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authorChristophe Leroy <christophe.leroy@csgroup.eu>2021-11-15 11:12:22 +0100
committerMichael Ellerman <mpe@ellerman.id.au>2021-11-25 11:25:32 +1100
commit8b8a8f0ab3f5519e45c526f826a655817486c5bb (patch)
tree582258ab2bd7909fa1abeb803043832923002863
parenta3bcfc182b2c968fd740101322bd128844724961 (diff)
powerpc/code-patching: Improve verification of patchability
Today, patch_instruction() assumes that it is called exclusively on valid addresses, and only checks that it is not called on an init address after init section has been freed. Improve verification by calling kernel_text_address() instead. kernel_text_address() already includes a verification of initmem release. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/bc683d499a411730504b132a924de0ccc2ef1f79.1636971137.git.christophe.leroy@csgroup.eu
-rw-r--r--arch/powerpc/include/asm/setup.h1
-rw-r--r--arch/powerpc/lib/code-patching.c5
-rw-r--r--arch/powerpc/mm/mem.c2
3 files changed, 2 insertions, 6 deletions
diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h
index 6c1a7d217d1a..426a2d8d028f 100644
--- a/arch/powerpc/include/asm/setup.h
+++ b/arch/powerpc/include/asm/setup.h
@@ -9,7 +9,6 @@ extern void ppc_printk_progress(char *s, unsigned short hex);
extern unsigned int rtas_data;
extern unsigned long long memory_limit;
-extern bool init_mem_is_free;
extern void *zalloc_maybe_bootmem(size_t size, gfp_t mask);
struct device_node;
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index c5ed98823835..5e2fe133639e 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -190,10 +190,9 @@ static int do_patch_instruction(u32 *addr, struct ppc_inst instr)
int patch_instruction(u32 *addr, struct ppc_inst 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);
+ if (!kernel_text_address((unsigned long)addr))
return 0;
- }
+
return do_patch_instruction(addr, instr);
}
NOKPROBE_SYMBOL(patch_instruction);
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index bd5d91a31183..8e301cd8925b 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -26,7 +26,6 @@
#include <mm/mmu_decl.h>
unsigned long long memory_limit;
-bool init_mem_is_free;
unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
EXPORT_SYMBOL(empty_zero_page);
@@ -312,7 +311,6 @@ void free_initmem(void)
{
ppc_md.progress = ppc_printk_progress;
mark_initmem_nx();
- init_mem_is_free = true;
free_initmem_default(POISON_FREE_INITMEM);
}