From b988e7797d09379057cf991ae082f9ad7a309a63 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Fri, 2 Dec 2022 09:31:42 +0100 Subject: [PATCH] powerpc/feature-fixups: Do not patch init section after init Once init section is freed, attempting to patch init code ends up in the weed. Commit 51c3c62b58b3 ("powerpc: Avoid code patching freed init sections") protected patch_instruction() against that, but it is the responsibility of the caller to ensure that the patched memory is valid. In the same spirit as jump_label with its jump_label_can_update() function, add is_fixup_addr_valid() function to skip patching on freed init section. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/8e9311fc1b057e4e6a2a3a0701ebcc74b787affe.1669969781.git.christophe.leroy@csgroup.eu --- arch/powerpc/lib/feature-fixups.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c index 25168a59d1ce..80def1c2afcb 100644 --- a/arch/powerpc/lib/feature-fixups.c +++ b/arch/powerpc/lib/feature-fixups.c @@ -118,6 +118,12 @@ void do_feature_fixups(unsigned long value, void *fixup_start, void *fixup_end) } #ifdef CONFIG_PPC_BARRIER_NOSPEC +static bool is_fixup_addr_valid(void *dest, size_t size) +{ + return system_state < SYSTEM_FREEING_INITMEM || + !init_section_contains(dest, size); +} + static int do_patch_fixups(long *start, long *end, unsigned int *instrs, int num) { int i; @@ -126,6 +132,9 @@ static int do_patch_fixups(long *start, long *end, unsigned int *instrs, int num int j; unsigned int *dest = (void *)start + *start; + if (!is_fixup_addr_valid(dest, sizeof(*instrs) * num)) + continue; + pr_devel("patching dest %lx\n", (unsigned long)dest); for (j = 0; j < num; j++) @@ -144,6 +153,9 @@ static int do_patch_entry_fixups(long *start, long *end, unsigned int *instrs, for (i = 0; start < end; start++, i++) { unsigned int *dest = (void *)start + *start; + if (!is_fixup_addr_valid(dest, sizeof(*instrs) * 3)) + continue; + pr_devel("patching dest %lx\n", (unsigned long)dest); // See comment in do_entry_flush_fixups() RE order of patching