linux-kernel - [PATCH v2 12/23] x86,fpu: Remove .fixup usage

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20211110101325.604494664@infradead.org>
Date:   Wed, 10 Nov 2021 11:01:14 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     x86@...nel.org
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org,
        jpoimboe@...hat.com, mark.rutland@....com, dvyukov@...gle.com,
        seanjc@...gle.com, pbonzini@...hat.com, mbenes@...e.cz
Subject: [PATCH v2 12/23] x86,fpu: Remove .fixup usage

Employ EX_TYPE_EFAULT_REG to store '-EFAULT' into the %[err] register
on exception. All the callers only ever test for 0, so the change
from -1 to -EFAULT is immaterial.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/kernel/fpu/legacy.h |    6 +-----
 arch/x86/kernel/fpu/xstate.h |    6 +-----
 2 files changed, 2 insertions(+), 10 deletions(-)

--- a/arch/x86/kernel/fpu/legacy.h
+++ b/arch/x86/kernel/fpu/legacy.h
@@ -35,11 +35,7 @@ static inline void ldmxcsr(u32 mxcsr)
 	int err;							\
 	asm volatile("1:" #insn "\n\t"					\
 		     "2:\n"						\
-		     ".section .fixup,\"ax\"\n"				\
-		     "3:  movl $-1,%[err]\n"				\
-		     "    jmp  2b\n"					\
-		     ".previous\n"					\
-		     _ASM_EXTABLE(1b, 3b)				\
+		     _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %[err]) \
 		     : [err] "=r" (err), output				\
 		     : "0"(0), input);					\
 	err;								\
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -108,11 +108,7 @@ static inline u64 xfeatures_mask_indepen
 		     "\n"						\
 		     "xor %[err], %[err]\n"				\
 		     "3:\n"						\
-		     ".pushsection .fixup,\"ax\"\n"			\
-		     "4: movl $-2, %[err]\n"				\
-		     "jmp 3b\n"						\
-		     ".popsection\n"					\
-		     _ASM_EXTABLE(661b, 4b)				\
+		     _ASM_EXTABLE_TYPE_REG(661b, 3b, EX_TYPE_EFAULT_REG, %[err]) \
 		     : [err] "=r" (err)					\
 		     : "D" (st), "m" (*st), "a" (lmask), "d" (hmask)	\
 		     : "memory")