mainline build failure of powerpc allmodconfig for prom_init_check
Linus Torvalds
torvalds at linux-foundation.org
Mon Jul 18 00:44:22 AEST 2022
On Sun, Jul 17, 2022 at 2:13 AM Sudip Mukherjee
<sudipm.mukherjee at gmail.com> wrote:
>
> I was trying to check it. With gcc-11 the assembly code generated is
> not using memset, but using __memset.
> But with gcc-12, I can see the assembly code is using memset. One
> example from the assembly:
You could try making the 'args' array in 'struct prom_args' be marked
'volatile'.
Ie something like this:
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -115,6 +115,6 @@ struct prom_args {
__be32 service;
__be32 nargs;
__be32 nret;
- __be32 args[10];
+ volatile __be32 args[10];
};
because I think it's just the compilers turning the small loop over
those fields into a "memset()".
Linus
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