2023-08-03 15:16:53

by Zhangjin Wu

Subject: [PATCH v1 3/3] tools/nolibc: stackprotector.h: make __stack_chk_init static

This allows to generate smaller text/data/dec size.

As the _start_c() function added by crt.h, __stack_chk_init() is called
from _start_c() instead of the assembly _start. So, it is able to mark
it with static now.

Signed-off-by: Zhangjin Wu <[email protected]>
---
tools/include/nolibc/crt.h | 2 +-
tools/include/nolibc/stackprotector.h | 5 ++---
2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/tools/include/nolibc/crt.h b/tools/include/nolibc/crt.h
index 32e128b0fb62..a5f33fef1672 100644
--- a/tools/include/nolibc/crt.h
+++ b/tools/include/nolibc/crt.h
@@ -10,7 +10,7 @@
char **environ __attribute__((weak));
const unsigned long *_auxv __attribute__((weak));

-void __stack_chk_init(void);
+static void __stack_chk_init(void);
static void exit(int);

void _start_c(long *sp)
diff --git a/tools/include/nolibc/stackprotector.h b/tools/include/nolibc/stackprotector.h
index b620f2b9578d..13f1d0e60387 100644
--- a/tools/include/nolibc/stackprotector.h
+++ b/tools/include/nolibc/stackprotector.h
@@ -37,8 +37,7 @@ void __stack_chk_fail_local(void)
__attribute__((weak,section(".data.nolibc_stack_chk")))
uintptr_t __stack_chk_guard;

-__attribute__((weak,section(".text.nolibc_stack_chk"))) __no_stack_protector
-void __stack_chk_init(void)
+static __no_stack_protector void __stack_chk_init(void)
{
my_syscall3(__NR_getrandom, &__stack_chk_guard, sizeof(__stack_chk_guard), 0);
/* a bit more randomness in case getrandom() fails, ensure the guard is never 0 */
@@ -46,7 +45,7 @@ void __stack_chk_init(void)
__stack_chk_guard ^= (uintptr_t) &__stack_chk_guard;
}
#else /* !defined(_NOLIBC_STACKPROTECTOR) */
-__inline__ void __stack_chk_init(void) {}
+static void __stack_chk_init(void) {}
#endif /* defined(_NOLIBC_STACKPROTECTOR) */

#endif /* _NOLIBC_STACKPROTECTOR_H */
--
2.25.1

2023-08-04 16:29:34

by Thomas Weißschuh

Subject: Re: [PATCH v1 3/3] tools/nolibc: stackprotector.h: make __stack_chk_init static

On 2023-08-03 22:47:01+0800, Zhangjin Wu wrote:
> This allows to generate smaller text/data/dec size.
>
> As the _start_c() function added by crt.h, __stack_chk_init() is called
> from _start_c() instead of the assembly _start. So, it is able to mark
> it with static now.
>
> Signed-off-by: Zhangjin Wu <[email protected]>

Reviewed-by: Thomas Weißschuh <[email protected]>

> ---
> tools/include/nolibc/crt.h | 2 +-
> tools/include/nolibc/stackprotector.h | 5 ++---
> 2 files changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/tools/include/nolibc/crt.h b/tools/include/nolibc/crt.h
> index 32e128b0fb62..a5f33fef1672 100644
> --- a/tools/include/nolibc/crt.h
> +++ b/tools/include/nolibc/crt.h
> @@ -10,7 +10,7 @@
> char **environ __attribute__((weak));
> const unsigned long *_auxv __attribute__((weak));
>
> -void __stack_chk_init(void);
> +static void __stack_chk_init(void);
> static void exit(int);
>
> void _start_c(long *sp)
> diff --git a/tools/include/nolibc/stackprotector.h b/tools/include/nolibc/stackprotector.h
> index b620f2b9578d..13f1d0e60387 100644
> --- a/tools/include/nolibc/stackprotector.h
> +++ b/tools/include/nolibc/stackprotector.h
> @@ -37,8 +37,7 @@ void __stack_chk_fail_local(void)
> __attribute__((weak,section(".data.nolibc_stack_chk")))
> uintptr_t __stack_chk_guard;
>
> -__attribute__((weak,section(".text.nolibc_stack_chk"))) __no_stack_protector
> -void __stack_chk_init(void)
> +static __no_stack_protector void __stack_chk_init(void)
> {
> my_syscall3(__NR_getrandom, &__stack_chk_guard, sizeof(__stack_chk_guard), 0);
> /* a bit more randomness in case getrandom() fails, ensure the guard is never 0 */
> @@ -46,7 +45,7 @@ void __stack_chk_init(void)
> __stack_chk_guard ^= (uintptr_t) &__stack_chk_guard;
> }
> #else /* !defined(_NOLIBC_STACKPROTECTOR) */
> -__inline__ void __stack_chk_init(void) {}
> +static void __stack_chk_init(void) {}
> #endif /* defined(_NOLIBC_STACKPROTECTOR) */
>
> #endif /* _NOLIBC_STACKPROTECTOR_H */
> --
> 2.25.1
>