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From: Alistair Francis <alistair.francis@opensource.wdc.com>
To: linux-perf-users@vger.kernel.org, linux-riscv@lists.infradead.org
Cc: dvhart@infradead.org, tglx@linutronix.de,
	alexander.shishkin@linux.intel.com, jolsa@redhat.com,
	namhyung@kernel.org, mingo@redhat.com, atish.patra@wdc.com,
	linux-kernel@vger.kernel.org, arnd@arndb.de,
	alistair23@gmail.com, mark.rutland@arm.com, acme@kernel.org,
	peterz@infradead.org, dave@stgolabs.net,
	Alistair Francis <alistair.francis@wdc.com>,
	Davidlohr Bueso <dbueso@suse.de>
Subject: [PATCH v5 2/4] perf bench futex: Add support for 32-bit systems with 64-bit time_t
Date: Fri, 22 Oct 2021 11:33:41 +1000	[thread overview]
Message-ID: <20211022013343.2262938-2-alistair.francis@opensource.wdc.com> (raw)
In-Reply-To: <20211022013343.2262938-1-alistair.francis@opensource.wdc.com>

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).

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
---
 tools/perf/bench/futex.h | 43 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 40 insertions(+), 3 deletions(-)

diff --git a/tools/perf/bench/futex.h b/tools/perf/bench/futex.h
index ebdc2b032afc1..6a7dd86871eb8 100644
--- a/tools/perf/bench/futex.h
+++ b/tools/perf/bench/futex.h
@@ -8,10 +8,12 @@
 #ifndef _FUTEX_H
 #define _FUTEX_H
 
+#include <errno.h>
 #include <unistd.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <linux/futex.h>
+#include <linux/time_types.h>
 
 struct bench_futex_parameters {
 	bool silent;
@@ -28,7 +30,7 @@ struct bench_futex_parameters {
 };
 
 /**
- * futex_syscall() - SYS_futex syscall wrapper
+ * 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 +51,49 @@ 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


  reply	other threads:[~2021-10-22  1:34 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-22  1:33 [PATCH v5 1/4] perf bench futex: Call the futex syscall from a function Alistair Francis
2021-10-22  1:33 ` Alistair Francis [this message]
2021-10-22  1:33 ` [PATCH v5 3/4] selftests: " Alistair Francis
2021-10-22  1:33 ` [PATCH v5 4/4] selftests: futex: Add support for 32-bit systems with 64-bit time_t Alistair Francis
2021-10-27 23:56 ` [PATCH v5 1/4] perf bench futex: Call the futex syscall from a function Arnaldo Carvalho de Melo

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