lkml.org 
[lkml]   [2021]   [Dec]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip: x86/core] x86/futex: Remove .fixup usage
The following commit has been merged into the x86/core branch of tip:

Commit-ID: 4c132d1d844a53fc4e4b5c34e36ef10d6124b783
Gitweb: https://git.kernel.org/tip/4c132d1d844a53fc4e4b5c34e36ef10d6124b783
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Wed, 10 Nov 2021 11:01:11 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Sat, 11 Dec 2021 09:09:47 +01:00

x86/futex: Remove .fixup usage

Use the new EX_TYPE_IMM_REG to store -EFAULT into the designated 'ret'
register, this removes the need for anonymous .fixup code.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20211110101325.426016322@infradead.org
---
arch/x86/include/asm/extable_fixup_types.h | 2 ++-
arch/x86/include/asm/futex.h | 28 ++++++---------------
2 files changed, 10 insertions(+), 20 deletions(-)

diff --git a/arch/x86/include/asm/extable_fixup_types.h b/arch/x86/include/asm/extable_fixup_types.h
index 9d597fe..7469038 100644
--- a/arch/x86/include/asm/extable_fixup_types.h
+++ b/arch/x86/include/asm/extable_fixup_types.h
@@ -42,6 +42,8 @@
#define EX_TYPE_DEFAULT_MCE_SAFE 14
#define EX_TYPE_FAULT_MCE_SAFE 15
#define EX_TYPE_POP_ZERO 16
+
#define EX_TYPE_IMM_REG 17 /* reg := (long)imm */
+#define EX_TYPE_EFAULT_REG (EX_TYPE_IMM_REG | EX_DATA_IMM(-EFAULT))

#endif
diff --git a/arch/x86/include/asm/futex.h b/arch/x86/include/asm/futex.h
index f9c0011..99d345b 100644
--- a/arch/x86/include/asm/futex.h
+++ b/arch/x86/include/asm/futex.h
@@ -17,13 +17,9 @@ do { \
int oldval = 0, ret; \
asm volatile("1:\t" insn "\n" \
"2:\n" \
- "\t.section .fixup,\"ax\"\n" \
- "3:\tmov\t%3, %1\n" \
- "\tjmp\t2b\n" \
- "\t.previous\n" \
- _ASM_EXTABLE_UA(1b, 3b) \
+ _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %1) \
: "=r" (oldval), "=r" (ret), "+m" (*uaddr) \
- : "i" (-EFAULT), "0" (oparg), "1" (0)); \
+ : "0" (oparg), "1" (0)); \
if (ret) \
goto label; \
*oval = oldval; \
@@ -39,15 +35,11 @@ do { \
"3:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \
"\tjnz\t2b\n" \
"4:\n" \
- "\t.section .fixup,\"ax\"\n" \
- "5:\tmov\t%5, %1\n" \
- "\tjmp\t4b\n" \
- "\t.previous\n" \
- _ASM_EXTABLE_UA(1b, 5b) \
- _ASM_EXTABLE_UA(3b, 5b) \
+ _ASM_EXTABLE_TYPE_REG(1b, 4b, EX_TYPE_EFAULT_REG, %1) \
+ _ASM_EXTABLE_TYPE_REG(3b, 4b, EX_TYPE_EFAULT_REG, %1) \
: "=&a" (oldval), "=&r" (ret), \
"+m" (*uaddr), "=&r" (tem) \
- : "r" (oparg), "i" (-EFAULT), "1" (0)); \
+ : "r" (oparg), "1" (0)); \
if (ret) \
goto label; \
*oval = oldval; \
@@ -95,15 +87,11 @@ static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
if (!user_access_begin(uaddr, sizeof(u32)))
return -EFAULT;
asm volatile("\n"
- "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n"
+ "1:\t" LOCK_PREFIX "cmpxchgl %3, %2\n"
"2:\n"
- "\t.section .fixup, \"ax\"\n"
- "3:\tmov %3, %0\n"
- "\tjmp 2b\n"
- "\t.previous\n"
- _ASM_EXTABLE_UA(1b, 3b)
+ _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %0) \
: "+r" (ret), "=a" (oldval), "+m" (*uaddr)
- : "i" (-EFAULT), "r" (newval), "1" (oldval)
+ : "r" (newval), "1" (oldval)
: "memory"
);
user_access_end();
\
 
 \ /
  Last update: 2021-12-13 11:15    [W:0.370 / U:0.396 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site