Messages in this thread Patch in this message | | | From | Alistair Francis <> | Subject | [PATCH v5 1/6] perf bench futex: Add support for 32-bit systems with 64-bit time_t | Date | Fri, 10 Dec 2021 09:58:52 +1000 |
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From: Alistair Francis <alistair.francis@wdc.com>
Some 32-bit architectures (such are 32-bit RISC-V) only have a 64-bit time_t and as such don't have the SYS_futex syscall. This patch will allow us to use the SYS_futex_time64 syscall on those platforms.
This also converts the futex calls to be y2038 safe (when built for a 5.1+ kernel).
This is a revert of commit ba4026b09d83acf56c040b6933eac7916c27e728 "Revert "perf bench futex: Add support for 32-bit systems with 64-bit time_t"".
The original commit was reverted as including linux/time_types.h would fail to compile on older kernels. This commit doesn't include linux/time_types.h to avoid this issue.
Signed-off-by: Alistair Francis <alistair.francis@wdc.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alistair Francis <alistair23@gmail.com> Cc: Atish Patra <atish.patra@wdc.com> Cc: Darren Hart <dvhart@infradead.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-riscv@lists.infradead.org Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> --- tools/perf/bench/futex.h | 52 +++++++++++++++++++++++++++++++++++++--- 1 file changed, 49 insertions(+), 3 deletions(-)
diff --git a/tools/perf/bench/futex.h b/tools/perf/bench/futex.h index ebdc2b032afc..385d2bdfaa9f 100644 --- a/tools/perf/bench/futex.h +++ b/tools/perf/bench/futex.h @@ -8,6 +8,7 @@ #ifndef _FUTEX_H #define _FUTEX_H +#include <errno.h> #include <unistd.h> #include <sys/syscall.h> #include <sys/types.h> @@ -28,7 +29,17 @@ struct bench_futex_parameters { }; /** - * futex_syscall() - SYS_futex syscall wrapper + * This is copied from linux/time_types.h. + * We copy this here to avoid compilation failures when running + * on systems that don't ship with linux/time_types.h. + */ +struct __kernel_old_timespec { + __kernel_old_time_t tv_sec; /* seconds */ + long tv_nsec; /* nanoseconds */ +}; + +/** + * futex_syscall() - __NR_futex syscall wrapper * @uaddr: address of first futex * @op: futex op code * @val: typically expected value of uaddr, but varies by op @@ -49,14 +60,49 @@ static inline int futex_syscall(volatile u_int32_t *uaddr, int op, u_int32_t val, struct timespec *timeout, volatile u_int32_t *uaddr2, int val3, int opflags) { - return syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3); +#if defined(__NR_futex_time64) + if (sizeof(*timeout) != sizeof(struct __kernel_old_timespec)) { + int ret = syscall(__NR_futex_time64, uaddr, op | opflags, val, timeout, + uaddr2, val3); + if (ret == 0 || errno != ENOSYS) + return ret; + } +#endif + +#if defined(__NR_futex) + if (sizeof(*timeout) == sizeof(struct __kernel_old_timespec)) + return syscall(__NR_futex, uaddr, op | opflags, val, timeout, uaddr2, val3); + + if (timeout && timeout->tv_sec == (long)timeout->tv_sec) { + struct __kernel_old_timespec ts32; + + ts32.tv_sec = (__kernel_long_t) timeout->tv_sec; + ts32.tv_nsec = (__kernel_long_t) timeout->tv_nsec; + + return syscall(__NR_futex, uaddr, op | opflags, val, ts32, uaddr2, val3); + } else if (!timeout) { + return syscall(__NR_futex, uaddr, op | opflags, val, NULL, uaddr2, val3); + } +#endif + + errno = ENOSYS; + return -1; } static inline int futex_syscall_nr_requeue(volatile u_int32_t *uaddr, int op, u_int32_t val, int nr_requeue, volatile u_int32_t *uaddr2, int val3, int opflags) { - return syscall(SYS_futex, uaddr, op | opflags, val, nr_requeue, uaddr2, val3); +#if defined(__NR_futex_time64) + int ret = syscall(__NR_futex_time64, uaddr, op | opflags, val, nr_requeue, + uaddr2, val3); + if (ret == 0 || errno != ENOSYS) + return ret; +#endif + +#if defined(__NR_futex) + return syscall(__NR_futex, uaddr, op | opflags, val, nr_requeue, uaddr2, val3); +#endif } /** -- 2.31.1
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