powerpc/lib: fix book3s/32 boot failure due to code patching

commit b45ba4a51cde29b2939365ef0c07ad34c8321789 upstream.

Commit 51c3c62b58b3 ("powerpc: Avoid code patching freed init
sections") accesses 'init_mem_is_free' flag too early, before the
kernel is relocated. This provokes early boot failure (before the
console is active).

As it is not necessary to do this verification that early, this
patch moves the test into patch_instruction() instead of
__patch_instruction().

This modification also has the advantage of avoiding unnecessary
remappings.

Fixes: 51c3c62b58b3 ("powerpc: Avoid code patching freed init sections")
Cc: stable@vger.kernel.org # 4.13+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 14535ad4cdd17f773c22bd23578fc82edf830086..c312955977ce76e4f42528c9effb16f4fd6eee53 100644 (file)
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -23,7 +23,7 @@ int patch_instruction(unsigned int *addr, unsigned int instr)
        int err;
 
        /* Make sure we aren't patching a freed init section */
-       if (init_mem_is_free && init_section_contains(addr, 4)) {
+       if (*PTRRELOC(&init_mem_is_free) && init_section_contains(addr, 4)) {
                pr_debug("Skipping init section patching addr: 0x%px\n", addr);
                return 0;
        }