Messages in this thread Patch in this message | | | From | Lai Jiangshan <> | Subject | [PATCH 11/11] x86/entry: Remove the branch in sync_regs() | Date | Wed, 8 Dec 2021 19:08:33 +0800 |
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From: Lai Jiangshan <laijs@linux.alibaba.com>
In non-xenpv, the sp0 is the trampoline stack, and sync_regs() is called on non-xenpv only since error_entry is not called on xenpv, so the stack must be the trampoline stack or one of the IST stack and the check in sync_regs() is unneeded.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com> --- arch/x86/kernel/traps.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index a6c0bc9ee36f..63cdb7aedd67 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -708,13 +708,15 @@ DEFINE_IDTENTRY_RAW(exc_int3) /* * Help handler running on a per-cpu (IST or entry trampoline) stack * to switch to the normal thread stack if the interrupted code was in - * user mode. The actual stack switch is done in entry_64.S + * user mode. The actual stack switch is done in entry_64.S. It is not + * called from XENPV and the caller has ensured it is not on the thread + * stack. */ asmlinkage __visible noinstr struct pt_regs *sync_regs(struct pt_regs *eregs) { struct pt_regs *regs = (struct pt_regs *)this_cpu_read(cpu_current_top_of_stack) - 1; - if (regs != eregs) - *regs = *eregs; + + *regs = *eregs; return regs; } -- 2.19.1.6.gb485710b
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