From a73ad3331fdbf4191cf99b83ea9ac7082b6757ba Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Thu, 25 Dec 2008 10:39:01 -0800 Subject: [PATCH] x86: unify the implementation of FPU traps On 32 bits, we may suffer IRQ 13, or supposedly we might have a buggy implementation which gives spurious trap 16. We did not check for this on 64 bits, but there is no reason we can't make the code the same in both cases. Furthermore, this is presumably rare, so do the spurious check last, instead of first. Signed-off-by: H. Peter Anvin --- arch/x86/kernel/traps.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index f37cee75ab58..f5a640ba04bc 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -689,12 +689,7 @@ void math_error(void __user *ip) cwd = get_fpu_cwd(task); swd = get_fpu_swd(task); - err = swd & ~cwd & 0x3f; - -#ifdef CONFIG_X86_32 - if (!err) - return; -#endif + err = swd & ~cwd; if (err & 0x001) { /* Invalid op */ /* @@ -712,7 +707,9 @@ void math_error(void __user *ip) } else if (err & 0x020) { /* Precision */ info.si_code = FPE_FLTRES; } else { - info.si_code = __SI_FAULT|SI_KERNEL; /* WTF? */ + /* If we're using IRQ 13, or supposedly even some trap 16 + implementations, it's possible we get a spurious trap... */ + return; /* Spurious trap, no error */ } force_sig_info(SIGFPE, &info, task); }