[GIT PULL] x86/pti fixes

From: Ingo Molnar
Date: Sat Jul 21 2018 - 08:52:51 EST


Linus,

Please pull the latest x86-pti-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-pti-urgent-for-linus

# HEAD: 6f6060a5c9cc76fdbc22748264e6aa3779ec2427 x86/apm: Don't access __preempt_count with zeroed fs

An APM fix, and a BTS hardware-tracing fix related to PTI changes.

Thanks,

Ingo

------------------>
Hugh Dickins (1):
x86/events/intel/ds: Fix bts_interrupt_threshold alignment

Ville Syrjälä (1):
x86/apm: Don't access __preempt_count with zeroed fs


arch/x86/events/intel/ds.c | 8 +++++---
arch/x86/include/asm/apm.h | 6 ------
arch/x86/kernel/apm_32.c | 5 +++++
3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 8a10a045b57b..8cf03f101938 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -408,9 +408,11 @@ static int alloc_bts_buffer(int cpu)
ds->bts_buffer_base = (unsigned long) cea;
ds_update_cea(cea, buffer, BTS_BUFFER_SIZE, PAGE_KERNEL);
ds->bts_index = ds->bts_buffer_base;
- max = BTS_RECORD_SIZE * (BTS_BUFFER_SIZE / BTS_RECORD_SIZE);
- ds->bts_absolute_maximum = ds->bts_buffer_base + max;
- ds->bts_interrupt_threshold = ds->bts_absolute_maximum - (max / 16);
+ max = BTS_BUFFER_SIZE / BTS_RECORD_SIZE;
+ ds->bts_absolute_maximum = ds->bts_buffer_base +
+ max * BTS_RECORD_SIZE;
+ ds->bts_interrupt_threshold = ds->bts_absolute_maximum -
+ (max / 16) * BTS_RECORD_SIZE;
return 0;
}

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;
}

diff --git a/arch/x86/kernel/apm_32.c b/arch/x86/kernel/apm_32.c
index 5d0de79fdab0..ec00d1ff5098 100644
--- a/arch/x86/kernel/apm_32.c
+++ b/arch/x86/kernel/apm_32.c
@@ -240,6 +240,7 @@
#include <asm/olpc.h>
#include <asm/paravirt.h>
#include <asm/reboot.h>
+#include <asm/nospec-branch.h>

#if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
extern int (*console_blank_hook)(int);
@@ -614,11 +615,13 @@ static long __apm_bios_call(void *_call)
gdt[0x40 / 8] = bad_bios_desc;

apm_irq_save(flags);
+ firmware_restrict_branch_speculation_start();
APM_DO_SAVE_SEGS;
apm_bios_call_asm(call->func, call->ebx, call->ecx,
&call->eax, &call->ebx, &call->ecx, &call->edx,
&call->esi);
APM_DO_RESTORE_SEGS;
+ firmware_restrict_branch_speculation_end();
apm_irq_restore(flags);
gdt[0x40 / 8] = save_desc_40;
put_cpu();
@@ -690,10 +693,12 @@ static long __apm_bios_call_simple(void *_call)
gdt[0x40 / 8] = bad_bios_desc;

apm_irq_save(flags);
+ firmware_restrict_branch_speculation_start();
APM_DO_SAVE_SEGS;
error = apm_bios_call_simple_asm(call->func, call->ebx, call->ecx,
&call->eax);
APM_DO_RESTORE_SEGS;
+ firmware_restrict_branch_speculation_end();
apm_irq_restore(flags);
gdt[0x40 / 8] = save_desc_40;
put_cpu();