From: Lai Jiangshan <jiangshanlai@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org, Lai Jiangshan <laijs@linux.alibaba.com>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH 1/4] x86/entry: Make paranoid_exit() callable
Date: Mon, 13 Dec 2021 23:03:37 +0800 [thread overview]
Message-ID: <20211213150340.9419-2-jiangshanlai@gmail.com> (raw)
In-Reply-To: <20211213150340.9419-1-jiangshanlai@gmail.com>
From: Lai Jiangshan <laijs@linux.alibaba.com>
Move the last JMP out of paranoid_exit() and make it callable.
It will allow asm_exc_nmi() to call it and avoid duplicated code.
No functional change intended.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
arch/x86/entry/entry_64.S | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 44dadea935f7..3dc3cec03425 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -439,7 +439,8 @@ SYM_CODE_START(\asmsym)
call \cfunc
- jmp paranoid_exit
+ call paranoid_exit
+ jmp restore_regs_and_return_to_kernel
/* Switch to the regular task stack and use the noist entry point */
.Lfrom_usermode_switch_stack_\@:
@@ -516,7 +517,8 @@ SYM_CODE_START(\asmsym)
* identical to the stack in the IRET frame or the VC fall-back stack,
* so it is definitely mapped even with PTI enabled.
*/
- jmp paranoid_exit
+ call paranoid_exit
+ jmp restore_regs_and_return_to_kernel
/* Switch to the regular task stack */
.Lfrom_usermode_switch_stack_\@:
@@ -546,7 +548,8 @@ SYM_CODE_START(\asmsym)
movq $-1, ORIG_RAX(%rsp) /* no syscall to restart */
call \cfunc
- jmp paranoid_exit
+ call paranoid_exit
+ jmp restore_regs_and_return_to_kernel
_ASM_NOKPROBE(\asmsym)
SYM_CODE_END(\asmsym)
@@ -935,7 +938,7 @@ SYM_CODE_END(paranoid_entry)
* Y User space GSBASE, must be restored unconditionally
*/
SYM_CODE_START_LOCAL(paranoid_exit)
- UNWIND_HINT_REGS
+ UNWIND_HINT_REGS offset=8
/*
* The order of operations is important. RESTORE_CR3 requires
* kernel GSBASE.
@@ -951,16 +954,17 @@ SYM_CODE_START_LOCAL(paranoid_exit)
/* With FSGSBASE enabled, unconditionally restore GSBASE */
wrgsbase %rbx
- jmp restore_regs_and_return_to_kernel
+ ret
.Lparanoid_exit_checkgs:
/* On non-FSGSBASE systems, conditionally do SWAPGS */
testl %ebx, %ebx
- jnz restore_regs_and_return_to_kernel
+ jnz .Lparanoid_exit_done
/* We are returning to a context with user GSBASE */
swapgs
- jmp restore_regs_and_return_to_kernel
+.Lparanoid_exit_done:
+ ret
SYM_CODE_END(paranoid_exit)
/*
--
2.19.1.6.gb485710b
next prev parent reply other threads:[~2021-12-13 15:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-13 15:03 [PATCH 0/4] x86/nmi: NMI cleanups Lai Jiangshan
2021-12-13 15:03 ` Lai Jiangshan [this message]
2021-12-20 18:56 ` [PATCH 1/4] x86/entry: Make paranoid_exit() callable Borislav Petkov
2021-12-21 2:22 ` Lai Jiangshan
2021-12-21 10:49 ` Borislav Petkov
2021-12-13 15:03 ` [PATCH 2/4] x86/entry: Call paranoid_exit() in asm_exc_nmi() Lai Jiangshan
2021-12-13 15:03 ` [PATCH 3/4] x86/nmi: Use DEFINE_IDTENTRY_NMI for NMI handler Lai Jiangshan
2021-12-13 15:03 ` [PATCH 4/4] x86/nmi: Convert nmi_cr2/nmi_dr7 to be func-local variable Lai Jiangshan
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