From b05e37035298148b6c311eccf06ac50fd389f0b2 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Wed, 4 Oct 2006 20:01:58 +0200 Subject: [PATCH] [S390] user-copy optimization fallout. Fix new restore_sigregs function. It copies the user space copy of the old psw without correcting the psw.mask and the psw.addr high order bit. While we are at it, simplify save_sigregs a bit. Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/signal.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c index 642095ec7c..4392a77cba 100644 --- a/arch/s390/kernel/signal.c +++ b/arch/s390/kernel/signal.c @@ -113,17 +113,15 @@ sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, /* Returns non-zero on fault. */ static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs) { - unsigned long old_mask = regs->psw.mask; _sigregs user_sregs; save_access_regs(current->thread.acrs); /* Copy a 'clean' PSW mask to the user to avoid leaking information about whether PER is currently on. */ - regs->psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask); - memcpy(&user_sregs.regs.psw, ®s->psw, sizeof(sregs->regs.psw) + - sizeof(sregs->regs.gprs)); - regs->psw.mask = old_mask; + user_sregs.regs.psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask); + user_sregs.regs.psw.addr = regs->psw.addr; + memcpy(&user_sregs.regs.gprs, ®s->gprs, sizeof(sregs->regs.gprs)); memcpy(&user_sregs.regs.acrs, current->thread.acrs, sizeof(sregs->regs.acrs)); /* @@ -139,7 +137,6 @@ static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs) /* Returns positive number on error */ static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs) { - unsigned long old_mask = regs->psw.mask; int err; _sigregs user_sregs; @@ -147,12 +144,12 @@ static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs) current_thread_info()->restart_block.fn = do_no_restart_syscall; err = __copy_from_user(&user_sregs, sregs, sizeof(_sigregs)); - regs->psw.mask = PSW_MASK_MERGE(old_mask, regs->psw.mask); - regs->psw.addr |= PSW_ADDR_AMODE; if (err) return err; - memcpy(®s->psw, &user_sregs.regs.psw, sizeof(sregs->regs.psw) + - sizeof(sregs->regs.gprs)); + regs->psw.mask = PSW_MASK_MERGE(regs->psw.mask, + user_sregs.regs.psw.mask); + regs->psw.addr = PSW_ADDR_AMODE | user_sregs.regs.psw.addr; + memcpy(®s->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs)); memcpy(¤t->thread.acrs, &user_sregs.regs.acrs, sizeof(sregs->regs.acrs)); restore_access_regs(current->thread.acrs); -- 2.39.5