Some architectures cannot always report accurately what kind of
floating-point exception triggered a floating-point exception trap.
This can occur with fp exceptions occurring on lanes in a vector
instruction on arm64 for example.
Rather than have every architecture come up with its own way of
describing such a condition, this patch adds a common FPE_FLTUNK
si_code value to report that an fp exception caused a trap but we
cannot be certain which kind of fp exception it was.
Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx>
--
Changes since v1:
Reported by James Morse:
* Bump NSIGFPE BUILD_BUG_ON() check for x86 compat.
FPE_FLTUNK does not current have any implications for x86, since it
is not currently used and has no implications for the way siginfo
is populated.
---
arch/x86/kernel/signal_compat.c | 2 +-
include/uapi/asm-generic/siginfo.h | 3 ++-
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/signal_compat.c b/arch/x86/kernel/signal_compat.c
index ac057f9..954ad99 100644
--- a/arch/x86/kernel/signal_compat.c
+++ b/arch/x86/kernel/signal_compat.c
@@ -26,7 +26,7 @@ static inline void signal_compat_build_tests(void)
* new fields are handled in copy_siginfo_to_user32()!
*/
BUILD_BUG_ON(NSIGILL != 11);
- BUILD_BUG_ON(NSIGFPE != 13);
+ BUILD_BUG_ON(NSIGFPE != 14);
BUILD_BUG_ON(NSIGSEGV != 4);
BUILD_BUG_ON(NSIGBUS != 5);
BUILD_BUG_ON(NSIGTRAP != 4);
diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
index 85dc965..10304de 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -229,7 +229,8 @@ typedef struct siginfo {
# define __FPE_INVASC 12 /* invalid ASCII digit */
# define __FPE_INVDEC 13 /* invalid decimal digit */
#endif
-#define NSIGFPE 13
+#define FPE_FLTUNK 14 /* undiagnosed floating-point exception */
+#define NSIGFPE 14
/*
* SIGSEGV si_codes
--
2.1.4
