February 2018 - Linux-stable-mirror

[Linux-stable-mirror] Patch "x86/cpufeature: Blacklist SPEC_CTRL/PRED_CMD on early Spectre v2 microcodes" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/cpufeature: Blacklist SPEC_CTRL/PRED_CMD on early Spectre v2 microcodes to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86cpufeature_Blacklist_SPEC_CTRLPRED_CMD_on_early_Spectre_v2_microcodes.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. Subject: x86/cpufeature: Blacklist SPEC_CTRL/PRED_CMD on early Spectre v2 microcodes From: David Woodhouse dwmw(a)amazon.co.uk Date: Thu Jan 25 16:14:14 2018 +0000 From: David Woodhouse dwmw(a)amazon.co.uk commit a5b2966364538a0e68c9fa29bc0a3a1651799035 This doesn't refuse to load the affected microcodes; it just refuses to use the Spectre v2 mitigation features if they're detected, by clearing the appropriate feature bits. The AMD CPUID bits are handled here too, because hypervisors *may* have been exposing those bits even on Intel chips, for fine-grained control of what's available. It is non-trivial to use x86_match_cpu() for this table because that doesn't handle steppings. And the approach taken in commit bd9240a18 almost made me lose my lunch. Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: gnomes(a)lxorguk.ukuu.org.uk Cc: ak(a)linux.intel.com Cc: ashok.raj(a)intel.com Cc: dave.hansen(a)intel.com Cc: karahmed(a)amazon.de Cc: arjan(a)linux.intel.com Cc: torvalds(a)linux-foundation.org Cc: peterz(a)infradead.org Cc: bp(a)alien8.de Cc: pbonzini(a)redhat.com Cc: tim.c.chen(a)linux.intel.com Cc: gregkh(a)linux-foundation.org Link: https://lkml.kernel.org/r/1516896855-7642-7-git-send-email-dwmw@amazon.co.uk Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/cpu/intel.c | 66 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -102,6 +102,59 @@ static void probe_xeon_phi_r3mwait(struc ELF_HWCAP2 |= HWCAP2_RING3MWAIT; } +/* + * Early microcode releases for the Spectre v2 mitigation were broken. + * Information taken from; + * - https://newsroom.intel.com/wp-content/uploads/sites/11/2018/01/microcode-up… + * - https://kb.vmware.com/s/article/52345 + * - Microcode revisions observed in the wild + * - Release note from 20180108 microcode release + */ +struct sku_microcode { + u8 model; + u8 stepping; + u32 microcode; +}; +static const struct sku_microcode spectre_bad_microcodes[] = { + { INTEL_FAM6_KABYLAKE_DESKTOP, 0x0B, 0x84 }, + { INTEL_FAM6_KABYLAKE_DESKTOP, 0x0A, 0x84 }, + { INTEL_FAM6_KABYLAKE_DESKTOP, 0x09, 0x84 }, + { INTEL_FAM6_KABYLAKE_MOBILE, 0x0A, 0x84 }, + { INTEL_FAM6_KABYLAKE_MOBILE, 0x09, 0x84 }, + { INTEL_FAM6_SKYLAKE_X, 0x03, 0x0100013e }, + { INTEL_FAM6_SKYLAKE_X, 0x04, 0x0200003c }, + { INTEL_FAM6_SKYLAKE_MOBILE, 0x03, 0xc2 }, + { INTEL_FAM6_SKYLAKE_DESKTOP, 0x03, 0xc2 }, + { INTEL_FAM6_BROADWELL_CORE, 0x04, 0x28 }, + { INTEL_FAM6_BROADWELL_GT3E, 0x01, 0x1b }, + { INTEL_FAM6_BROADWELL_XEON_D, 0x02, 0x14 }, + { INTEL_FAM6_BROADWELL_XEON_D, 0x03, 0x07000011 }, + { INTEL_FAM6_BROADWELL_X, 0x01, 0x0b000025 }, + { INTEL_FAM6_HASWELL_ULT, 0x01, 0x21 }, + { INTEL_FAM6_HASWELL_GT3E, 0x01, 0x18 }, + { INTEL_FAM6_HASWELL_CORE, 0x03, 0x23 }, + { INTEL_FAM6_HASWELL_X, 0x02, 0x3b }, + { INTEL_FAM6_HASWELL_X, 0x04, 0x10 }, + { INTEL_FAM6_IVYBRIDGE_X, 0x04, 0x42a }, + /* Updated in the 20180108 release; blacklist until we know otherwise */ + { INTEL_FAM6_ATOM_GEMINI_LAKE, 0x01, 0x22 }, + /* Observed in the wild */ + { INTEL_FAM6_SANDYBRIDGE_X, 0x06, 0x61b }, + { INTEL_FAM6_SANDYBRIDGE_X, 0x07, 0x712 }, +}; + +static bool bad_spectre_microcode(struct cpuinfo_x86 *c) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(spectre_bad_microcodes); i++) { + if (c->x86_model == spectre_bad_microcodes[i].model && + c->x86_mask == spectre_bad_microcodes[i].stepping) + return (c->microcode <= spectre_bad_microcodes[i].microcode); + } + return false; +} + static void early_init_intel(struct cpuinfo_x86 *c) { u64 misc_enable; @@ -122,6 +175,19 @@ static void early_init_intel(struct cpui if (c->x86 >= 6 && !cpu_has(c, X86_FEATURE_IA64)) c->microcode = intel_get_microcode_revision(); + if ((cpu_has(c, X86_FEATURE_SPEC_CTRL) || + cpu_has(c, X86_FEATURE_STIBP) || + cpu_has(c, X86_FEATURE_AMD_SPEC_CTRL) || + cpu_has(c, X86_FEATURE_AMD_PRED_CMD) || + cpu_has(c, X86_FEATURE_AMD_STIBP)) && bad_spectre_microcode(c)) { + pr_warn("Intel Spectre v2 broken microcode detected; disabling SPEC_CTRL\n"); + clear_cpu_cap(c, X86_FEATURE_SPEC_CTRL); + clear_cpu_cap(c, X86_FEATURE_STIBP); + clear_cpu_cap(c, X86_FEATURE_AMD_SPEC_CTRL); + clear_cpu_cap(c, X86_FEATURE_AMD_PRED_CMD); + clear_cpu_cap(c, X86_FEATURE_AMD_STIBP); + } + /* * Atom erratum AAE44/AAF40/AAG38/AAH41: * Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are queue-4.15/x86pti_Do_not_enable_PTI_on_CPUs_which_are_not_vulnerable_to_Meltdown.patch queue-4.15/x86cpufeature_Blacklist_SPEC_CTRLPRED_CMD_on_early_Spectre_v2_microcodes.patch queue-4.15/x86cpufeatures_Add_Intel_feature_bits_for_Speculation_Control.patch queue-4.15/KVM_VMX_Make_indirect_call_speculation_safe.patch queue-4.15/x86msr_Add_definitions_for_new_speculation_control_MSRs.patch queue-4.15/x86cpufeatures_Add_CPUID_7_EDX_CPUID_leaf.patch queue-4.15/x86cpufeatures_Add_AMD_feature_bits_for_Speculation_Control.patch queue-4.15/x86speculation_Add_basic_IBPB_(Indirect_Branch_Prediction_Barrier)_support.patch queue-4.15/x86speculation_Simplify_indirect_branch_prediction_barrier().patch queue-4.15/KVM_x86_Make_indirect_calls_in_emulator_speculation_safe.patch queue-4.15/x86retpoline_Simplify_vmexit_fill_RSB().patch queue-4.15/x86cpufeatures_Clean_up_Spectre_v2_related_CPUID_flags.patch

6 years, 11 months

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[Linux-stable-mirror] Patch "x86/alternative: Print unadorned pointers" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/alternative: Print unadorned pointers to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86alternative_Print_unadorned_pointers.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. Subject: x86/alternative: Print unadorned pointers From: Borislav Petkov bp(a)suse.de Date: Fri Jan 26 13:11:36 2018 +0100 From: Borislav Petkov bp(a)suse.de commit 0e6c16c652cadaffd25a6bb326ec10da5bcec6b4 After commit ad67b74d2469 ("printk: hash addresses printed with %p") pointers are being hashed when printed. However, this makes the alternative debug output completely useless. Switch to %px in order to see the unadorned kernel pointers. Signed-off-by: Borislav Petkov <bp(a)suse.de> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: riel(a)redhat.com Cc: ak(a)linux.intel.com Cc: peterz(a)infradead.org Cc: David Woodhouse <dwmw2(a)infradead.org> Cc: jikos(a)kernel.org Cc: luto(a)amacapital.net Cc: dave.hansen(a)intel.com Cc: torvalds(a)linux-foundation.org Cc: keescook(a)google.com Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: tim.c.chen(a)linux.intel.com Cc: gregkh(a)linux-foundation.org Cc: pjt(a)google.com Link: https://lkml.kernel.org/r/20180126121139.31959-2-bp@alien8.de Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/alternative.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -298,7 +298,7 @@ recompute_jump(struct alt_instr *a, u8 * tgt_rip = next_rip + o_dspl; n_dspl = tgt_rip - orig_insn; - DPRINTK("target RIP: %p, new_displ: 0x%x", tgt_rip, n_dspl); + DPRINTK("target RIP: %px, new_displ: 0x%x", tgt_rip, n_dspl); if (tgt_rip - orig_insn >= 0) { if (n_dspl - 2 <= 127) @@ -355,7 +355,7 @@ static void __init_or_module noinline op add_nops(instr + (a->instrlen - a->padlen), a->padlen); local_irq_restore(flags); - DUMP_BYTES(instr, a->instrlen, "%p: [%d:%d) optimized NOPs: ", + DUMP_BYTES(instr, a->instrlen, "%px: [%d:%d) optimized NOPs: ", instr, a->instrlen - a->padlen, a->padlen); } @@ -376,7 +376,7 @@ void __init_or_module noinline apply_alt u8 *instr, *replacement; u8 insnbuf[MAX_PATCH_LEN]; - DPRINTK("alt table %p -> %p", start, end); + DPRINTK("alt table %px, -> %px", start, end); /* * The scan order should be from start to end. A later scanned * alternative code can overwrite previously scanned alternative code. @@ -400,14 +400,14 @@ void __init_or_module noinline apply_alt continue; } - DPRINTK("feat: %d*32+%d, old: (%p, len: %d), repl: (%p, len: %d), pad: %d", + DPRINTK("feat: %d*32+%d, old: (%px len: %d), repl: (%px, len: %d), pad: %d", a->cpuid >> 5, a->cpuid & 0x1f, instr, a->instrlen, replacement, a->replacementlen, a->padlen); - DUMP_BYTES(instr, a->instrlen, "%p: old_insn: ", instr); - DUMP_BYTES(replacement, a->replacementlen, "%p: rpl_insn: ", replacement); + DUMP_BYTES(instr, a->instrlen, "%px: old_insn: ", instr); + DUMP_BYTES(replacement, a->replacementlen, "%px: rpl_insn: ", replacement); memcpy(insnbuf, replacement, a->replacementlen); insnbuf_sz = a->replacementlen; @@ -433,7 +433,7 @@ void __init_or_module noinline apply_alt a->instrlen - a->replacementlen); insnbuf_sz += a->instrlen - a->replacementlen; } - DUMP_BYTES(insnbuf, insnbuf_sz, "%p: final_insn: ", instr); + DUMP_BYTES(insnbuf, insnbuf_sz, "%px: final_insn: ", instr); text_poke_early(instr, insnbuf, insnbuf_sz); } Patches currently in stable-queue which might be from bp(a)suse.de are queue-4.15/x86pti_Do_not_enable_PTI_on_CPUs_which_are_not_vulnerable_to_Meltdown.patch queue-4.15/x86cpufeatures_Add_Intel_feature_bits_for_Speculation_Control.patch queue-4.15/x86alternative_Print_unadorned_pointers.patch queue-4.15/x86cpufeatures_Add_CPUID_7_EDX_CPUID_leaf.patch queue-4.15/x86bugs_Drop_one_mitigation_from_dmesg.patch queue-4.15/x86speculation_Simplify_indirect_branch_prediction_barrier().patch queue-4.15/x86nospec_Fix_header_guards_names.patch queue-4.15/x86retpoline_Simplify_vmexit_fill_RSB().patch queue-4.15/x86cpufeatures_Clean_up_Spectre_v2_related_CPUID_flags.patch

6 years, 11 months

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[Linux-stable-mirror] Patch "x86/bugs: Drop one "mitigation" from dmesg" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/bugs: Drop one "mitigation" from dmesg to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86bugs_Drop_one_mitigation_from_dmesg.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. Subject: x86/bugs: Drop one "mitigation" from dmesg From: Borislav Petkov bp(a)suse.de Date: Fri Jan 26 13:11:39 2018 +0100 From: Borislav Petkov bp(a)suse.de commit 55fa19d3e51f33d9cd4056d25836d93abf9438db Make [ 0.031118] Spectre V2 mitigation: Mitigation: Full generic retpoline into [ 0.031118] Spectre V2: Mitigation: Full generic retpoline to reduce the mitigation mitigations strings. Signed-off-by: Borislav Petkov <bp(a)suse.de> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: riel(a)redhat.com Cc: ak(a)linux.intel.com Cc: peterz(a)infradead.org Cc: David Woodhouse <dwmw2(a)infradead.org> Cc: jikos(a)kernel.org Cc: luto(a)amacapital.net Cc: dave.hansen(a)intel.com Cc: torvalds(a)linux-foundation.org Cc: keescook(a)google.com Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: tim.c.chen(a)linux.intel.com Cc: pjt(a)google.com Link: https://lkml.kernel.org/r/20180126121139.31959-5-bp@alien8.de Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/cpu/bugs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -91,7 +91,7 @@ static const char *spectre_v2_strings[] }; #undef pr_fmt -#define pr_fmt(fmt) "Spectre V2 mitigation: " fmt +#define pr_fmt(fmt) "Spectre V2 : " fmt static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE; static bool spectre_v2_bad_module; Patches currently in stable-queue which might be from bp(a)suse.de are queue-4.15/x86pti_Do_not_enable_PTI_on_CPUs_which_are_not_vulnerable_to_Meltdown.patch queue-4.15/x86cpufeatures_Add_Intel_feature_bits_for_Speculation_Control.patch queue-4.15/x86alternative_Print_unadorned_pointers.patch queue-4.15/x86cpufeatures_Add_CPUID_7_EDX_CPUID_leaf.patch queue-4.15/x86bugs_Drop_one_mitigation_from_dmesg.patch queue-4.15/x86speculation_Simplify_indirect_branch_prediction_barrier().patch queue-4.15/x86nospec_Fix_header_guards_names.patch queue-4.15/x86retpoline_Simplify_vmexit_fill_RSB().patch queue-4.15/x86cpufeatures_Clean_up_Spectre_v2_related_CPUID_flags.patch

6 years, 11 months

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[Linux-stable-mirror] Patch "KVM: x86: Make indirect calls in emulator speculation safe" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled KVM: x86: Make indirect calls in emulator speculation safe to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: KVM_x86_Make_indirect_calls_in_emulator_speculation_safe.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. Subject: KVM: x86: Make indirect calls in emulator speculation safe From: Peter Zijlstra peterz(a)infradead.org Date: Thu Jan 25 10:58:13 2018 +0100 From: Peter Zijlstra peterz(a)infradead.org commit 1a29b5b7f347a1a9230c1e0af5b37e3e571588ab Replace the indirect calls with CALL_NOSPEC. Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: David Woodhouse <dwmw(a)amazon.co.uk> Cc: Andrea Arcangeli <aarcange(a)redhat.com> Cc: Andi Kleen <ak(a)linux.intel.com> Cc: Ashok Raj <ashok.raj(a)intel.com> Cc: Greg KH <gregkh(a)linuxfoundation.org> Cc: Jun Nakajima <jun.nakajima(a)intel.com> Cc: David Woodhouse <dwmw2(a)infradead.org> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: rga(a)amazon.de Cc: Dave Hansen <dave.hansen(a)intel.com> Cc: Asit Mallick <asit.k.mallick(a)intel.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Jason Baron <jbaron(a)akamai.com> Cc: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Dan Williams <dan.j.williams(a)intel.com> Cc: Arjan Van De Ven <arjan.van.de.ven(a)intel.com> Cc: Tim Chen <tim.c.chen(a)linux.intel.com> Link: https://lkml.kernel.org/r/20180125095843.595615683@infradead.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kvm/emulate.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -25,6 +25,7 @@ #include <asm/kvm_emulate.h> #include <linux/stringify.h> #include <asm/debugreg.h> +#include <asm/nospec-branch.h> #include "x86.h" #include "tss.h" @@ -1021,8 +1022,8 @@ static __always_inline u8 test_cc(unsign void (*fop)(void) = (void *)em_setcc + 4 * (condition & 0xf); flags = (flags & EFLAGS_MASK) | X86_EFLAGS_IF; - asm("push %[flags]; popf; call *%[fastop]" - : "=a"(rc) : [fastop]"r"(fop), [flags]"r"(flags)); + asm("push %[flags]; popf; " CALL_NOSPEC + : "=a"(rc) : [thunk_target]"r"(fop), [flags]"r"(flags)); return rc; } @@ -5335,9 +5336,9 @@ static int fastop(struct x86_emulate_ctx if (!(ctxt->d & ByteOp)) fop += __ffs(ctxt->dst.bytes) * FASTOP_SIZE; - asm("push %[flags]; popf; call *%[fastop]; pushf; pop %[flags]\n" + asm("push %[flags]; popf; " CALL_NOSPEC " ; pushf; pop %[flags]\n" : "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags), - [fastop]"+S"(fop), ASM_CALL_CONSTRAINT + [thunk_target]"+S"(fop), ASM_CALL_CONSTRAINT : "c"(ctxt->src2.val)); ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK); Patches currently in stable-queue which might be from peterz(a)infradead.org are queue-4.15/x86pti_Do_not_enable_PTI_on_CPUs_which_are_not_vulnerable_to_Meltdown.patch queue-4.15/x86cpufeature_Blacklist_SPEC_CTRLPRED_CMD_on_early_Spectre_v2_microcodes.patch queue-4.15/x86cpufeatures_Add_Intel_feature_bits_for_Speculation_Control.patch queue-4.15/KVM_VMX_Make_indirect_call_speculation_safe.patch queue-4.15/x86msr_Add_definitions_for_new_speculation_control_MSRs.patch queue-4.15/x86alternative_Print_unadorned_pointers.patch queue-4.15/x86cpufeatures_Add_CPUID_7_EDX_CPUID_leaf.patch queue-4.15/x86bugs_Drop_one_mitigation_from_dmesg.patch queue-4.15/x86cpufeatures_Add_AMD_feature_bits_for_Speculation_Control.patch queue-4.15/x86speculation_Add_basic_IBPB_(Indirect_Branch_Prediction_Barrier)_support.patch queue-4.15/x86speculation_Simplify_indirect_branch_prediction_barrier().patch queue-4.15/x86nospec_Fix_header_guards_names.patch queue-4.15/KVM_x86_Make_indirect_calls_in_emulator_speculation_safe.patch queue-4.15/x86retpoline_Simplify_vmexit_fill_RSB().patch queue-4.15/x86cpufeatures_Clean_up_Spectre_v2_related_CPUID_flags.patch

6 years, 11 months

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[Linux-stable-mirror] Patch "module/retpoline: Warn about missing retpoline in module" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled module/retpoline: Warn about missing retpoline in module to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: moduleretpoline_Warn_about_missing_retpoline_in_module.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. Subject: module/retpoline: Warn about missing retpoline in module From: Andi Kleen ak(a)linux.intel.com Date: Thu Jan 25 15:50:28 2018 -0800 From: Andi Kleen ak(a)linux.intel.com commit caf7501a1b4ec964190f31f9c3f163de252273b8 There's a risk that a kernel which has full retpoline mitigations becomes vulnerable when a module gets loaded that hasn't been compiled with the right compiler or the right option. To enable detection of that mismatch at module load time, add a module info string "retpoline" at build time when the module was compiled with retpoline support. This only covers compiled C source, but assembler source or prebuilt object files are not checked. If a retpoline enabled kernel detects a non retpoline protected module at load time, print a warning and report it in the sysfs vulnerability file. [ tglx: Massaged changelog ] Signed-off-by: Andi Kleen <ak(a)linux.intel.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: David Woodhouse <dwmw2(a)infradead.org> Cc: gregkh(a)linuxfoundation.org Cc: torvalds(a)linux-foundation.org Cc: jeyu(a)kernel.org Cc: arjan(a)linux.intel.com Link: https://lkml.kernel.org/r/20180125235028.31211-1-andi@firstfloor.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/cpu/bugs.c | 17 ++++++++++++++++- include/linux/module.h | 9 +++++++++ kernel/module.c | 11 +++++++++++ scripts/mod/modpost.c | 9 +++++++++ 4 files changed, 45 insertions(+), 1 deletion(-) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -11,6 +11,7 @@ #include <linux/init.h> #include <linux/utsname.h> #include <linux/cpu.h> +#include <linux/module.h> #include <asm/nospec-branch.h> #include <asm/cmdline.h> @@ -93,6 +94,19 @@ static const char *spectre_v2_strings[] #define pr_fmt(fmt) "Spectre V2 mitigation: " fmt static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE; +static bool spectre_v2_bad_module; + +#ifdef RETPOLINE +bool retpoline_module_ok(bool has_retpoline) +{ + if (spectre_v2_enabled == SPECTRE_V2_NONE || has_retpoline) + return true; + + pr_err("System may be vunerable to spectre v2\n"); + spectre_v2_bad_module = true; + return false; +} +#endif static void __init spec2_print_if_insecure(const char *reason) { @@ -278,6 +292,7 @@ ssize_t cpu_show_spectre_v2(struct devic if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2)) return sprintf(buf, "Not affected\n"); - return sprintf(buf, "%s\n", spectre_v2_strings[spectre_v2_enabled]); + return sprintf(buf, "%s%s\n", spectre_v2_strings[spectre_v2_enabled], + spectre_v2_bad_module ? " - vulnerable module loaded" : ""); } #endif --- a/include/linux/module.h +++ b/include/linux/module.h @@ -801,6 +801,15 @@ static inline void module_bug_finalize(c static inline void module_bug_cleanup(struct module *mod) {} #endif /* CONFIG_GENERIC_BUG */ +#ifdef RETPOLINE +extern bool retpoline_module_ok(bool has_retpoline); +#else +static inline bool retpoline_module_ok(bool has_retpoline) +{ + return true; +} +#endif + #ifdef CONFIG_MODULE_SIG static inline bool module_sig_ok(struct module *module) { --- a/kernel/module.c +++ b/kernel/module.c @@ -2863,6 +2863,15 @@ static int check_modinfo_livepatch(struc } #endif /* CONFIG_LIVEPATCH */ +static void check_modinfo_retpoline(struct module *mod, struct load_info *info) +{ + if (retpoline_module_ok(get_modinfo(info, "retpoline"))) + return; + + pr_warn("%s: loading module not compiled with retpoline compiler.\n", + mod->name); +} + /* Sets info->hdr and info->len. */ static int copy_module_from_user(const void __user *umod, unsigned long len, struct load_info *info) @@ -3029,6 +3038,8 @@ static int check_modinfo(struct module * add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK); } + check_modinfo_retpoline(mod, info); + if (get_modinfo(info, "staging")) { add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK); pr_warn("%s: module is from the staging directory, the quality " --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -2165,6 +2165,14 @@ static void add_intree_flag(struct buffe buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n"); } +/* Cannot check for assembler */ +static void add_retpoline(struct buffer *b) +{ + buf_printf(b, "\n#ifdef RETPOLINE\n"); + buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n"); + buf_printf(b, "#endif\n"); +} + static void add_staging_flag(struct buffer *b, const char *name) { static const char *staging_dir = "drivers/staging"; @@ -2506,6 +2514,7 @@ int main(int argc, char **argv) err |= check_modname_len(mod); add_header(&buf, mod); add_intree_flag(&buf, !external_module); + add_retpoline(&buf); add_staging_flag(&buf, mod->name); err |= add_versions(&buf, mod); add_depends(&buf, mod, modules); Patches currently in stable-queue which might be from ak(a)linux.intel.com are queue-4.15/x86pti_Do_not_enable_PTI_on_CPUs_which_are_not_vulnerable_to_Meltdown.patch queue-4.15/x86cpufeature_Blacklist_SPEC_CTRLPRED_CMD_on_early_Spectre_v2_microcodes.patch queue-4.15/x86cpufeatures_Add_Intel_feature_bits_for_Speculation_Control.patch queue-4.15/KVM_VMX_Make_indirect_call_speculation_safe.patch queue-4.15/x86msr_Add_definitions_for_new_speculation_control_MSRs.patch queue-4.15/x86alternative_Print_unadorned_pointers.patch queue-4.15/x86cpubugs_Make_retpoline_module_warning_conditional.patch queue-4.15/x86cpufeatures_Add_CPUID_7_EDX_CPUID_leaf.patch queue-4.15/x86bugs_Drop_one_mitigation_from_dmesg.patch queue-4.15/x86cpufeatures_Add_AMD_feature_bits_for_Speculation_Control.patch queue-4.15/moduleretpoline_Warn_about_missing_retpoline_in_module.patch queue-4.15/x86speculation_Add_basic_IBPB_(Indirect_Branch_Prediction_Barrier)_support.patch queue-4.15/x86speculation_Simplify_indirect_branch_prediction_barrier().patch queue-4.15/x86nospec_Fix_header_guards_names.patch queue-4.15/KVM_x86_Make_indirect_calls_in_emulator_speculation_safe.patch queue-4.15/x86retpoline_Simplify_vmexit_fill_RSB().patch queue-4.15/x86cpufeatures_Clean_up_Spectre_v2_related_CPUID_flags.patch

6 years, 11 months

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[Linux-stable-mirror] Patch "KVM: VMX: Make indirect call speculation safe" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled KVM: VMX: Make indirect call speculation safe to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: KVM_VMX_Make_indirect_call_speculation_safe.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. Subject: KVM: VMX: Make indirect call speculation safe From: Peter Zijlstra peterz(a)infradead.org Date: Thu Jan 25 10:58:14 2018 +0100 From: Peter Zijlstra peterz(a)infradead.org commit c940a3fb1e2e9b7d03228ab28f375fb5a47ff699 Replace indirect call with CALL_NOSPEC. Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: David Woodhouse <dwmw(a)amazon.co.uk> Cc: Andrea Arcangeli <aarcange(a)redhat.com> Cc: Andi Kleen <ak(a)linux.intel.com> Cc: Ashok Raj <ashok.raj(a)intel.com> Cc: Greg KH <gregkh(a)linuxfoundation.org> Cc: Jun Nakajima <jun.nakajima(a)intel.com> Cc: David Woodhouse <dwmw2(a)infradead.org> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: rga(a)amazon.de Cc: Dave Hansen <dave.hansen(a)intel.com> Cc: Asit Mallick <asit.k.mallick(a)intel.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Jason Baron <jbaron(a)akamai.com> Cc: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Dan Williams <dan.j.williams(a)intel.com> Cc: Arjan Van De Ven <arjan.van.de.ven(a)intel.com> Cc: Tim Chen <tim.c.chen(a)linux.intel.com> Link: https://lkml.kernel.org/r/20180125095843.645776917@infradead.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kvm/vmx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -9129,14 +9129,14 @@ static void vmx_handle_external_intr(str #endif "pushf\n\t" __ASM_SIZE(push) " $%c[cs]\n\t" - "call *%[entry]\n\t" + CALL_NOSPEC : #ifdef CONFIG_X86_64 [sp]"=&r"(tmp), #endif ASM_CALL_CONSTRAINT : - [entry]"r"(entry), + THUNK_TARGET(entry), [ss]"i"(__KERNEL_DS), [cs]"i"(__KERNEL_CS) ); Patches currently in stable-queue which might be from peterz(a)infradead.org are queue-4.15/x86pti_Do_not_enable_PTI_on_CPUs_which_are_not_vulnerable_to_Meltdown.patch queue-4.15/x86cpufeature_Blacklist_SPEC_CTRLPRED_CMD_on_early_Spectre_v2_microcodes.patch queue-4.15/x86cpufeatures_Add_Intel_feature_bits_for_Speculation_Control.patch queue-4.15/KVM_VMX_Make_indirect_call_speculation_safe.patch queue-4.15/x86msr_Add_definitions_for_new_speculation_control_MSRs.patch queue-4.15/x86alternative_Print_unadorned_pointers.patch queue-4.15/x86cpufeatures_Add_CPUID_7_EDX_CPUID_leaf.patch queue-4.15/x86bugs_Drop_one_mitigation_from_dmesg.patch queue-4.15/x86cpufeatures_Add_AMD_feature_bits_for_Speculation_Control.patch queue-4.15/x86speculation_Add_basic_IBPB_(Indirect_Branch_Prediction_Barrier)_support.patch queue-4.15/x86speculation_Simplify_indirect_branch_prediction_barrier().patch queue-4.15/x86nospec_Fix_header_guards_names.patch queue-4.15/KVM_x86_Make_indirect_calls_in_emulator_speculation_safe.patch queue-4.15/x86retpoline_Simplify_vmexit_fill_RSB().patch queue-4.15/x86cpufeatures_Clean_up_Spectre_v2_related_CPUID_flags.patch

6 years, 11 months

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[Linux-stable-mirror] Patch "x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86speculation_Add_basic_IBPB_(Indirect_Branch_Prediction_Barrier)_support.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. Subject: x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support From: David Woodhouse dwmw(a)amazon.co.uk Date: Thu Jan 25 16:14:15 2018 +0000 From: David Woodhouse dwmw(a)amazon.co.uk commit 20ffa1caecca4db8f79fe665acdeaa5af815a24d Expose indirect_branch_prediction_barrier() for use in subsequent patches. [ tglx: Add IBPB status to spectre_v2 sysfs file ] Co-developed-by: KarimAllah Ahmed <karahmed(a)amazon.de> Signed-off-by: KarimAllah Ahmed <karahmed(a)amazon.de> Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Cc: gnomes(a)lxorguk.ukuu.org.uk Cc: ak(a)linux.intel.com Cc: ashok.raj(a)intel.com Cc: dave.hansen(a)intel.com Cc: arjan(a)linux.intel.com Cc: torvalds(a)linux-foundation.org Cc: peterz(a)infradead.org Cc: bp(a)alien8.de Cc: pbonzini(a)redhat.com Cc: tim.c.chen(a)linux.intel.com Cc: gregkh(a)linux-foundation.org Link: https://lkml.kernel.org/r/1516896855-7642-8-git-send-email-dwmw@amazon.co.uk Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/include/asm/cpufeatures.h | 2 ++ arch/x86/include/asm/nospec-branch.h | 13 +++++++++++++ arch/x86/kernel/cpu/bugs.c | 10 +++++++++- 3 files changed, 24 insertions(+), 1 deletion(-) --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -210,6 +210,8 @@ #define X86_FEATURE_MBA ( 7*32+18) /* Memory Bandwidth Allocation */ #define X86_FEATURE_RSB_CTXSW ( 7*32+19) /* Fill RSB on context switches */ +#define X86_FEATURE_IBPB ( 7*32+21) /* Indirect Branch Prediction Barrier enabled*/ + /* Virtualization flags: Linux defined, word 8 */ #define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */ #define X86_FEATURE_VNMI ( 8*32+ 1) /* Intel Virtual NMI */ --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -218,5 +218,18 @@ static inline void vmexit_fill_RSB(void) #endif } +static inline void indirect_branch_prediction_barrier(void) +{ + asm volatile(ALTERNATIVE("", + "movl %[msr], %%ecx\n\t" + "movl %[val], %%eax\n\t" + "movl $0, %%edx\n\t" + "wrmsr", + X86_FEATURE_IBPB) + : : [msr] "i" (MSR_IA32_PRED_CMD), + [val] "i" (PRED_CMD_IBPB) + : "eax", "ecx", "edx", "memory"); +} + #endif /* __ASSEMBLY__ */ #endif /* __NOSPEC_BRANCH_H__ */ --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -263,6 +263,13 @@ retpoline_auto: setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW); pr_info("Filling RSB on context switch\n"); } + + /* Initialize Indirect Branch Prediction Barrier if supported */ + if (boot_cpu_has(X86_FEATURE_SPEC_CTRL) || + boot_cpu_has(X86_FEATURE_AMD_PRED_CMD)) { + setup_force_cpu_cap(X86_FEATURE_IBPB); + pr_info("Enabling Indirect Branch Prediction Barrier\n"); + } } #undef pr_fmt @@ -292,7 +299,8 @@ ssize_t cpu_show_spectre_v2(struct devic if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2)) return sprintf(buf, "Not affected\n"); - return sprintf(buf, "%s%s\n", spectre_v2_strings[spectre_v2_enabled], + return sprintf(buf, "%s%s%s\n", spectre_v2_strings[spectre_v2_enabled], + boot_cpu_has(X86_FEATURE_IBPB) ? ", IPBP" : "", spectre_v2_bad_module ? " - vulnerable module loaded" : ""); } #endif Patches currently in stable-queue which might be from karahmed(a)amazon.de are queue-4.14/x86pti_Do_not_enable_PTI_on_CPUs_which_are_not_vulnerable_to_Meltdown.patch queue-4.14/x86cpufeature_Blacklist_SPEC_CTRLPRED_CMD_on_early_Spectre_v2_microcodes.patch queue-4.14/x86cpufeatures_Add_Intel_feature_bits_for_Speculation_Control.patch queue-4.14/x86msr_Add_definitions_for_new_speculation_control_MSRs.patch queue-4.14/x86cpufeatures_Add_CPUID_7_EDX_CPUID_leaf.patch queue-4.14/x86cpufeatures_Add_AMD_feature_bits_for_Speculation_Control.patch queue-4.14/x86speculation_Add_basic_IBPB_(Indirect_Branch_Prediction_Barrier)_support.patch queue-4.14/x86speculation_Simplify_indirect_branch_prediction_barrier().patch queue-4.14/x86retpoline_Simplify_vmexit_fill_RSB().patch queue-4.14/x86cpufeatures_Clean_up_Spectre_v2_related_CPUID_flags.patch

6 years, 11 months

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[Linux-stable-mirror] Patch "x86/speculation: Simplify indirect_branch_prediction_barrier()" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/speculation: Simplify indirect_branch_prediction_barrier() to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86speculation_Simplify_indirect_branch_prediction_barrier().patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. Subject: x86/speculation: Simplify indirect_branch_prediction_barrier() From: Borislav Petkov bp(a)suse.de Date: Sat Jan 27 16:24:34 2018 +0000 From: Borislav Petkov bp(a)suse.de commit 64e16720ea0879f8ab4547e3b9758936d483909b Make it all a function which does the WRMSR instead of having a hairy inline asm. [dwmw2: export it, fix CONFIG_RETPOLINE issues] Signed-off-by: Borislav Petkov <bp(a)suse.de> Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: ak(a)linux.intel.com Cc: dave.hansen(a)intel.com Cc: karahmed(a)amazon.de Cc: arjan(a)linux.intel.com Cc: torvalds(a)linux-foundation.org Cc: peterz(a)infradead.org Cc: bp(a)alien8.de Cc: pbonzini(a)redhat.com Cc: tim.c.chen(a)linux.intel.com Cc: gregkh(a)linux-foundation.org Link: https://lkml.kernel.org/r/1517070274-12128-4-git-send-email-dwmw@amazon.co.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/include/asm/nospec-branch.h | 13 ++++--------- arch/x86/include/asm/processor.h | 3 +++ arch/x86/kernel/cpu/bugs.c | 6 ++++++ 3 files changed, 13 insertions(+), 9 deletions(-) --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -164,15 +164,10 @@ static inline void vmexit_fill_RSB(void) static inline void indirect_branch_prediction_barrier(void) { - asm volatile(ALTERNATIVE("", - "movl %[msr], %%ecx\n\t" - "movl %[val], %%eax\n\t" - "movl $0, %%edx\n\t" - "wrmsr", - X86_FEATURE_USE_IBPB) - : : [msr] "i" (MSR_IA32_PRED_CMD), - [val] "i" (PRED_CMD_IBPB) - : "eax", "ecx", "edx", "memory"); + alternative_input("", + "call __ibp_barrier", + X86_FEATURE_USE_IBPB, + ASM_NO_INPUT_CLOBBER("eax", "ecx", "edx", "memory")); } #endif /* __ASSEMBLY__ */ --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -970,4 +970,7 @@ bool xen_set_default_idle(void); void stop_this_cpu(void *dummy); void df_debug(struct pt_regs *regs, long error_code); + +void __ibp_barrier(void); + #endif /* _ASM_X86_PROCESSOR_H */ --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -311,3 +311,9 @@ ssize_t cpu_show_spectre_v2(struct devic spectre_v2_module_string()); } #endif + +void __ibp_barrier(void) +{ + __wrmsr(MSR_IA32_PRED_CMD, PRED_CMD_IBPB, 0); +} +EXPORT_SYMBOL_GPL(__ibp_barrier); Patches currently in stable-queue which might be from bp(a)suse.de are queue-4.14/x86pti_Do_not_enable_PTI_on_CPUs_which_are_not_vulnerable_to_Meltdown.patch queue-4.14/x86cpufeatures_Add_Intel_feature_bits_for_Speculation_Control.patch queue-4.14/x86alternative_Print_unadorned_pointers.patch queue-4.14/x86cpufeatures_Add_CPUID_7_EDX_CPUID_leaf.patch queue-4.14/x86bugs_Drop_one_mitigation_from_dmesg.patch queue-4.14/x86speculation_Simplify_indirect_branch_prediction_barrier().patch queue-4.14/x86nospec_Fix_header_guards_names.patch queue-4.14/x86retpoline_Simplify_vmexit_fill_RSB().patch queue-4.14/x86cpufeatures_Clean_up_Spectre_v2_related_CPUID_flags.patch

6 years, 11 months

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[Linux-stable-mirror] Patch "x86/retpoline: Remove the esp/rsp thunk" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/retpoline: Remove the esp/rsp thunk to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86retpoline_Remove_the_esprsp_thunk.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. Subject: x86/retpoline: Remove the esp/rsp thunk From: Waiman Long longman(a)redhat.com Date: Mon Jan 22 17:09:34 2018 -0500 From: Waiman Long longman(a)redhat.com commit 1df37383a8aeabb9b418698f0bcdffea01f4b1b2 It doesn't make sense to have an indirect call thunk with esp/rsp as retpoline code won't work correctly with the stack pointer register. Removing it will help compiler writers to catch error in case such a thunk call is emitted incorrectly. Fixes: 76b043848fd2 ("x86/retpoline: Add initial retpoline support") Suggested-by: Jeff Law <law(a)redhat.com> Signed-off-by: Waiman Long <longman(a)redhat.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Acked-by: David Woodhouse <dwmw(a)amazon.co.uk> Cc: Tom Lendacky <thomas.lendacky(a)amd.com> Cc: Kees Cook <keescook(a)google.com> Cc: Andi Kleen <ak(a)linux.intel.com> Cc: Tim Chen <tim.c.chen(a)linux.intel.com> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Jiri Kosina <jikos(a)kernel.org> Cc: Andy Lutomirski <luto(a)amacapital.net> Cc: Dave Hansen <dave.hansen(a)intel.com> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Arjan van de Ven <arjan(a)linux.intel.com> Cc: Greg Kroah-Hartman <gregkh(a)linux-foundation.org> Cc: Paul Turner <pjt(a)google.com> Link: https://lkml.kernel.org/r/1516658974-27852-1-git-send-email-longman@redhat.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/include/asm/asm-prototypes.h | 1 - arch/x86/lib/retpoline.S | 1 - 2 files changed, 2 deletions(-) --- a/arch/x86/include/asm/asm-prototypes.h +++ b/arch/x86/include/asm/asm-prototypes.h @@ -38,5 +38,4 @@ INDIRECT_THUNK(dx) INDIRECT_THUNK(si) INDIRECT_THUNK(di) INDIRECT_THUNK(bp) -INDIRECT_THUNK(sp) #endif /* CONFIG_RETPOLINE */ --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -36,7 +36,6 @@ GENERATE_THUNK(_ASM_DX) GENERATE_THUNK(_ASM_SI) GENERATE_THUNK(_ASM_DI) GENERATE_THUNK(_ASM_BP) -GENERATE_THUNK(_ASM_SP) #ifdef CONFIG_64BIT GENERATE_THUNK(r8) GENERATE_THUNK(r9) Patches currently in stable-queue which might be from law(a)redhat.com are queue-4.14/x86retpoline_Remove_the_esprsp_thunk.patch

6 years, 11 months

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[Linux-stable-mirror] Patch "x86/retpoline: Simplify vmexit_fill_RSB()" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/retpoline: Simplify vmexit_fill_RSB() to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86retpoline_Simplify_vmexit_fill_RSB().patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. Subject: x86/retpoline: Simplify vmexit_fill_RSB() From: Borislav Petkov bp(a)alien8.de Date: Sat Jan 27 16:24:33 2018 +0000 From: Borislav Petkov bp(a)alien8.de commit 1dde7415e99933bb7293d6b2843752cbdb43ec11 Simplify it to call an asm-function instead of pasting 41 insn bytes at every call site. Also, add alignment to the macro as suggested here: https://support.google.com/faqs/answer/7625886 [dwmw2: Clean up comments, let it clobber %ebx and just tell the compiler] Signed-off-by: Borislav Petkov <bp(a)suse.de> Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: ak(a)linux.intel.com Cc: dave.hansen(a)intel.com Cc: karahmed(a)amazon.de Cc: arjan(a)linux.intel.com Cc: torvalds(a)linux-foundation.org Cc: peterz(a)infradead.org Cc: bp(a)alien8.de Cc: pbonzini(a)redhat.com Cc: tim.c.chen(a)linux.intel.com Cc: gregkh(a)linux-foundation.org Link: https://lkml.kernel.org/r/1517070274-12128-3-git-send-email-dwmw@amazon.co.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/entry/entry_32.S | 3 - arch/x86/entry/entry_64.S | 3 - arch/x86/include/asm/asm-prototypes.h | 3 + arch/x86/include/asm/nospec-branch.h | 70 +++------------------------------- arch/x86/lib/Makefile | 1 arch/x86/lib/retpoline.S | 56 +++++++++++++++++++++++++++ 6 files changed, 71 insertions(+), 65 deletions(-) --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -252,7 +252,8 @@ ENTRY(__switch_to_asm) * exist, overwrite the RSB with entries which capture * speculative execution to prevent attack. */ - FILL_RETURN_BUFFER %ebx, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW + /* Clobbers %ebx */ + FILL_RETURN_BUFFER RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW #endif /* restore callee-saved registers */ --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -495,7 +495,8 @@ ENTRY(__switch_to_asm) * exist, overwrite the RSB with entries which capture * speculative execution to prevent attack. */ - FILL_RETURN_BUFFER %r12, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW + /* Clobbers %rbx */ + FILL_RETURN_BUFFER RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW #endif /* restore callee-saved registers */ --- a/arch/x86/include/asm/asm-prototypes.h +++ b/arch/x86/include/asm/asm-prototypes.h @@ -38,4 +38,7 @@ INDIRECT_THUNK(dx) INDIRECT_THUNK(si) INDIRECT_THUNK(di) INDIRECT_THUNK(bp) +asmlinkage void __fill_rsb(void); +asmlinkage void __clear_rsb(void); + #endif /* CONFIG_RETPOLINE */ --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -7,50 +7,6 @@ #include <asm/alternative-asm.h> #include <asm/cpufeatures.h> -/* - * Fill the CPU return stack buffer. - * - * Each entry in the RSB, if used for a speculative 'ret', contains an - * infinite 'pause; lfence; jmp' loop to capture speculative execution. - * - * This is required in various cases for retpoline and IBRS-based - * mitigations for the Spectre variant 2 vulnerability. Sometimes to - * eliminate potentially bogus entries from the RSB, and sometimes - * purely to ensure that it doesn't get empty, which on some CPUs would - * allow predictions from other (unwanted!) sources to be used. - * - * We define a CPP macro such that it can be used from both .S files and - * inline assembly. It's possible to do a .macro and then include that - * from C via asm(".include <asm/nospec-branch.h>") but let's not go there. - */ - -#define RSB_CLEAR_LOOPS 32 /* To forcibly overwrite all entries */ -#define RSB_FILL_LOOPS 16 /* To avoid underflow */ - -/* - * Google experimented with loop-unrolling and this turned out to be - * the optimal version — two calls, each with their own speculation - * trap should their return address end up getting used, in a loop. - */ -#define __FILL_RETURN_BUFFER(reg, nr, sp) \ - mov $(nr/2), reg; \ -771: \ - call 772f; \ -773: /* speculation trap */ \ - pause; \ - lfence; \ - jmp 773b; \ -772: \ - call 774f; \ -775: /* speculation trap */ \ - pause; \ - lfence; \ - jmp 775b; \ -774: \ - dec reg; \ - jnz 771b; \ - add $(BITS_PER_LONG/8) * nr, sp; - #ifdef __ASSEMBLY__ /* @@ -121,17 +77,10 @@ #endif .endm - /* - * A simpler FILL_RETURN_BUFFER macro. Don't make people use the CPP - * monstrosity above, manually. - */ -.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req +/* This clobbers the BX register */ +.macro FILL_RETURN_BUFFER nr:req ftr:req #ifdef CONFIG_RETPOLINE - ANNOTATE_NOSPEC_ALTERNATIVE - ALTERNATIVE "jmp .Lskip_rsb_\@", \ - __stringify(__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)) \ - \ftr -.Lskip_rsb_\@: + ALTERNATIVE "", "call __clear_rsb", \ftr #endif .endm @@ -206,15 +155,10 @@ extern char __indirect_thunk_end[]; static inline void vmexit_fill_RSB(void) { #ifdef CONFIG_RETPOLINE - unsigned long loops; - - asm volatile (ANNOTATE_NOSPEC_ALTERNATIVE - ALTERNATIVE("jmp 910f", - __stringify(__FILL_RETURN_BUFFER(%0, RSB_CLEAR_LOOPS, %1)), - X86_FEATURE_RETPOLINE) - "910:" - : "=r" (loops), ASM_CALL_CONSTRAINT - : : "memory" ); + alternative_input("", + "call __fill_rsb", + X86_FEATURE_RETPOLINE, + ASM_NO_INPUT_CLOBBER(_ASM_BX, "memory")); #endif } --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -27,6 +27,7 @@ lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o lib-$(CONFIG_RETPOLINE) += retpoline.o +OBJECT_FILES_NON_STANDARD_retpoline.o :=y obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -7,6 +7,7 @@ #include <asm/alternative-asm.h> #include <asm/export.h> #include <asm/nospec-branch.h> +#include <asm/bitsperlong.h> .macro THUNK reg .section .text.__x86.indirect_thunk @@ -46,3 +47,58 @@ GENERATE_THUNK(r13) GENERATE_THUNK(r14) GENERATE_THUNK(r15) #endif + +/* + * Fill the CPU return stack buffer. + * + * Each entry in the RSB, if used for a speculative 'ret', contains an + * infinite 'pause; lfence; jmp' loop to capture speculative execution. + * + * This is required in various cases for retpoline and IBRS-based + * mitigations for the Spectre variant 2 vulnerability. Sometimes to + * eliminate potentially bogus entries from the RSB, and sometimes + * purely to ensure that it doesn't get empty, which on some CPUs would + * allow predictions from other (unwanted!) sources to be used. + * + * Google experimented with loop-unrolling and this turned out to be + * the optimal version - two calls, each with their own speculation + * trap should their return address end up getting used, in a loop. + */ +.macro STUFF_RSB nr:req sp:req + mov $(\nr / 2), %_ASM_BX + .align 16 +771: + call 772f +773: /* speculation trap */ + pause + lfence + jmp 773b + .align 16 +772: + call 774f +775: /* speculation trap */ + pause + lfence + jmp 775b + .align 16 +774: + dec %_ASM_BX + jnz 771b + add $((BITS_PER_LONG/8) * \nr), \sp +.endm + +#define RSB_FILL_LOOPS 16 /* To avoid underflow */ + +ENTRY(__fill_rsb) + STUFF_RSB RSB_FILL_LOOPS, %_ASM_SP + ret +END(__fill_rsb) +EXPORT_SYMBOL_GPL(__fill_rsb) + +#define RSB_CLEAR_LOOPS 32 /* To forcibly overwrite all entries */ + +ENTRY(__clear_rsb) + STUFF_RSB RSB_CLEAR_LOOPS, %_ASM_SP + ret +END(__clear_rsb) +EXPORT_SYMBOL_GPL(__clear_rsb) Patches currently in stable-queue which might be from bp(a)suse.de are queue-4.14/x86pti_Do_not_enable_PTI_on_CPUs_which_are_not_vulnerable_to_Meltdown.patch queue-4.14/x86cpufeatures_Add_Intel_feature_bits_for_Speculation_Control.patch queue-4.14/x86alternative_Print_unadorned_pointers.patch queue-4.14/x86cpufeatures_Add_CPUID_7_EDX_CPUID_leaf.patch queue-4.14/x86bugs_Drop_one_mitigation_from_dmesg.patch queue-4.14/x86speculation_Simplify_indirect_branch_prediction_barrier().patch queue-4.14/x86nospec_Fix_header_guards_names.patch queue-4.14/x86retpoline_Simplify_vmexit_fill_RSB().patch queue-4.14/x86cpufeatures_Clean_up_Spectre_v2_related_CPUID_flags.patch

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Linux-stable-mirror February 2018