Commit 252eb558 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman

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: 95902e6c ("powerpc/mm: Implement STRICT_KERNEL_RWX on PPC32")
Cc: stable@vger.kernel.org # v4.14+
Reported-by: default avatarMeelis Roos <mroos@linux.ee>
Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent f3f1dfd6
...@@ -21,6 +21,7 @@ ...@@ -21,6 +21,7 @@
#include <asm/tlbflush.h> #include <asm/tlbflush.h>
#include <asm/page.h> #include <asm/page.h>
#include <asm/code-patching.h> #include <asm/code-patching.h>
#include <asm/setup.h>
static int __patch_instruction(unsigned int *addr, unsigned int instr) static int __patch_instruction(unsigned int *addr, unsigned int instr)
{ {
...@@ -146,11 +147,8 @@ 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 * During early early boot patch_instruction is called
* when text_poke_area is not ready, but we still need * when text_poke_area is not ready, but we still need
* to allow patching. We just do the plain old patching * 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); return __patch_instruction(addr, instr);
local_irq_save(flags); local_irq_save(flags);
......
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