
|
* C extern interface:
|
|
* extern long execve(char *name, char **argv, char **envp)
|
|
*
|
|
* asm input arguments:
|
|
* rdi: name, rsi: argv, rdx: envp
|
|
*
|
|
* We want to fallback into:
|
|
* extern long sys_execve(char *name, char **argv,char **envp, struct pt_regs *regs)
|
|
*
|
|
* do_sys_execve asm fallback arguments:
|
|
* rdi: name, rsi: argv, rdx: envp, rcx: fake frame on the stack
|
|
*/
|
|
ENTRY(kernel_execve)
|
|
CFI_STARTPROC
|
|
FAKE_STACK_FRAME $0
|
|
SAVE_ALL
|
|
movq %rsp,%rcx
|
|
call sys_execve
|
|
movq %rax, RAX(%rsp)
|
|
RESTORE_REST
|
|
testq %rax,%rax
|
|
je int_ret_from_sys_call
|
|
RESTORE_ARGS
|
|
UNFAKE_STACK_FRAME
|
|
ret
|
|
CFI_ENDPROC
|
|
END(kernel_execve)
|
|
|
|
/* Call softirq on interrupt stack. Interrupts are off. */
|
|
ENTRY(call_softirq)
|
|
CFI_STARTPROC
|
|
push %rbp
|
|
CFI_ADJUST_CFA_OFFSET 8
|
|
CFI_REL_OFFSET rbp,0
|
|
mov %rsp,%rbp
|
|
CFI_DEF_CFA_REGISTER rbp
|
|
incl PER_CPU_VAR(irq_count)
|
|
cmove PER_CPU_VAR(irq_stack_ptr),%rsp
|
|
push %rbp # backlink for old unwinder
|
|
call __do_softirq
|
|
leaveq
|
|
CFI_DEF_CFA_REGISTER rsp
|
|
CFI_ADJUST_CFA_OFFSET -8
|
|
decl PER_CPU_VAR(irq_count)
|
|
ret
|
|
CFI_ENDPROC
|
|
END(call_softirq)
|
|
|
|
#ifdef CONFIG_XEN
|
|
zeroentry xen_hypervisor_callback xen_do_hypervisor_callback
|
|
|
|
/*
|
|
* A note on the "critical region" in our callback handler.
|
|
* We want to avoid stacking callback handlers due to events occurring
|
|
* during handling of the last event. To do this, we keep events disabled
|
|
* until we've done all processing. HOWEVER, we must enable events before
|
|
* popping the stack frame (can't be done atomically) and so it would still
|
|
* be possible to get enough handler activations to overflow the stack.
|
|
* Although unlikely, bugs of that kind are hard to track down, so we'd
|
|
* like to avoid the possibility.
|
|
* So, on entry to the handler we detect whether we interrupted an
|
|
* existing activation in its critical region -- if so, we pop the current
|
|
* activation and restart the handler using the previous one.
|
|
*/
|
|
ENTRY(xen_do_hypervisor_callback) # do_hypervisor_callback(struct *pt_regs)
|
|
CFI_STARTPROC
|
|
/*
|
|
* Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will
|
|
* see the correct pointer to the pt_regs
|
|
*/
|
|
movq %rdi, %rsp # we don't return, adjust the stack frame
|
|
CFI_ENDPROC
|
|
DEFAULT_FRAME
|
|
11: incl PER_CPU_VAR(irq_count)
|
|
movq %rsp,%rbp
|
|
CFI_DEF_CFA_REGISTER rbp
|
|
cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp
|
|
pushq %rbp # backlink for old unwinder
|
|
call xen_evtchn_do_upcall
|
|
popq %rsp
|
|
CFI_DEF_CFA_REGISTER rsp
|
|
decl PER_CPU_VAR(irq_count)
|
|
jmp error_exit
|
|
CFI_ENDPROC
|
|
END(do_hypervisor_callback)
|
|
|
|
/*
|
|
* Hypervisor uses this for application faults while it executes.
|
|
* We get here for two reasons:
|
|
* 1. Fault while reloading DS, ES, FS or GS
|
|
* 2. Fault while executing IRET
|
|
* Category 1 we do not need to fix up as Xen has already reloaded all segment
|
|
* registers that could be reloaded and zeroed the others.
|
|
* Category 2 we fix up by killing the current process. We cannot use the
|
|
* normal Linux return path in this case because if we use the IRET hypercall
|
|
* to pop the stack frame we end up in an infinite loop of failsafe callbacks.
|
|
* We distinguish between categories by comparing each saved segment register
|
|
* with its current contents: any discrepancy means we in category 1.
|
|
*/
|
|
ENTRY(xen_failsafe_callback)
|
|
INTR_FRAME 1 (6*8)
|
|
/*CFI_REL_OFFSET gs,GS*/
|
|
/*CFI_REL_OFFSET fs,FS*/
|
|
/*CFI_REL_OFFSET es,ES*/
|
|
/*CFI_REL_OFFSET ds,DS*/
|
|
CFI_REL_OFFSET r11,8
|
|
CFI_REL_OFFSET rcx,0
|
|
movw %ds,%cx
|
|
cmpw %cx,0x10(%rsp)
|
|
CFI_REMEMBER_STATE
|
|
jne 1f
|
|
movw %es,%cx
|
|
cmpw %cx,0x18(%rsp)
|
|
jne 1f
|
|
movw %fs,%cx
|
|
cmpw %cx,0x20(%rsp)
|
|
jne 1f
|
|
movw %gs,%cx
|
|
cmpw %cx,0x28(%rsp)
|
|
jne 1f
|
|
/* All segments match their saved values => Category 2 (Bad IRET). */
|
|
movq (%rsp),%rcx
|
|
CFI_RESTORE rcx
|
|
movq 8(%rsp),%r11
|
|
CFI_RESTORE r11
|
|
addq $0x30,%rsp
|
|
CFI_ADJUST_CFA_OFFSET -0x30
|
|
pushq_cfi $0 /* RIP */
|
|
pushq_cfi %r11
|
|
pushq_cfi %rcx
|
|
jmp general_protection
|
|
CFI_RESTORE_STATE
|
|
1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */
|
|
movq (%rsp),%rcx
|
|
CFI_RESTORE rcx
|
|
movq 8(%rsp),%r11
|
|
CFI_RESTORE r11
|
|
addq $0x30,%rsp
|
|
CFI_ADJUST_CFA_OFFSET -0x30
|
|
pushq_cfi $0
|
|
SAVE_ALL
|
|
jmp error_exit
|
|
CFI_ENDPROC
|
|
END(xen_failsafe_callback)
|
|
|
|
apicinterrupt XEN_HVM_EVTCHN_CALLBACK \
|
|
xen_hvm_callback_vector xen_evtchn_do_upcall
|
|
|
|
#endif /* CONFIG_XEN */
|
|
|
|
/*
|
|
* Some functions should be protected against kprobes
|
|
*/
|
|
.pushsection .kprobes.text, "ax"
|
|
|
|
paranoidzeroentry_ist debug do_debug DEBUG_STACK
|
|
paranoidzeroentry_ist int3 do_int3 DEBUG_STACK
|
|
paranoiderrorentry stack_segment do_stack_segment
|
|
#ifdef CONFIG_XEN
|
|
zeroentry xen_debug do_debug
|
|
zeroentry xen_int3 do_int3
|
|
errorentry xen_stack_segment do_stack_segment
|
|
#endif
|
|
errorentry general_protection do_general_protection
|
|
errorentry page_fault do_page_fault
|
|
#ifdef CONFIG_X86_MCE
|
|
paranoidzeroentry machine_check *machine_check_vector(%rip)
|
|
#endif
|
|
|
|
/*
|
|
* "Paranoid" exit path from exception stack.
|
|
* Paranoid because this is used by NMIs and cannot take
|
|
* any kernel state for granted.
|
|
* We don't do kernel preemption checks here, because only
|
|
* NMI should be common and it does not enable IRQs and
|
|
* cannot get reschedule ticks.
|
|
*
|
|
* "trace" is 0 for the NMI handler only, because irq-tracing
|
|
* is fundamentally NMI-unsafe. (we cannot change the soft and
|
|
* hard flags at once, atomically)
|
|
*/
|
|
|
|
/* ebx: no swapgs flag */
|
|
ENTRY(paranoid_exit)
|
|
INTR_FRAME
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
testl %ebx,%ebx /* swapgs needed? */
|
|
jnz paranoid_restore
|
|
testl $3,CS(%rsp)
|
|
jnz paranoid_userspace
|
|
paranoid_swapgs:
|
|
TRACE_IRQS_IRETQ 0
|
|
SWAPGS_UNSAFE_STACK
|
|
RESTORE_ALL 8
|
|
jmp irq_return
|
|
paranoid_restore:
|
|
TRACE_IRQS_IRETQ 0
|
|
RESTORE_ALL 8
|
|
jmp irq_return
|
|
paranoid_userspace:
|
|
GET_THREAD_INFO(%rcx)
|
|
movl TI_flags(%rcx),%ebx
|
|
andl $_TIF_WORK_MASK,%ebx
|
|
jz paranoid_swapgs
|
|
movq %rsp,%rdi /* &pt_regs */
|
|
call sync_regs
|
|
movq %rax,%rsp /* switch stack for scheduling */
|
|
testl $_TIF_NEED_RESCHED,%ebx
|
|
jnz paranoid_schedule
|
|
movl %ebx,%edx /* arg3: thread flags */
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
xorl %esi,%esi /* arg2: oldset */
|
|
movq %rsp,%rdi /* arg1: &pt_regs */
|
|
call do_notify_resume
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
jmp paranoid_userspace
|
|
paranoid_schedule:
|
|
TRACE_IRQS_ON
|
|
ENABLE_INTERRUPTS(CLBR_ANY)
|
|
call schedule
|
|
DISABLE_INTERRUPTS(CLBR_ANY)
|
|
TRACE_IRQS_OFF
|
|
jmp paranoid_userspace
|
|
CFI_ENDPROC
|
|
END(paranoid_exit)
|
|
|
|
/*
|
|
* Exception entry point. This expects an error code/orig_rax on the stack.
|
|
* returns in "no swapgs flag" in %ebx.
|
|
*/
|
|
ENTRY(error_entry)
|
|
XCPT_FRAME
|
|
CFI_ADJUST_CFA_OFFSET 15*8
|
|
/* oldrax contains error code */
|
|
cld
|
|
movq_cfi rdi, RDI+8
|
|
movq_cfi rsi, RSI+8
|
|
movq_cfi rdx, RDX+8
|
|
movq_cfi rcx, RCX+8
|
|
movq_cfi rax, RAX+8
|
|
movq_cfi r8, R8+8
|
|
movq_cfi r9, R9+8
|
|
movq_cfi r10, R10+8
|
|
movq_cfi r11, R11+8
|
|
movq_cfi rbx, RBX+8
|
|
movq_cfi rbp, RBP+8
|
|
movq_cfi r12, R12+8
|
|
movq_cfi r13, R13+8
|
|
movq_cfi r14, R14+8
|
|
movq_cfi r15, R15+8
|
|
xorl %ebx,%ebx
|
|
testl $3,CS+8(%rsp)
|
|
je error_kernelspace
|
|
error_swapgs:
|
|
SWAPGS
|
|
error_sti:
|
|
TRACE_IRQS_OFF
|
|
ret
|
|
CFI_ENDPROC
|
|
|
|
/*
|
|
* There are two places in the kernel that can potentially fault with
|
|
* usergs. Handle them here. The exception handlers after iret run with
|
|
* kernel gs again, so don't set the user space flag. B stepping K8s
|
|
* sometimes report an truncated RIP for IRET exceptions returning to
|
|
* compat mode. Check for these here too.
|
|
*/
|
|
error_kernelspace:
|
|
incl %ebx
|
|
leaq irq_return(%rip),%rcx
|
|
cmpq %rcx,RIP+8(%rsp)
|
|
je error_swapgs
|
|
movl %ecx,%eax /* zero extend */
|
|
cmpq %rax,RIP+8(%rsp)
|
|
je bstep_iret
|
|
cmpq $gs_change,RIP+8(%rsp)
|
|
je error_swapgs
|
|
jmp error_sti
|
|
|
|
bstep_iret:
|
|
/* Fix truncated RIP */
|
|
movq %rcx,RIP+8(%rsp)
|
|
jmp error_swapgs
|
|
END(error_entry)
|
|
|
|
|
|
/* ebx: no swapgs flag (1: don't need swapgs, 0: need it) */
|
|
ENTRY(error_exit)
|
|
DEFAULT_FRAME
|
|
movl %ebx,%eax
|
|
RESTORE_REST
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
TRACE_IRQS_OFF
|
|
GET_THREAD_INFO(%rcx)
|
|
testl %eax,%eax
|
|
jne retint_kernel
|
|
LOCKDEP_SYS_EXIT_IRQ
|
|
movl TI_flags(%rcx),%edx
|
|
movl $_TIF_WORK_MASK,%edi
|
|
andl %edi,%edx
|
|
jnz retint_careful
|
|
jmp retint_swapgs
|
|
CFI_ENDPROC
|
|
END(error_exit)
|
|
|
|
|
|
/* runs on exception stack */
|
|
ENTRY(nmi)
|
|
INTR_FRAME
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
pushq_cfi $-1
|
|
subq $15*8, %rsp
|
|
CFI_ADJUST_CFA_OFFSET 15*8
|
|
call save_paranoid
|
|
DEFAULT_FRAME 0
|
|
/* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */
|
|
movq %rsp,%rdi
|
|
movq $-1,%rsi
|
|
call do_nmi
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
/* paranoidexit; without TRACE_IRQS_OFF */
|
|
/* ebx: no swapgs flag */
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
testl %ebx,%ebx /* swapgs needed? */
|
|
jnz nmi_restore
|
|
testl $3,CS(%rsp)
|
|
jnz nmi_userspace
|
|
nmi_swapgs:
|
|
SWAPGS_UNSAFE_STACK
|
|
nmi_restore:
|
|
RESTORE_ALL 8
|
|
jmp irq_return
|
|
nmi_userspace:
|
|
GET_THREAD_INFO(%rcx)
|
|
movl TI_flags(%rcx),%ebx
|
|
andl $_TIF_WORK_MASK,%ebx
|
|
jz nmi_swapgs
|
|
movq %rsp,%rdi /* &pt_regs */
|
|
call sync_regs
|
|
movq %rax,%rsp /* switch stack for scheduling */
|
|
testl $_TIF_NEED_RESCHED,%ebx
|
|
jnz nmi_schedule
|
|
movl %ebx,%edx /* arg3: thread flags */
|
|
ENABLE_INTERRUPTS(CLBR_NONE)
|
|
xorl %esi,%esi /* arg2: oldset */
|
|
movq %rsp,%rdi /* arg1: &pt_regs */
|
|
call do_notify_resume
|
|
DISABLE_INTERRUPTS(CLBR_NONE)
|
|
jmp nmi_userspace
|
|
nmi_schedule:
|
|
ENABLE_INTERRUPTS(CLBR_ANY)
|
|
call schedule
|
|
DISABLE_INTERRUPTS(CLBR_ANY)
|
|
jmp nmi_userspace
|
|
CFI_ENDPROC
|
|
#else
|
|
jmp paranoid_exit
|
|
CFI_ENDPROC
|
|
#endif
|
|
END(nmi)
|
|
|
|
ENTRY(ignore_sysret)
|
|
CFI_STARTPROC
|
|
mov $-ENOSYS,%eax
|
|
sysret
|
|
CFI_ENDPROC
|
|
END(ignore_sysret)
|
|
|
|
/*
|
|
* End of kprobes section
|
|
*/
|
|
.popsection
|