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

diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h
index 6c1a7d217d1a28bcd8b227b3ef57860b9e6a5477..426a2d8d028f1c47d6c51b667b2ed5e7e0586095 100644 (file)
--- 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 c5ed9882383521ec65c30a96cbc09037e9624ae3..5e2fe133639efd1af6227cf5386fda5c96deeb68 100644 (file)
--- 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 bd5d91a31183b3c1101246c373b3975c242d6061..8e301cd8925b2bde870fd8cddd933a6128b4924e 100644 (file)
--- 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);
 }