diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0084-x86-cpu-x86-pti-Do-not-enable-PTI-on-AMD-processors.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0084-x86-cpu-x86-pti-Do-not-enable-PTI-on-AMD-processors.patch | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0084-x86-cpu-x86-pti-Do-not-enable-PTI-on-AMD-processors.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0084-x86-cpu-x86-pti-Do-not-enable-PTI-on-AMD-processors.patch new file mode 100644 index 00000000..6e315ccf --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0084-x86-cpu-x86-pti-Do-not-enable-PTI-on-AMD-processors.patch @@ -0,0 +1,48 @@ +From ebd4f926752058a42c6da41e80b44a82aa4d14f5 Mon Sep 17 00:00:00 2001 +From: Tom Lendacky <thomas.lendacky@amd.com> +Date: Tue, 26 Dec 2017 23:43:54 -0600 +Subject: [PATCH 084/103] x86/cpu, x86/pti: Do not enable PTI on AMD processors + +commit 694d99d40972f12e59a3696effee8a376b79d7c8 upstream. + +AMD processors are not subject to the types of attacks that the kernel +page table isolation feature protects against. The AMD microarchitecture +does not allow memory references, including speculative references, that +access higher privileged data when running in a lesser privileged mode +when that access would result in a page fault. + +Disable page table isolation by default on AMD processors by not setting +the X86_BUG_CPU_INSECURE feature, which controls whether X86_FEATURE_PTI +is set. + +Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Reviewed-by: Borislav Petkov <bp@suse.de> +Cc: Dave Hansen <dave.hansen@linux.intel.com> +Cc: Andy Lutomirski <luto@kernel.org> +Cc: stable@vger.kernel.org +Link: https://lkml.kernel.org/r/20171227054354.20369.94587.stgit@tlendack-t1.amdoffice.net +Cc: Nick Lowe <nick.lowe@gmail.com> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/kernel/cpu/common.c | 4 ++-- + 1 file changed, 2 insertions(+), 2 deletions(-) + +diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c +index 7b9ae04..d198ae0 100644 +--- a/arch/x86/kernel/cpu/common.c ++++ b/arch/x86/kernel/cpu/common.c +@@ -883,8 +883,8 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) + + setup_force_cpu_cap(X86_FEATURE_ALWAYS); + +- /* Assume for now that ALL x86 CPUs are insecure */ +- setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN); ++ if (c->x86_vendor != X86_VENDOR_AMD) ++ setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN); + + setup_force_cpu_bug(X86_BUG_SPECTRE_V1); + setup_force_cpu_bug(X86_BUG_SPECTRE_V2); +-- +2.7.4 + |