Re: [PATCH] riscv: kexec: Cleanup riscv_kexec_relocate

[Song Shuai]

Hi, Andreas:

在 2023/8/30 15:24, Andreas Schwab 写道:
> On Aug 30 2023, Song Shuai wrote:
>
> > @@ -52,21 +42,27 @@ SYM_CODE_START(riscv_kexec_relocate)
> >   	 * the start of the loop below so that we jump there in
> >   	 * any case.
> >   	 */
> > -	la	s8, 1f
> > -	sub	s8, s8, s7
> > -	csrw	CSR_STVEC, s8
> > +	la	s6, 1f
> > +	sub	s6, s6, s4
> > +	csrw	CSR_STVEC, s6
> > +
> > +	/*
> > +	 * With C-extension, here we get 42 Bytes and the next
> > +	 * .align directive would pad zeros here up to 44 Bytes.
> > +	 * So manually put a nop here to avoid zeros padding.
> > +	*/
> > +	nop
> >   
> >   	/* Process entries in a loop */
> >   .align 2
>
> While you are at it, I'd suggest being explicit about .palign
> vs. .balign.
How about this commemt:

Due to the stvec.BASE 4-byte alignment constraint, the following .align
(alias of .p2align) directive will align the next instruction to
a 4-byte boundary by padding zeros for this .rodata section.

With C-extension, here we get 42 Bytes and would be padded with zeros
up to 44 Bytes. So manually put a nop here to avoid it.

--
Thanks
Song Shuai