kernel_optimize_test/arch/x86/kernel/acpi/wakeup_64.S
Jiri Slaby 559ceeed62 x86/asm/suspend: Get rid of bogus_64_magic
bogus_64_magic is only a dead-end loop. There is no need for an
out-of-order function (and unannotated local label), so just handle it
in-place and also store 0xbad-m-a-g-i-c to %rcx beforehand, in case
someone is inspecting registers.

Here a qemu+gdb example:

  Remote debugging using localhost:1235
  wakeup_long64 () at arch/x86/kernel/acpi/wakeup_64.S:26
  26              jmp 1b
  (gdb) info registers
  rax            0x123456789abcdef0       1311768467463790320
  rbx            0x0      0
  rcx            0xbad6d61676963  3286910041024867
  		 ^^^^^^^^^^^^^^^

 [ bp: Add the gdb example. ]

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Cc: linux-pm@vger.kernel.org
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190906075550.23435-1-jslaby@suse.cz
2019-09-06 10:34:15 +02:00

140 lines
2.9 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
.text
#include <linux/linkage.h>
#include <asm/segment.h>
#include <asm/pgtable_types.h>
#include <asm/page_types.h>
#include <asm/msr.h>
#include <asm/asm-offsets.h>
#include <asm/frame.h>
# Copyright 2003 Pavel Machek <pavel@suse.cz
.code64
/*
* Hooray, we are in Long 64-bit mode (but still running in low memory)
*/
ENTRY(wakeup_long64)
movq saved_magic, %rax
movq $0x123456789abcdef0, %rdx
cmpq %rdx, %rax
je 2f
/* stop here on a saved_magic mismatch */
movq $0xbad6d61676963, %rcx
1:
jmp 1b
2:
movw $__KERNEL_DS, %ax
movw %ax, %ss
movw %ax, %ds
movw %ax, %es
movw %ax, %fs
movw %ax, %gs
movq saved_rsp, %rsp
movq saved_rbx, %rbx
movq saved_rdi, %rdi
movq saved_rsi, %rsi
movq saved_rbp, %rbp
movq saved_rip, %rax
jmp *%rax
ENDPROC(wakeup_long64)
ENTRY(do_suspend_lowlevel)
FRAME_BEGIN
subq $8, %rsp
xorl %eax, %eax
call save_processor_state
movq $saved_context, %rax
movq %rsp, pt_regs_sp(%rax)
movq %rbp, pt_regs_bp(%rax)
movq %rsi, pt_regs_si(%rax)
movq %rdi, pt_regs_di(%rax)
movq %rbx, pt_regs_bx(%rax)
movq %rcx, pt_regs_cx(%rax)
movq %rdx, pt_regs_dx(%rax)
movq %r8, pt_regs_r8(%rax)
movq %r9, pt_regs_r9(%rax)
movq %r10, pt_regs_r10(%rax)
movq %r11, pt_regs_r11(%rax)
movq %r12, pt_regs_r12(%rax)
movq %r13, pt_regs_r13(%rax)
movq %r14, pt_regs_r14(%rax)
movq %r15, pt_regs_r15(%rax)
pushfq
popq pt_regs_flags(%rax)
movq $.Lresume_point, saved_rip(%rip)
movq %rsp, saved_rsp
movq %rbp, saved_rbp
movq %rbx, saved_rbx
movq %rdi, saved_rdi
movq %rsi, saved_rsi
addq $8, %rsp
movl $3, %edi
xorl %eax, %eax
call x86_acpi_enter_sleep_state
/* in case something went wrong, restore the machine status and go on */
jmp .Lresume_point
.align 4
.Lresume_point:
/* We don't restore %rax, it must be 0 anyway */
movq $saved_context, %rax
movq saved_context_cr4(%rax), %rbx
movq %rbx, %cr4
movq saved_context_cr3(%rax), %rbx
movq %rbx, %cr3
movq saved_context_cr2(%rax), %rbx
movq %rbx, %cr2
movq saved_context_cr0(%rax), %rbx
movq %rbx, %cr0
pushq pt_regs_flags(%rax)
popfq
movq pt_regs_sp(%rax), %rsp
movq pt_regs_bp(%rax), %rbp
movq pt_regs_si(%rax), %rsi
movq pt_regs_di(%rax), %rdi
movq pt_regs_bx(%rax), %rbx
movq pt_regs_cx(%rax), %rcx
movq pt_regs_dx(%rax), %rdx
movq pt_regs_r8(%rax), %r8
movq pt_regs_r9(%rax), %r9
movq pt_regs_r10(%rax), %r10
movq pt_regs_r11(%rax), %r11
movq pt_regs_r12(%rax), %r12
movq pt_regs_r13(%rax), %r13
movq pt_regs_r14(%rax), %r14
movq pt_regs_r15(%rax), %r15
#ifdef CONFIG_KASAN
/*
* The suspend path may have poisoned some areas deeper in the stack,
* which we now need to unpoison.
*/
movq %rsp, %rdi
call kasan_unpoison_task_stack_below
#endif
xorl %eax, %eax
addq $8, %rsp
FRAME_END
jmp restore_processor_state
ENDPROC(do_suspend_lowlevel)
.data
saved_rbp: .quad 0
saved_rsi: .quad 0
saved_rdi: .quad 0
saved_rbx: .quad 0
saved_rip: .quad 0
saved_rsp: .quad 0
ENTRY(saved_magic) .quad 0