From c3ee82ce47af63eca2075d8af956d468f508942e Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Sat, 18 May 2019 18:11:13 +0200 Subject: x86/boot: Provide KASAN compatible aliases for string routines The KASAN subsystem wraps calls to memcpy(), memset() and memmove() to sanitize the arguments before invoking the actual routines, which have been renamed to __memcpy(), __memset() and __memmove(), respectively. When CONFIG_KASAN is enabled for the kernel build but KASAN code generation is disabled for the compilation unit (which is needed for things like the EFI stub or the decompressor), the string routines are just #define'd to their __ prefixed names so that they are simply invoked directly. This does however rely on those __ prefixed names to exist in the symbol namespace, which is not currently the case for the x86 decompressor, which may lead to errors like drivers/firmware/efi/libstub/tpm.o: In function `efi_retrieve_tpm2_eventlog': tpm.c:(.text+0x2a8): undefined reference to `__memcpy' So let's expose the __ prefixed symbols in the decompressor when KASAN is enabled. Signed-off-by: Ard Biesheuvel Acked-by: Jarkko Sakkinen Cc: Andrey Konovalov Cc: Borislav Petkov Cc: Linus Torvalds Cc: Matthew Garrett Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/boot/compressed/string.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) (limited to 'arch') 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 -- cgit From 2ac44ab608705948564791ce1d15d43ba81a1e38 Mon Sep 17 00:00:00 2001 From: Frank van der Linden Date: Wed, 22 May 2019 22:17:45 +0000 Subject: x86/CPU/AMD: Don't force the CPB cap when running under a hypervisor For F17h AMD CPUs, the CPB capability ('Core Performance Boost') is forcibly set, because some versions of that chip incorrectly report that they do not have it. However, a hypervisor may filter out the CPB capability, for good reasons. For example, KVM currently does not emulate setting the CPB bit in MSR_K7_HWCR, and unchecked MSR access errors will be thrown when trying to set it as a guest: unchecked MSR access error: WRMSR to 0xc0010015 (tried to write 0x0000000001000011) at rIP: 0xffffffff890638f4 (native_write_msr+0x4/0x20) Call Trace: boost_set_msr+0x50/0x80 [acpi_cpufreq] cpuhp_invoke_callback+0x86/0x560 sort_range+0x20/0x20 cpuhp_thread_fun+0xb0/0x110 smpboot_thread_fn+0xef/0x160 kthread+0x113/0x130 kthread_create_worker_on_cpu+0x70/0x70 ret_from_fork+0x35/0x40 To avoid this issue, don't forcibly set the CPB capability for a CPU when running under a hypervisor. Signed-off-by: Frank van der Linden Acked-by: Borislav Petkov Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: bp@alien8.de Cc: jiaxun.yang@flygoat.com Fixes: 0237199186e7 ("x86/CPU/AMD: Set the CPB bit unconditionally on F17h") Link: http://lkml.kernel.org/r/20190522221745.GA15789@dev-dsk-fllinden-2c-c1893d73.us-west-2.amazon.com [ Minor edits to the changelog. ] Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/amd.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'arch') 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); } -- cgit