signal: Add FPE_FLTUNK si_code for undiagnosable fp exceptions

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@arm.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

diff --git a/arch/x86/kernel/signal_compat.c b/arch/x86/kernel/signal_compat.c
index 0d930d8987cc7c88454ff96acc671222583ac1c5..d2884e951bb588edf0ef209551c3fdf99f3f85de 100644 (file)
--- 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 99c902e460c2534609c6c385543e527adc36fa57..4b3520bf67ba1ab5d6e8a47fe6acbd1f3072977d 100644 (file)
--- 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