From: Changbin Du <changbin.du@gmail.com>
To: Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
Changbin Du <changbin.du@gmail.com>
Subject: [PATCH] x86/mm: determine whether the fault address is canonical
Date: Fri, 4 Oct 2019 21:45:01 +0800 [thread overview]
Message-ID: <20191004134501.30651-1-changbin.du@gmail.com> (raw)
We know the answer, so don't ask the user.
Signed-off-by: Changbin Du <changbin.du@gmail.com>
---
arch/x86/mm/extable.c | 5 ++++-
arch/x86/mm/mm_internal.h | 11 +++++++++++
2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 4d75bc656f97..5196e586756f 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -8,6 +8,8 @@
#include <asm/traps.h>
#include <asm/kdebug.h>
+#include "mm_internal.h"
+
typedef bool (*ex_handler_t)(const struct exception_table_entry *,
struct pt_regs *, int, unsigned long,
unsigned long);
@@ -123,7 +125,8 @@ __visible bool ex_handler_uaccess(const struct exception_table_entry *fixup,
unsigned long error_code,
unsigned long fault_addr)
{
- WARN_ONCE(trapnr == X86_TRAP_GP, "General protection fault in user access. Non-canonical address?");
+ WARN_ONCE(trapnr == X86_TRAP_GP, "General protection fault at %s address in user access.",
+ is_canonical_addr(fault_addr) ? "canonical" : "non-canonical");
regs->ip = ex_fixup_addr(fixup);
return true;
}
diff --git a/arch/x86/mm/mm_internal.h b/arch/x86/mm/mm_internal.h
index eeae142062ed..4c8a0fdd1c64 100644
--- a/arch/x86/mm/mm_internal.h
+++ b/arch/x86/mm/mm_internal.h
@@ -2,6 +2,17 @@
#ifndef __X86_MM_INTERNAL_H
#define __X86_MM_INTERNAL_H
+static inline bool is_canonical_addr(u64 addr)
+{
+#ifdef CONFIG_X86_64
+ int shift = 64 - boot_cpu_data.x86_phys_bits;
+
+ return ((int64_t)addr << shift >> shift) == addr;
+#else
+ return true;
+#endif
+}
+
void *alloc_low_pages(unsigned int num);
static inline void *alloc_low_page(void)
{
--
2.20.1
next reply other threads:[~2019-10-04 13:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-04 13:45 Changbin Du [this message]
2019-10-04 14:39 ` [PATCH] x86/mm: determine whether the fault address is canonical Dave Hansen
2019-10-04 15:31 ` Sean Christopherson
2019-10-07 14:32 ` Ingo Molnar
2019-10-07 14:44 ` Ingo Molnar
2019-10-07 15:13 ` Sean Christopherson
2019-10-04 14:59 ` Andy Lutomirski
2019-10-04 15:14 ` Dave Hansen
2019-10-06 2:29 ` Changbin Du
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