[PATCH] sh: machvec: Use char[] for section boundaries

Kees Cook
2022-09-07T23:43:58Z

As done for other sections, define the extern as a character array,
which relaxes many of the compiler-time object size checks, which would
otherwise assume it's a single long. Solves the following build error:

arch/sh/kernel/machvec.c: error: array subscript 'struct sh_machine_vector[0]' is partly outside array bounds of 'long int[1]' [-Werror=array-bounds]: => 105:33

Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: linux-sh@vger.kernel.org
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/lkml/alpine.DEB.2.22.394.2209050944290.964530@ramsan.of.borg/
Fixes: 9655ad03af2d ("sh: Fixup machvec support.")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/sh/include/asm/sections.h | 2 +-
arch/sh/kernel/machvec.c | 10 +++++-----
2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/sh/include/asm/sections.h b/arch/sh/include/asm/sections.h
index 8edb824049b9..0cb0ca149ac3 100644
--- a/arch/sh/include/asm/sections.h
+++ b/arch/sh/include/asm/sections.h
@@ -4,7 +4,7 @@

#include <asm-generic/sections.h>

-extern long __machvec_start, __machvec_end;
+extern char __machvec_start[], __machvec_end[];
extern char __uncached_start, __uncached_end;
extern char __start_eh_frame[], __stop_eh_frame[];

diff --git a/arch/sh/kernel/machvec.c b/arch/sh/kernel/machvec.c
index d606679a211e..57efaf5b82ae 100644
--- a/arch/sh/kernel/machvec.c
+++ b/arch/sh/kernel/machvec.c
@@ -20,8 +20,8 @@
#define MV_NAME_SIZE 32

#define for_each_mv(mv) \
- for ((mv) = (struct sh_machine_vector *)&__machvec_start; \
- (mv) && (unsigned long)(mv) < (unsigned long)&__machvec_end; \
+ for ((mv) = (struct sh_machine_vector *)__machvec_start; \
+ (mv) && (unsigned long)(mv) < (unsigned long)__machvec_end; \
(mv)++)

static struct sh_machine_vector * __init get_mv_byname(const char *name)
@@ -87,8 +87,8 @@ void __init sh_mv_setup(void)
if (!machvec_selected) {
unsigned long machvec_size;

- machvec_size = ((unsigned long)&__machvec_end -
- (unsigned long)&__machvec_start);
+ machvec_size = ((unsigned long)__machvec_end -
+ (unsigned long)__machvec_start);

/*
* Sanity check for machvec section alignment. Ensure
@@ -102,7 +102,7 @@ void __init sh_mv_setup(void)
* vector (usually the only one) from .machvec.init.
*/
if (machvec_size >= sizeof(struct sh_machine_vector))
- sh_mv = *(struct sh_machine_vector *)&__machvec_start;
+ sh_mv = *(struct sh_machine_vector *)__machvec_start;
}

pr_notice("Booting machvec: %s\n", get_system_type());
--
2.34.1