x86: unify the implementation of FPU traps (a73ad333) · Commits · 戴 / test

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 <hpa@zytor.com>

arch/x86/kernel/traps.c

+4 −7

Original line number	Original line	Diff line number	Diff line
	@@ -689,12 +689,7 @@ void math_error(void __user *ip)
	cwd = get_fpu_cwd(task);		cwd = get_fpu_cwd(task);
	swd = get_fpu_swd(task);		swd = get_fpu_swd(task);

	err = swd & ~cwd & 0x3f;		err = swd & ~cwd;

	#ifdef CONFIG_X86_32
	if (!err)
	return;
	#endif

	if (err & 0x001) { /* Invalid op */		if (err & 0x001) { /* Invalid op */
	/*		/*
	@@ -712,7 +707,9 @@ void math_error(void __user *ip)
	} else if (err & 0x020) { /* Precision */		} else if (err & 0x020) { /* Precision */
	info.si_code = FPE_FLTRES;		info.si_code = FPE_FLTRES;
	} else {		} 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);		force_sig_info(SIGFPE, &info, task);
	}		}

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