| Message ID | 1519228960-10883-2-git-send-email-Dave.Martin@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Dave, On 21/02/18 16:02, Dave Martin wrote: > Some architectures cannot always report accurately what kind of > floating-point exception triggered a floating-point exception trap. > > This can occur with fp exceptions occuring on lanes in a vector (Nit: occurring) > instruction on arm64 for example. > > Rather than have every architecture come up with its own way of > descrbing such a condition, this patch adds a common FPE_FLTUNK do (Nits: describing; 'to report') > report that an fp exception caused a trap but we cannot be certain > which kind of fp exception it was. > 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 It looks like x86's compat relies on this value not changing: | arch/x86/kernel/signal_compat.c: BUILD_BUG_ON(NSIGFPE != 13); | include/uapi/asm-generic/siginfo.h:#define NSIGFPE 13 (from v4.16-rc2) Thanks, James
On Thu, Feb 22, 2018 at 12:14:17PM +0000, James Morse wrote: > Hi Dave, > > On 21/02/18 16:02, Dave Martin wrote: > > Some architectures cannot always report accurately what kind of > > floating-point exception triggered a floating-point exception trap. > > > > This can occur with fp exceptions occuring on lanes in a vector > > (Nit: occurring) > > > instruction on arm64 for example. > > > > Rather than have every architecture come up with its own way of > > descrbing such a condition, this patch adds a common FPE_FLTUNK do > > (Nits: describing; 'to report') > > > report that an fp exception caused a trap but we cannot be certain Hmmm, this wasn't my best effort... > > which kind of fp exception it was. > > > > 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 > > It looks like x86's compat relies on this value not changing: > | arch/x86/kernel/signal_compat.c: BUILD_BUG_ON(NSIGFPE != 13); > | include/uapi/asm-generic/siginfo.h:#define NSIGFPE 13 > > (from v4.16-rc2) Hmmm, that's embarrassing -- thanks for spotting! I think we can justifiably bump the number there, since x86 won't use FPT_FLTUNK (for now, perhaps for ever) and anyway it doesn't add any new information to siginfo. I'll respin with these changes. Cheers ---Dave
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
Some architectures cannot always report accurately what kind of floating-point exception triggered a floating-point exception trap. This can occur with fp exceptions occuring on lanes in a vector instruction on arm64 for example. Rather than have every architecture come up with its own way of descrbing such a condition, this patch adds a common FPE_FLTUNK do 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> --- include/uapi/asm-generic/siginfo.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)