x86/cpufeatures: Make CPU bugs sticky

commit 6cbd2171e89b13377261d15e64384df60ecb530e upstream.

There is currently no way to force CPU bug bits like CPU feature bits. That
makes it impossible to set a bug bit once at boot and have it stick for all
upcoming CPUs.

Extend the force set/clear arrays to handle bug bits as well.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Link: https://lkml.kernel.org/r/20171204150606.992156574@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 1a3cc3b..c54aba9 100644 (file)
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -258,6 +258,8 @@ extern const char * const x86_power_flags[32];
        set_bit(bit, (unsigned long *)cpu_caps_set);    \
 } while (0)
 
+#define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
+
 #define cpu_has_fpu            boot_cpu_has(X86_FEATURE_FPU)
 #define cpu_has_vme            boot_cpu_has(X86_FEATURE_VME)
 #define cpu_has_de             boot_cpu_has(X86_FEATURE_DE)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 3cd77eb..243ce08 100644 (file)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -130,8 +130,8 @@ extern struct cpuinfo_x86   boot_cpu_data;
 extern struct cpuinfo_x86      new_cpu_data;
 
 extern struct tss_struct       doublefault_tss;
-extern __u32                   cpu_caps_cleared[NCAPINTS];
-extern __u32                   cpu_caps_set[NCAPINTS];
+extern __u32                   cpu_caps_cleared[NCAPINTS + NBUGINTS];
+extern __u32                   cpu_caps_set[NCAPINTS + NBUGINTS];
 
 #ifdef CONFIG_SMP
 DECLARE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info);

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 21d9960..f33ea66 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -424,8 +424,8 @@ static const char *__cpuinit table_lookup_model(struct cpuinfo_x86 *c)
        return NULL;            /* Not found */
 }
 
-__u32 cpu_caps_cleared[NCAPINTS] __cpuinitdata;
-__u32 cpu_caps_set[NCAPINTS] __cpuinitdata;
+__u32 cpu_caps_cleared[NCAPINTS + NBUGINTS] __cpuinitdata;
+__u32 cpu_caps_set[NCAPINTS + NBUGINTS] __cpuinitdata;
 
 void load_percpu_segment(int cpu)
 {
@@ -636,7 +636,7 @@ static void apply_forced_caps(struct cpuinfo_x86 *c)
 {
        int i;
 
-       for (i = 0; i < NCAPINTS; i++) {
+       for (i = 0; i < NCAPINTS + NBUGINTS; i++) {
                c->x86_capability[i] &= ~cpu_caps_cleared[i];
                c->x86_capability[i] |= cpu_caps_set[i];
        }