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powerpc/lib: fix book3s/32 boot failure due to code patching

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Commit 51c3c62b58 ("powerpc: Avoid code patching freed init
sections") accesses 'init_mem_is_free' flag too early, before the
kernel is relocated. This provokes early boot failure (before the
console is active).

As it is not necessary to do this verification that early, this
patch moves the test into patch_instruction() instead of
__patch_instruction().

This modification also has the advantage of avoiding unnecessary
remappings.

Fixes: 51c3c62b58 ("powerpc: Avoid code patching freed init sections")
Cc: stable@vger.kernel.org # 4.13+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Christophe Leroy 2018-10-01 12:21:10 +00:00 committed by Michael Ellerman
parent 242cdad873
commit b45ba4a51c
1 changed files with 12 additions and 8 deletions
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20
arch/powerpc/lib/code-patching.c
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@ -28,12 +28,6 @@ static int __patch_instruction(unsigned int *exec_addr, unsigned int instr,
{
int err;
/* Make sure we aren't patching a freed init section */
if (init_mem_is_free && init_section_contains(exec_addr, 4)) {
pr_debug("Skipping init section patching addr: 0x%px\n", exec_addr);
return 0;
}
__put_user_size(instr, patch_addr, 4, err);
if (err)
return err;
@ -148,7 +142,7 @@ static inline int unmap_patch_area(unsigned long addr)
return 0;
}
int patch_instruction(unsigned int *addr, unsigned int instr)
static int do_patch_instruction(unsigned int *addr, unsigned int instr)
{
int err;
unsigned int *patch_addr = NULL;
@ -188,12 +182,22 @@ int patch_instruction(unsigned int *addr, unsigned int instr)
}
#else /* !CONFIG_STRICT_KERNEL_RWX */
int patch_instruction(unsigned int *addr, unsigned int instr)
static int do_patch_instruction(unsigned int *addr, unsigned int instr)
{
return raw_patch_instruction(addr, instr);
}
#endif /* CONFIG_STRICT_KERNEL_RWX */
int patch_instruction(unsigned int *addr, unsigned int instr)
{
/* Make sure we aren't patching a freed init section */
if (init_mem_is_free && init_section_contains(addr, 4)) {
pr_debug("Skipping init section patching addr: 0x%px\n", addr);
return 0;
}
return do_patch_instruction(addr, instr);
}
NOKPROBE_SYMBOL(patch_instruction);
int patch_branch(unsigned int *addr, unsigned long target, int flags)