um: fix FPU state preservation around signal handlers (6de5a8a5) · Commits · 戴 / test

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 <elicooper@gmx.com>

arch/x86/um/signal.c

+3 −15

Original line number	Diff line number	Diff line
		@@ -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;
		}

Admin message