#ifndef _PERF_SYS_H
#define _PERF_SYS_H

#include <unistd.h>
#include <sys/types.h>
#include <sys/syscall.h>
#include <linux/types.h>
#include <linux/compiler.h>
#include <linux/perf_event.h>
#include <asm/barrier.h>

#if defined(__i386__)
#define cpu_relax()	asm volatile("rep; nop" ::: "memory");
#define CPUINFO_PROC	{"model name"}
#endif

#if defined(__x86_64__)
#define cpu_relax()	asm volatile("rep; nop" ::: "memory");
#define CPUINFO_PROC	{"model name"}
#endif

#ifdef __powerpc__
#define CPUINFO_PROC	{"cpu"}
#endif

#ifdef __s390__
#define CPUINFO_PROC	{"vendor_id"}
#endif

#ifdef __sh__
#define CPUINFO_PROC	{"cpu type"}
#endif

#ifdef __hppa__
#define CPUINFO_PROC	{"cpu"}
#endif

#ifdef __sparc__
#define CPUINFO_PROC	{"cpu"}
#endif

#ifdef __alpha__
#define CPUINFO_PROC	{"cpu model"}
#endif

#ifdef __ia64__
#define cpu_relax()	asm volatile ("hint @pause" ::: "memory")
#define CPUINFO_PROC	{"model name"}
#endif

#ifdef __arm__
#define CPUINFO_PROC	{"model name", "Processor"}
#endif

#ifdef __aarch64__
#define cpu_relax()	asm volatile("yield" ::: "memory")
#endif

#ifdef __mips__
#define CPUINFO_PROC	{"cpu model"}
#endif

#ifdef __arc__
#define CPUINFO_PROC	{"Processor"}
#endif

#ifdef __metag__
#define CPUINFO_PROC	{"CPU"}
#endif

#ifdef __xtensa__
#define CPUINFO_PROC	{"core ID"}
#endif

#ifdef __tile__
#define cpu_relax()	asm volatile ("mfspr zero, PASS" ::: "memory")
#define CPUINFO_PROC    {"model name"}
#endif

#ifndef cpu_relax
#define cpu_relax() barrier()
#endif

static inline int
sys_perf_event_open(struct perf_event_attr *attr,
		      pid_t pid, int cpu, int group_fd,
		      unsigned long flags)
{
	int fd;

	fd = syscall(__NR_perf_event_open, attr, pid, cpu,
		     group_fd, flags);

#ifdef HAVE_ATTR_TEST
	if (unlikely(test_attr__enabled))
		test_attr__open(attr, pid, cpu, fd, group_fd, flags);
#endif
	return fd;
}

#endif /* _PERF_SYS_H */
;id=10ff4c5239a137abfc896ec73ef3d15a0f86a16a'>tree</a><a class='active' href='/cgit.cgi/linux/net-next.git/commit/?h=nds-private-remove&amp;id=10ff4c5239a137abfc896ec73ef3d15a0f86a16a'>commit</a><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=10ff4c5239a137abfc896ec73ef3d15a0f86a16a'>diff</a></td><td class='form'><form class='right' method='get' action='/cgit.cgi/linux/net-next.git/log/'>
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<tr><th>author</th><td>Javier Martinez Canillas &lt;javier@osg.samsung.com&gt;</td><td class='right'>2016-04-16 21:14:52 -0400</td></tr>
<tr><th>committer</th><td>Wolfram Sang &lt;wsa@the-dreams.de&gt;</td><td class='right'>2016-04-22 15:31:54 +0200</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/?h=nds-private-remove&amp;id=10ff4c5239a137abfc896ec73ef3d15a0f86a16a'>10ff4c5239a137abfc896ec73ef3d15a0f86a16a</a> (<a href='/cgit.cgi/linux/net-next.git/patch/?id=10ff4c5239a137abfc896ec73ef3d15a0f86a16a'>patch</a>)</td></tr>
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<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/?h=nds-private-remove&amp;id=609d5a1b2b35bb62b4b3750396e55453160c2a17'>609d5a1b2b35bb62b4b3750396e55453160c2a17</a> (<a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=10ff4c5239a137abfc896ec73ef3d15a0f86a16a&amp;id2=609d5a1b2b35bb62b4b3750396e55453160c2a17'>diff</a>)</td></tr></table>
<div class='commit-subject'>i2c: exynos5: Fix possible ABBA deadlock by keeping I2C clock prepared</div><div class='commit-msg'>The exynos5 I2C controller driver always prepares and enables a clock
before using it and then disables unprepares it when the clock is not
used anymore.

But this can cause a possible ABBA deadlock in some scenarios since a
driver that uses regmap to access its I2C registers, will first grab
the regmap lock and then the I2C xfer function will grab the prepare
lock when preparing the I2C clock. But since the clock driver also
uses regmap for I2C accesses, preparing a clock will first grab the
prepare lock and then the regmap lock when using the regmap API.

An example of this happens on the Exynos5422 Odroid XU4 board where a
s2mps11 PMIC is used and both the s2mps11 regulators and clk drivers
share the same I2C regmap.

The possible deadlock is reported by the kernel lockdep:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(sec_core:428:(regmap)-&gt;lock);
                                lock(prepare_lock);
                                lock(sec_core:428:(regmap)-&gt;lock);
   lock(prepare_lock);

  *** DEADLOCK ***

Fix it by leaving the code prepared on probe and use {en,dis}able in
the I2C transfer function.

This patch is similar to commit 34e81ad5f0b6 ("i2c: s3c2410: fix ABBA
deadlock by keeping clock prepared") that fixes the same bug in other
driver for an I2C controller found in Samsung SoCs.

Reported-by: Anand Moon &lt;linux.amoon@gmail.com&gt;
Signed-off-by: Javier Martinez Canillas &lt;javier@osg.samsung.com&gt;
Reviewed-by: Anand Moon &lt;linux.amoon@gmail.com&gt;
Reviewed-by: Krzysztof Kozlowski &lt;k.kozlowski@samsung.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
Cc: stable@kernel.org
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=10ff4c5239a137abfc896ec73ef3d15a0f86a16a'>Diffstat</a></div><table summary='diffstat' class='diffstat'>