diff options
Diffstat (limited to 'arch/arm64/kernel/syscall.c')
| -rw-r--r-- | arch/arm64/kernel/syscall.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index ad198262b981..c442fcec6b9e 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -14,6 +14,7 @@ #include <asm/syscall.h> #include <asm/thread_info.h> #include <asm/unistd.h> +#include <asm/unistd_compat_32.h> long compat_arm_syscall(struct pt_regs *regs, int scno); long sys_ni_syscall(void); @@ -53,17 +54,15 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno, syscall_set_return_value(current, regs, 0, ret); /* - * Ultimately, this value will get limited by KSTACK_OFFSET_MAX(), - * but not enough for arm64 stack utilization comfort. To keep - * reasonable stack head room, reduce the maximum offset to 9 bits. + * This value will get limited by KSTACK_OFFSET_MAX(), which is 10 + * bits. The actual entropy will be further reduced by the compiler + * when applying stack alignment constraints: the AAPCS mandates a + * 16-byte aligned SP at function boundaries, which will remove the + * 4 low bits from any entropy chosen here. * - * The actual entropy will be further reduced by the compiler when - * applying stack alignment constraints: the AAPCS mandates a - * 16-byte (i.e. 4-bit) aligned SP at function boundaries. - * - * The resulting 5 bits of entropy is seen in SP[8:4]. + * The resulting 6 bits of entropy is seen in SP[9:4]. */ - choose_random_kstack_offset(get_random_u16() & 0x1FF); + choose_random_kstack_offset(get_random_u16()); } static inline bool has_syscall_work(unsigned long flags) @@ -155,7 +154,7 @@ void do_el0_svc(struct pt_regs *regs) #ifdef CONFIG_COMPAT void do_el0_svc_compat(struct pt_regs *regs) { - el0_svc_common(regs, regs->regs[7], __NR_compat_syscalls, + el0_svc_common(regs, regs->regs[7], __NR_compat32_syscalls, compat_sys_call_table); } #endif |