[PATCH v1 5/6] powerpc/feature-fixups: Do not patch init section after init
From: Christophe Leroy <hidden>
Date: 2022-09-27 14:37:56
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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 <redacted>
---
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 a03ed9931224..1d4342dc4b8d 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
--
2.37.1