From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org, joao@overdrivepizza.com, hjl.tools@gmail.com,
jpoimboe@redhat.com, andrew.cooper3@citrix.com
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
ndesaulniers@google.com, keescook@chromium.org,
samitolvanen@google.com, mark.rutland@arm.com,
alyssa.milburn@intel.com
Subject: [PATCH 15/29] x86: Disable IBT around firmware
Date: Fri, 18 Feb 2022 17:49:17 +0100 [thread overview]
Message-ID: <20220218171409.456054276@infradead.org> (raw)
In-Reply-To: 20220218164902.008644515@infradead.org
Assume firmware isn't IBT clean and disable it across calls.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/include/asm/efi.h | 9 +++++++--
arch/x86/include/asm/ibt.h | 10 ++++++++++
arch/x86/kernel/apm_32.c | 7 +++++++
arch/x86/kernel/cpu/common.c | 28 ++++++++++++++++++++++++++++
4 files changed, 52 insertions(+), 2 deletions(-)
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -7,6 +7,7 @@
#include <asm/tlb.h>
#include <asm/nospec-branch.h>
#include <asm/mmu_context.h>
+#include <asm/ibt.h>
#include <linux/build_bug.h>
#include <linux/kernel.h>
#include <linux/pgtable.h>
@@ -120,8 +121,12 @@ extern asmlinkage u64 __efi_call(void *f
efi_enter_mm(); \
})
-#define arch_efi_call_virt(p, f, args...) \
- efi_call((void *)p->f, args) \
+#define arch_efi_call_virt(p, f, args...) ({ \
+ u64 ret, ibt = ibt_save(); \
+ ret = efi_call((void *)p->f, args); \
+ ibt_restore(ibt); \
+ ret; \
+})
#define arch_efi_call_virt_teardown() \
({ \
--- a/arch/x86/include/asm/ibt.h
+++ b/arch/x86/include/asm/ibt.h
@@ -6,6 +6,8 @@
#ifndef __ASSEMBLY__
+#include <linux/types.h>
+
#ifdef CONFIG_X86_64
#define ASM_ENDBR "endbr64\n\t"
#else
@@ -25,6 +27,9 @@ static inline bool is_endbr(const void *
return val == ~0xfa1e0ff3;
}
+extern u64 ibt_save(void);
+extern void ibt_restore(u64 save);
+
#else /* __ASSEMBLY__ */
#ifdef CONFIG_X86_64
@@ -39,10 +44,15 @@ static inline bool is_endbr(const void *
#ifndef __ASSEMBLY__
+#include <linux/types.h>
+
#define ASM_ENDBR
#define __noendbr
+static inline u64 ibt_save(void) { return 0; }
+static inline void ibt_restore(u64 save) { }
+
#else /* __ASSEMBLY__ */
#define ENDBR
--- a/arch/x86/kernel/apm_32.c
+++ b/arch/x86/kernel/apm_32.c
@@ -232,6 +232,7 @@
#include <asm/paravirt.h>
#include <asm/reboot.h>
#include <asm/nospec-branch.h>
+#include <asm/ibt.h>
#if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
extern int (*console_blank_hook)(int);
@@ -598,6 +599,7 @@ static long __apm_bios_call(void *_call)
struct desc_struct save_desc_40;
struct desc_struct *gdt;
struct apm_bios_call *call = _call;
+ u64 ibt;
cpu = get_cpu();
BUG_ON(cpu != 0);
@@ -607,11 +609,13 @@ static long __apm_bios_call(void *_call)
apm_irq_save(flags);
firmware_restrict_branch_speculation_start();
+ ibt = ibt_save();
APM_DO_SAVE_SEGS;
apm_bios_call_asm(call->func, call->ebx, call->ecx,
&call->eax, &call->ebx, &call->ecx, &call->edx,
&call->esi);
APM_DO_RESTORE_SEGS;
+ ibt_restore(ibt);
firmware_restrict_branch_speculation_end();
apm_irq_restore(flags);
gdt[0x40 / 8] = save_desc_40;
@@ -676,6 +680,7 @@ static long __apm_bios_call_simple(void
struct desc_struct save_desc_40;
struct desc_struct *gdt;
struct apm_bios_call *call = _call;
+ u64 ibt;
cpu = get_cpu();
BUG_ON(cpu != 0);
@@ -685,10 +690,12 @@ static long __apm_bios_call_simple(void
apm_irq_save(flags);
firmware_restrict_branch_speculation_start();
+ ibt = ibt_save();
APM_DO_SAVE_SEGS;
error = apm_bios_call_simple_asm(call->func, call->ebx, call->ecx,
&call->eax);
APM_DO_RESTORE_SEGS;
+ ibt_restore(ibt);
firmware_restrict_branch_speculation_end();
apm_irq_restore(flags);
gdt[0x40 / 8] = save_desc_40;
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -592,6 +592,34 @@ static __init int setup_disable_pku(char
__setup("nopku", setup_disable_pku);
#endif /* CONFIG_X86_64 */
+#ifdef CONFIG_X86_IBT
+
+u64 ibt_save(void)
+{
+ u64 msr = 0;
+
+ if (cpu_feature_enabled(X86_FEATURE_IBT)) {
+ rdmsrl(MSR_IA32_S_CET, msr);
+ wrmsrl(MSR_IA32_S_CET, msr & ~CET_ENDBR_EN);
+ }
+
+ return msr;
+}
+
+void ibt_restore(u64 save)
+{
+ u64 msr;
+
+ if (cpu_feature_enabled(X86_FEATURE_IBT)) {
+ rdmsrl(MSR_IA32_S_CET, msr);
+ msr &= ~CET_ENDBR_EN;
+ msr |= (save & CET_ENDBR_EN);
+ wrmsrl(MSR_IA32_S_CET, msr);
+ }
+}
+
+#endif
+
static __always_inline void setup_cet(struct cpuinfo_x86 *c)
{
u64 msr;
next prev parent reply other threads:[~2022-02-18 17:16 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-18 16:49 [PATCH 00/29] x86: Kernel IBT Peter Zijlstra
2022-02-18 16:49 ` [PATCH 01/29] static_call: Avoid building empty .static_call_sites Peter Zijlstra
2022-02-18 16:49 ` [PATCH 02/29] x86/module: Fix the paravirt vs alternative order Peter Zijlstra
2022-02-18 20:28 ` Josh Poimboeuf
2022-02-18 21:22 ` Peter Zijlstra
2022-02-18 23:28 ` Josh Poimboeuf
2022-02-18 16:49 ` [PATCH 03/29] objtool: Add --dry-run Peter Zijlstra
2022-02-18 16:49 ` [PATCH 04/29] x86/livepatch: Validate __fentry__ location Peter Zijlstra
2022-02-18 21:08 ` Josh Poimboeuf
2022-02-23 10:09 ` Peter Zijlstra
2022-02-23 10:21 ` Miroslav Benes
2022-02-23 10:57 ` Peter Zijlstra
2022-02-23 12:41 ` Steven Rostedt
2022-02-23 14:05 ` Peter Zijlstra
2022-02-23 14:16 ` Steven Rostedt
2022-02-23 14:23 ` Steven Rostedt
2022-02-23 14:33 ` Steven Rostedt
2022-02-23 14:49 ` Peter Zijlstra
2022-02-23 15:54 ` Peter Zijlstra
2022-02-18 16:49 ` [PATCH 05/29] x86: Base IBT bits Peter Zijlstra
2022-02-18 20:49 ` Andrew Cooper
2022-02-18 21:11 ` David Laight
2022-02-18 21:24 ` Andrew Cooper
2022-02-18 22:37 ` David Laight
2022-02-18 21:26 ` Peter Zijlstra
2022-02-18 21:14 ` Josh Poimboeuf
2022-02-18 21:21 ` Peter Zijlstra
2022-02-18 22:12 ` Joao Moreira
2022-02-19 1:07 ` Edgecombe, Rick P
2022-02-18 16:49 ` [PATCH 06/29] x86/ibt: Add ANNOTATE_NOENDBR Peter Zijlstra
2022-02-18 16:49 ` [PATCH 07/29] x86/entry: Sprinkle ENDBR dust Peter Zijlstra
2022-02-19 0:23 ` Josh Poimboeuf
2022-02-19 23:08 ` Peter Zijlstra
2022-02-19 0:36 ` Josh Poimboeuf
2022-02-18 16:49 ` [PATCH 08/29] x86/linkage: Add ENDBR to SYM_FUNC_START*() Peter Zijlstra
2022-02-18 16:49 ` [PATCH 09/29] x86/ibt,paravirt: Sprinkle ENDBR Peter Zijlstra
2022-02-18 16:49 ` [PATCH 10/29] x86/bpf: Add ENDBR instructions to prologue Peter Zijlstra
2022-02-18 16:49 ` [PATCH 11/29] x86/ibt,crypto: Add ENDBR for the jump-table entries Peter Zijlstra
2022-02-18 16:49 ` [PATCH 12/29] x86/ibt,kvm: Add ENDBR to fastops Peter Zijlstra
2022-02-18 16:49 ` [PATCH 13/29] x86/ibt,ftrace: Add ENDBR to samples/ftrace Peter Zijlstra
2022-02-18 16:49 ` [PATCH 14/29] x86/ibt: Add IBT feature, MSR and #CP handling Peter Zijlstra
2022-02-18 19:31 ` Andrew Cooper
2022-02-18 21:15 ` Peter Zijlstra
2022-02-19 1:20 ` Edgecombe, Rick P
2022-02-19 1:21 ` Josh Poimboeuf
2022-02-19 9:24 ` Peter Zijlstra
2022-02-21 8:24 ` Kees Cook
2022-02-22 4:38 ` Edgecombe, Rick P
2022-02-22 9:32 ` Peter Zijlstra
2022-02-18 16:49 ` Peter Zijlstra [this message]
2022-02-21 8:27 ` [PATCH 15/29] x86: Disable IBT around firmware Kees Cook
2022-02-21 10:06 ` Peter Zijlstra
2022-02-21 13:22 ` Peter Zijlstra
2022-02-21 15:54 ` Kees Cook
2022-02-21 16:10 ` Peter Zijlstra
2022-02-18 16:49 ` [PATCH 16/29] x86/bugs: Disable Retpoline when IBT Peter Zijlstra
2022-02-19 2:15 ` Josh Poimboeuf
2022-02-22 15:00 ` Peter Zijlstra
2022-02-25 0:19 ` Josh Poimboeuf
2022-02-18 16:49 ` [PATCH 17/29] x86/ibt: Annotate text references Peter Zijlstra
2022-02-19 5:22 ` Josh Poimboeuf
2022-02-19 9:39 ` Peter Zijlstra
2022-02-18 16:49 ` [PATCH 18/29] x86/ibt,ftrace: Annotate ftrace code patching Peter Zijlstra
2022-02-18 16:49 ` [PATCH 19/29] x86/ibt,xen: Annotate away warnings Peter Zijlstra
2022-02-18 20:24 ` Andrew Cooper
2022-02-18 21:05 ` Peter Zijlstra
2022-02-18 23:07 ` Andrew Cooper
2022-02-21 14:20 ` Peter Zijlstra
2022-02-18 16:49 ` [PATCH 20/29] x86/ibt,sev: Annotations Peter Zijlstra
2022-02-18 16:49 ` [PATCH 21/29] objtool: Rename --duplicate to --lto Peter Zijlstra
2022-02-26 19:42 ` Josh Poimboeuf
2022-02-26 21:48 ` Josh Poimboeuf
2022-02-28 11:05 ` Peter Zijlstra
2022-02-28 18:32 ` Josh Poimboeuf
2022-02-28 20:09 ` Peter Zijlstra
2022-02-28 20:18 ` Josh Poimboeuf
2022-03-01 14:19 ` Miroslav Benes
2022-02-18 16:49 ` [PATCH 22/29] Kbuild: Prepare !CLANG whole module objtool Peter Zijlstra
2022-02-18 16:49 ` [PATCH 23/29] objtool: Read the NOENDBR annotation Peter Zijlstra
2022-02-18 16:49 ` [PATCH 24/29] x86/text-patching: Make text_gen_insn() IBT aware Peter Zijlstra
2022-02-24 1:18 ` Joao Moreira
2022-02-24 9:10 ` Peter Zijlstra
2022-02-18 16:49 ` [PATCH 25/29] x86/ibt: Dont generate ENDBR in .discard.text Peter Zijlstra
2022-02-18 16:49 ` [PATCH 26/29] objtool: Add IBT validation / fixups Peter Zijlstra
2022-02-18 16:49 ` [PATCH 27/29] x86/ibt: Finish --ibt-fix-direct on module loading Peter Zijlstra
2022-02-18 16:49 ` [PATCH 28/29] x86/ibt: Ensure module init/exit points have references Peter Zijlstra
2022-02-18 16:49 ` [PATCH 29/29] x86/alternative: Use .ibt_endbr_sites to seal indirect calls Peter Zijlstra
2022-02-19 1:29 ` [PATCH 00/29] x86: Kernel IBT Edgecombe, Rick P
2022-02-19 9:58 ` Peter Zijlstra
2022-02-19 16:00 ` Andrew Cooper
2022-02-21 8:42 ` Kees Cook
2022-02-21 9:24 ` Peter Zijlstra
2022-02-23 7:26 ` Kees Cook
2022-02-24 16:47 ` Mike Rapoport
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