diff --git a/arch/openrisc/include/asm/processor.h b/arch/openrisc/include/asm/processor.h index 3ff893a67c13..ae43fe79b2b5 100644 --- a/arch/openrisc/include/asm/processor.h +++ b/arch/openrisc/include/asm/processor.h @@ -26,6 +26,8 @@ | SPR_SR_DCE | SPR_SR_SM) #define USER_SR (SPR_SR_DME | SPR_SR_IME | SPR_SR_ICE \ | SPR_SR_DCE | SPR_SR_IEE | SPR_SR_TEE) +/* SR bits user space may change via sigreturn, the rest stay kernel owned */ +#define SPR_SR_USER_MASK (SPR_SR_F | SPR_SR_CY | SPR_SR_OV) /* * User space process size. This is hardcoded into a few places, diff --git a/arch/openrisc/kernel/signal.c b/arch/openrisc/kernel/signal.c index f70a13ee0593..2be5af3b9832 100644 --- a/arch/openrisc/kernel/signal.c +++ b/arch/openrisc/kernel/signal.c @@ -74,6 +74,7 @@ static long save_fp_state(struct sigcontext __user *sc) static int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) { + unsigned long old_sr = regs->sr; int err = 0; /* Always make any pending restarted system calls return -EINTR */ @@ -89,8 +90,8 @@ static int restore_sigcontext(struct pt_regs *regs, err |= __copy_from_user(®s->sr, &sc->regs.sr, sizeof(unsigned long)); err |= restore_fp_state(sc); - /* make sure the SM-bit is cleared so user-mode cannot fool us */ - regs->sr &= ~SPR_SR_SM; + /* keep the privileged SR bits kernel owned, restore only user flags */ + regs->sr = (old_sr & ~SPR_SR_USER_MASK) | (regs->sr & SPR_SR_USER_MASK); regs->orig_gpr11 = -1; /* Avoid syscall restart checks */