From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
jpoimboe@redhat.com, brgerst@gmail.com, jiangshanlai@gmail.com,
Andrew.Cooper3@citrix.com, mark.rutland@arm.com,
Linus Torvalds <torvalds@linux-foundation.org>,
Borislav Petkov <bp@suse.de>
Subject: [PATCH 2/6] x86/entry: Simplify entry_INT80_compat()
Date: Fri, 06 May 2022 14:14:33 +0200 [thread overview]
Message-ID: <20220506121631.221072885@infradead.org> (raw)
In-Reply-To: 20220506121431.563656641@infradead.org
From: Linus Torvalds <torvalds@linux-foundation.org>
Instead of playing silly games with rdi, use rax for simpler and more
consistent code.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[peterz: Changelog and fix off-by-one in offsets]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
---
arch/x86/entry/entry_64_compat.S | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -362,26 +362,25 @@ SYM_CODE_START(entry_INT80_compat)
/* switch to thread stack expects orig_ax and rdi to be pushed */
pushq %rax /* pt_regs->orig_ax */
- pushq %rdi /* pt_regs->di */
/* Need to switch before accessing the thread stack. */
- SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi
+ SWITCH_TO_KERNEL_CR3 scratch_reg=%rax
/* In the Xen PV case we already run on the thread stack. */
ALTERNATIVE "", "jmp .Lint80_keep_stack", X86_FEATURE_XENPV
- movq %rsp, %rdi
+ movq %rsp, %rax
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
- pushq 6*8(%rdi) /* regs->ss */
- pushq 5*8(%rdi) /* regs->rsp */
- pushq 4*8(%rdi) /* regs->eflags */
- pushq 3*8(%rdi) /* regs->cs */
- pushq 2*8(%rdi) /* regs->ip */
- pushq 1*8(%rdi) /* regs->orig_ax */
- pushq (%rdi) /* pt_regs->di */
+ pushq 5*8(%rax) /* regs->ss */
+ pushq 4*8(%rax) /* regs->rsp */
+ pushq 3*8(%rax) /* regs->eflags */
+ pushq 2*8(%rax) /* regs->cs */
+ pushq 1*8(%rax) /* regs->ip */
+ pushq 0*8(%rax) /* regs->orig_ax */
.Lint80_keep_stack:
+ pushq %rdi /* pt_regs->di */
pushq %rsi /* pt_regs->si */
xorl %esi, %esi /* nospec si */
pushq %rdx /* pt_regs->dx */
next prev parent reply other threads:[~2022-05-06 12:20 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-06 12:14 [PATCH 0/6] x86: Various cleanups and fixes Peter Zijlstra
2022-05-06 12:14 ` [PATCH 1/6] x86/mm: Simplify RESERVE_BRK() Peter Zijlstra
2022-05-06 15:09 ` [tip: x86/asm] " tip-bot2 for Josh Poimboeuf
2022-05-06 12:14 ` Peter Zijlstra [this message]
2022-05-06 15:09 ` [tip: x86/asm] x86/entry: Simplify entry_INT80_compat() tip-bot2 for Linus Torvalds
2022-05-06 12:14 ` [PATCH 3/6] x86/entry: Use PUSH_AND_CLEAR_REGS for compat Peter Zijlstra
2022-05-06 15:09 ` [tip: x86/asm] " tip-bot2 for Peter Zijlstra
2022-05-07 2:54 ` [PATCH 3/6] " Lai Jiangshan
2022-05-19 16:24 ` Guenter Roeck
2022-05-19 17:00 ` Peter Zijlstra
2022-05-19 17:11 ` Josh Poimboeuf
2022-05-19 17:35 ` Josh Poimboeuf
2022-05-20 1:11 ` Lai Jiangshan
2022-05-20 2:46 ` Guenter Roeck
2022-05-20 15:55 ` Josh Poimboeuf
2022-05-06 12:14 ` [PATCH 4/6] x86/entry: Remove skip_r11rcx Peter Zijlstra
2022-05-06 15:09 ` [tip: x86/asm] " tip-bot2 for Peter Zijlstra
2022-05-07 2:52 ` [PATCH 4/6] " Lai Jiangshan
2022-05-06 12:14 ` [PATCH 5/6] linkage: Fix issue with missing symbol size Peter Zijlstra
2022-05-06 15:08 ` [tip: x86/asm] " tip-bot2 for Peter Zijlstra
2022-05-06 12:14 ` [PATCH 6/6] objtool: Fix STACK_FRAME_NON_STANDARD reloc type Peter Zijlstra
2022-05-06 15:08 ` [tip: x86/asm] " tip-bot2 for Peter Zijlstra
2022-05-06 16:05 ` [PATCH 6/6] " Josh Poimboeuf
2022-05-06 20:26 ` [tip: x86/asm] " tip-bot2 for Peter Zijlstra
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