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powerpc/feature-fixups: Do not patch init section after init

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Once init section is freed, attempting to patch init code
ends up in the weed.

Commit 51c3c62b58 ("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 <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8e9311fc1b057e4e6a2a3a0701ebcc74b787affe.1669969781.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2022-12-02 09:31:42 +01:00 committed by Michael Ellerman
parent 3d1dbbca33
commit b988e7797d
1 changed files with 12 additions and 0 deletions
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12
arch/powerpc/lib/feature-fixups.c
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@ -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