From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org
Subject: [PATCH] linux: Avoid shifting a negative signed on POSIX timer interface
Date: Mon, 29 Aug 2022 16:00:43 -0300 [thread overview]
Message-ID: <20220829190043.946822-1-adhemerval.zanella@linaro.org> (raw)
The current macros uses pid as signed value, which triggers a compiler
warning for process and thread timers. Replace MAKE_PROCESS_CPUCLOCK
with static inline function that expects the pid as unsigned. These
are similar to what Linux does internally.
Checked on x86_64-linux-gnu.
---
nptl/pthread_getcpuclockid.c | 2 +-
sysdeps/unix/sysv/linux/clock_getcpuclockid.c | 2 +-
sysdeps/unix/sysv/linux/clock_nanosleep.c | 2 +-
.../unix/sysv/linux/kernel-posix-cpu-timers.h | 30 +++++++++++++++----
sysdeps/unix/sysv/linux/timer_create.c | 4 +--
5 files changed, 29 insertions(+), 11 deletions(-)
diff --git a/nptl/pthread_getcpuclockid.c b/nptl/pthread_getcpuclockid.c
index 344bd6560e..b8bf09f550 100644
--- a/nptl/pthread_getcpuclockid.c
+++ b/nptl/pthread_getcpuclockid.c
@@ -35,7 +35,7 @@ __pthread_getcpuclockid (pthread_t threadid, clockid_t *clockid)
/* The clockid_t value is a simple computation from the TID. */
- const clockid_t tidclock = MAKE_THREAD_CPUCLOCK (pd->tid, CPUCLOCK_SCHED);
+ const clockid_t tidclock = make_thread_cpuclock (pd->tid, CPUCLOCK_SCHED);
*clockid = tidclock;
return 0;
diff --git a/sysdeps/unix/sysv/linux/clock_getcpuclockid.c b/sysdeps/unix/sysv/linux/clock_getcpuclockid.c
index 5534127ed7..355d3c86af 100644
--- a/sysdeps/unix/sysv/linux/clock_getcpuclockid.c
+++ b/sysdeps/unix/sysv/linux/clock_getcpuclockid.c
@@ -29,7 +29,7 @@ __clock_getcpuclockid (pid_t pid, clockid_t *clock_id)
/* The clockid_t value is a simple computation from the PID.
But we do a clock_getres call to validate it. */
- const clockid_t pidclock = MAKE_PROCESS_CPUCLOCK (pid, CPUCLOCK_SCHED);
+ const clockid_t pidclock = make_process_cpuclock (pid, CPUCLOCK_SCHED);
#ifndef __NR_clock_getres_time64
# define __NR_clock_getres_time64 __NR_clock_getres
diff --git a/sysdeps/unix/sysv/linux/clock_nanosleep.c b/sysdeps/unix/sysv/linux/clock_nanosleep.c
index befe6ecb8c..e610fd4e8d 100644
--- a/sysdeps/unix/sysv/linux/clock_nanosleep.c
+++ b/sysdeps/unix/sysv/linux/clock_nanosleep.c
@@ -34,7 +34,7 @@ __clock_nanosleep_time64 (clockid_t clock_id, int flags,
if (clock_id == CLOCK_THREAD_CPUTIME_ID)
return EINVAL;
if (clock_id == CLOCK_PROCESS_CPUTIME_ID)
- clock_id = MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED);
+ clock_id = PROCESS_CLOCK;
/* If the call is interrupted by a signal handler or encounters an error,
it returns a positive value similar to errno. */
diff --git a/sysdeps/unix/sysv/linux/kernel-posix-cpu-timers.h b/sysdeps/unix/sysv/linux/kernel-posix-cpu-timers.h
index 164a90ddeb..9c74bb1cf5 100644
--- a/sysdeps/unix/sysv/linux/kernel-posix-cpu-timers.h
+++ b/sysdeps/unix/sysv/linux/kernel-posix-cpu-timers.h
@@ -1,4 +1,12 @@
-/* Parameters for the Linux kernel ABI for CPU clocks. */
+/*
+ Parameters for the Linux kernel ABI for CPU clocks, the bit fields within
+ a clockid:
+
+ - The most significant 29 bits hold either a pid or a file descriptor.
+ - Bit 2 indicates whether a cpu clock refers to a thread or a process.
+ - Bits 1 and 0 give the type: PROF=0, VIRT=1, SCHED=2, or FD=3.
+ - A clockid is invalid if bits 2, 1, and 0 are all set.
+ */
#define CPUCLOCK_PID(clock) ((pid_t) ~((clock) >> 3))
#define CPUCLOCK_PERTHREAD(clock) \
@@ -6,13 +14,23 @@
#define CPUCLOCK_PID_MASK 7
#define CPUCLOCK_PERTHREAD_MASK 4
#define CPUCLOCK_WHICH(clock) ((clock) & (clockid_t) CPUCLOCK_CLOCK_MASK)
-#define CPUCLOCK_CLOCK_MASK 3
+#define CPUCLOCK_CLOCK_MASK 3KE_PROCESS_CPUCLOCK
#define CPUCLOCK_PROF 0
#define CPUCLOCK_VIRT 1
#define CPUCLOCK_SCHED 2
#define CPUCLOCK_MAX 3
-#define MAKE_PROCESS_CPUCLOCK(pid, clock) \
- ((~(clockid_t) (pid) << 3) | (clockid_t) (clock))
-#define MAKE_THREAD_CPUCLOCK(tid, clock) \
- MAKE_PROCESS_CPUCLOCK((tid), (clock) | CPUCLOCK_PERTHREAD_MASK)
+static inline clockid_t
+make_process_cpuclock (unsigned int pid, clockid_t clock)
+{
+ return ((~pid) << 3) | clock;
+}
+
+static inline clockid_t
+make_thread_cpuclock (unsigned int tid, clockid_t clock)
+{
+ return make_process_cpuclock (tid, clock | CPUCLOCK_PERTHREAD_MASK);
+}
+
+#define PROCESS_CLOCK make_process_cpuclock (0, CPUCLOCK_SCHED)
+#define THREAD_CLOCK make_thread_cpuclock (0, CPUCLOCK_SCHED)
diff --git a/sysdeps/unix/sysv/linux/timer_create.c b/sysdeps/unix/sysv/linux/timer_create.c
index a8b2a41d9e..290324a7ea 100644
--- a/sysdeps/unix/sysv/linux/timer_create.c
+++ b/sysdeps/unix/sysv/linux/timer_create.c
@@ -33,9 +33,9 @@ ___timer_create (clockid_t clock_id, struct sigevent *evp, timer_t *timerid)
{
{
clockid_t syscall_clockid = (clock_id == CLOCK_PROCESS_CPUTIME_ID
- ? MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED)
+ ? PROCESS_CLOCK
: clock_id == CLOCK_THREAD_CPUTIME_ID
- ? MAKE_THREAD_CPUCLOCK (0, CPUCLOCK_SCHED)
+ ? THREAD_CLOCK
: clock_id);
/* If the user wants notification via a thread we need to handle
--
2.34.1
next reply other threads:[~2022-08-29 19:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-29 19:00 Adhemerval Zanella [this message]
2022-08-29 19:49 ` Andreas Schwab
2022-08-29 19:49 ` Andreas Schwab
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