Messages in this thread | | | Subject | Re: [PATCH v2] powerpc: fix boot on BOOK3S_32 with CONFIG_STRICT_KERNEL_RWX | From | Christophe LEROY <> | Date | Wed, 22 Nov 2017 08:16:28 +0100 |
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Le 22/11/2017 à 00:07, Balbir Singh a écrit : > On Wed, Nov 22, 2017 at 1:28 AM, Christophe Leroy > <christophe.leroy@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 <mroos@linux.ee> >> Cc: Balbir Singh <bsingharora@gmail.com> >> Signed-off-by: Christophe Leroy <christophe.leroy@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. >
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