From 252eb55816a6f69ef9464cad303cdb3326cdc61d Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 21 Nov 2017 15:28:20 +0100 Subject: [PATCH] powerpc: Fix boot on BOOK3S_32 with CONFIG_STRICT_KERNEL_RWX 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: 95902e6c8864 ("powerpc/mm: Implement STRICT_KERNEL_RWX on PPC32") Cc: stable@vger.kernel.org # v4.14+ Reported-by: Meelis Roos Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman --- 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 #include #include +#include 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); local_irq_save(flags); -- 2.30.2