Le 22/11/2017 à 00:07, Balbir Singh a écrit :
On Wed, Nov 22, 2017 at 1:28 AM, Christophe Leroy <christophe.le...@c-s.fr> wrote:On powerpc32, patch_instruction() is called by apply_feature_fixups() which is called from early_init() There is the following note in front of early_init(): * Note that the kernel may be running at an address which is different * from the address that it was linked at, so we must use RELOC/PTRRELOC * to access static data (including strings). -- paulus Therefore, slab_is_available() cannot be called yet, and text_poke_area must be addressed with PTRRELOC() Fixes: 37bc3e5fd764f ("powerpc/lib/code-patching: Use alternate map for patch_instruction()") Reported-by: Meelis Roos <mr...@linux.ee> Cc: Balbir Singh <bsinghar...@gmail.com> Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr> --- v2: Added missing asm/setup.h arch/powerpc/lib/code-patching.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index c9de03e0c1f1..d469224c4ada 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -21,6 +21,7 @@ #include <asm/tlbflush.h> #include <asm/page.h> #include <asm/code-patching.h> +#include <asm/setup.h> static int __patch_instruction(unsigned int *addr, unsigned int instr) { @@ -146,11 +147,8 @@ int patch_instruction(unsigned int *addr, unsigned int instr) * During early early boot patch_instruction is called * when text_poke_area is not ready, but we still need * to allow patching. We just do the plain old patching - * We use slab_is_available and per cpu read * via this_cpu_read - * of text_poke_area. Per-CPU areas might not be up early - * this can create problems with just using this_cpu_read() */ - if (!slab_is_available() || !this_cpu_read(text_poke_area)) + if (!this_cpu_read(*PTRRELOC(&text_poke_area))) return __patch_instruction(addr, instr);On ppc64, we call apply_feature_fixups() in early_setup() after we've relocated ourselves. Sorry for missing the ppc32 case. I would like to avoid PTRRELOC when unnecessary.
What do you suggest then ? Some #ifdef PPC32 around that ? Christophe
Balbir Singh.
