MIPS: ZBOOT: implement stack protector in compressed boot phase

This patch implements the stack protector code in MIPS compressed boot
phase based on the same code added to arm in commit
8779657d29c0ebcc0c94ede4df2f497baf1b563f "stackprotector: Introduce
CONFIG_CC_STACKPROTECTOR_STRONG" by Kees Cook <keescook@chromium.org>

Signed-off-by: Ben Chan <benchan@chromium.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Olof Johansson <olofj@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7175/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/boot/compressed/decompress.c b/arch/mips/boot/compressed/decompress.c
index c00c4ddf45148133a0cb1c405e9aefb17ea57c3f..b49c7adbfa895140f1194acb35d294a2a8647511 100644 (file)
--- a/arch/mips/boot/compressed/decompress.c
+++ b/arch/mips/boot/compressed/decompress.c
@@ -67,10 +67,24 @@ void error(char *x)
 #include "../../../../lib/decompress_unxz.c"
 #endif
 
+unsigned long __stack_chk_guard;
+
+void __stack_chk_guard_setup(void)
+{
+       __stack_chk_guard = 0x000a0dff;
+}
+
+void __stack_chk_fail(void)
+{
+       error("stack-protector: Kernel stack is corrupted\n");
+}
+
 void decompress_kernel(unsigned long boot_heap_start)
 {
        unsigned long zimage_start, zimage_size;
 
+       __stack_chk_guard_setup();
+
        zimage_start = (unsigned long)(&__image_begin);
        zimage_size = (unsigned long)(&__image_end) -
            (unsigned long)(&__image_begin);