From 6de5a8a5001687df720b36729c799991cc0faff5 Mon Sep 17 00:00:00 2001 From: Eli Cooper Date: Sun, 20 Mar 2016 00:58:39 +0800 Subject: [PATCH] um: fix FPU state preservation around signal handlers This patch makes UML saves/restores FPU state from/to the fpstate in pt_regs when setting up or returning from a signal stack, rather than calling ptrace directly. This ensures that FPU state is correctly preserved around signal handlers in a multi-threaded scenario. Signed-off-by: Eli Cooper --- arch/x86/um/signal.c | 18 +++--------------- 1 file changed, 3 insertions(+), 15 deletions(-) diff --git a/arch/x86/um/signal.c b/arch/x86/um/signal.c index 14fcd01ed992..dac23ee4e5a1 100644 --- a/arch/x86/um/signal.c +++ b/arch/x86/um/signal.c @@ -225,20 +225,10 @@ static int copy_sc_from_user(struct pt_regs *regs, } else #endif { - struct user_i387_struct fp; - - err = copy_from_user(&fp, (void *)sc.fpstate, + err = copy_from_user(regs->regs.fp, (void *)sc.fpstate, sizeof(struct user_i387_struct)); if (err) return 1; - - err = restore_fp_registers(pid, (unsigned long *) &fp); - if (err < 0) { - printk(KERN_ERR "copy_sc_from_user - " - "restore_fp_registers failed, errno = %d\n", - -err); - return 1; - } } return 0; } @@ -325,10 +315,8 @@ static int copy_sc_to_user(struct sigcontext __user *to, } else #endif { - struct user_i387_struct fp; - - err = save_fp_registers(pid, (unsigned long *) &fp); - if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct))) + if (copy_to_user(to_fp, regs->regs.fp, + sizeof(struct user_i387_struct))) return 1; } -- 2.20.1