Commit 90d4fed5 authored by Benjamin Gray's avatar Benjamin Gray Committed by Michael Ellerman
Browse files

powerpc/64: Convert patch_instruction() to patch_u32() 

This use of patch_instruction() is working on 32 bit data, and can fail
if the data looks like a prefixed instruction and the extra write
crosses a page boundary. Use patch_u32() to fix the write size.

Fixes: 8734b41b ("powerpc/module_64: Fix livepatching for RO modules")
Link: https://lore.kernel.org/all/20230203004649.1f59dbd4@yea/


Signed-off-by: default avatarBenjamin Gray <bgray@linux.ibm.com>
Tested-by: default avatarHari Bathini <hbathini@linux.ibm.com>
Acked-by: default avatarNaveen N Rao <naveen@kernel.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240515024445.236364-4-bgray@linux.ibm.com
parent dbf828aa

arch/powerpc/kernel/module_64.c

+2 −3
Original line number Diff line number Diff line
@@ -651,12 +651,11 @@ static inline int create_stub(const Elf64_Shdr *sechdrs, 
	// func_desc_t is 8 bytes if ABIv2, else 16 bytes

	desc = func_desc(addr);

	for (i = 0; i < sizeof(func_desc_t) / sizeof(u32); i++) {

		if (patch_instruction(((u32 *)&entry->funcdata) + i,

				      ppc_inst(((u32 *)(&desc))[i])))

		if (patch_u32(((u32 *)&entry->funcdata) + i, ((u32 *)&desc)[i]))

			return 0;

	}



	if (patch_instruction(&entry->magic, ppc_inst(STUB_MAGIC)))

	if (patch_u32(&entry->magic, STUB_MAGIC))

		return 0;



	return 1;