diff options
| author | Ville Syrjälä <ville.syrjala@linux.intel.com> | 2018-07-09 15:35:34 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-07-16 17:59:57 +0200 |
| commit | 6f6060a5c9cc76fdbc22748264e6aa3779ec2427 (patch) | |
| tree | 318fd074c9c46448f2a4620b8515aac06dbd461a /arch/x86/include | |
| parent | x86/events/intel/ds: Fix bts_interrupt_threshold alignment (diff) | |
| download | linux-6f6060a5c9cc76fdbc22748264e6aa3779ec2427.tar.xz linux-6f6060a5c9cc76fdbc22748264e6aa3779ec2427.zip | |
x86/apm: Don't access __preempt_count with zeroed fs
APM_DO_POP_SEGS does not restore fs/gs which were zeroed by
APM_DO_ZERO_SEGS. Trying to access __preempt_count with
zeroed fs doesn't really work.
Move the ibrs call outside the APM_DO_SAVE_SEGS/APM_DO_RESTORE_SEGS
invocations so that fs is actually restored before calling
preempt_enable().
Fixes the following sort of oopses:
[ 0.313581] general protection fault: 0000 [#1] PREEMPT SMP
[ 0.313803] Modules linked in:
[ 0.314040] CPU: 0 PID: 268 Comm: kapmd Not tainted 4.16.0-rc1-triton-bisect-00090-gdd84441a7971 #19
[ 0.316161] EIP: __apm_bios_call_simple+0xc8/0x170
[ 0.316161] EFLAGS: 00210016 CPU: 0
[ 0.316161] EAX: 00000102 EBX: 00000000 ECX: 00000102 EDX: 00000000
[ 0.316161] ESI: 0000530e EDI: dea95f64 EBP: dea95f18 ESP: dea95ef0
[ 0.316161] DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068
[ 0.316161] CR0: 80050033 CR2: 00000000 CR3: 015d3000 CR4: 000006d0
[ 0.316161] Call Trace:
[ 0.316161] ? cpumask_weight.constprop.15+0x20/0x20
[ 0.316161] on_cpu0+0x44/0x70
[ 0.316161] apm+0x54e/0x720
[ 0.316161] ? __switch_to_asm+0x26/0x40
[ 0.316161] ? __schedule+0x17d/0x590
[ 0.316161] kthread+0xc0/0xf0
[ 0.316161] ? proc_apm_show+0x150/0x150
[ 0.316161] ? kthread_create_worker_on_cpu+0x20/0x20
[ 0.316161] ret_from_fork+0x2e/0x38
[ 0.316161] Code: da 8e c2 8e e2 8e ea 57 55 2e ff 1d e0 bb 5d b1 0f 92 c3 5d 5f 07 1f 89 47 0c 90 8d b4 26 00 00 00 00 90 8d b4 26 00 00 00 00 90 <64> ff 0d 84 16 5c b1 74 7f 8b 45 dc 8e e0 8b 45 d8 8e e8 8b 45
[ 0.316161] EIP: __apm_bios_call_simple+0xc8/0x170 SS:ESP: 0068:dea95ef0
[ 0.316161] ---[ end trace 656253db2deaa12c ]---
Fixes: dd84441a7971 ("x86/speculation: Use IBRS if available before calling into firmware")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/20180709133534.5963-1-ville.syrjala@linux.intel.com
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/apm.h | 6 |
1 files changed, 0 insertions, 6 deletions
diff --git a/arch/x86/include/asm/apm.h b/arch/x86/include/asm/apm.h index c356098b6fb9..4d4015ddcf26 100644 --- a/arch/x86/include/asm/apm.h +++ b/arch/x86/include/asm/apm.h @@ -7,8 +7,6 @@ #ifndef _ASM_X86_MACH_DEFAULT_APM_H #define _ASM_X86_MACH_DEFAULT_APM_H -#include <asm/nospec-branch.h> - #ifdef APM_ZERO_SEGS # define APM_DO_ZERO_SEGS \ "pushl %%ds\n\t" \ @@ -34,7 +32,6 @@ static inline void apm_bios_call_asm(u32 func, u32 ebx_in, u32 ecx_in, * N.B. We do NOT need a cld after the BIOS call * because we always save and restore the flags. */ - firmware_restrict_branch_speculation_start(); __asm__ __volatile__(APM_DO_ZERO_SEGS "pushl %%edi\n\t" "pushl %%ebp\n\t" @@ -47,7 +44,6 @@ static inline void apm_bios_call_asm(u32 func, u32 ebx_in, u32 ecx_in, "=S" (*esi) : "a" (func), "b" (ebx_in), "c" (ecx_in) : "memory", "cc"); - firmware_restrict_branch_speculation_end(); } static inline bool apm_bios_call_simple_asm(u32 func, u32 ebx_in, @@ -60,7 +56,6 @@ static inline bool apm_bios_call_simple_asm(u32 func, u32 ebx_in, * N.B. We do NOT need a cld after the BIOS call * because we always save and restore the flags. */ - firmware_restrict_branch_speculation_start(); __asm__ __volatile__(APM_DO_ZERO_SEGS "pushl %%edi\n\t" "pushl %%ebp\n\t" @@ -73,7 +68,6 @@ static inline bool apm_bios_call_simple_asm(u32 func, u32 ebx_in, "=S" (si) : "a" (func), "b" (ebx_in), "c" (ecx_in) : "memory", "cc"); - firmware_restrict_branch_speculation_end(); return error; } |