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x86/entry/64: Move the switch_to_thread_stack() call to interrupt_entry() 

We can also move the CLD, SWAPGS, and the switch_to_thread_stack() call
to the interrupt_entry() helper function. As we do not want call depths
of two, convert switch_to_thread_stack() to a macro.

However, switch_to_thread_stack() has another user in entry_64_compat.S,
which currently expects it to be a function. To keep the code changes
in this patch minimal, create a wrapper function.

The switch to a macro means that there is some binary code duplication
if CONFIG_IA32_EMULATION=y is enabled. Therefore, the size reduction
differs whether CONFIG_IA32_EMULATION is enabled or not:

CONFIG_IA32_EMULATION=y (-0.13k):
   text	   data	    bss	    dec	    hex	filename
  17158	      0	      0	  17158	   4306	entry_64.o-orig
  17028	      0	      0	  17028	   4284	entry_64.o

CONFIG_IA32_EMULATION=n (-0.27k):
   text	   data	    bss	    dec	    hex	filename
  17158	      0	      0	  17158	   4306	entry_64.o-orig
  16882	      0	      0	  16882	   41f2	entry_64.o

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: dan.j.williams@intel.com
Link: http://lkml.kernel.org/r/20180220210113.6725-4-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Dominik Brodowski 2018-02-20 22:01:10 +01:00 committed by Ingo Molnar
parent 2ba6474104
commit 90a6acc4e7
1 changed files with 37 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
arch/x86/entry/entry_64.S
View File

@ -537,6 +537,31 @@ END(irq_entries_start)
decl PER_CPU_VAR(irq_count)
.endm
/*
* Switch to the thread stack. This is called with the IRET frame and
* orig_ax on the stack. (That is, RDI..R12 are not on the stack and
* space has not been allocated for them.)
*/
.macro DO_SWITCH_TO_THREAD_STACK
pushq %rdi
/* Need to switch before accessing the thread stack. */
SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi
movq %rsp, %rdi
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
UNWIND_HINT sp_offset=16 sp_reg=ORC_REG_DI
pushq 7*8(%rdi) /* regs->ss */
pushq 6*8(%rdi) /* regs->rsp */
pushq 5*8(%rdi) /* regs->eflags */
pushq 4*8(%rdi) /* regs->cs */
pushq 3*8(%rdi) /* regs->ip */
pushq 2*8(%rdi) /* regs->orig_ax */
pushq 8(%rdi) /* return address */
UNWIND_HINT_FUNC
movq (%rdi), %rdi
.endm
/*
* Interrupt entry/exit.
*
@ -544,8 +569,16 @@ END(irq_entries_start)
*
* Entry runs with interrupts off.
*/
/* 8(%rsp): ~(interrupt number) */
ENTRY(interrupt_entry)
UNWIND_HINT_FUNC
cld
testb $3, CS-ORIG_RAX+8(%rsp)
jz 1f
SWAPGS
DO_SWITCH_TO_THREAD_STACK
1:
PUSH_AND_CLEAR_REGS save_ret=1
ENCODE_FRAME_POINTER 8
@ -577,14 +610,6 @@ END(interrupt_entry)
/* 0(%rsp): ~(interrupt number) */
.macro interrupt func
cld
testb $3, CS-ORIG_RAX(%rsp)
jz 1f
SWAPGS
call switch_to_thread_stack
1:
call interrupt_entry
UNWIND_HINT_REGS indirect=1
@ -858,33 +883,16 @@ apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt
*/
#define CPU_TSS_IST(x) PER_CPU_VAR(cpu_tss_rw) + (TSS_ist + ((x) - 1) * 8)
/*
* Switch to the thread stack. This is called with the IRET frame and
* orig_ax on the stack. (That is, RDI..R12 are not on the stack and
* space has not been allocated for them.)
*/
#if defined(CONFIG_IA32_EMULATION)
/* entry_64_compat.S::entry_INT80_compat expects this to be an ASM function */
ENTRY(switch_to_thread_stack)
UNWIND_HINT_FUNC
pushq %rdi
/* Need to switch before accessing the thread stack. */
SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi
movq %rsp, %rdi
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
UNWIND_HINT sp_offset=16 sp_reg=ORC_REG_DI
DO_SWITCH_TO_THREAD_STACK
pushq 7*8(%rdi) /* regs->ss */
pushq 6*8(%rdi) /* regs->rsp */
pushq 5*8(%rdi) /* regs->eflags */
pushq 4*8(%rdi) /* regs->cs */
pushq 3*8(%rdi) /* regs->ip */
pushq 2*8(%rdi) /* regs->orig_ax */
pushq 8(%rdi) /* return address */
UNWIND_HINT_FUNC
movq (%rdi), %rdi
ret
END(switch_to_thread_stack)
#endif
.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1
ENTRY(\sym)