Re: [Linux-ia64] Re: prctl patch for fpu faults

[Jesse Barnes <jbarnes@sgi.com>]

Here's another one.  Please let me know if it's ok.

Thanks,
Jesse

diff -Naur linux-2.4.10-ia64/arch/ia64/kernel/traps.c linux-2.4.10-ia64-fpswa/arch/ia64/kernel/traps.c
--- linux-2.4.10-ia64/arch/ia64/kernel/traps.c	Mon Oct  8 16:55:54 2001
+++ linux-2.4.10-ia64-fpswa/arch/ia64/kernel/traps.c	Mon Oct  8 17:04:03 2001
@@ -311,7 +311,8 @@
 
 	if (jiffies - last_time > 5*HZ)
 		fpu_swa_count = 0;
-	if (++fpu_swa_count < 5) {
+	if ((current->thread & IA64_THREAD_FPSWA_ALLPRINT) ||
+	    (++fpu_swa_count < 5 && !(current->thread.flags & IA64_THREAD_FPSWA_NOPRINT)) {
 		last_time = jiffies;
 		printk(KERN_WARNING "%s(%d): floating-point assist fault at ip %016lx\n",
 		       current->comm, current->pid, regs->cr_iip + ia64_psr(regs)->ri);
@@ -512,7 +513,7 @@
 	      case 32: /* fp fault */
 	      case 33: /* fp trap */
 		result = handle_fpu_swa((vector = 32) ? 1 : 0, regs, isr);
-		if (result < 0) {
+		if (result < 0 || (current->thread.flags & IA64_THREAD_FPSWA_SIGFPE)) {
 			siginfo.si_signo = SIGFPE;
 			siginfo.si_errno = 0;
 			siginfo.si_code = FPE_FLTINV;
diff -Naur linux-2.4.10-ia64/include/asm-ia64/processor.h linux-2.4.10-ia64-fpswa/include/asm-ia64/processor.h
--- linux-2.4.10-ia64/include/asm-ia64/processor.h	Mon Oct  8 16:55:55 2001
+++ linux-2.4.10-ia64-fpswa/include/asm-ia64/processor.h	Mon Oct  8 17:05:46 2001
@@ -168,8 +168,13 @@
 #define IA64_THREAD_UAC_NOPRINT	(__IA64_UL(1) << 3)	/* don't log unaligned accesses */
 #define IA64_THREAD_UAC_SIGBUS	(__IA64_UL(1) << 4)	/* generate SIGBUS on unaligned acc. */
 #define IA64_THREAD_KRBS_SYNCED	(__IA64_UL(1) << 5)	/* krbs synced with process vm? */
+#define IA64_THREAD_FPSWA_NOPRINT (__IA64_UL(1) << 6)   /* don't log any fpswa faults */
+#define IA64_THREAD_FPSWA_ALLPRINT (__IA64_UL(1) << 7)  /* log all fpswa faults */
+#define IA64_THREAD_FPSWA_SIGFPE  (__IA64_UL(1) << 8)   /* send a SIGFPE for fpswa faults */
 #define IA64_KERNEL_DEATH	(__IA64_UL(1) << 63)	/* see die_if_kernel()... */
 
+#define IA64_THREAD_FPSWA_SHIFT 6
+#define IA64_THREAD_FPSWA_MASK  (IA64_THREAD_FPSWA_NOPRINT | IA64_THREAD_FPSWA_ALLPRINT | IA64_THREAD_FPSWA_SIGFPE)
 #define IA64_THREAD_UAC_SHIFT	3
 #define IA64_THREAD_UAC_MASK	(IA64_THREAD_UAC_NOPRINT | IA64_THREAD_UAC_SIGBUS)
 
@@ -322,6 +327,18 @@
 #define GET_UNALIGN_CTL(task,addr)								\
 ({												\
 	put_user(((task)->thread.flags & IA64_THREAD_UAC_MASK) >> IA64_THREAD_UAC_SHIFT,	\
+		 (int *) (addr));								\
+})
+
+#define SET_FPSWA_CTL(task,value)								\
+({												\
+	(task)->thread.flags = (((task)->thread.flags & ~IA64_THREAD_FPSWA_MASK)		\
+				| (((value) << IA64_THREAD_FPSWA_SHIFT) & IA64_THREAD_FPSWA_MASK));	\
+	0;											\
+})
+#define GET_FPSWA_CTL(task,addr)								\
+({												\
+	put_user(((task)->thread.flags & IA64_THREAD_FPSWA_MASK) >> IA64_THREAD_FPSWA_SHIFT,	\
 		 (int *) (addr));								\
 })
 
diff -Naur linux-2.4.10-ia64/include/linux/prctl.h linux-2.4.10-ia64-fpswa/include/linux/prctl.h
--- linux-2.4.10-ia64/include/linux/prctl.h	Thu Jul 19 20:39:57 2001
+++ linux-2.4.10-ia64-fpswa/include/linux/prctl.h	Mon Oct  8 16:56:39 2001
@@ -20,4 +20,8 @@
 #define PR_GET_KEEPCAPS   7
 #define PR_SET_KEEPCAPS   8
 
+/* controls the printing of fpswa fault warnings */
+#define PR_GET_FPSWA  9
+#define PR_SET_FPSWA 10
+
 #endif /* _LINUX_PRCTL_H */
diff -Naur linux-2.4.10-ia64/kernel/sys.c linux-2.4.10-ia64-fpswa/kernel/sys.c
--- linux-2.4.10-ia64/kernel/sys.c	Tue Sep 18 14:10:43 2001
+++ linux-2.4.10-ia64-fpswa/kernel/sys.c	Mon Oct  8 16:56:39 2001
@@ -1245,6 +1245,22 @@
 #endif
 			break;
 
+	        case PR_SET_FPSWA:
+#ifdef SET_FPSWA_CTL
+			error = SET_FPSWA_CTL(current, arg2);
+#else
+			error = -EINVAL;
+#endif
+			break;
+
+	        case PR_GET_FPSWA:
+#ifdef GET_FPSWA_CTL
+			error = GET_FPSWA_CTL(current, arg2);
+#else
+			error = -EINVAL;
+#endif
+			break;
+
 		case PR_GET_KEEPCAPS:
 			if (current->keep_capabilities)
 				error = 1;