426 lines
12 KiB
C
426 lines
12 KiB
C
#ifndef ASM_X86__SYSTEM_H
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#define ASM_X86__SYSTEM_H
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#include <asm/asm.h>
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#include <asm/segment.h>
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#include <asm/cpufeature.h>
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#include <asm/cmpxchg.h>
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#include <asm/nops.h>
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#include <linux/kernel.h>
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#include <linux/irqflags.h>
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/* entries in ARCH_DLINFO: */
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#ifdef CONFIG_IA32_EMULATION
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# define AT_VECTOR_SIZE_ARCH 2
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#else
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# define AT_VECTOR_SIZE_ARCH 1
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#endif
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#ifdef CONFIG_X86_32
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struct task_struct; /* one of the stranger aspects of C forward declarations */
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struct task_struct *__switch_to(struct task_struct *prev,
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struct task_struct *next);
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/*
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* Saving eflags is important. It switches not only IOPL between tasks,
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* it also protects other tasks from NT leaking through sysenter etc.
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*/
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#define switch_to(prev, next, last) \
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do { \
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/* \
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* Context-switching clobbers all registers, so we clobber \
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* them explicitly, via unused output variables. \
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* (EAX and EBP is not listed because EBP is saved/restored \
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* explicitly for wchan access and EAX is the return value of \
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* __switch_to()) \
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*/ \
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unsigned long ebx, ecx, edx, esi, edi; \
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\
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asm volatile("pushfl\n\t" /* save flags */ \
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"pushl %%ebp\n\t" /* save EBP */ \
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"movl %%esp,%[prev_sp]\n\t" /* save ESP */ \
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"movl %[next_sp],%%esp\n\t" /* restore ESP */ \
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"movl $1f,%[prev_ip]\n\t" /* save EIP */ \
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"pushl %[next_ip]\n\t" /* restore EIP */ \
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"jmp __switch_to\n" /* regparm call */ \
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"1:\t" \
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"popl %%ebp\n\t" /* restore EBP */ \
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"popfl\n" /* restore flags */ \
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\
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/* output parameters */ \
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: [prev_sp] "=m" (prev->thread.sp), \
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[prev_ip] "=m" (prev->thread.ip), \
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"=a" (last), \
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\
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/* clobbered output registers: */ \
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"=b" (ebx), "=c" (ecx), "=d" (edx), \
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"=S" (esi), "=D" (edi) \
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\
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/* input parameters: */ \
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: [next_sp] "m" (next->thread.sp), \
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[next_ip] "m" (next->thread.ip), \
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\
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/* regparm parameters for __switch_to(): */ \
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[prev] "a" (prev), \
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[next] "d" (next) \
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\
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: /* reloaded segment registers */ \
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"memory"); \
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} while (0)
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/*
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* disable hlt during certain critical i/o operations
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*/
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#define HAVE_DISABLE_HLT
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#else
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#define __SAVE(reg, offset) "movq %%" #reg ",(14-" #offset ")*8(%%rsp)\n\t"
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#define __RESTORE(reg, offset) "movq (14-" #offset ")*8(%%rsp),%%" #reg "\n\t"
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/* frame pointer must be last for get_wchan */
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#define SAVE_CONTEXT "pushf ; pushq %%rbp ; movq %%rsi,%%rbp\n\t"
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#define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp ; popf\t"
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#define __EXTRA_CLOBBER \
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, "rcx", "rbx", "rdx", "r8", "r9", "r10", "r11", \
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"r12", "r13", "r14", "r15"
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/* Save restore flags to clear handle leaking NT */
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#define switch_to(prev, next, last) \
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asm volatile(SAVE_CONTEXT \
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"movq %%rsp,%P[threadrsp](%[prev])\n\t" /* save RSP */ \
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"movq %P[threadrsp](%[next]),%%rsp\n\t" /* restore RSP */ \
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"call __switch_to\n\t" \
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".globl thread_return\n" \
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"thread_return:\n\t" \
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"movq %%gs:%P[pda_pcurrent],%%rsi\n\t" \
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"movq %P[thread_info](%%rsi),%%r8\n\t" \
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LOCK_PREFIX "btr %[tif_fork],%P[ti_flags](%%r8)\n\t" \
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"movq %%rax,%%rdi\n\t" \
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"jc ret_from_fork\n\t" \
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RESTORE_CONTEXT \
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: "=a" (last) \
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: [next] "S" (next), [prev] "D" (prev), \
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[threadrsp] "i" (offsetof(struct task_struct, thread.sp)), \
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[ti_flags] "i" (offsetof(struct thread_info, flags)), \
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[tif_fork] "i" (TIF_FORK), \
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[thread_info] "i" (offsetof(struct task_struct, stack)), \
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[pda_pcurrent] "i" (offsetof(struct x8664_pda, pcurrent)) \
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: "memory", "cc" __EXTRA_CLOBBER)
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#endif
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#ifdef __KERNEL__
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#define _set_base(addr, base) do { unsigned long __pr; \
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__asm__ __volatile__ ("movw %%dx,%1\n\t" \
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"rorl $16,%%edx\n\t" \
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"movb %%dl,%2\n\t" \
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"movb %%dh,%3" \
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:"=&d" (__pr) \
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:"m" (*((addr)+2)), \
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"m" (*((addr)+4)), \
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"m" (*((addr)+7)), \
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"0" (base) \
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); } while (0)
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#define _set_limit(addr, limit) do { unsigned long __lr; \
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__asm__ __volatile__ ("movw %%dx,%1\n\t" \
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"rorl $16,%%edx\n\t" \
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"movb %2,%%dh\n\t" \
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"andb $0xf0,%%dh\n\t" \
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"orb %%dh,%%dl\n\t" \
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"movb %%dl,%2" \
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:"=&d" (__lr) \
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:"m" (*(addr)), \
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"m" (*((addr)+6)), \
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"0" (limit) \
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); } while (0)
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#define set_base(ldt, base) _set_base(((char *)&(ldt)) , (base))
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#define set_limit(ldt, limit) _set_limit(((char *)&(ldt)) , ((limit)-1))
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extern void native_load_gs_index(unsigned);
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/*
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* Load a segment. Fall back on loading the zero
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* segment if something goes wrong..
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*/
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#define loadsegment(seg, value) \
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asm volatile("\n" \
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"1:\t" \
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"movl %k0,%%" #seg "\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3:\t" \
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"movl %k1, %%" #seg "\n\t" \
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"jmp 2b\n" \
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".previous\n" \
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_ASM_EXTABLE(1b,3b) \
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: :"r" (value), "r" (0) : "memory")
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/*
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* Save a segment register away
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*/
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#define savesegment(seg, value) \
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asm("mov %%" #seg ",%0":"=r" (value) : : "memory")
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static inline unsigned long get_limit(unsigned long segment)
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{
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unsigned long __limit;
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asm("lsll %1,%0" : "=r" (__limit) : "r" (segment));
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return __limit + 1;
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}
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static inline void native_clts(void)
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{
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asm volatile("clts");
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}
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/*
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* Volatile isn't enough to prevent the compiler from reordering the
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* read/write functions for the control registers and messing everything up.
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* A memory clobber would solve the problem, but would prevent reordering of
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* all loads stores around it, which can hurt performance. Solution is to
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* use a variable and mimic reads and writes to it to enforce serialization
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*/
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static unsigned long __force_order;
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static inline unsigned long native_read_cr0(void)
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{
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unsigned long val;
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asm volatile("mov %%cr0,%0\n\t" : "=r" (val), "=m" (__force_order));
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return val;
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}
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static inline void native_write_cr0(unsigned long val)
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{
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asm volatile("mov %0,%%cr0": : "r" (val), "m" (__force_order));
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}
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static inline unsigned long native_read_cr2(void)
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{
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unsigned long val;
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asm volatile("mov %%cr2,%0\n\t" : "=r" (val), "=m" (__force_order));
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return val;
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}
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static inline void native_write_cr2(unsigned long val)
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{
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asm volatile("mov %0,%%cr2": : "r" (val), "m" (__force_order));
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}
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static inline unsigned long native_read_cr3(void)
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{
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unsigned long val;
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asm volatile("mov %%cr3,%0\n\t" : "=r" (val), "=m" (__force_order));
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return val;
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}
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static inline void native_write_cr3(unsigned long val)
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{
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asm volatile("mov %0,%%cr3": : "r" (val), "m" (__force_order));
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}
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static inline unsigned long native_read_cr4(void)
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{
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unsigned long val;
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asm volatile("mov %%cr4,%0\n\t" : "=r" (val), "=m" (__force_order));
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return val;
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}
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static inline unsigned long native_read_cr4_safe(void)
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{
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unsigned long val;
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/* This could fault if %cr4 does not exist. In x86_64, a cr4 always
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* exists, so it will never fail. */
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#ifdef CONFIG_X86_32
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asm volatile("1: mov %%cr4, %0\n"
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"2:\n"
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_ASM_EXTABLE(1b, 2b)
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: "=r" (val), "=m" (__force_order) : "0" (0));
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#else
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val = native_read_cr4();
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#endif
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return val;
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}
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static inline void native_write_cr4(unsigned long val)
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{
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asm volatile("mov %0,%%cr4": : "r" (val), "m" (__force_order));
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}
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#ifdef CONFIG_X86_64
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static inline unsigned long native_read_cr8(void)
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{
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unsigned long cr8;
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asm volatile("movq %%cr8,%0" : "=r" (cr8));
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return cr8;
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}
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static inline void native_write_cr8(unsigned long val)
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{
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asm volatile("movq %0,%%cr8" :: "r" (val) : "memory");
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}
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#endif
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static inline void native_wbinvd(void)
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{
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asm volatile("wbinvd": : :"memory");
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}
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#ifdef CONFIG_PARAVIRT
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#include <asm/paravirt.h>
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#else
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#define read_cr0() (native_read_cr0())
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#define write_cr0(x) (native_write_cr0(x))
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#define read_cr2() (native_read_cr2())
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#define write_cr2(x) (native_write_cr2(x))
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#define read_cr3() (native_read_cr3())
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#define write_cr3(x) (native_write_cr3(x))
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#define read_cr4() (native_read_cr4())
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#define read_cr4_safe() (native_read_cr4_safe())
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#define write_cr4(x) (native_write_cr4(x))
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#define wbinvd() (native_wbinvd())
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#ifdef CONFIG_X86_64
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#define read_cr8() (native_read_cr8())
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#define write_cr8(x) (native_write_cr8(x))
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#define load_gs_index native_load_gs_index
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#endif
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/* Clear the 'TS' bit */
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#define clts() (native_clts())
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#endif/* CONFIG_PARAVIRT */
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#define stts() write_cr0(read_cr0() | X86_CR0_TS)
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#endif /* __KERNEL__ */
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static inline void clflush(volatile void *__p)
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{
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asm volatile("clflush %0" : "+m" (*(volatile char __force *)__p));
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}
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#define nop() asm volatile ("nop")
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void disable_hlt(void);
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void enable_hlt(void);
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void cpu_idle_wait(void);
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extern unsigned long arch_align_stack(unsigned long sp);
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extern void free_init_pages(char *what, unsigned long begin, unsigned long end);
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void default_idle(void);
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/*
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* Force strict CPU ordering.
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* And yes, this is required on UP too when we're talking
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* to devices.
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*/
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#ifdef CONFIG_X86_32
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/*
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* Some non-Intel clones support out of order store. wmb() ceases to be a
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* nop for these.
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*/
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#define mb() alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2)
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#define rmb() alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2)
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#define wmb() alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM)
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#else
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#define mb() asm volatile("mfence":::"memory")
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#define rmb() asm volatile("lfence":::"memory")
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#define wmb() asm volatile("sfence" ::: "memory")
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#endif
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/**
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* read_barrier_depends - Flush all pending reads that subsequents reads
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* depend on.
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*
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* No data-dependent reads from memory-like regions are ever reordered
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* over this barrier. All reads preceding this primitive are guaranteed
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* to access memory (but not necessarily other CPUs' caches) before any
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* reads following this primitive that depend on the data return by
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* any of the preceding reads. This primitive is much lighter weight than
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* rmb() on most CPUs, and is never heavier weight than is
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* rmb().
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*
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* These ordering constraints are respected by both the local CPU
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* and the compiler.
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*
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* Ordering is not guaranteed by anything other than these primitives,
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* not even by data dependencies. See the documentation for
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* memory_barrier() for examples and URLs to more information.
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*
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* For example, the following code would force ordering (the initial
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* value of "a" is zero, "b" is one, and "p" is "&a"):
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*
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* <programlisting>
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* CPU 0 CPU 1
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*
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* b = 2;
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* memory_barrier();
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* p = &b; q = p;
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* read_barrier_depends();
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* d = *q;
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* </programlisting>
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*
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* because the read of "*q" depends on the read of "p" and these
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* two reads are separated by a read_barrier_depends(). However,
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* the following code, with the same initial values for "a" and "b":
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*
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* <programlisting>
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* CPU 0 CPU 1
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*
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* a = 2;
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* memory_barrier();
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* b = 3; y = b;
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* read_barrier_depends();
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* x = a;
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* </programlisting>
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*
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* does not enforce ordering, since there is no data dependency between
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* the read of "a" and the read of "b". Therefore, on some CPUs, such
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* as Alpha, "y" could be set to 3 and "x" to 0. Use rmb()
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* in cases like this where there are no data dependencies.
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**/
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#define read_barrier_depends() do { } while (0)
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#ifdef CONFIG_SMP
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#define smp_mb() mb()
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#ifdef CONFIG_X86_PPRO_FENCE
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# define smp_rmb() rmb()
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#else
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# define smp_rmb() barrier()
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#endif
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#ifdef CONFIG_X86_OOSTORE
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# define smp_wmb() wmb()
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#else
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# define smp_wmb() barrier()
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#endif
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#define smp_read_barrier_depends() read_barrier_depends()
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#define set_mb(var, value) do { (void)xchg(&var, value); } while (0)
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#else
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#define smp_mb() barrier()
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#define smp_rmb() barrier()
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#define smp_wmb() barrier()
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#define smp_read_barrier_depends() do { } while (0)
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#define set_mb(var, value) do { var = value; barrier(); } while (0)
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#endif
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/*
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* Stop RDTSC speculation. This is needed when you need to use RDTSC
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* (or get_cycles or vread that possibly accesses the TSC) in a defined
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* code region.
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*
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* (Could use an alternative three way for this if there was one.)
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*/
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static inline void rdtsc_barrier(void)
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{
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alternative(ASM_NOP3, "mfence", X86_FEATURE_MFENCE_RDTSC);
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alternative(ASM_NOP3, "lfence", X86_FEATURE_LFENCE_RDTSC);
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}
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#endif /* ASM_X86__SYSTEM_H */
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