Messages in this thread | | | Date | Thu, 2 Sep 2021 12:16:35 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 11/24] x86/entry: Replace the most of asm code of error_entry to C code |
| |
On Wed, Sep 01, 2021 at 01:50:12AM +0800, Lai Jiangshan wrote: > diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S > index 42d2918f5646..bc9e2f5ad370 100644 > --- a/arch/x86/entry/entry_64.S > +++ b/arch/x86/entry/entry_64.S > @@ -972,83 +972,14 @@ SYM_CODE_START_LOCAL(error_entry) > cld > PUSH_AND_CLEAR_REGS save_ret=1 > ENCODE_FRAME_POINTER 8 > > popq %r12 /* save return addr in %12 */ > movq %rsp, %rdi /* arg0 = pt_regs pointer */ > + call do_error_entry > movq %rax, %rsp /* switch stack */ > ENCODE_FRAME_POINTER > pushq %r12 > ret
There's only a single error_entry callsite, which is idtentry_body. One of the things I wanted to do is change this lot so we change to the task_stack in 'C', using an adaptation of call_on_irqstack() and basically don't return frrom C until we're done with \cfunc.
That is, once we call C, stay there, and don't do this back and forth between C and asm.
As is, the resulting asm in error_entry is somewhat confusing given that we sometimes don't actually switch stacks.
| |