diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0012-x86-pti-Do-not-enable-PTI-on-CPUs-which-are-not-vuln.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0012-x86-pti-Do-not-enable-PTI-on-CPUs-which-are-not-vuln.patch | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0012-x86-pti-Do-not-enable-PTI-on-CPUs-which-are-not-vuln.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0012-x86-pti-Do-not-enable-PTI-on-CPUs-which-are-not-vuln.patch new file mode 100644 index 00000000..b1f180c1 --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0012-x86-pti-Do-not-enable-PTI-on-CPUs-which-are-not-vuln.patch @@ -0,0 +1,116 @@ +From 50f378f14484a86ee783e0e4da697e32295c6694 Mon Sep 17 00:00:00 2001 +From: David Woodhouse <dwmw@amazon.co.uk> +Date: Thu, 25 Jan 2018 16:14:13 +0000 +Subject: [PATCH 12/42] x86/pti: Do not enable PTI on CPUs which are not + vulnerable to Meltdown + +(cherry picked from commit fec9434a12f38d3aeafeb75711b71d8a1fdef621) + +Also, for CPUs which don't speculate at all, don't report that they're +vulnerable to the Spectre variants either. + +Leave the cpu_no_meltdown[] match table with just X86_VENDOR_AMD in it +for now, even though that could be done with a simple comparison, on the +assumption that we'll have more to add. + +Based on suggestions from Dave Hansen and Alan Cox. + +Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +Reviewed-by: Borislav Petkov <bp@suse.de> +Acked-by: Dave Hansen <dave.hansen@intel.com> +Cc: gnomes@lxorguk.ukuu.org.uk +Cc: ak@linux.intel.com +Cc: ashok.raj@intel.com +Cc: karahmed@amazon.de +Cc: arjan@linux.intel.com +Cc: torvalds@linux-foundation.org +Cc: peterz@infradead.org +Cc: bp@alien8.de +Cc: pbonzini@redhat.com +Cc: tim.c.chen@linux.intel.com +Cc: gregkh@linux-foundation.org +Link: https://lkml.kernel.org/r/1516896855-7642-6-git-send-email-dwmw@amazon.co.uk +Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/kernel/cpu/common.c | 48 +++++++++++++++++++++++++++++++++++++++----- + 1 file changed, 43 insertions(+), 5 deletions(-) + +diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c +index 4267273..cfa026f 100644 +--- a/arch/x86/kernel/cpu/common.c ++++ b/arch/x86/kernel/cpu/common.c +@@ -44,6 +44,8 @@ + #include <asm/pat.h> + #include <asm/microcode.h> + #include <asm/microcode_intel.h> ++#include <asm/intel-family.h> ++#include <asm/cpu_device_id.h> + + #ifdef CONFIG_X86_LOCAL_APIC + #include <asm/uv/uv.h> +@@ -838,6 +840,41 @@ static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c) + #endif + } + ++static const __initdata struct x86_cpu_id cpu_no_speculation[] = { ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CEDARVIEW, X86_FEATURE_ANY }, ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CLOVERVIEW, X86_FEATURE_ANY }, ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_LINCROFT, X86_FEATURE_ANY }, ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_PENWELL, X86_FEATURE_ANY }, ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_PINEVIEW, X86_FEATURE_ANY }, ++ { X86_VENDOR_CENTAUR, 5 }, ++ { X86_VENDOR_INTEL, 5 }, ++ { X86_VENDOR_NSC, 5 }, ++ { X86_VENDOR_ANY, 4 }, ++ {} ++}; ++ ++static const __initdata struct x86_cpu_id cpu_no_meltdown[] = { ++ { X86_VENDOR_AMD }, ++ {} ++}; ++ ++static bool __init cpu_vulnerable_to_meltdown(struct cpuinfo_x86 *c) ++{ ++ u64 ia32_cap = 0; ++ ++ if (x86_match_cpu(cpu_no_meltdown)) ++ return false; ++ ++ if (cpu_has(c, X86_FEATURE_ARCH_CAPABILITIES)) ++ rdmsrl(MSR_IA32_ARCH_CAPABILITIES, ia32_cap); ++ ++ /* Rogue Data Cache Load? No! */ ++ if (ia32_cap & ARCH_CAP_RDCL_NO) ++ return false; ++ ++ return true; ++} ++ + /* + * Do minimum CPU detection early. + * Fields really needed: vendor, cpuid_level, family, model, mask, +@@ -884,11 +921,12 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) + + setup_force_cpu_cap(X86_FEATURE_ALWAYS); + +- 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); ++ if (!x86_match_cpu(cpu_no_speculation)) { ++ if (cpu_vulnerable_to_meltdown(c)) ++ setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN); ++ setup_force_cpu_bug(X86_BUG_SPECTRE_V1); ++ setup_force_cpu_bug(X86_BUG_SPECTRE_V2); ++ } + + fpu__init_system(c); + +-- +2.7.4 + |