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-rw-r--r--arch/x86/include/asm/msr-index.h2
-rw-r--r--arch/x86/include/asm/processor.h2
-rw-r--r--arch/x86/include/asm/thread_info.h6
-rw-r--r--arch/x86/include/uapi/asm/prctl.h11
-rw-r--r--arch/x86/kernel/cpu/intel.c18
-rw-r--r--arch/x86/kernel/process.c78
-rw-r--r--fs/exec.c1
-rw-r--r--include/linux/thread_info.h4
8 files changed, 109 insertions, 13 deletions
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index b1f75daca34b..673f9ac50f6d 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -558,6 +558,8 @@
/* MISC_FEATURES_ENABLES non-architectural features */
#define MSR_MISC_FEATURES_ENABLES 0x00000140
+#define MSR_MISC_FEATURES_ENABLES_CPUID_FAULT_BIT 0
+#define MSR_MISC_FEATURES_ENABLES_CPUID_FAULT BIT_ULL(MSR_MISC_FEATURES_ENABLES_CPUID_FAULT_BIT)
#define MSR_MISC_FEATURES_ENABLES_RING3MWAIT_BIT 1
#define MSR_IA32_TSC_DEADLINE 0x000006E0
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index f385eca5407a..a80c1b3997ed 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -884,6 +884,8 @@ extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
extern int get_tsc_mode(unsigned long adr);
extern int set_tsc_mode(unsigned int val);
+DECLARE_PER_CPU(u64, msr_misc_features_shadow);
+
/* Register/unregister a process' MPX related resource */
#define MPX_ENABLE_MANAGEMENT() mpx_enable_management()
#define MPX_DISABLE_MANAGEMENT() mpx_disable_management()
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index ad6f5eb07a95..9fc44b95f7cb 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -87,6 +87,7 @@ struct thread_info {
#define TIF_SECCOMP 8 /* secure computing */
#define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */
#define TIF_UPROBE 12 /* breakpointed or singlestepping */
+#define TIF_NOCPUID 15 /* CPUID is not accessible in userland */
#define TIF_NOTSC 16 /* TSC is not accessible in userland */
#define TIF_IA32 17 /* IA32 compatibility process */
#define TIF_NOHZ 19 /* in adaptive nohz mode */
@@ -110,6 +111,7 @@ struct thread_info {
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
#define _TIF_UPROBE (1 << TIF_UPROBE)
+#define _TIF_NOCPUID (1 << TIF_NOCPUID)
#define _TIF_NOTSC (1 << TIF_NOTSC)
#define _TIF_IA32 (1 << TIF_IA32)
#define _TIF_NOHZ (1 << TIF_NOHZ)
@@ -138,7 +140,7 @@ struct thread_info {
/* flags to check in __switch_to() */
#define _TIF_WORK_CTXSW \
- (_TIF_IO_BITMAP|_TIF_NOTSC|_TIF_BLOCKSTEP)
+ (_TIF_IO_BITMAP|_TIF_NOCPUID|_TIF_NOTSC|_TIF_BLOCKSTEP)
#define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY)
#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)
@@ -239,6 +241,8 @@ static inline int arch_within_stack_frames(const void * const stack,
extern void arch_task_cache_init(void);
extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
extern void arch_release_task_struct(struct task_struct *tsk);
+extern void arch_setup_new_exec(void);
+#define arch_setup_new_exec arch_setup_new_exec
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_X86_THREAD_INFO_H */
diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h
index 835aa51c7f6e..c45765517092 100644
--- a/arch/x86/include/uapi/asm/prctl.h
+++ b/arch/x86/include/uapi/asm/prctl.h
@@ -1,10 +1,13 @@
#ifndef _ASM_X86_PRCTL_H
#define _ASM_X86_PRCTL_H
-#define ARCH_SET_GS 0x1001
-#define ARCH_SET_FS 0x1002
-#define ARCH_GET_FS 0x1003
-#define ARCH_GET_GS 0x1004
+#define ARCH_SET_GS 0x1001
+#define ARCH_SET_FS 0x1002
+#define ARCH_GET_FS 0x1003
+#define ARCH_GET_GS 0x1004
+
+#define ARCH_GET_CPUID 0x1011
+#define ARCH_SET_CPUID 0x1012
#define ARCH_MAP_VDSO_X32 0x2001
#define ARCH_MAP_VDSO_32 0x2002
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index a07f8295c9ed..dfa90a3a5145 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -90,16 +90,12 @@ static void probe_xeon_phi_r3mwait(struct cpuinfo_x86 *c)
return;
}
- if (ring3mwait_disabled) {
- msr_clear_bit(MSR_MISC_FEATURES_ENABLES,
- MSR_MISC_FEATURES_ENABLES_RING3MWAIT_BIT);
+ if (ring3mwait_disabled)
return;
- }
-
- msr_set_bit(MSR_MISC_FEATURES_ENABLES,
- MSR_MISC_FEATURES_ENABLES_RING3MWAIT_BIT);
set_cpu_cap(c, X86_FEATURE_RING3MWAIT);
+ this_cpu_or(msr_misc_features_shadow,
+ 1UL << MSR_MISC_FEATURES_ENABLES_RING3MWAIT_BIT);
if (c == &boot_cpu_data)
ELF_HWCAP2 |= HWCAP2_RING3MWAIT;
@@ -505,9 +501,15 @@ static void init_intel_misc_features(struct cpuinfo_x86 *c)
if (rdmsrl_safe(MSR_MISC_FEATURES_ENABLES, &msr))
return;
- /* Check features and update capabilities */
+ /* Clear all MISC features */
+ this_cpu_write(msr_misc_features_shadow, 0);
+
+ /* Check features and update capabilities and shadow control bits */
init_cpuid_fault(c);
probe_xeon_phi_r3mwait(c);
+
+ msr = this_cpu_read(msr_misc_features_shadow);
+ wrmsrl(MSR_MISC_FEATURES_ENABLES, msr);
}
static void init_intel(struct cpuinfo_x86 *c)
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index b12e95eceb83..0bb88428cbf2 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -37,6 +37,7 @@
#include <asm/vm86.h>
#include <asm/switch_to.h>
#include <asm/desc.h>
+#include <asm/prctl.h>
/*
* per-CPU TSS segments. Threads are completely 'soft' on Linux,
@@ -172,6 +173,73 @@ int set_tsc_mode(unsigned int val)
return 0;
}
+DEFINE_PER_CPU(u64, msr_misc_features_shadow);
+
+static void set_cpuid_faulting(bool on)
+{
+ u64 msrval;
+
+ msrval = this_cpu_read(msr_misc_features_shadow);
+ msrval &= ~MSR_MISC_FEATURES_ENABLES_CPUID_FAULT;
+ msrval |= (on << MSR_MISC_FEATURES_ENABLES_CPUID_FAULT_BIT);
+ this_cpu_write(msr_misc_features_shadow, msrval);
+ wrmsrl(MSR_MISC_FEATURES_ENABLES, msrval);
+}
+
+static void disable_cpuid(void)
+{
+ preempt_disable();
+ if (!test_and_set_thread_flag(TIF_NOCPUID)) {
+ /*
+ * Must flip the CPU state synchronously with
+ * TIF_NOCPUID in the current running context.
+ */
+ set_cpuid_faulting(true);
+ }
+ preempt_enable();
+}
+
+static void enable_cpuid(void)
+{
+ preempt_disable();
+ if (test_and_clear_thread_flag(TIF_NOCPUID)) {
+ /*
+ * Must flip the CPU state synchronously with
+ * TIF_NOCPUID in the current running context.
+ */
+ set_cpuid_faulting(false);
+ }
+ preempt_enable();
+}
+
+static int get_cpuid_mode(void)
+{
+ return !test_thread_flag(TIF_NOCPUID);
+}
+
+static int set_cpuid_mode(struct task_struct *task, unsigned long cpuid_enabled)
+{
+ if (!static_cpu_has(X86_FEATURE_CPUID_FAULT))
+ return -ENODEV;
+
+ if (cpuid_enabled)
+ enable_cpuid();
+ else
+ disable_cpuid();
+
+ return 0;
+}
+
+/*
+ * Called immediately after a successful exec.
+ */
+void arch_setup_new_exec(void)
+{
+ /* If cpuid was previously disabled for this task, re-enable it. */
+ if (test_thread_flag(TIF_NOCPUID))
+ enable_cpuid();
+}
+
static inline void switch_to_bitmap(struct tss_struct *tss,
struct thread_struct *prev,
struct thread_struct *next,
@@ -225,6 +293,9 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
if ((tifp ^ tifn) & _TIF_NOTSC)
cr4_toggle_bits(X86_CR4_TSD);
+
+ if ((tifp ^ tifn) & _TIF_NOCPUID)
+ set_cpuid_faulting(!!(tifn & _TIF_NOCPUID));
}
/*
@@ -549,5 +620,12 @@ out:
long do_arch_prctl_common(struct task_struct *task, int option,
unsigned long cpuid_enabled)
{
+ switch (option) {
+ case ARCH_GET_CPUID:
+ return get_cpuid_mode();
+ case ARCH_SET_CPUID:
+ return set_cpuid_mode(task, cpuid_enabled);
+ }
+
return -EINVAL;
}
diff --git a/fs/exec.c b/fs/exec.c
index 65145a3df065..72934df68471 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1320,6 +1320,7 @@ void setup_new_exec(struct linux_binprm * bprm)
else
set_dumpable(current->mm, suid_dumpable);
+ arch_setup_new_exec();
perf_event_exec();
__set_task_comm(current, kbasename(bprm->filename), true);
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index 58373875e8ee..55125d674338 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -101,6 +101,10 @@ static inline void check_object_size(const void *ptr, unsigned long n,
{ }
#endif /* CONFIG_HARDENED_USERCOPY */
+#ifndef arch_setup_new_exec
+static inline void arch_setup_new_exec(void) { }
+#endif
+
#endif /* __KERNEL__ */
#endif /* _LINUX_THREAD_INFO_H */