[patch 04/18] loongarch/syscall: Use syscall_enter_from_user_mode_randomize_stack()
Jinjie Ruan
ruanjinjie at huawei.com
Wed Jul 8 19:37:44 PDT 2026
On 7/8/2026 3:06 AM, 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 at kernel.org>
> Cc: Huacai Chen <chenhuacai at kernel.org>
> Cc: loongarch at lists.linux.dev
> ---
> 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);
Reviewed-by: Jinjie Ruan <ruanjinjie at huawei.com>
>
> if (nr < NR_syscalls) {
> syscall_fn = sys_call_table[array_index_nospec(nr, NR_syscalls)];
>
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