From: Tony Luck <tony.luck@intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Tony Luck <tony.luck@intel.com>,
x86@kernel.org, Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Darren Hart <dvhart@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org,
linux-mm@kvack.org
Subject: [PATCH v2 2/3] x86/mce: Add new return value to get_user() for machine check
Date: Mon, 11 Jan 2021 13:44:51 -0800 [thread overview]
Message-ID: <20210111214452.1826-3-tony.luck@intel.com> (raw)
In-Reply-To: <20210111214452.1826-1-tony.luck@intel.com>
When an exception occurs during any of the get_user() functions
fixup_exception() passes the trap number of the exception in regs->ax
to the fixup code.
Check for X86_TRAP_MC and return -ENXIO ("No such device or address")
so that callers can take action to avoid repeating an access to an
address that has an uncorrectable error.
Signed-off-by: Tony Luck <tony.luck@intel.com>
---
arch/x86/lib/getuser.S | 8 +++++++-
arch/x86/mm/extable.c | 1 +
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S
index fa1bc2104b32..c49a449fced6 100644
--- a/arch/x86/lib/getuser.S
+++ b/arch/x86/lib/getuser.S
@@ -17,7 +17,7 @@
*
* Inputs: %[r|e]ax contains the address.
*
- * Outputs: %[r|e]ax is error code (0 or -EFAULT)
+ * Outputs: %[r|e]ax is error code (0 or -EFAULT or -ENXIO)
* %[r|e]dx contains zero-extended value
* %ecx contains the high half for 32-bit __get_user_8
*
@@ -34,6 +34,7 @@
#include <asm/asm.h>
#include <asm/smap.h>
#include <asm/export.h>
+#include <asm/trapnr.h>
#define ASM_BARRIER_NOSPEC ALTERNATIVE "", "lfence", X86_FEATURE_LFENCE_RDTSC
@@ -168,8 +169,13 @@ SYM_CODE_START_LOCAL(.Lbad_get_user_clac)
ASM_CLAC
bad_get_user:
xor %edx,%edx
+ cmpl $X86_TRAP_MC,%eax
+ je mce_get_user
mov $(-EFAULT),%_ASM_AX
ret
+mce_get_user:
+ mov $(-ENXIO),%_ASM_AX
+ ret
SYM_CODE_END(.Lbad_get_user_clac)
#ifdef CONFIG_X86_32
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index b93d6cd08a7f..ac4fcb820c40 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -77,6 +77,7 @@ __visible bool ex_handler_uaccess(const struct exception_table_entry *fixup,
{
WARN_ONCE(trapnr == X86_TRAP_GP, "General protection fault in user access. Non-canonical address?");
regs->ip = ex_fixup_addr(fixup);
+ regs->ax = trapnr;
return true;
}
EXPORT_SYMBOL(ex_handler_uaccess);
--
2.21.1
next prev parent reply other threads:[~2021-01-11 21:46 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-08 22:22 [PATCH 0/2] Fix infinite machine check loop in futex_wait_setup() Tony Luck
2021-01-08 22:22 ` [PATCH 1/2] x86/mce: Avoid infinite loop for copy from user recovery Tony Luck
2021-01-08 22:22 ` [PATCH 2/2] futex, x86/mce: Avoid double machine checks Tony Luck
2021-01-08 22:47 ` Peter Zijlstra
2021-01-08 23:08 ` Luck, Tony
2021-01-08 23:14 ` Peter Zijlstra
2021-01-08 23:20 ` Luck, Tony
2021-01-11 21:44 ` [PATCH v2 0/3] Fix infinite machine check loop in futex_wait_setup() Tony Luck
2021-01-11 21:44 ` [PATCH v2 1/3] x86/mce: Avoid infinite loop for copy from user recovery Tony Luck
2021-01-11 22:11 ` Andy Lutomirski
2021-01-11 22:20 ` Luck, Tony
2021-01-12 17:00 ` Andy Lutomirski
2021-01-12 17:16 ` Luck, Tony
2021-01-12 17:21 ` Andy Lutomirski
2021-01-12 18:23 ` Luck, Tony
2021-01-12 18:57 ` Andy Lutomirski
2021-01-12 20:52 ` Luck, Tony
2021-01-12 22:04 ` Andy Lutomirski
2021-01-13 1:50 ` Luck, Tony
2021-01-13 4:15 ` Andy Lutomirski
2021-01-13 10:00 ` Borislav Petkov
2021-01-13 16:06 ` Luck, Tony
2021-01-13 16:19 ` Borislav Petkov
2021-01-13 16:32 ` Luck, Tony
2021-01-13 17:35 ` Borislav Petkov
2021-01-14 20:22 ` Borislav Petkov
2021-01-14 21:05 ` Luck, Tony
2021-01-11 21:44 ` Tony Luck [this message]
2021-01-11 21:44 ` [PATCH v2 3/3] futex, x86/mce: Avoid double machine checks Tony Luck
2021-01-14 17:22 ` [PATCH v2 0/3] Fix infinite machine check loop in futex_wait_setup() Andy Lutomirski
2021-01-15 0:38 ` [PATCH v3] x86/mce: Avoid infinite loop for copy from user recovery Tony Luck
2021-01-15 15:27 ` Borislav Petkov
2021-01-15 19:34 ` Luck, Tony
2021-01-15 20:51 ` [PATCH v4] " Luck, Tony
2021-01-15 23:23 ` Luck, Tony
2021-01-19 10:56 ` Borislav Petkov
2021-01-19 23:57 ` Luck, Tony
2021-01-20 12:18 ` Borislav Petkov
2021-01-20 17:17 ` Luck, Tony
2021-01-21 21:09 ` Luck, Tony
2021-01-25 22:55 ` [PATCH v5] " Luck, Tony
2021-01-26 11:03 ` Borislav Petkov
2021-01-26 22:36 ` Luck, Tony
2021-01-28 17:57 ` Borislav Petkov
2021-02-01 18:58 ` Luck, Tony
2021-02-02 11:01 ` Borislav Petkov
2021-02-02 16:04 ` Luck, Tony
2021-02-02 21:06 ` Borislav Petkov
2021-02-02 22:12 ` Luck, Tony
2021-01-18 15:39 ` [PATCH v3] " Borislav Petkov
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