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[PATCH 4.4.y 059/101] x86/bugs: Expose /sys/../spec_store_bypass

by Srivatsa S. Bhat

From: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> commit c456442cd3a59eeb1d60293c26cbe2ff2c4e42cf upstream Add the sysfs file for the new vulerability. It does not do much except show the words 'Vulnerable' for recent x86 cores. Intel cores prior to family 6 are known not to be vulnerable, and so are some Atoms and some Xeon Phi. It assumes that older Cyrix, Centaur, etc. cores are immune. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: Borislav Petkov <bp(a)suse.de> Reviewed-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Srivatsa S. Bhat <srivatsa(a)csail.mit.edu> Reviewed-by: Matt Helsley (VMware) <matt.helsley(a)gmail.com> Reviewed-by: Alexey Makhalov <amakhalov(a)vmware.com> Reviewed-by: Bo Gan <ganb(a)vmware.com> --- Documentation/ABI/testing/sysfs-devices-system-cpu | 1 + arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/kernel/cpu/bugs.c | 5 ++++ arch/x86/kernel/cpu/common.c | 23 ++++++++++++++++++++ drivers/base/cpu.c | 8 +++++++ include/linux/cpu.h | 2 ++ 6 files changed, 40 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index ea6a043..50f9568 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -276,6 +276,7 @@ What: /sys/devices/system/cpu/vulnerabilities /sys/devices/system/cpu/vulnerabilities/meltdown /sys/devices/system/cpu/vulnerabilities/spectre_v1 /sys/devices/system/cpu/vulnerabilities/spectre_v2 + /sys/devices/system/cpu/vulnerabilities/spec_store_bypass Date: January 2018 Contact: Linux kernel mailing list <linux-kernel(a)vger.kernel.org> Description: Information about CPU vulnerabilities diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index bc76bf3..08cf4f7 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -315,5 +315,6 @@ #define X86_BUG_CPU_MELTDOWN X86_BUG(14) /* CPU is affected by meltdown attack and needs kernel page table isolation */ #define X86_BUG_SPECTRE_V1 X86_BUG(15) /* CPU is affected by Spectre variant 1 attack with conditional branches */ #define X86_BUG_SPECTRE_V2 X86_BUG(16) /* CPU is affected by Spectre variant 2 attack with indirect branches */ +#define X86_BUG_SPEC_STORE_BYPASS X86_BUG(17) /* CPU is affected by speculative store bypass attack */ #endif /* _ASM_X86_CPUFEATURES_H */ diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index e71e281..0ad13b1 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -403,4 +403,9 @@ ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, c { return cpu_show_common(dev, attr, buf, X86_BUG_SPECTRE_V2); } + +ssize_t cpu_show_spec_store_bypass(struct device *dev, struct device_attribute *attr, char *buf) +{ + return cpu_show_common(dev, attr, buf, X86_BUG_SPEC_STORE_BYPASS); +} #endif diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 97558d1..eb78ddf 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -835,10 +835,33 @@ static const __initconst struct x86_cpu_id cpu_no_meltdown[] = { {} }; +static const __initconst struct x86_cpu_id cpu_no_spec_store_bypass[] = { + { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_PINEVIEW }, + { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_LINCROFT }, + { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_PENWELL }, + { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CLOVERVIEW }, + { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CEDARVIEW }, + { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT1 }, + { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_AIRMONT }, + { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT2 }, + { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_MERRIFIELD }, + { X86_VENDOR_INTEL, 6, INTEL_FAM6_CORE_YONAH }, + { X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNL }, + { X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNM }, + { X86_VENDOR_CENTAUR, 5, }, + { X86_VENDOR_INTEL, 5, }, + { X86_VENDOR_NSC, 5, }, + { X86_VENDOR_ANY, 4, }, + {} +}; + static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) { u64 ia32_cap = 0; + if (!x86_match_cpu(cpu_no_spec_store_bypass)) + setup_force_cpu_bug(X86_BUG_SPEC_STORE_BYPASS); + if (x86_match_cpu(cpu_no_speculation)) return; diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 3db71af..143edea 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -518,14 +518,22 @@ ssize_t __weak cpu_show_spectre_v2(struct device *dev, return sprintf(buf, "Not affected\n"); } +ssize_t __weak cpu_show_spec_store_bypass(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "Not affected\n"); +} + static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL); static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL); static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL); +static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL); static struct attribute *cpu_root_vulnerabilities_attrs[] = { &dev_attr_meltdown.attr, &dev_attr_spectre_v1.attr, &dev_attr_spectre_v2.attr, + &dev_attr_spec_store_bypass.attr, NULL }; diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 7e04bcd..2f9d120 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -46,6 +46,8 @@ extern ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf); extern ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf); +extern ssize_t cpu_show_spec_store_bypass(struct device *dev, + struct device_attribute *attr, char *buf); extern __printf(4, 5) struct device *cpu_device_create(struct device *parent, void *drvdata,

7 years, 3 months

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[PATCH 4.4.y 058/101] x86/cpu/intel: Add Knights Mill to Intel family

by Srivatsa S. Bhat

From: Piotr Luc <piotr.luc(a)intel.com> commit 0047f59834e5947d45f34f5f12eb330d158f700b upstream Add CPUID of Knights Mill (KNM) processor to Intel family list. Signed-off-by: Piotr Luc <piotr.luc(a)intel.com> Reviewed-by: Dave Hansen <dave.hansen(a)intel.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Brian Gerst <brgerst(a)gmail.com> Cc: Denys Vlasenko <dvlasenk(a)redhat.com> Cc: H. Peter Anvin <hpa(a)zytor.com> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Link: http://lkml.kernel.org/r/20161012180520.30976-1-piotr.luc@intel.com Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Srivatsa S. Bhat <srivatsa(a)csail.mit.edu> Reviewed-by: Matt Helsley (VMware) <matt.helsley(a)gmail.com> Reviewed-by: Alexey Makhalov <amakhalov(a)vmware.com> Reviewed-by: Bo Gan <ganb(a)vmware.com> --- arch/x86/include/asm/intel-family.h | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/include/asm/intel-family.h b/arch/x86/include/asm/intel-family.h index 0b27c1e..e13ff5a 100644 --- a/arch/x86/include/asm/intel-family.h +++ b/arch/x86/include/asm/intel-family.h @@ -67,5 +67,6 @@ /* Xeon Phi */ #define INTEL_FAM6_XEON_PHI_KNL 0x57 /* Knights Landing */ +#define INTEL_FAM6_XEON_PHI_KNM 0x85 /* Knights Mill */ #endif /* _ASM_X86_INTEL_FAMILY_H */

7 years, 3 months

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[PATCH 4.4.y 057/101] x86/cpu: Rename Merrifield2 to Moorefield

by Srivatsa S. Bhat

From: Andy Shevchenko <andriy.shevchenko(a)linux.intel.com> commit f5fbf848303c8704d0e1a1e7cabd08fd0a49552f upstream Merrifield2 is actually Moorefield. Rename it accordingly and drop tail digit from Merrifield1. Signed-off-by: Andy Shevchenko <andriy.shevchenko(a)linux.intel.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Link: http://lkml.kernel.org/r/20160906184254.94440-1-andriy.shevchenko@linux.int… Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Srivatsa S. Bhat <srivatsa(a)csail.mit.edu> Reviewed-by: Matt Helsley (VMware) <matt.helsley(a)gmail.com> Reviewed-by: Alexey Makhalov <amakhalov(a)vmware.com> Reviewed-by: Bo Gan <ganb(a)vmware.com> --- arch/x86/include/asm/intel-family.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/intel-family.h b/arch/x86/include/asm/intel-family.h index 12fa187..0b27c1e 100644 --- a/arch/x86/include/asm/intel-family.h +++ b/arch/x86/include/asm/intel-family.h @@ -58,8 +58,8 @@ #define INTEL_FAM6_ATOM_SILVERMONT1 0x37 /* BayTrail/BYT / Valleyview */ #define INTEL_FAM6_ATOM_SILVERMONT2 0x4D /* Avaton/Rangely */ #define INTEL_FAM6_ATOM_AIRMONT 0x4C /* CherryTrail / Braswell */ -#define INTEL_FAM6_ATOM_MERRIFIELD1 0x4A /* Tangier */ -#define INTEL_FAM6_ATOM_MERRIFIELD2 0x5A /* Annidale */ +#define INTEL_FAM6_ATOM_MERRIFIELD 0x4A /* Tangier */ +#define INTEL_FAM6_ATOM_MOOREFIELD 0x5A /* Annidale */ #define INTEL_FAM6_ATOM_GOLDMONT 0x5C #define INTEL_FAM6_ATOM_DENVERTON 0x5F /* Goldmont Microserver */ #define INTEL_FAM6_ATOM_GEMINI_LAKE 0x7A

7 years, 3 months

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[PATCH 4.4.y 056/101] x86/bugs, KVM: Support the combination of guest and host IBRS

by Srivatsa S. Bhat

From: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> commit 5cf687548705412da47c9cec342fd952d71ed3d5 upstream A guest may modify the SPEC_CTRL MSR from the value used by the kernel. Since the kernel doesn't use IBRS, this means a value of zero is what is needed in the host. But the 336996-Speculative-Execution-Side-Channel-Mitigations.pdf refers to the other bits as reserved so the kernel should respect the boot time SPEC_CTRL value and use that. This allows to deal with future extensions to the SPEC_CTRL interface if any at all. Note: This uses wrmsrl() instead of native_wrmsl(). I does not make any difference as paravirt will over-write the callq *0xfff.. with the wrmsrl assembler code. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: Borislav Petkov <bp(a)suse.de> Reviewed-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> [ Srivatsa: Backported to 4.4.y, skipping the KVM changes in this patch. ] Signed-off-by: Srivatsa S. Bhat <srivatsa(a)csail.mit.edu> Reviewed-by: Matt Helsley (VMware) <matt.helsley(a)gmail.com> Reviewed-by: Alexey Makhalov <amakhalov(a)vmware.com> Reviewed-by: Bo Gan <ganb(a)vmware.com> --- arch/x86/include/asm/nospec-branch.h | 10 ++++++++++ arch/x86/kernel/cpu/bugs.c | 18 ++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index daec318..11db69a 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -183,6 +183,16 @@ enum spectre_v2_mitigation { extern void x86_spec_ctrl_set(u64); extern u64 x86_spec_ctrl_get_default(void); +/* + * On VMENTER we must preserve whatever view of the SPEC_CTRL MSR + * the guest has, while on VMEXIT we restore the host view. This + * would be easier if SPEC_CTRL were architecturally maskable or + * shadowable for guests but this is not (currently) the case. + * Takes the guest view of SPEC_CTRL MSR as a parameter. + */ +extern void x86_spec_ctrl_set_guest(u64); +extern void x86_spec_ctrl_restore_host(u64); + extern char __indirect_thunk_start[]; extern char __indirect_thunk_end[]; diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 42c2204..e71e281 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -122,6 +122,24 @@ u64 x86_spec_ctrl_get_default(void) } EXPORT_SYMBOL_GPL(x86_spec_ctrl_get_default); +void x86_spec_ctrl_set_guest(u64 guest_spec_ctrl) +{ + if (!boot_cpu_has(X86_FEATURE_IBRS)) + return; + if (x86_spec_ctrl_base != guest_spec_ctrl) + wrmsrl(MSR_IA32_SPEC_CTRL, guest_spec_ctrl); +} +EXPORT_SYMBOL_GPL(x86_spec_ctrl_set_guest); + +void x86_spec_ctrl_restore_host(u64 guest_spec_ctrl) +{ + if (!boot_cpu_has(X86_FEATURE_IBRS)) + return; + if (x86_spec_ctrl_base != guest_spec_ctrl) + wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base); +} +EXPORT_SYMBOL_GPL(x86_spec_ctrl_restore_host); + #ifdef RETPOLINE static bool spectre_v2_bad_module;

7 years, 3 months

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[PATCH 4.4.y 055/101] x86/bugs: Read SPEC_CTRL MSR during boot and re-use reserved bits

by Srivatsa S. Bhat

From: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> commit 1b86883ccb8d5d9506529d42dbe1a5257cb30b18 upstream The 336996-Speculative-Execution-Side-Channel-Mitigations.pdf refers to all the other bits as reserved. The Intel SDM glossary defines reserved as implementation specific - aka unknown. As such at bootup this must be taken it into account and proper masking for the bits in use applied. A copy of this document is available at https://bugzilla.kernel.org/show_bug.cgi?id=199511 [ tglx: Made x86_spec_ctrl_base __ro_after_init ] [ Srivatsa: Removed __ro_after_init for 4.4.y ] Suggested-by: Jon Masters <jcm(a)redhat.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: Borislav Petkov <bp(a)suse.de> Reviewed-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Srivatsa S. Bhat <srivatsa(a)csail.mit.edu> Reviewed-by: Matt Helsley (VMware) <matt.helsley(a)gmail.com> Reviewed-by: Alexey Makhalov <amakhalov(a)vmware.com> Reviewed-by: Bo Gan <ganb(a)vmware.com> --- arch/x86/include/asm/nospec-branch.h | 24 ++++++++++++++++++++---- arch/x86/kernel/cpu/bugs.c | 27 +++++++++++++++++++++++++++ 2 files changed, 47 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 6403016..daec318 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -172,6 +172,17 @@ enum spectre_v2_mitigation { SPECTRE_V2_IBRS, }; +/* + * The Intel specification for the SPEC_CTRL MSR requires that we + * preserve any already set reserved bits at boot time (e.g. for + * future additions that this kernel is not currently aware of). + * We then set any additional mitigation bits that we want + * ourselves and always use this as the base for SPEC_CTRL. + * We also use this when handling guest entry/exit as below. + */ +extern void x86_spec_ctrl_set(u64); +extern u64 x86_spec_ctrl_get_default(void); + extern char __indirect_thunk_start[]; extern char __indirect_thunk_end[]; @@ -208,8 +219,9 @@ void alternative_msr_write(unsigned int msr, u64 val, unsigned int feature) static inline void indirect_branch_prediction_barrier(void) { - alternative_msr_write(MSR_IA32_PRED_CMD, PRED_CMD_IBPB, - X86_FEATURE_USE_IBPB); + u64 val = PRED_CMD_IBPB; + + alternative_msr_write(MSR_IA32_PRED_CMD, val, X86_FEATURE_USE_IBPB); } /* @@ -220,14 +232,18 @@ static inline void indirect_branch_prediction_barrier(void) */ #define firmware_restrict_branch_speculation_start() \ do { \ + u64 val = x86_spec_ctrl_get_default() | SPEC_CTRL_IBRS; \ + \ preempt_disable(); \ - alternative_msr_write(MSR_IA32_SPEC_CTRL, SPEC_CTRL_IBRS, \ + alternative_msr_write(MSR_IA32_SPEC_CTRL, val, \ X86_FEATURE_USE_IBRS_FW); \ } while (0) #define firmware_restrict_branch_speculation_end() \ do { \ - alternative_msr_write(MSR_IA32_SPEC_CTRL, 0, \ + u64 val = x86_spec_ctrl_get_default(); \ + \ + alternative_msr_write(MSR_IA32_SPEC_CTRL, val, \ X86_FEATURE_USE_IBRS_FW); \ preempt_enable(); \ } while (0) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 75f3d49..42c2204 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -27,6 +27,12 @@ static void __init spectre_v2_select_mitigation(void); +/* + * Our boot-time value of the SPEC_CTRL MSR. We read it once so that any + * writes to SPEC_CTRL contain whatever reserved bits have been set. + */ +static u64 x86_spec_ctrl_base; + void __init check_bugs(void) { identify_boot_cpu(); @@ -36,6 +42,13 @@ void __init check_bugs(void) print_cpu_info(&boot_cpu_data); } + /* + * Read the SPEC_CTRL MSR to account for reserved bits which may + * have unknown values. + */ + if (boot_cpu_has(X86_FEATURE_IBRS)) + rdmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base); + /* Select the proper spectre mitigation before patching alternatives */ spectre_v2_select_mitigation(); @@ -94,6 +107,20 @@ static const char *spectre_v2_strings[] = { static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE; +void x86_spec_ctrl_set(u64 val) +{ + if (val & ~SPEC_CTRL_IBRS) + WARN_ONCE(1, "SPEC_CTRL MSR value 0x%16llx is unknown.\n", val); + else + wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base | val); +} +EXPORT_SYMBOL_GPL(x86_spec_ctrl_set); + +u64 x86_spec_ctrl_get_default(void) +{ + return x86_spec_ctrl_base; +} +EXPORT_SYMBOL_GPL(x86_spec_ctrl_get_default); #ifdef RETPOLINE static bool spectre_v2_bad_module;

7 years, 3 months

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[PATCH 4.4.y 054/101] x86/bugs: Concentrate bug reporting into a separate function

by Srivatsa S. Bhat

From: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> commit d1059518b4789cabe34bb4b714d07e6089c82ca1 upstream Those SysFS functions have a similar preamble, as such make common code to handle them. Suggested-by: Borislav Petkov <bp(a)suse.de> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: Borislav Petkov <bp(a)suse.de> Reviewed-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Srivatsa S. Bhat <srivatsa(a)csail.mit.edu> Reviewed-by: Matt Helsley (VMware) <matt.helsley(a)gmail.com> Reviewed-by: Alexey Makhalov <amakhalov(a)vmware.com> Reviewed-by: Bo Gan <ganb(a)vmware.com> --- arch/x86/kernel/cpu/bugs.c | 46 +++++++++++++++++++++++++++++++------------- 1 file changed, 32 insertions(+), 14 deletions(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index b294fdc..75f3d49 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -314,30 +314,48 @@ retpoline_auto: #undef pr_fmt #ifdef CONFIG_SYSFS -ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf) + +ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr, + char *buf, unsigned int bug) { - if (!boot_cpu_has_bug(X86_BUG_CPU_MELTDOWN)) + if (!boot_cpu_has_bug(bug)) return sprintf(buf, "Not affected\n"); - if (boot_cpu_has(X86_FEATURE_KAISER)) - return sprintf(buf, "Mitigation: PTI\n"); + + switch (bug) { + case X86_BUG_CPU_MELTDOWN: + if (boot_cpu_has(X86_FEATURE_KAISER)) + return sprintf(buf, "Mitigation: PTI\n"); + + break; + + case X86_BUG_SPECTRE_V1: + return sprintf(buf, "Mitigation: __user pointer sanitization\n"); + + case X86_BUG_SPECTRE_V2: + return sprintf(buf, "%s%s%s%s\n", spectre_v2_strings[spectre_v2_enabled], + boot_cpu_has(X86_FEATURE_USE_IBPB) ? ", IBPB" : "", + boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "", + spectre_v2_module_string()); + + default: + break; + } + return sprintf(buf, "Vulnerable\n"); } +ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf) +{ + return cpu_show_common(dev, attr, buf, X86_BUG_CPU_MELTDOWN); +} + ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf) { - if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V1)) - return sprintf(buf, "Not affected\n"); - return sprintf(buf, "Mitigation: __user pointer sanitization\n"); + return cpu_show_common(dev, attr, buf, X86_BUG_SPECTRE_V1); } ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf) { - if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2)) - return sprintf(buf, "Not affected\n"); - - return sprintf(buf, "%s%s%s%s\n", spectre_v2_strings[spectre_v2_enabled], - boot_cpu_has(X86_FEATURE_USE_IBPB) ? ", IBPB" : "", - boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "", - spectre_v2_module_string()); + return cpu_show_common(dev, attr, buf, X86_BUG_SPECTRE_V2); } #endif

7 years, 3 months

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[PATCH 4.4.y 053/101] x86/bugs: Concentrate bug detection into a separate function

by Srivatsa S. Bhat

From: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> commit 4a28bfe3267b68e22c663ac26185aa16c9b879ef upstream Combine the various logic which goes through all those x86_cpu_id matching structures in one function. Suggested-by: Borislav Petkov <bp(a)suse.de> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: Borislav Petkov <bp(a)suse.de> Reviewed-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Srivatsa S. Bhat <srivatsa(a)csail.mit.edu> Reviewed-by: Matt Helsley (VMware) <matt.helsley(a)gmail.com> Reviewed-by: Alexey Makhalov <amakhalov(a)vmware.com> Reviewed-by: Bo Gan <ganb(a)vmware.com> --- arch/x86/kernel/cpu/common.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 48499b4..97558d1 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -835,21 +835,27 @@ static const __initconst struct x86_cpu_id cpu_no_meltdown[] = { {} }; -static bool __init cpu_vulnerable_to_meltdown(struct cpuinfo_x86 *c) +static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) { u64 ia32_cap = 0; + if (x86_match_cpu(cpu_no_speculation)) + return; + + setup_force_cpu_bug(X86_BUG_SPECTRE_V1); + setup_force_cpu_bug(X86_BUG_SPECTRE_V2); + if (x86_match_cpu(cpu_no_meltdown)) - return false; + return; 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; - return true; + setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN); } /* @@ -898,12 +904,7 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) setup_force_cpu_cap(X86_FEATURE_ALWAYS); - 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); - } + cpu_set_bug_bits(c); fpu__init_system(c);

7 years, 3 months

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[PATCH 4.4.y 052/101] x86/nospec: Simplify alternative_msr_write()

by Srivatsa S. Bhat

From: Linus Torvalds <torvalds(a)linux-foundation.org> commit 1aa7a5735a41418d8e01fa7c9565eb2657e2ea3f upstream The macro is not type safe and I did look for why that "g" constraint for the asm doesn't work: it's because the asm is more fundamentally wrong. It does movl %[val], %%eax but "val" isn't a 32-bit value, so then gcc will pass it in a register, and generate code like movl %rsi, %eax and gas will complain about a nonsensical 'mov' instruction (it's moving a 64-bit register to a 32-bit one). Passing it through memory will just hide the real bug - gcc still thinks the memory location is 64-bit, but the "movl" will only load the first 32 bits and it all happens to work because x86 is little-endian. Convert it to a type safe inline function with a little trick which hands the feature into the ALTERNATIVE macro. Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Srivatsa S. Bhat <srivatsa(a)csail.mit.edu> Reviewed-by: Matt Helsley (VMware) <matt.helsley(a)gmail.com> Reviewed-by: Alexey Makhalov <amakhalov(a)vmware.com> Reviewed-by: Bo Gan <ganb(a)vmware.com> --- arch/x86/include/asm/nospec-branch.h | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index b9dd1d9..6403016 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -195,15 +195,16 @@ static inline void vmexit_fill_RSB(void) #endif } -#define alternative_msr_write(_msr, _val, _feature) \ - asm volatile(ALTERNATIVE("", \ - "movl %[msr], %%ecx\n\t" \ - "movl %[val], %%eax\n\t" \ - "movl $0, %%edx\n\t" \ - "wrmsr", \ - _feature) \ - : : [msr] "i" (_msr), [val] "i" (_val) \ - : "eax", "ecx", "edx", "memory") +static __always_inline +void alternative_msr_write(unsigned int msr, u64 val, unsigned int feature) +{ + asm volatile(ALTERNATIVE("", "wrmsr", %c[feature]) + : : "c" (msr), + "a" (val), + "d" (val >> 32), + [feature] "i" (feature) + : "memory"); +} static inline void indirect_branch_prediction_barrier(void) {

7 years, 3 months

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[PATCH 4.4.y 050/101] xen: set cpu capabilities from xen_start_kernel()

by Srivatsa S. Bhat

From: Juergen Gross <jgross(a)suse.com> Upstream commit: 0808e80cb760de2733c0527d2090ed2205a1eef8 ("xen: set cpu capabilities from xen_start_kernel()") There is no need to set the same capabilities for each cpu individually. This can easily be done for all cpus when starting the kernel. Signed-off-by: Juergen Gross <jgross(a)suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky(a)oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Srivatsa S. Bhat <srivatsa(a)csail.mit.edu> Reviewed-by: Matt Helsley (VMware) <matt.helsley(a)gmail.com> Reviewed-by: Alexey Makhalov <amakhalov(a)vmware.com> Reviewed-by: Bo Gan <ganb(a)vmware.com> --- arch/x86/xen/enlighten.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index cbef64b..2d7ab4e 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -460,6 +460,14 @@ static void __init xen_init_cpuid_mask(void) cpuid_leaf1_ecx_set_mask = (1 << (X86_FEATURE_MWAIT % 32)); } +static void __init xen_init_capabilities(void) +{ + if (xen_pv_domain()) { + setup_clear_cpu_cap(X86_BUG_SYSRET_SS_ATTRS); + setup_force_cpu_cap(X86_FEATURE_XENPV); + } +} + static void xen_set_debugreg(int reg, unsigned long val) { HYPERVISOR_set_debugreg(reg, val); @@ -1587,6 +1595,7 @@ asmlinkage __visible void __init xen_start_kernel(void) xen_init_irq_ops(); xen_init_cpuid_mask(); + xen_init_capabilities(); #ifdef CONFIG_X86_LOCAL_APIC /* @@ -1883,14 +1892,6 @@ bool xen_hvm_need_lapic(void) } EXPORT_SYMBOL_GPL(xen_hvm_need_lapic); -static void xen_set_cpu_features(struct cpuinfo_x86 *c) -{ - if (xen_pv_domain()) { - clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS); - set_cpu_cap(c, X86_FEATURE_XENPV); - } -} - const struct hypervisor_x86 x86_hyper_xen = { .name = "Xen", .detect = xen_platform, @@ -1898,7 +1899,6 @@ const struct hypervisor_x86 x86_hyper_xen = { .init_platform = xen_hvm_guest_init, #endif .x2apic_available = xen_x2apic_para_available, - .set_cpu_features = xen_set_cpu_features, }; EXPORT_SYMBOL(x86_hyper_xen);

7 years, 3 months

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[PATCH 4.4.y 049/101] selftest/seccomp: Fix the seccomp(2) signature

by Srivatsa S. Bhat

From: Mickaël Salaün <mic(a)digikod.net> commit 505ce68c6da3432454c62e43c24a22ea5b1d754b upstream Signed-off-by: Mickaël Salaün <mic(a)digikod.net> Cc: Andy Lutomirski <luto(a)amacapital.net> Cc: Kees Cook <keescook(a)chromium.org> Cc: Shuah Khan <shuahkh(a)osg.samsung.com> Cc: Will Drewry <wad(a)chromium.org> Acked-by: Kees Cook <keescook(a)chromium.org> Signed-off-by: Shuah Khan <shuahkh(a)osg.samsung.com> Signed-off-by: Srivatsa S. Bhat <srivatsa(a)csail.mit.edu> Reviewed-by: Matt Helsley (VMware) <matt.helsley(a)gmail.com> Reviewed-by: Alexey Makhalov <amakhalov(a)vmware.com> Reviewed-by: Bo Gan <ganb(a)vmware.com> --- tools/testing/selftests/seccomp/seccomp_bpf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index d446346..29487e0 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -1481,10 +1481,10 @@ TEST_F(TRACE_syscall, syscall_dropped) #endif #ifndef seccomp -int seccomp(unsigned int op, unsigned int flags, struct sock_fprog *filter) +int seccomp(unsigned int op, unsigned int flags, void *args) { errno = 0; - return syscall(__NR_seccomp, op, flags, filter); + return syscall(__NR_seccomp, op, flags, args); } #endif

7 years, 3 months

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