Re: [patch 04/18] loongarch/syscall: Use syscall_enter_from_user_mode_randomize_stack()

[Radu Rendec]

On Tue, 2026-07-07 at 21:06 +0200, Thomas Gleixner wrote:
> syscall_enter_from_user_mode_randomize_stack() replaces
> syscall_enter_from_user_mode() and the subsequent invocation of
> add_random_kstack_offset().
> 
> The advantage is that it applies the stack randomization right after
> enter_from_user_mode() and thereby avoids the overhead of get/put_cpu_var()
> as that code is invoked with interrupts disabled.
> 
> No functional change.
> 
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxx>
> Cc: Huacai Chen <chenhuacai@xxxxxxxxxx>
> Cc: loongarch@xxxxxxxxxxxxxxx
> ---
>  arch/loongarch/kernel/syscall.c |    5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> --- a/arch/loongarch/kernel/syscall.c
> +++ b/arch/loongarch/kernel/syscall.c
> @@ -11,7 +11,6 @@
>  #include <linux/linkage.h>
>  #include <linux/nospec.h>
>  #include <linux/objtool.h>
> -#include <linux/randomize_kstack.h>
>  #include <linux/syscalls.h>
>  #include <linux/unistd.h>
>  
> @@ -70,9 +69,7 @@ void noinstr __no_stack_protector do_sys
>  	regs->orig_a0 = regs->regs[4];
>  	regs->regs[4] = -ENOSYS;
>  
> -	nr = syscall_enter_from_user_mode(regs, nr);
> -
> -	add_random_kstack_offset();
> +	nr = syscall_enter_from_user_mode_randomize_stack(regs, nr);
>  
>  	if (nr < NR_syscalls) {
>  		syscall_fn = sys_call_table[array_index_nospec(nr, NR_syscalls)];

Reviewed-by: Radu Rendec <radu@xxxxxxxxxx>