Q: http://patchwork.ozlabs.org/project/netdev/list/
F: drivers/net/ethernet/mellanox/mlxsw/
+MEMBARRIER SUPPORT
+M: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+M: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
+L: linux-kernel@vger.kernel.org
+S: Supported
+F: kernel/membarrier.c
+F: include/uapi/linux/membarrier.h
+
MEMORY MANAGEMENT
L: linux-mm@kvack.org
W: http://www.linux-mm.org
372 i386 recvmsg sys_recvmsg compat_sys_recvmsg
373 i386 shutdown sys_shutdown
374 i386 userfaultfd sys_userfaultfd
+375 i386 membarrier sys_membarrier
321 common bpf sys_bpf
322 64 execveat stub_execveat
323 common userfaultfd sys_userfaultfd
+324 common membarrier sys_membarrier
#
# x32-specific system call numbers start at 512 to avoid cache impact
static ssize_t iotlb_dump_cr(struct omap_iommu *obj, struct cr_regs *cr,
struct seq_file *s)
{
- return seq_printf(s, "%08x %08x %01x\n", cr->cam, cr->ram,
+ seq_printf(s, "%08x %08x %01x\n", cr->cam, cr->ram,
(cr->cam & MMU_CAM_P) ? 1 : 0);
+ return 0;
}
static size_t omap_dump_tlb_entries(struct omap_iommu *obj, struct seq_file *s)
struct inode *inode = d_inode(dentry);
const struct proc_ns_operations *ns_ops = dentry->d_fsdata;
- return seq_printf(seq, "%s:[%lu]", ns_ops->name, inode->i_ino);
+ seq_printf(seq, "%s:[%lu]", ns_ops->name, inode->i_ino);
+ return 0;
}
static const struct super_operations nsfs_ops = {
struct dlm_migratable_lockres *mres)
{
struct dlm_migratable_lock *ml;
- struct list_head *queue;
+ struct list_head *queue, *iter;
struct list_head *tmpq = NULL;
struct dlm_lock *newlock = NULL;
struct dlm_lockstatus *lksb = NULL;
spin_lock(&res->spinlock);
for (j = DLM_GRANTED_LIST; j <= DLM_BLOCKED_LIST; j++) {
tmpq = dlm_list_idx_to_ptr(res, j);
- list_for_each_entry(lock, tmpq, list) {
+ list_for_each(iter, tmpq) {
+ lock = list_entry(iter,
+ struct dlm_lock, list);
if (lock->ml.cookie == ml->cookie)
break;
lock = NULL;
* @esc: set of characters that need escaping
*
* Puts string into buffer, replacing each occurrence of character from
- * @esc with usual octal escape. Returns 0 in case of success, -1 - in
- * case of overflow.
+ * @esc with usual octal escape.
+ * Use seq_has_overflowed() to check for errors.
*/
-int seq_escape(struct seq_file *m, const char *s, const char *esc)
+void seq_escape(struct seq_file *m, const char *s, const char *esc)
{
char *end = m->buf + m->size;
- char *p;
+ char *p;
char c;
- for (p = m->buf + m->count; (c = *s) != '\0' && p < end; s++) {
+ for (p = m->buf + m->count; (c = *s) != '\0' && p < end; s++) {
if (!strchr(esc, c)) {
*p++ = c;
continue;
continue;
}
seq_set_overflow(m);
- return -1;
- }
+ return;
+ }
m->count = p - m->buf;
- return 0;
}
EXPORT_SYMBOL(seq_escape);
-int seq_vprintf(struct seq_file *m, const char *f, va_list args)
+void seq_vprintf(struct seq_file *m, const char *f, va_list args)
{
int len;
len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
if (m->count + len < m->size) {
m->count += len;
- return 0;
+ return;
}
}
seq_set_overflow(m);
- return -1;
}
EXPORT_SYMBOL(seq_vprintf);
-int seq_printf(struct seq_file *m, const char *f, ...)
+void seq_printf(struct seq_file *m, const char *f, ...)
{
- int ret;
va_list args;
va_start(args, f);
- ret = seq_vprintf(m, f, args);
+ seq_vprintf(m, f, args);
va_end(args);
-
- return ret;
}
EXPORT_SYMBOL(seq_printf);
}
EXPORT_SYMBOL(seq_open_private);
-int seq_putc(struct seq_file *m, char c)
+void seq_putc(struct seq_file *m, char c)
{
- if (m->count < m->size) {
- m->buf[m->count++] = c;
- return 0;
- }
- return -1;
+ if (m->count >= m->size)
+ return;
+
+ m->buf[m->count++] = c;
}
EXPORT_SYMBOL(seq_putc);
-int seq_puts(struct seq_file *m, const char *s)
+void seq_puts(struct seq_file *m, const char *s)
{
int len = strlen(s);
- if (m->count + len < m->size) {
- memcpy(m->buf + m->count, s, len);
- m->count += len;
- return 0;
+
+ if (m->count + len >= m->size) {
+ seq_set_overflow(m);
+ return;
}
- seq_set_overflow(m);
- return -1;
+ memcpy(m->buf + m->count, s, len);
+ m->count += len;
}
EXPORT_SYMBOL(seq_puts);
* This routine is very quick when you show lots of numbers.
* In usual cases, it will be better to use seq_printf(). It's easier to read.
*/
-int seq_put_decimal_ull(struct seq_file *m, char delimiter,
- unsigned long long num)
+void seq_put_decimal_ull(struct seq_file *m, char delimiter,
+ unsigned long long num)
{
int len;
if (num < 10) {
m->buf[m->count++] = num + '0';
- return 0;
+ return;
}
len = num_to_str(m->buf + m->count, m->size - m->count, num);
if (!len)
goto overflow;
m->count += len;
- return 0;
+ return;
+
overflow:
seq_set_overflow(m);
- return -1;
}
EXPORT_SYMBOL(seq_put_decimal_ull);
-int seq_put_decimal_ll(struct seq_file *m, char delimiter,
- long long num)
+void seq_put_decimal_ll(struct seq_file *m, char delimiter, long long num)
{
if (num < 0) {
if (m->count + 3 >= m->size) {
seq_set_overflow(m);
- return -1;
+ return;
}
if (delimiter)
m->buf[m->count++] = delimiter;
num = -num;
delimiter = '-';
}
- return seq_put_decimal_ull(m, delimiter, num);
-
+ seq_put_decimal_ull(m, delimiter, num);
}
EXPORT_SYMBOL(seq_put_decimal_ll);
ssize_t seq_read(struct file *, char __user *, size_t, loff_t *);
loff_t seq_lseek(struct file *, loff_t, int);
int seq_release(struct inode *, struct file *);
-int seq_escape(struct seq_file *, const char *, const char *);
-int seq_putc(struct seq_file *m, char c);
-int seq_puts(struct seq_file *m, const char *s);
int seq_write(struct seq_file *seq, const void *data, size_t len);
-__printf(2, 3) int seq_printf(struct seq_file *, const char *, ...);
-__printf(2, 0) int seq_vprintf(struct seq_file *, const char *, va_list args);
+__printf(2, 0)
+void seq_vprintf(struct seq_file *m, const char *fmt, va_list args);
+__printf(2, 3)
+void seq_printf(struct seq_file *m, const char *fmt, ...);
+void seq_putc(struct seq_file *m, char c);
+void seq_puts(struct seq_file *m, const char *s);
+void seq_put_decimal_ull(struct seq_file *m, char delimiter,
+ unsigned long long num);
+void seq_put_decimal_ll(struct seq_file *m, char delimiter, long long num);
+void seq_escape(struct seq_file *m, const char *s, const char *esc);
void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
int rowsize, int groupsize, const void *buf, size_t len,
void *__seq_open_private(struct file *, const struct seq_operations *, int);
int seq_open_private(struct file *, const struct seq_operations *, int);
int seq_release_private(struct inode *, struct file *);
-int seq_put_decimal_ull(struct seq_file *m, char delimiter,
- unsigned long long num);
-int seq_put_decimal_ll(struct seq_file *m, char delimiter,
- long long num);
static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
{
const char __user *const __user *argv,
const char __user *const __user *envp, int flags);
+asmlinkage long sys_membarrier(int cmd, int flags);
+
#endif
__SYSCALL(__NR_bpf, sys_bpf)
#define __NR_execveat 281
__SC_COMP(__NR_execveat, sys_execveat, compat_sys_execveat)
+#define __NR_membarrier 282
+__SYSCALL(__NR_membarrier, sys_membarrier)
#undef __NR_syscalls
-#define __NR_syscalls 282
+#define __NR_syscalls 283
/*
* All syscalls below here should go away really,
header-y += media.h
header-y += media-bus-format.h
header-y += mei.h
+header-y += membarrier.h
header-y += memfd.h
header-y += mempolicy.h
header-y += meye.h
--- /dev/null
+#ifndef _UAPI_LINUX_MEMBARRIER_H
+#define _UAPI_LINUX_MEMBARRIER_H
+
+/*
+ * linux/membarrier.h
+ *
+ * membarrier system call API
+ *
+ * Copyright (c) 2010, 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+/**
+ * enum membarrier_cmd - membarrier system call command
+ * @MEMBARRIER_CMD_QUERY: Query the set of supported commands. It returns
+ * a bitmask of valid commands.
+ * @MEMBARRIER_CMD_SHARED: Execute a memory barrier on all running threads.
+ * Upon return from system call, the caller thread
+ * is ensured that all running threads have passed
+ * through a state where all memory accesses to
+ * user-space addresses match program order between
+ * entry to and return from the system call
+ * (non-running threads are de facto in such a
+ * state). This covers threads from all processes
+ * running on the system. This command returns 0.
+ *
+ * Command to be passed to the membarrier system call. The commands need to
+ * be a single bit each, except for MEMBARRIER_CMD_QUERY which is assigned to
+ * the value 0.
+ */
+enum membarrier_cmd {
+ MEMBARRIER_CMD_QUERY = 0,
+ MEMBARRIER_CMD_SHARED = (1 << 0),
+};
+
+#endif /* _UAPI_LINUX_MEMBARRIER_H */
bugs/quirks. Disable this only if your target machine is
unaffected by PCI quirks.
+config MEMBARRIER
+ bool "Enable membarrier() system call" if EXPERT
+ default y
+ help
+ Enable the membarrier() system call that allows issuing memory
+ barriers across all running threads, which can be used to distribute
+ the cost of user-space memory barriers asymmetrically by transforming
+ pairs of memory barriers into pairs consisting of membarrier() and a
+ compiler barrier.
+
+ If unsure, say Y.
+
config EMBEDDED
bool "Embedded system"
option allnoconfig_y
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o
obj-$(CONFIG_TORTURE_TEST) += torture.o
+obj-$(CONFIG_MEMBARRIER) += membarrier.o
obj-$(CONFIG_HAS_IOMEM) += memremap.o
--- /dev/null
+/*
+ * Copyright (C) 2010, 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * membarrier system call
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/syscalls.h>
+#include <linux/membarrier.h>
+
+/*
+ * Bitmask made from a "or" of all commands within enum membarrier_cmd,
+ * except MEMBARRIER_CMD_QUERY.
+ */
+#define MEMBARRIER_CMD_BITMASK (MEMBARRIER_CMD_SHARED)
+
+/**
+ * sys_membarrier - issue memory barriers on a set of threads
+ * @cmd: Takes command values defined in enum membarrier_cmd.
+ * @flags: Currently needs to be 0. For future extensions.
+ *
+ * If this system call is not implemented, -ENOSYS is returned. If the
+ * command specified does not exist, or if the command argument is invalid,
+ * this system call returns -EINVAL. For a given command, with flags argument
+ * set to 0, this system call is guaranteed to always return the same value
+ * until reboot.
+ *
+ * All memory accesses performed in program order from each targeted thread
+ * is guaranteed to be ordered with respect to sys_membarrier(). If we use
+ * the semantic "barrier()" to represent a compiler barrier forcing memory
+ * accesses to be performed in program order across the barrier, and
+ * smp_mb() to represent explicit memory barriers forcing full memory
+ * ordering across the barrier, we have the following ordering table for
+ * each pair of barrier(), sys_membarrier() and smp_mb():
+ *
+ * The pair ordering is detailed as (O: ordered, X: not ordered):
+ *
+ * barrier() smp_mb() sys_membarrier()
+ * barrier() X X O
+ * smp_mb() X O O
+ * sys_membarrier() O O O
+ */
+SYSCALL_DEFINE2(membarrier, int, cmd, int, flags)
+{
+ if (unlikely(flags))
+ return -EINVAL;
+ switch (cmd) {
+ case MEMBARRIER_CMD_QUERY:
+ return MEMBARRIER_CMD_BITMASK;
+ case MEMBARRIER_CMD_SHARED:
+ if (num_online_cpus() > 1)
+ synchronize_sched();
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
/* execveat */
cond_syscall(sys_execveat);
+
+/* membarrier */
+cond_syscall(sys_membarrier);
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <asm/fixmap.h>
+#include <asm/early_ioremap.h>
#ifdef CONFIG_MMU
static int early_ioremap_debug __initdata;
ERR(!wb, "%s", cert_dst);
}
X509_NAME_oneline(X509_get_subject_name(x509), buf, sizeof(buf));
- ERR(!i2d_X509_bio(wb, x509), cert_dst);
+ ERR(!i2d_X509_bio(wb, x509), "%s", cert_dst);
if (kbuild_verbose)
fprintf(stderr, "Extracted cert: %s\n", buf);
}
TARGETS += ftrace
TARGETS += futex
TARGETS += kcmp
+TARGETS += membarrier
TARGETS += memfd
TARGETS += memory-hotplug
TARGETS += mount
--- /dev/null
+membarrier_test
--- /dev/null
+CFLAGS += -g -I../../../../usr/include/
+
+all:
+ $(CC) $(CFLAGS) membarrier_test.c -o membarrier_test
+
+TEST_PROGS := membarrier_test
+
+include ../lib.mk
+
+clean:
+ $(RM) membarrier_test
--- /dev/null
+#define _GNU_SOURCE
+#define __EXPORTED_HEADERS__
+
+#include <linux/membarrier.h>
+#include <asm-generic/unistd.h>
+#include <sys/syscall.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+
+#include "../kselftest.h"
+
+enum test_membarrier_status {
+ TEST_MEMBARRIER_PASS = 0,
+ TEST_MEMBARRIER_FAIL,
+ TEST_MEMBARRIER_SKIP,
+};
+
+static int sys_membarrier(int cmd, int flags)
+{
+ return syscall(__NR_membarrier, cmd, flags);
+}
+
+static enum test_membarrier_status test_membarrier_cmd_fail(void)
+{
+ int cmd = -1, flags = 0;
+
+ if (sys_membarrier(cmd, flags) != -1) {
+ printf("membarrier: Wrong command should fail but passed.\n");
+ return TEST_MEMBARRIER_FAIL;
+ }
+ return TEST_MEMBARRIER_PASS;
+}
+
+static enum test_membarrier_status test_membarrier_flags_fail(void)
+{
+ int cmd = MEMBARRIER_CMD_QUERY, flags = 1;
+
+ if (sys_membarrier(cmd, flags) != -1) {
+ printf("membarrier: Wrong flags should fail but passed.\n");
+ return TEST_MEMBARRIER_FAIL;
+ }
+ return TEST_MEMBARRIER_PASS;
+}
+
+static enum test_membarrier_status test_membarrier_success(void)
+{
+ int cmd = MEMBARRIER_CMD_SHARED, flags = 0;
+
+ if (sys_membarrier(cmd, flags) != 0) {
+ printf("membarrier: Executing MEMBARRIER_CMD_SHARED failed. %s.\n",
+ strerror(errno));
+ return TEST_MEMBARRIER_FAIL;
+ }
+
+ printf("membarrier: MEMBARRIER_CMD_SHARED success.\n");
+ return TEST_MEMBARRIER_PASS;
+}
+
+static enum test_membarrier_status test_membarrier(void)
+{
+ enum test_membarrier_status status;
+
+ status = test_membarrier_cmd_fail();
+ if (status)
+ return status;
+ status = test_membarrier_flags_fail();
+ if (status)
+ return status;
+ status = test_membarrier_success();
+ if (status)
+ return status;
+ return TEST_MEMBARRIER_PASS;
+}
+
+static enum test_membarrier_status test_membarrier_query(void)
+{
+ int flags = 0, ret;
+
+ printf("membarrier MEMBARRIER_CMD_QUERY ");
+ ret = sys_membarrier(MEMBARRIER_CMD_QUERY, flags);
+ if (ret < 0) {
+ printf("failed. %s.\n", strerror(errno));
+ switch (errno) {
+ case ENOSYS:
+ /*
+ * It is valid to build a kernel with
+ * CONFIG_MEMBARRIER=n. However, this skips the tests.
+ */
+ return TEST_MEMBARRIER_SKIP;
+ case EINVAL:
+ default:
+ return TEST_MEMBARRIER_FAIL;
+ }
+ }
+ if (!(ret & MEMBARRIER_CMD_SHARED)) {
+ printf("command MEMBARRIER_CMD_SHARED is not supported.\n");
+ return TEST_MEMBARRIER_FAIL;
+ }
+ printf("syscall available.\n");
+ return TEST_MEMBARRIER_PASS;
+}
+
+int main(int argc, char **argv)
+{
+ switch (test_membarrier_query()) {
+ case TEST_MEMBARRIER_FAIL:
+ return ksft_exit_fail();
+ case TEST_MEMBARRIER_SKIP:
+ return ksft_exit_skip();
+ }
+ switch (test_membarrier()) {
+ case TEST_MEMBARRIER_FAIL:
+ return ksft_exit_fail();
+ case TEST_MEMBARRIER_SKIP:
+ return ksft_exit_skip();
+ }
+
+ printf("membarrier: tests done!\n");
+ return ksft_exit_pass();
+}
projects / cascardo / linux.git / commitdiff