x86: prioritize the FPU traps for the error code (adf77bac) · Commits · 戴 / test

arch/x86/kernel/traps.c

+15 −19

Original line number	Diff line number	Diff line
		@@ -664,7 +664,7 @@ void math_error(void __user *ip)
		{
		struct task_struct *task;
		siginfo_t info;
		unsigned short cwd, swd;
		unsigned short cwd, swd, err;

		/*
		* Save the info for the exception handler and clear the error.
		@@ -675,7 +675,6 @@ void math_error(void __user *ip)
		task->thread.error_code = 0;
		info.si_signo = SIGFPE;
		info.si_errno = 0;
		info.si_code = __SI_FAULT;
		info.si_addr = ip;
		/*
		* (~cwd & swd) will mask out exceptions that are not set to unmasked
		@@ -689,34 +688,31 @@ void math_error(void __user *ip)
		*/
		cwd = get_fpu_cwd(task);
		swd = get_fpu_swd(task);
		switch (swd & ~cwd & 0x3f) {
		case 0x000: /* No unmasked exception */
		#ifdef CONFIG_X86_32

		err = swd & ~cwd & 0x3f;

		#if CONFIG_X86_32
		if (!err)
		return;
		#endif
		default: /* Multiple exceptions */
		break;
		case 0x001: /* Invalid Op */

		if (err & 0x001) { /* Invalid op */
		/*
		* swd & 0x240 == 0x040: Stack Underflow
		* swd & 0x240 == 0x240: Stack Overflow
		* User must clear the SF bit (0x40) if set
		*/
		info.si_code = FPE_FLTINV;
		break;
		case 0x002: /* Denormalize */
		case 0x010: /* Underflow */
		info.si_code = FPE_FLTUND;
		break;
		case 0x004: /* Zero Divide */
		} else if (err & 0x004) { /* Divide by Zero */
		info.si_code = FPE_FLTDIV;
		break;
		case 0x008: /* Overflow */
		} else if (err & 0x008) { /* Overflow */
		info.si_code = FPE_FLTOVF;
		break;
		case 0x020: /* Precision */
		} else if (err & 0x012) { /* Denormal, Underflow */
		info.si_code = FPE_FLTUND;
		} else if (err & 0x020) { /* Precision */
		info.si_code = FPE_FLTRES;
		break;
		} else {
		info.si_code = __SI_FAULT\|SI_KERNEL; /* WTF? */
		}
		force_sig_info(SIGFPE, &info, task);
		}

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