Commit af3fdce4 authored by Michael Ellerman's avatar Michael Ellerman
Browse files

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

This reverts commit 8b8a8f0a.

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: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 3d030e30

arch/powerpc/include/asm/setup.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

arch/powerpc/lib/code-patching.c

+3 −2
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/mm/mem.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

}