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authorPaul Mackerras <paulus@samba.org>2002-08-13 06:27:23 -0700
committerLinus Torvalds <torvalds@home.transmeta.com>2002-08-13 06:27:23 -0700
commitfcc6fcc61d5d2e32f689bbfcacd031e4c3d40268 (patch)
tree67e671cdf4df365b5e31e1ba02b601088c8b9095
parente1b19d6e06a98874018c66990465dcc69b69c4bf (diff)
[PATCH] add FP exception mode prctl
This patch that adds a prctl so that processes can set their floating-point exception mode on PPC and on PPC64. We need this because the FP exception mode is controlled by bits in the machine state register, which can only be accessed by the kernel, and because the exception mode setting interacts with the lazy FPU save/restore that the kernel does.
-rw-r--r--include/linux/prctl.h8
-rw-r--r--kernel/sys.c13
2 files changed, 21 insertions, 0 deletions
diff --git a/include/linux/prctl.h b/include/linux/prctl.h
index bbe6c00bfbd3..2cc14f5e5396 100644
--- a/include/linux/prctl.h
+++ b/include/linux/prctl.h
@@ -26,4 +26,12 @@
# define PR_FPEMU_NOPRINT 1 /* silently emulate fp operations accesses */
# define PR_FPEMU_SIGFPE 2 /* don't emulate fp operations, send SIGFPE instead */
+/* Get/set floating-point exception mode (if meaningful) */
+#define PR_GET_FPEXC 11
+#define PR_SET_FPEXC 12
+# define PR_FP_EXC_DISABLED 0 /* FP exceptions disabled */
+# define PR_FP_EXC_NONRECOV 1 /* async non-recoverable exc. mode */
+# define PR_FP_EXC_ASYNC 2 /* async recoverable exception mode */
+# define PR_FP_EXC_PRECISE 3 /* precise exception mode */
+
#endif /* _LINUX_PRCTL_H */
diff --git a/kernel/sys.c b/kernel/sys.c
index 316a63de74ea..8a6d5da46335 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -37,6 +37,12 @@
#ifndef GET_FPEMU_CTL
# define GET_FPEMU_CTL(a,b) (-EINVAL)
#endif
+#ifndef SET_FPEXC_CTL
+# define SET_FPEXC_CTL(a,b) (-EINVAL)
+#endif
+#ifndef GET_FPEXC_CTL
+# define GET_FPEXC_CTL(a,b) (-EINVAL)
+#endif
/*
* this is where the system-wide overflow UID and GID are defined, for
@@ -1283,6 +1289,13 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
case PR_GET_FPEMU:
error = GET_FPEMU_CTL(current, arg2);
break;
+ case PR_SET_FPEXC:
+ error = SET_FPEXC_CTL(current, arg2);
+ break;
+ case PR_GET_FPEXC:
+ error = GET_FPEXC_CTL(current, arg2);
+ break;
+
case PR_GET_KEEPCAPS:
if (current->keep_capabilities)