Re: [PATCH] x86: static_cpu_has_safe: discard dynamic check after init

From: Borislav Petkov
Date: Tue Jan 19 2016 - 08:57:54 EST

On Tue, Jan 19, 2016 at 12:25:47AM +0100, Borislav Petkov wrote:
> Luckily, I have this disassembler tool which dumps the alternatives
> sections in a more readable format. I can dump all the static_cpu_has()
> call sites tomorrow and we can see what gcc generates.

Ok, below is the list of all 12(!) places where static_cpu_has() has
generated a 2-byte JMP. Which has saved us a whopping 36 bytes! On an
x86_64 allyesconfig!

Patch removing it below. I better look at a 32-bit allyesconfig too
first, though.

old insn VA: 0xffffffff8146b5ac, CPU feat: X86_FEATURE_PCOMMIT, size: 2, padlen: 0
wmb_pmem:
ffffffff8146b5ac: eb 02 jmp ffffffff8146b5b0
repl insn: 0xffffffff8ca7c651, size: 0

old insn VA: 0xffffffff8200dcd6, CPU feat: X86_FEATURE_PCOMMIT, size: 2, padlen: 0
arch_has_wmb_pmem:
ffffffff8200dcd6: eb 02 jmp ffffffff8200dcda
repl insn: 0xffffffff8ca7ebd8, size: 0

old insn VA: 0xffffffff828afe51, CPU feat: X86_FEATURE_PCOMMIT, size: 2, padlen: 0
arch_has_wmb_pmem:
ffffffff828afe51: eb 02 jmp ffffffff828afe55
repl insn: 0xffffffff8ca80f98, size: 0

old insn VA: 0xffffffff81072f77, CPU feat: X86_FEATURE_NRIPS, size: 2, padlen: 0
rdpmc_interception:
ffffffff81072f77: eb 4d jmp ffffffff81072fc6
repl insn: 0xffffffff8ca79f6b, size: 0

old insn VA: 0xffffffff8107437d, CPU feat: X86_FEATURE_NRIPS, size: 2, padlen: 0
svm_queue_exception:
ffffffff8107437d: eb 6f jmp ffffffff810743ee
repl insn: 0xffffffff8ca79f9f, size: 0

old insn VA: 0xffffffff8107741b, CPU feat: X86_FEATURE_NRIPS, size: 2, padlen: 0
svm_check_intercept:
ffffffff8107741b: eb 67 jmp ffffffff81077484
repl insn: 0xffffffff8ca79fed, size: 0

old insn VA: 0xffffffff8107741b, CPU feat: X86_FEATURE_NRIPS, size: 2, padlen: 0
svm_check_intercept:
ffffffff8107741b: eb 67 jmp ffffffff81077484
repl insn: 0xffffffff8ca79fed, size: 0

old insn VA: 0xffffffff81075c4f, CPU feat: X86_FEATURE_TSCRATEMSR, size: 2, padlen: 0
svm_hardware_enable:
ffffffff81075c4f: eb 57 jmp ffffffff81075ca8
repl insn: 0xffffffff8ca79fb9, size: 0

old insn VA: 0xffffffff81072c00, CPU feat: X86_FEATURE_DECODEASSISTS, size: 2, padlen: 0
invlpg_interception:
ffffffff81072c00: eb 55 jmp ffffffff81072c57
repl insn: 0xffffffff8ca79f51, size: 0

old insn VA: 0xffffffff8107097c, CPU feat: X86_FEATURE_FLUSHBYASID, size: 2, padlen: 0
svm_flush_tlb:
ffffffff8107097c: eb 35 jmp ffffffff810709b3
repl insn: 0xffffffff8ca79ee9, size: 0

old insn VA: 0xffffffff8108c0d0, CPU feat: X86_BUG_SYSRET_SS_ATTRS, size: 2, padlen: 0
__switch_to:
ffffffff8108c0d0: eb 70 jmp ffffffff8108c142
repl insn: 0xffffffff8ca7a1a7, size: 0

old insn VA: 0xffffffff81075d90, CPU feat: X86_BUG_AMD_TLB_MMATCH, size: 2, padlen: 0
svm_hardware_enable:
ffffffff81075d90: eb 7c jmp ffffffff81075e0e
repl insn: 0xffffffff8ca79fd3, size: 0

---
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 9b18ed9..68a2d1f 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -350,16 +350,6 @@ config DEBUG_IMR_SELFTEST

If unsure say N here.

-config X86_DEBUG_STATIC_CPU_HAS
- bool "Debug alternatives"
- depends on DEBUG_KERNEL
- ---help---
- This option causes additional code to be generated which
- fails if static_cpu_has() is used before alternatives have
- run.
-
- If unsure, say N.
-
config X86_DEBUG_FPU
bool "Debug the x86 FPU code"
depends on DEBUG_KERNEL
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 0366374..c2d7a97 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -477,7 +477,7 @@ __visible long do_fast_syscall_32(struct pt_regs *regs)
* We don't allow syscalls at all from VM86 mode, but we still
* need to check VM, because we might be returning from sys_vm86.
*/
- return static_cpu_has(X86_FEATURE_SEP) &&
+ return static_cpu_has_safe(X86_FEATURE_SEP) &&
regs->cs == __USER_CS && regs->ss == __USER_DS &&
regs->ip == landing_pad &&
(regs->flags & (X86_EFLAGS_RF | X86_EFLAGS_TF | X86_EFLAGS_VM)) == 0;
diff --git a/arch/x86/include/asm/archrandom.h b/arch/x86/include/asm/archrandom.h
index 69f1366..2fb511b 100644
--- a/arch/x86/include/asm/archrandom.h
+++ b/arch/x86/include/asm/archrandom.h
@@ -114,8 +114,8 @@ GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_INT, ASM_NOP4);

#endif /* CONFIG_X86_64 */

-#define arch_has_random() static_cpu_has(X86_FEATURE_RDRAND)
-#define arch_has_random_seed() static_cpu_has(X86_FEATURE_RDSEED)
+#define arch_has_random() static_cpu_has_safe(X86_FEATURE_RDRAND)
+#define arch_has_random_seed() static_cpu_has_safe(X86_FEATURE_RDSEED)

#else

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 7ad8c94..5fe399a 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -419,89 +419,6 @@ extern bool __static_cpu_has_safe(u16 bit);
* These are only valid after alternatives have run, but will statically
* patch the target code for additional performance.
*/
-static __always_inline __pure bool __static_cpu_has(u16 bit)
-{
-#ifdef CC_HAVE_ASM_GOTO
-
-#ifdef CONFIG_X86_DEBUG_STATIC_CPU_HAS
-
- /*
- * Catch too early usage of this before alternatives
- * have run.
- */
- asm_volatile_goto("1: jmp %l[t_warn]\n"
- "2:\n"
- ".section .altinstructions,\"a\"\n"
- " .long 1b - .\n"
- " .long 0\n" /* no replacement */
- " .word %P0\n" /* 1: do replace */
- " .byte 2b - 1b\n" /* source len */
- " .byte 0\n" /* replacement len */
- " .byte 0\n" /* pad len */
- ".previous\n"
- /* skipping size check since replacement size = 0 */
- : : "i" (X86_FEATURE_ALWAYS) : : t_warn);
-
-#endif
-
- asm_volatile_goto("1: jmp %l[t_no]\n"
- "2:\n"
- ".section .altinstructions,\"a\"\n"
- " .long 1b - .\n"
- " .long 0\n" /* no replacement */
- " .word %P0\n" /* feature bit */
- " .byte 2b - 1b\n" /* source len */
- " .byte 0\n" /* replacement len */
- " .byte 0\n" /* pad len */
- ".previous\n"
- /* skipping size check since replacement size = 0 */
- : : "i" (bit) : : t_no);
- return true;
- t_no:
- return false;
-
-#ifdef CONFIG_X86_DEBUG_STATIC_CPU_HAS
- t_warn:
- warn_pre_alternatives();
- return false;
-#endif
-
-#else /* CC_HAVE_ASM_GOTO */
-
- u8 flag;
- /* Open-coded due to __stringify() in ALTERNATIVE() */
- asm volatile("1: movb $0,%0\n"
- "2:\n"
- ".section .altinstructions,\"a\"\n"
- " .long 1b - .\n"
- " .long 3f - .\n"
- " .word %P1\n" /* feature bit */
- " .byte 2b - 1b\n" /* source len */
- " .byte 4f - 3f\n" /* replacement len */
- " .byte 0\n" /* pad len */
- ".previous\n"
- ".section .discard,\"aw\",@progbits\n"
- " .byte 0xff + (4f-3f) - (2b-1b)\n" /* size check */
- ".previous\n"
- ".section .altinstr_replacement,\"ax\"\n"
- "3: movb $1,%0\n"
- "4:\n"
- ".previous\n"
- : "=qm" (flag) : "i" (bit));
- return flag;
-
-#endif /* CC_HAVE_ASM_GOTO */
-}
-
-#define static_cpu_has(bit) \
-( \
- __builtin_constant_p(boot_cpu_has(bit)) ? \
- boot_cpu_has(bit) : \
- __builtin_constant_p(bit) ? \
- __static_cpu_has(bit) : \
- boot_cpu_has(bit) \
-)
-
static __always_inline __pure bool _static_cpu_has_safe(u16 bit)
{
#ifdef CC_HAVE_ASM_GOTO
@@ -588,7 +505,6 @@ static __always_inline __pure bool _static_cpu_has_safe(u16 bit)
/*
* gcc 3.x is too stupid to do the static test; fall back to dynamic.
*/
-#define static_cpu_has(bit) boot_cpu_has(bit)
#define static_cpu_has_safe(bit) boot_cpu_has(bit)
#endif

@@ -596,7 +512,6 @@ static __always_inline __pure bool _static_cpu_has_safe(u16 bit)
#define set_cpu_bug(c, bit) set_cpu_cap(c, (bit))
#define clear_cpu_bug(c, bit) clear_cpu_cap(c, (bit))

-#define static_cpu_has_bug(bit) static_cpu_has((bit))
#define static_cpu_has_bug_safe(bit) static_cpu_has_safe((bit))
#define boot_cpu_has_bug(bit) cpu_has_bug(&boot_cpu_data, (bit))

diff --git a/arch/x86/include/asm/mwait.h b/arch/x86/include/asm/mwait.h
index c70689b..2bd6e47 100644
--- a/arch/x86/include/asm/mwait.h
+++ b/arch/x86/include/asm/mwait.h
@@ -96,7 +96,7 @@ static inline void __sti_mwait(unsigned long eax, unsigned long ecx)
static inline void mwait_idle_with_hints(unsigned long eax, unsigned long ecx)
{
if (!current_set_polling_and_test()) {
- if (static_cpu_has_bug(X86_BUG_CLFLUSH_MONITOR)) {
+ if (static_cpu_has_bug_safe(X86_BUG_CLFLUSH_MONITOR)) {
mb();
clflush((void *)&current_thread_info()->flags);
mb();
diff --git a/arch/x86/include/asm/pmem.h b/arch/x86/include/asm/pmem.h
index 1544fab..5d7abb4 100644
--- a/arch/x86/include/asm/pmem.h
+++ b/arch/x86/include/asm/pmem.h
@@ -142,7 +142,7 @@ static inline bool __arch_has_wmb_pmem(void)
* We require that wmb() be an 'sfence', that is only guaranteed on
* 64-bit builds
*/
- return static_cpu_has(X86_FEATURE_PCOMMIT);
+ return static_cpu_has_safe(X86_FEATURE_PCOMMIT);
}
#endif /* CONFIG_ARCH_HAS_PMEM_API */
#endif /* __ASM_X86_PMEM_H__ */
diff --git a/arch/x86/include/asm/qspinlock.h b/arch/x86/include/asm/qspinlock.h
index eaba080..f456616 100644
--- a/arch/x86/include/asm/qspinlock.h
+++ b/arch/x86/include/asm/qspinlock.h
@@ -43,7 +43,7 @@ static inline void queued_spin_unlock(struct qspinlock *lock)
#define virt_spin_lock virt_spin_lock
static inline bool virt_spin_lock(struct qspinlock *lock)
{
- if (!static_cpu_has(X86_FEATURE_HYPERVISOR))
+ if (!static_cpu_has_safe(X86_FEATURE_HYPERVISOR))
return false;

/*
diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index 18ca99f..f8a6cfb 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -32,11 +32,11 @@ static void show_cpuinfo_misc(struct seq_file *m, struct cpuinfo_x86 *c)
"fpu_exception\t: %s\n"
"cpuid level\t: %d\n"
"wp\t\t: %s\n",
- static_cpu_has_bug(X86_BUG_FDIV) ? "yes" : "no",
- static_cpu_has_bug(X86_BUG_F00F) ? "yes" : "no",
- static_cpu_has_bug(X86_BUG_COMA) ? "yes" : "no",
- static_cpu_has(X86_FEATURE_FPU) ? "yes" : "no",
- static_cpu_has(X86_FEATURE_FPU) ? "yes" : "no",
+ static_cpu_has_bug_safe(X86_BUG_FDIV) ? "yes" : "no",
+ static_cpu_has_bug_safe(X86_BUG_F00F) ? "yes" : "no",
+ static_cpu_has_bug_safe(X86_BUG_COMA) ? "yes" : "no",
+ static_cpu_has_safe(X86_FEATURE_FPU) ? "yes" : "no",
+ static_cpu_has_safe(X86_FEATURE_FPU) ? "yes" : "no",
c->cpuid_level,
c->wp_works_ok ? "yes" : "no");
}
diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index 0bc3490..9b0163c 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -275,7 +275,7 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset,

fpu__activate_fpstate_read(fpu);

- if (!static_cpu_has(X86_FEATURE_FPU))
+ if (!static_cpu_has_safe(X86_FEATURE_FPU))
return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);

if (!cpu_has_fxsr)
@@ -306,7 +306,7 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset,
fpu__activate_fpstate_write(fpu);
fpstate_sanitize_xstate(fpu);

- if (!static_cpu_has(X86_FEATURE_FPU))
+ if (!static_cpu_has_safe(X86_FEATURE_FPU))
return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);

if (!cpu_has_fxsr)
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 31c6a60..05b6ede 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -162,7 +162,7 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
if (!access_ok(VERIFY_WRITE, buf, size))
return -EACCES;

- if (!static_cpu_has(X86_FEATURE_FPU))
+ if (!static_cpu_has_safe(X86_FEATURE_FPU))
return fpregs_soft_get(current, NULL, 0,
sizeof(struct user_i387_ia32_struct), NULL,
(struct _fpstate_32 __user *) buf) ? -1 : 1;
@@ -267,7 +267,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)

fpu__activate_curr(fpu);

- if (!static_cpu_has(X86_FEATURE_FPU))
+ if (!static_cpu_has_safe(X86_FEATURE_FPU))
return fpregs_soft_set(current, NULL,
0, sizeof(struct user_i387_ia32_struct),
NULL, buf) != 0;
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index b9d99e0..c49a284 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -411,7 +411,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV))
__switch_to_xtra(prev_p, next_p, tss);

- if (static_cpu_has_bug(X86_BUG_SYSRET_SS_ATTRS)) {
+ if (static_cpu_has_bug_safe(X86_BUG_SYSRET_SS_ATTRS)) {
/*
* AMD CPUs have a misfeature: SYSRET sets the SS selector but
* does not update the cached descriptor. As a result, if we
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index c8eda14..89d5ad7 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -32,7 +32,7 @@ static inline bool guest_cpuid_has_xsave(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;

- if (!static_cpu_has(X86_FEATURE_XSAVE))
+ if (!static_cpu_has_safe(X86_FEATURE_XSAVE))
return false;

best = kvm_find_cpuid_entry(vcpu, 1, 0);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index c13a64b..1892bdd 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -516,7 +516,7 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
struct vcpu_svm *svm = to_svm(vcpu);

if (svm->vmcb->control.next_rip != 0) {
- WARN_ON_ONCE(!static_cpu_has(X86_FEATURE_NRIPS));
+ WARN_ON_ONCE(!static_cpu_has_safe(X86_FEATURE_NRIPS));
svm->next_rip = svm->vmcb->control.next_rip;
}

@@ -548,7 +548,7 @@ static void svm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
nested_svm_check_exception(svm, nr, has_error_code, error_code))
return;

- if (nr == BP_VECTOR && !static_cpu_has(X86_FEATURE_NRIPS)) {
+ if (nr == BP_VECTOR && !static_cpu_has_safe(X86_FEATURE_NRIPS)) {
unsigned long rip, old_rip = kvm_rip_read(&svm->vcpu);

/*
@@ -577,7 +577,7 @@ static void svm_init_erratum_383(void)
int err;
u64 val;

- if (!static_cpu_has_bug(X86_BUG_AMD_TLB_MMATCH))
+ if (!static_cpu_has_bug_safe(X86_BUG_AMD_TLB_MMATCH))
return;

/* Use _safe variants to not break nested virtualization */
@@ -631,7 +631,7 @@ static int has_svm(void)
static void svm_hardware_disable(void)
{
/* Make sure we clean up behind us */
- if (static_cpu_has(X86_FEATURE_TSCRATEMSR))
+ if (static_cpu_has_safe(X86_FEATURE_TSCRATEMSR))
wrmsrl(MSR_AMD64_TSC_RATIO, TSC_RATIO_DEFAULT);

cpu_svm_disable();
@@ -674,7 +674,7 @@ static int svm_hardware_enable(void)

wrmsrl(MSR_VM_HSAVE_PA, page_to_pfn(sd->save_area) << PAGE_SHIFT);

- if (static_cpu_has(X86_FEATURE_TSCRATEMSR)) {
+ if (static_cpu_has_safe(X86_FEATURE_TSCRATEMSR)) {
wrmsrl(MSR_AMD64_TSC_RATIO, TSC_RATIO_DEFAULT);
__this_cpu_write(current_tsc_ratio, TSC_RATIO_DEFAULT);
}
@@ -1233,7 +1233,7 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)
rdmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]);

- if (static_cpu_has(X86_FEATURE_TSCRATEMSR)) {
+ if (static_cpu_has_safe(X86_FEATURE_TSCRATEMSR)) {
u64 tsc_ratio = vcpu->arch.tsc_scaling_ratio;
if (tsc_ratio != __this_cpu_read(current_tsc_ratio)) {
__this_cpu_write(current_tsc_ratio, tsc_ratio);
@@ -1241,7 +1241,7 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
}
}
/* This assumes that the kernel never uses MSR_TSC_AUX */
- if (static_cpu_has(X86_FEATURE_RDTSCP))
+ if (static_cpu_has_safe(X86_FEATURE_RDTSCP))
wrmsrl(MSR_TSC_AUX, svm->tsc_aux);
}

@@ -2806,7 +2806,7 @@ static int iret_interception(struct vcpu_svm *svm)

static int invlpg_interception(struct vcpu_svm *svm)
{
- if (!static_cpu_has(X86_FEATURE_DECODEASSISTS))
+ if (!static_cpu_has_safe(X86_FEATURE_DECODEASSISTS))
return emulate_instruction(&svm->vcpu, 0) == EMULATE_DONE;

kvm_mmu_invlpg(&svm->vcpu, svm->vmcb->control.exit_info_1);
@@ -2823,7 +2823,7 @@ static int rdpmc_interception(struct vcpu_svm *svm)
{
int err;

- if (!static_cpu_has(X86_FEATURE_NRIPS))
+ if (!static_cpu_has_safe(X86_FEATURE_NRIPS))
return emulate_on_interception(svm);

err = kvm_rdpmc(&svm->vcpu);
@@ -2864,7 +2864,7 @@ static int cr_interception(struct vcpu_svm *svm)
unsigned long val;
int err;

- if (!static_cpu_has(X86_FEATURE_DECODEASSISTS))
+ if (!static_cpu_has_safe(X86_FEATURE_DECODEASSISTS))
return emulate_on_interception(svm);

if (unlikely((svm->vmcb->control.exit_info_1 & CR_VALID) == 0))
@@ -3710,7 +3710,7 @@ static void svm_flush_tlb(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);

- if (static_cpu_has(X86_FEATURE_FLUSHBYASID))
+ if (static_cpu_has_safe(X86_FEATURE_FLUSHBYASID))
svm->vmcb->control.tlb_ctl = TLB_CONTROL_FLUSH_ASID;
else
svm->asid_generation--;
@@ -4282,7 +4282,7 @@ static int svm_check_intercept(struct kvm_vcpu *vcpu,
}

/* TODO: Advertise NRIPS to guest hypervisor unconditionally */
- if (static_cpu_has(X86_FEATURE_NRIPS))
+ if (static_cpu_has_safe(X86_FEATURE_NRIPS))
vmcb->control.next_rip = info->next_rip;
vmcb->control.exit_code = icpt_info.exit_code;
vmexit = nested_svm_exit_handled(svm);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e2951b6..4bef603 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8993,7 +8993,7 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
if (cpu_has_secondary_exec_ctrls())
vmcs_set_secondary_exec_control(secondary_exec_ctl);

- if (static_cpu_has(X86_FEATURE_PCOMMIT) && nested) {
+ if (static_cpu_has_safe(X86_FEATURE_PCOMMIT) && nested) {
if (guest_cpuid_has_pcommit(vcpu))
vmx->nested.nested_vmx_secondary_ctls_high |=
SECONDARY_EXEC_PCOMMIT;
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index eef44d9..711e9bc 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1033,7 +1033,7 @@ static inline bool smap_violation(int error_code, struct pt_regs *regs)
if (!IS_ENABLED(CONFIG_X86_SMAP))
return false;

- if (!static_cpu_has(X86_FEATURE_SMAP))
+ if (!static_cpu_has_safe(X86_FEATURE_SMAP))
return false;

if (error_code & PF_USER)
diff --git a/arch/x86/ras/mce_amd_inj.c b/arch/x86/ras/mce_amd_inj.c
index 55d38cf..191650f 100644
--- a/arch/x86/ras/mce_amd_inj.c
+++ b/arch/x86/ras/mce_amd_inj.c
@@ -275,7 +275,7 @@ static void do_inject(void)
* only on the node base core. Refer to D18F3x44[NbMcaToMstCpuEn] for
* Fam10h and later BKDGs.
*/
- if (static_cpu_has(X86_FEATURE_AMD_DCM) && b == 4) {
+ if (static_cpu_has_safe(X86_FEATURE_AMD_DCM) && b == 4) {
toggle_nb_mca_mst_cpu(amd_get_nb_id(cpu));
cpu = get_nbc_for_node(amd_get_nb_id(cpu));
}
diff --git a/drivers/cpufreq/amd_freq_sensitivity.c b/drivers/cpufreq/amd_freq_sensitivity.c
index f6b79ab..87b0cf4 100644
--- a/drivers/cpufreq/amd_freq_sensitivity.c
+++ b/drivers/cpufreq/amd_freq_sensitivity.c
@@ -115,7 +115,7 @@ static int __init amd_freq_sensitivity_init(void)
if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
return -ENODEV;

- if (!static_cpu_has(X86_FEATURE_PROC_FEEDBACK))
+ if (!static_cpu_has_safe(X86_FEATURE_PROC_FEEDBACK))
return -ENODEV;

if (rdmsrl_safe(MSR_AMD64_FREQ_SENSITIVITY_ACTUAL, &val))
diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
index 0b5bf13..aa71612 100644
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -1193,7 +1193,7 @@ static int powernowk8_init(void)
unsigned int i, supported_cpus = 0;
int ret;

- if (static_cpu_has(X86_FEATURE_HW_PSTATE)) {
+ if (static_cpu_has_safe(X86_FEATURE_HW_PSTATE)) {
__request_acpi_cpufreq();
return -ENODEV;
}


--
Regards/Gruss,
Boris.

SUSE Linux GmbH, GF: Felix ImendÃrffer, Jane Smithard, Graham Norton, HRB 21284 (AG NÃrnberg)
--