On Sat, 1 May 2021 at 00:50, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote: > > It turns out that linux uses si_trapno very sparingly, and as such it > can be considered extra information for a very narrow selection of > signals, rather than information that is present with every fault > reported in siginfo. > > As such move si_trapno inside the union inside of _si_fault. This > results in no change in placement, and makes it eaiser to extend > _si_fault in the future as this reduces the number of special cases. > In particular with si_trapno included in the union it is no longer a > concern that the union must be pointer alligned on most architectures > because the union followes immediately after si_addr which is a > pointer. > Maybe add "Link: https://lkml.kernel.org/r/CAK8P3a0+uKYwL1NhY6Hvtieghba2hKYGD6hcKx5n8=4Gtt+pHA@xxxxxxxxxxxxxx"; > Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Acked-by: Marco Elver <elver@xxxxxxxxxx> By no longer guarding it with __ARCH_SI_TRAPNO we run the risk that it will be used by something else at some point. Is that intentional? Thanks, -- Marco > --- > include/linux/compat.h | 4 +--- > include/uapi/asm-generic/siginfo.h | 6 +----- > 2 files changed, 2 insertions(+), 8 deletions(-) > > diff --git a/include/linux/compat.h b/include/linux/compat.h > index f0d2dd35d408..24462ed63af4 100644 > --- a/include/linux/compat.h > +++ b/include/linux/compat.h > @@ -214,12 +214,10 @@ typedef struct compat_siginfo { > /* SIGILL, SIGFPE, SIGSEGV, SIGBUS, SIGTRAP, SIGEMT */ > struct { > compat_uptr_t _addr; /* faulting insn/memory ref. */ > -#ifdef __ARCH_SI_TRAPNO > - int _trapno; /* TRAP # which caused the signal */ > -#endif > #define __COMPAT_ADDR_BND_PKEY_PAD (__alignof__(compat_uptr_t) < sizeof(short) ? \ > sizeof(short) : __alignof__(compat_uptr_t)) > union { > + int _trapno; /* TRAP # which caused the signal */ > /* > * used when si_code=BUS_MCEERR_AR or > * used when si_code=BUS_MCEERR_AO > diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h > index 03d6f6d2c1fe..2abdf1d19aad 100644 > --- a/include/uapi/asm-generic/siginfo.h > +++ b/include/uapi/asm-generic/siginfo.h > @@ -63,9 +63,6 @@ union __sifields { > /* SIGILL, SIGFPE, SIGSEGV, SIGBUS, SIGTRAP, SIGEMT */ > struct { > void __user *_addr; /* faulting insn/memory ref. */ > -#ifdef __ARCH_SI_TRAPNO > - int _trapno; /* TRAP # which caused the signal */ > -#endif > #ifdef __ia64__ > int _imm; /* immediate value for "break" */ > unsigned int _flags; /* see ia64 si_flags */ > @@ -75,6 +72,7 @@ union __sifields { > #define __ADDR_BND_PKEY_PAD (__alignof__(void *) < sizeof(short) ? \ > sizeof(short) : __alignof__(void *)) > union { > + int _trapno; /* TRAP # which caused the signal */ > /* > * used when si_code=BUS_MCEERR_AR or > * used when si_code=BUS_MCEERR_AO > @@ -150,9 +148,7 @@ typedef struct siginfo { > #define si_int _sifields._rt._sigval.sival_int > #define si_ptr _sifields._rt._sigval.sival_ptr > #define si_addr _sifields._sigfault._addr > -#ifdef __ARCH_SI_TRAPNO > #define si_trapno _sifields._sigfault._trapno > -#endif > #define si_addr_lsb _sifields._sigfault._addr_lsb > #define si_lower _sifields._sigfault._addr_bnd._lower > #define si_upper _sifields._sigfault._addr_bnd._upper > -- > 2.30.1
