[GIT PULL] x86 fixes

Ingo Molnar
2019-06-02T17:44:48Z

Linus,

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

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

# HEAD: 2ac44ab608705948564791ce1d15d43ba81a1e38 x86/CPU/AMD: Don't force the CPB cap when running under a hypervisor

Two fixes: a quirk for KVM guests running on certain AMD CPUs, and a
KASAN related build fix.

Thanks,

Ingo

------------------>
Ard Biesheuvel (1):
x86/boot: Provide KASAN compatible aliases for string routines

Frank van der Linden (1):
x86/CPU/AMD: Don't force the CPB cap when running under a hypervisor

arch/x86/boot/compressed/string.c | 14 ++++++++++----
arch/x86/kernel/cpu/amd.c | 7 +++++--
2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/arch/x86/boot/compressed/string.c b/arch/x86/boot/compressed/string.c
index 19dbbcdd1a53..81fc1eaa3229 100644
--- a/arch/x86/boot/compressed/string.c
+++ b/arch/x86/boot/compressed/string.c
@@ -11,7 +11,7 @@
#include "../string.c"

#ifdef CONFIG_X86_32
-static void *__memcpy(void *dest, const void *src, size_t n)
+static void *____memcpy(void *dest, const void *src, size_t n)
{
int d0, d1, d2;
asm volatile(
@@ -25,7 +25,7 @@ static void *__memcpy(void *dest, const void *src, size_t n)
return dest;
}
#else
-static void *__memcpy(void *dest, const void *src, size_t n)
+static void *____memcpy(void *dest, const void *src, size_t n)
{
long d0, d1, d2;
asm volatile(
@@ -56,7 +56,7 @@ void *memmove(void *dest, const void *src, size_t n)
const unsigned char *s = src;

if (d <= s || d - s >= n)
- return __memcpy(dest, src, n);
+ return ____memcpy(dest, src, n);

while (n-- > 0)
d[n] = s[n];
@@ -71,5 +71,11 @@ void *memcpy(void *dest, const void *src, size_t n)
warn("Avoiding potentially unsafe overlapping memcpy()!");
return memmove(dest, src, n);
}
- return __memcpy(dest, src, n);
+ return ____memcpy(dest, src, n);
}
+
+#ifdef CONFIG_KASAN
+extern void *__memset(void *s, int c, size_t n) __alias(memset);
+extern void *__memmove(void *dest, const void *src, size_t n) __alias(memmove);
+extern void *__memcpy(void *dest, const void *src, size_t n) __alias(memcpy);
+#endif
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 80a405c2048a..8d4e50428b68 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -824,8 +824,11 @@ static void init_amd_zn(struct cpuinfo_x86 *c)
{
set_cpu_cap(c, X86_FEATURE_ZEN);

- /* Fix erratum 1076: CPB feature bit not being set in CPUID. */
- if (!cpu_has(c, X86_FEATURE_CPB))
+ /*
+ * Fix erratum 1076: CPB feature bit not being set in CPUID.
+ * Always set it, except when running under a hypervisor.
+ */
+ if (!cpu_has(c, X86_FEATURE_HYPERVISOR) && !cpu_has(c, X86_FEATURE_CPB))
set_cpu_cap(c, X86_FEATURE_CPB);
}