From eeddfa91cbb1a619af135c7a9ac14251ec094b7a Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Wed, 21 Oct 2015 10:04:07 -0200 Subject: Consolidate off_t/off64_t syscall argument passing This patch add three new macros (SYSCALL_LL, SYSCALL_LL64, and __ASSUME_WORDSIZE64_ILP32) to use along with off_t and off64_t argument syscalls. The rationale for this change is: 1. Remove multiple implementations for the same syscall for different architectures (for instance, pread have 6 different implementations). 2. Also remove the requirement to use syscall wrappers for cancellable entrypoints. The macro usage should be used along __ALIGNMENT_ARG to follow ABI constrains for architecture where it applies. For instance, pread can be rewritten as: return SYSCALL_CANCEL (pread, fd, buf, count, __ALIGNMENT_ARG SYSCALL_LL (offset)); Another macro, SYSCALL_LL64, is provided for off64_t. The macro __ASSUME_WORDSIZE64_ILP32 is used by the ABI to define is uses 64-bit register even if ABI is ILP32 (for instance x32 and mips64-n32). The changes itself are not currently used in any implementation, so no code change is expected. * sysdeps/unix/sysv/linux/generic/sysdep.h (__ALIGNMENT_ARG): Move definition. (__ALIGNMENT_COUNT): Likewise. * sysdeps/unix/sysv/linux/sysdep.h (__ALIGNMENT_ARG): To here. (__ALIGNMENT_COUNT): Likewise. (SYSCALL_LL): New define. (SYSCALL_LL64): Likewise. * sysdeps/unix/sysv/linux/mips/kernel-features.h: [_MIPS_SIM == _ABIO32] (__ASSUME_WORDSIZE64_ILP32): Define. * sysdeps/unix/sysv/linux/x86_64/kernel-features.h: [ILP32] (__ASUME_WORDSIZE64_ILP32): Likewise. --- sysdeps/unix/sysv/linux/generic/sysdep.h | 10 ---------- sysdeps/unix/sysv/linux/mips/kernel-features.h | 6 ++++++ sysdeps/unix/sysv/linux/sysdep.h | 23 +++++++++++++++++++++++ sysdeps/unix/sysv/linux/x86_64/kernel-features.h | 6 ++++++ 4 files changed, 35 insertions(+), 10 deletions(-) (limited to 'sysdeps') diff --git a/sysdeps/unix/sysv/linux/generic/sysdep.h b/sysdeps/unix/sysv/linux/generic/sysdep.h index 4f2c65d..b0422ff 100644 --- a/sysdeps/unix/sysv/linux/generic/sysdep.h +++ b/sysdeps/unix/sysv/linux/generic/sysdep.h @@ -31,13 +31,3 @@ #define __NR_pread __NR_pread64 #define __NR_pwrite __NR_pwrite64 #endif - -/* Provide a dummy argument that can be used to force register - alignment for register pairs if required by the syscall ABI. */ -#ifdef __ASSUME_ALIGNED_REGISTER_PAIRS -#define __ALIGNMENT_ARG 0, -#define __ALIGNMENT_COUNT(a,b) b -#else -#define __ALIGNMENT_ARG -#define __ALIGNMENT_COUNT(a,b) a -#endif diff --git a/sysdeps/unix/sysv/linux/mips/kernel-features.h b/sysdeps/unix/sysv/linux/mips/kernel-features.h index ef4b520..1fc8959 100644 --- a/sysdeps/unix/sysv/linux/mips/kernel-features.h +++ b/sysdeps/unix/sysv/linux/mips/kernel-features.h @@ -34,3 +34,9 @@ #if _MIPS_SIM == _ABIO32 # define __ASSUME_ALIGNED_REGISTER_PAIRS 1 #endif + +/* Define that mips64-n32 is a ILP32 ABI to set the correct interface to + pass 64-bits values through syscalls. */ +#if _MIPS_SIM == _ABIN32 +# define __ASSUME_WORDSIZE64_ILP32 1 +#endif diff --git a/sysdeps/unix/sysv/linux/sysdep.h b/sysdeps/unix/sysv/linux/sysdep.h index c98fc3a..4ac4c00 100644 --- a/sysdeps/unix/sysv/linux/sysdep.h +++ b/sysdeps/unix/sysv/linux/sysdep.h @@ -15,6 +15,8 @@ License along with the GNU C Library; if not, see . */ +#include + /* Set error number and return -1. A target may choose to return the internal function, __syscall_error, which sets errno and returns -1. We use -1l, instead of -1, so that it can be casted to (void *). */ @@ -23,3 +25,24 @@ __set_errno (err); \ -1l; \ }) + +/* Provide a dummy argument that can be used to force register + alignment for register pairs if required by the syscall ABI. */ +#ifdef __ASSUME_ALIGNED_REGISTER_PAIRS +#define __ALIGNMENT_ARG 0, +#define __ALIGNMENT_COUNT(a,b) b +#else +#define __ALIGNMENT_ARG +#define __ALIGNMENT_COUNT(a,b) a +#endif + +/* Provide a common macro to pass 64-bit value on syscalls. */ +#if __WORDSIZE == 64 || defined __ASSUME_WORDSIZE64_ILP32 +# define SYSCALL_LL(val) (val) +# define SYSCALL_LL64(val) (val) +#else +#define SYSCALL_LL(val) \ + __LONG_LONG_PAIR ((val) >> 31, (val)) +#define SYSCALL_LL64(val) \ + __LONG_LONG_PAIR ((long) ((val) >> 32), (long) ((val) & 0xffffffff)) +#endif diff --git a/sysdeps/unix/sysv/linux/x86_64/kernel-features.h b/sysdeps/unix/sysv/linux/x86_64/kernel-features.h index 9491c3e..7bf75cf 100644 --- a/sysdeps/unix/sysv/linux/x86_64/kernel-features.h +++ b/sysdeps/unix/sysv/linux/x86_64/kernel-features.h @@ -22,4 +22,10 @@ # define __ASSUME_GETCPU_SYSCALL 1 #endif +/* Define that x32 is a ILP32 ABI to set the correct interface to pass + 64-bits values through syscalls. */ +#ifdef __ILP32__ +# define __ASSUME_WORDSIZE64_ILP32 1 +#endif + #include_next -- cgit v1.1