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Revert "powerpc/code-patching: Improve verification of patchability"

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This reverts commit 8b8a8f0ab3.

As reported[1] by Sachin this causes problems with ftrace, and it also
causes the code patching selftests to fail as reported[2] by Stephen.

So revert it for now.

1: https://lore.kernel.org/linuxppc-dev/3668743C-09DF-4673-B15C-2FFE2A57F7D7@linux.vnet.ibm.com/
2: https://lore.kernel.org/linuxppc-dev/20211126161747.1f7795b0@canb.auug.org.au/

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Michael Ellerman 2021-11-29 17:41:52 +11:00
parent 3d030e3018
commit af3fdce4ab
3 changed files with 6 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/powerpc/include/asm/setup.h
View File

@ -9,6 +9,7 @@ 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;

5
arch/powerpc/lib/code-patching.c
View File

@ -190,9 +190,10 @@ 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 (!kernel_text_address((unsigned long)addr))
if (init_mem_is_free && init_section_contains(addr, 4)) {
pr_debug("Skipping init section patching addr: 0x%px\n", addr);
return 0;
}
return do_patch_instruction(addr, instr);
}
NOKPROBE_SYMBOL(patch_instruction);

2
arch/powerpc/mm/mem.c
View File

@ -26,6 +26,7 @@
#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);
@ -311,6 +312,7 @@ void free_initmem(void)
{
ppc_md.progress = ppc_printk_progress;
mark_initmem_nx();
init_mem_is_free = true;
free_initmem_default(POISON_FREE_INITMEM);
}