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Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0010-x86-speculation-Use-IBRS-if-available-before-calling.patch')
-rw-r--r--common/recipes-kernel/linux/linux-yocto-4.9.21/0010-x86-speculation-Use-IBRS-if-available-before-calling.patch232
1 files changed, 0 insertions, 232 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0010-x86-speculation-Use-IBRS-if-available-before-calling.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0010-x86-speculation-Use-IBRS-if-available-before-calling.patch
deleted file mode 100644
index d5bd585e..00000000
--- a/common/recipes-kernel/linux/linux-yocto-4.9.21/0010-x86-speculation-Use-IBRS-if-available-before-calling.patch
+++ /dev/null
@@ -1,232 +0,0 @@
-From d65c0b72013dac24f4e2d0b031ed8bc6b71bfcca Mon Sep 17 00:00:00 2001
-From: David Woodhouse <dwmw@amazon.co.uk>
-Date: Mon, 19 Feb 2018 10:50:54 +0000
-Subject: [PATCH 10/14] x86/speculation: Use IBRS if available before calling
- into firmware
-
-commit dd84441a797150dcc49298ec95c459a8891d8bb1 upstream.
-
-Retpoline means the kernel is safe because it has no indirect branches.
-But firmware isn't, so use IBRS for firmware calls if it's available.
-
-Block preemption while IBRS is set, although in practice the call sites
-already had to be doing that.
-
-Ignore hpwdt.c for now. It's taking spinlocks and calling into firmware
-code, from an NMI handler. I don't want to touch that with a bargepole.
-
-Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
-Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
-Cc: Linus Torvalds <torvalds@linux-foundation.org>
-Cc: Peter Zijlstra <peterz@infradead.org>
-Cc: arjan.van.de.ven@intel.com
-Cc: bp@alien8.de
-Cc: dave.hansen@intel.com
-Cc: jmattson@google.com
-Cc: karahmed@amazon.de
-Cc: kvm@vger.kernel.org
-Cc: pbonzini@redhat.com
-Cc: rkrcmar@redhat.com
-Link: http://lkml.kernel.org/r/1519037457-7643-2-git-send-email-dwmw@amazon.co.uk
-Signed-off-by: Ingo Molnar <mingo@kernel.org>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- arch/x86/include/asm/apm.h | 6 ++++++
- arch/x86/include/asm/cpufeatures.h | 1 +
- arch/x86/include/asm/efi.h | 17 ++++++++++++++--
- arch/x86/include/asm/nospec-branch.h | 39 +++++++++++++++++++++++++++---------
- arch/x86/kernel/cpu/bugs.c | 12 ++++++++++-
- 5 files changed, 63 insertions(+), 12 deletions(-)
-
-diff --git a/arch/x86/include/asm/apm.h b/arch/x86/include/asm/apm.h
-index 93eebc63..46e40ae 100644
---- a/arch/x86/include/asm/apm.h
-+++ b/arch/x86/include/asm/apm.h
-@@ -6,6 +6,8 @@
- #ifndef _ASM_X86_MACH_DEFAULT_APM_H
- #define _ASM_X86_MACH_DEFAULT_APM_H
-
-+#include <asm/nospec-branch.h>
-+
- #ifdef APM_ZERO_SEGS
- # define APM_DO_ZERO_SEGS \
- "pushl %%ds\n\t" \
-@@ -31,6 +33,7 @@ static inline void apm_bios_call_asm(u32 func, u32 ebx_in, u32 ecx_in,
- * N.B. We do NOT need a cld after the BIOS call
- * because we always save and restore the flags.
- */
-+ firmware_restrict_branch_speculation_start();
- __asm__ __volatile__(APM_DO_ZERO_SEGS
- "pushl %%edi\n\t"
- "pushl %%ebp\n\t"
-@@ -43,6 +46,7 @@ static inline void apm_bios_call_asm(u32 func, u32 ebx_in, u32 ecx_in,
- "=S" (*esi)
- : "a" (func), "b" (ebx_in), "c" (ecx_in)
- : "memory", "cc");
-+ firmware_restrict_branch_speculation_end();
- }
-
- static inline bool apm_bios_call_simple_asm(u32 func, u32 ebx_in,
-@@ -55,6 +59,7 @@ static inline bool apm_bios_call_simple_asm(u32 func, u32 ebx_in,
- * N.B. We do NOT need a cld after the BIOS call
- * because we always save and restore the flags.
- */
-+ firmware_restrict_branch_speculation_start();
- __asm__ __volatile__(APM_DO_ZERO_SEGS
- "pushl %%edi\n\t"
- "pushl %%ebp\n\t"
-@@ -67,6 +72,7 @@ static inline bool apm_bios_call_simple_asm(u32 func, u32 ebx_in,
- "=S" (si)
- : "a" (func), "b" (ebx_in), "c" (ecx_in)
- : "memory", "cc");
-+ firmware_restrict_branch_speculation_end();
- return error;
- }
-
-diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
-index 8eb23f5..ed7a1d2 100644
---- a/arch/x86/include/asm/cpufeatures.h
-+++ b/arch/x86/include/asm/cpufeatures.h
-@@ -203,6 +203,7 @@
- #define X86_FEATURE_KAISER ( 7*32+31) /* CONFIG_PAGE_TABLE_ISOLATION w/o nokaiser */
-
- #define X86_FEATURE_USE_IBPB ( 7*32+21) /* "" Indirect Branch Prediction Barrier enabled */
-+#define X86_FEATURE_USE_IBRS_FW ( 7*32+22) /* "" Use IBRS during runtime firmware calls */
-
- /* Virtualization flags: Linux defined, word 8 */
- #define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */
-diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
-index 389d700..9df22bb 100644
---- a/arch/x86/include/asm/efi.h
-+++ b/arch/x86/include/asm/efi.h
-@@ -5,6 +5,7 @@
- #include <asm/pgtable.h>
- #include <asm/processor-flags.h>
- #include <asm/tlb.h>
-+#include <asm/nospec-branch.h>
-
- /*
- * We map the EFI regions needed for runtime services non-contiguously,
-@@ -35,8 +36,18 @@
-
- extern unsigned long asmlinkage efi_call_phys(void *, ...);
-
--#define arch_efi_call_virt_setup() kernel_fpu_begin()
--#define arch_efi_call_virt_teardown() kernel_fpu_end()
-+#define arch_efi_call_virt_setup() \
-+({ \
-+ kernel_fpu_begin(); \
-+ firmware_restrict_branch_speculation_start(); \
-+})
-+
-+#define arch_efi_call_virt_teardown() \
-+({ \
-+ firmware_restrict_branch_speculation_end(); \
-+ kernel_fpu_end(); \
-+})
-+
-
- /*
- * Wrap all the virtual calls in a way that forces the parameters on the stack.
-@@ -72,6 +83,7 @@ struct efi_scratch {
- efi_sync_low_kernel_mappings(); \
- preempt_disable(); \
- __kernel_fpu_begin(); \
-+ firmware_restrict_branch_speculation_start(); \
- \
- if (efi_scratch.use_pgd) { \
- efi_scratch.prev_cr3 = read_cr3(); \
-@@ -90,6 +102,7 @@ struct efi_scratch {
- __flush_tlb_all(); \
- } \
- \
-+ firmware_restrict_branch_speculation_end(); \
- __kernel_fpu_end(); \
- preempt_enable(); \
- })
-diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
-index dace2de..031840a 100644
---- a/arch/x86/include/asm/nospec-branch.h
-+++ b/arch/x86/include/asm/nospec-branch.h
-@@ -219,17 +219,38 @@ 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 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_msr_write(MSR_IA32_PRED_CMD, PRED_CMD_IBPB,
-+ X86_FEATURE_USE_IBPB);
-+}
-+
-+/*
-+ * With retpoline, we must use IBRS to restrict branch prediction
-+ * before calling into firmware.
-+ */
-+static inline void firmware_restrict_branch_speculation_start(void)
-+{
-+ preempt_disable();
-+ alternative_msr_write(MSR_IA32_SPEC_CTRL, SPEC_CTRL_IBRS,
-+ X86_FEATURE_USE_IBRS_FW);
-+}
-+
-+static inline void firmware_restrict_branch_speculation_end(void)
-+{
-+ alternative_msr_write(MSR_IA32_SPEC_CTRL, 0,
-+ X86_FEATURE_USE_IBRS_FW);
-+ preempt_enable();
- }
-
- #endif /* __ASSEMBLY__ */
-diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
-index baddc9e..b8b0b6e 100644
---- a/arch/x86/kernel/cpu/bugs.c
-+++ b/arch/x86/kernel/cpu/bugs.c
-@@ -299,6 +299,15 @@ static void __init spectre_v2_select_mitigation(void)
- setup_force_cpu_cap(X86_FEATURE_USE_IBPB);
- pr_info("Spectre v2 mitigation: Enabling Indirect Branch Prediction Barrier\n");
- }
-+
-+ /*
-+ * Retpoline means the kernel is safe because it has no indirect
-+ * branches. But firmware isn't, so use IBRS to protect that.
-+ */
-+ if (boot_cpu_has(X86_FEATURE_IBRS)) {
-+ setup_force_cpu_cap(X86_FEATURE_USE_IBRS_FW);
-+ pr_info("Enabling Restricted Speculation for firmware calls\n");
-+ }
- }
-
- #undef pr_fmt
-@@ -325,8 +334,9 @@ ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, c
- if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
- return sprintf(buf, "Not affected\n");
-
-- return sprintf(buf, "%s%s%s\n", spectre_v2_strings[spectre_v2_enabled],
-+ 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());
- }
- #endif
---
-2.7.4
-
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-04-18 12:14:04 +0000