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| author | Jiri Slaby <jslaby@suse.cz> | 2019-09-06 09:55:49 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2019-09-06 10:34:15 +0200 |
| commit | 559ceeed62a5121783a8955c63aeb18aaa0ef224 (patch) | |
| tree | bcb93c9ad32ff3c9ee49ac50c80236d915f58b69 /arch/x86/kernel/acpi | |
| parent | x86/math64: Provide a sane mul_u64_u32_div() implementation for x86_64 (diff) | |
| download | linux-559ceeed62a5121783a8955c63aeb18aaa0ef224.tar.xz linux-559ceeed62a5121783a8955c63aeb18aaa0ef224.zip | |
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
Diffstat (limited to 'arch/x86/kernel/acpi')
| -rw-r--r-- | arch/x86/kernel/acpi/wakeup_64.S | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S index b0715c3ac18d..7f9ade13bbcf 100644 --- a/arch/x86/kernel/acpi/wakeup_64.S +++ b/arch/x86/kernel/acpi/wakeup_64.S @@ -18,8 +18,13 @@ ENTRY(wakeup_long64) movq saved_magic, %rax movq $0x123456789abcdef0, %rdx cmpq %rdx, %rax - jne bogus_64_magic + 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 @@ -37,9 +42,6 @@ ENTRY(wakeup_long64) jmp *%rax ENDPROC(wakeup_long64) -bogus_64_magic: - jmp bogus_64_magic - ENTRY(do_suspend_lowlevel) FRAME_BEGIN subq $8, %rsp |