From: Borislav Petkov <bp@alien8.de>
To: Tony Luck <tony.luck@intel.com>
Cc: X86 ML <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH v0 06/12] x86/mce: Prevent severity computation from being instrumented
Date: Thu, 4 Nov 2021 15:40:29 +0100 [thread overview]
Message-ID: <20211104144035.20107-7-bp@alien8.de> (raw)
In-Reply-To: <20211104144035.20107-1-bp@alien8.de>
From: Borislav Petkov <bp@suse.de>
Mark all the MCE severity computation logic noinstr and allow
instrumentation when it "calls out".
Fixes
vmlinux.o: warning: objtool: do_machine_check()+0xc5d: call to mce_severity() leaves .noinstr.text section
Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/kernel/cpu/mce/severity.c | 29 ++++++++++++++++++++---------
1 file changed, 20 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
index 00e97ebbd94a..03543765e9bf 100644
--- a/arch/x86/kernel/cpu/mce/severity.c
+++ b/arch/x86/kernel/cpu/mce/severity.c
@@ -263,24 +263,35 @@ static bool is_copy_from_user(struct pt_regs *regs)
* distinguish an exception taken in user from from one
* taken in the kernel.
*/
-static int error_context(struct mce *m, struct pt_regs *regs)
+static noinstr int error_context(struct mce *m, struct pt_regs *regs)
{
+ int fixup_type;
+ bool copy_user;
+
if ((m->cs & 3) == 3)
return IN_USER;
+
if (!mc_recoverable(m->mcgstatus))
return IN_KERNEL;
- switch (ex_get_fixup_type(m->ip)) {
+ instrumentation_begin();
+ fixup_type = ex_get_fixup_type(m->ip);
+ copy_user = is_copy_from_user(regs);
+ instrumentation_end();
+
+ switch (fixup_type) {
case EX_TYPE_UACCESS:
case EX_TYPE_COPY:
- if (!regs || !is_copy_from_user(regs))
+ if (!regs || !copy_user)
return IN_KERNEL;
m->kflags |= MCE_IN_KERNEL_COPYIN;
fallthrough;
+
case EX_TYPE_FAULT_MCE_SAFE:
case EX_TYPE_DEFAULT_MCE_SAFE:
m->kflags |= MCE_IN_KERNEL_RECOV;
return IN_KERNEL_RECOV;
+
default:
return IN_KERNEL;
}
@@ -315,8 +326,8 @@ static int mce_severity_amd_smca(struct mce *m, enum context err_ctx)
* See AMD Error Scope Hierarchy table in a newer BKDG. For example
* 49125_15h_Models_30h-3Fh_BKDG.pdf, section "RAS Features"
*/
-static int mce_severity_amd(struct mce *m, struct pt_regs *regs, int tolerant,
- char **msg, bool is_excp)
+static noinstr int mce_severity_amd(struct mce *m, struct pt_regs *regs, int tolerant,
+ char **msg, bool is_excp)
{
enum context ctx = error_context(m, regs);
@@ -368,8 +379,8 @@ static int mce_severity_amd(struct mce *m, struct pt_regs *regs, int tolerant,
return MCE_KEEP_SEVERITY;
}
-static int mce_severity_intel(struct mce *m, struct pt_regs *regs,
- int tolerant, char **msg, bool is_excp)
+static noinstr int mce_severity_intel(struct mce *m, struct pt_regs *regs,
+ int tolerant, char **msg, bool is_excp)
{
enum exception excp = (is_excp ? EXCP_CONTEXT : NO_EXCP);
enum context ctx = error_context(m, regs);
@@ -405,8 +416,8 @@ static int mce_severity_intel(struct mce *m, struct pt_regs *regs,
}
}
-int mce_severity(struct mce *m, struct pt_regs *regs, int tolerant, char **msg,
- bool is_excp)
+int noinstr mce_severity(struct mce *m, struct pt_regs *regs, int tolerant, char **msg,
+ bool is_excp)
{
if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
--
2.29.2
next prev parent reply other threads:[~2021-11-04 14:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-04 14:40 [PATCH v0 00/12] x86/mce: Correct the noinstr annotation Borislav Petkov
2021-11-04 14:40 ` [PATCH v0 01/12] x86/mce: Do not use memset to clear the banks bitmaps Borislav Petkov
2021-11-04 14:40 ` [PATCH v0 02/12] x86/mce: Remove function-local cpus variables Borislav Petkov
2021-11-04 14:40 ` [PATCH v0 03/12] x86/mce: Use mce_rdmsrl() in severity checking code Borislav Petkov
2021-11-04 14:40 ` [PATCH v0 04/12] x86/mce: Remove noinstr annotation from mce_setup() Borislav Petkov
2021-11-04 14:40 ` [PATCH v0 05/12] x86/mce: Allow instrumentation during task work queueing Borislav Petkov
2021-11-09 22:05 ` Borislav Petkov
2021-11-04 14:40 ` Borislav Petkov [this message]
2021-11-04 14:40 ` [PATCH v0 07/12] x86/mce: Mark mce_panic() noinstr Borislav Petkov
2021-11-04 14:40 ` [PATCH v0 08/12] x86/mce: Mark mce_end() noinstr Borislav Petkov
2021-11-04 14:40 ` [PATCH v0 09/12] x86/mce: Mark mce_read_aux() noinstr Borislav Petkov
2021-11-04 14:40 ` [PATCH v0 10/12] x86/mce: Move the tainting outside of the noinstr region Borislav Petkov
2021-11-04 14:40 ` [PATCH v0 11/12] x86/mce: Mark mce_timed_out() noinstr Borislav Petkov
2021-11-04 14:40 ` [PATCH v0 12/12] x86/mce: Mark mce_start() noinstr Borislav Petkov
2021-11-09 22:08 ` [PATCH v0 00/12] x86/mce: Correct the noinstr annotation Peter Zijlstra
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