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linux/lib/atomic64_test.c
Michael Ellerman ffba19ccae lib/atomic64_test.c: add a test that atomic64_inc_not_zero() returns an int 
atomic64_inc_not_zero() returns a "truth value" which in C is
traditionally an int.  That means callers are likely to expect the
result will fit in an int.

If an implementation returns a "true" value which does not fit in an
int, then there's a possibility that callers will truncate it when they
store it in an int.

In fact this happened in practice, see commit 966d2b04e0
("percpu-refcount: fix reference leak during percpu-atomic transition").

So add a test that the result fits in an int, even when the input
doesn't.  This catches the case where an implementation just passes the
non-zero input value out as the result.

Link: http://lkml.kernel.org/r/1499775133-1231-1-git-send-email-mpe@ellerman.id.au
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Douglas Miller <dougmill@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-14 15:05:13 -07:00

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/*
* Testsuite for atomic64_t functions
*
* Copyright © 2010 Luca Barbieri
*
* 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/atomic.h>
#include <linux/module.h>
#ifdef CONFIG_X86
#include <asm/cpufeature.h> /* for boot_cpu_has below */
#endif
#define TEST(bit, op, c_op, val) \
do { \
atomic##bit##_set(&v, v0); \
r = v0; \
atomic##bit##_##op(val, &v); \
r c_op val; \
WARN(atomic##bit##_read(&v) != r, "%Lx != %Lx\n", \
(unsigned long long)atomic##bit##_read(&v), \
(unsigned long long)r); \
} while (0)
/*
* Test for a atomic operation family,
* @test should be a macro accepting parameters (bit, op, ...)
*/
#define FAMILY_TEST(test, bit, op, args...) \
do { \
test(bit, op, ##args); \
test(bit, op##_acquire, ##args); \
test(bit, op##_release, ##args); \
test(bit, op##_relaxed, ##args); \
} while (0)
#define TEST_RETURN(bit, op, c_op, val) \
do { \
atomic##bit##_set(&v, v0); \
r = v0; \
r c_op val; \
BUG_ON(atomic##bit##_##op(val, &v) != r); \
BUG_ON(atomic##bit##_read(&v) != r); \
} while (0)
#define TEST_FETCH(bit, op, c_op, val) \
do { \
atomic##bit##_set(&v, v0); \
r = v0; \
r c_op val; \
BUG_ON(atomic##bit##_##op(val, &v) != v0); \
BUG_ON(atomic##bit##_read(&v) != r); \
} while (0)
#define RETURN_FAMILY_TEST(bit, op, c_op, val) \
do { \
FAMILY_TEST(TEST_RETURN, bit, op, c_op, val); \
} while (0)
#define FETCH_FAMILY_TEST(bit, op, c_op, val) \
do { \
FAMILY_TEST(TEST_FETCH, bit, op, c_op, val); \
} while (0)
#define TEST_ARGS(bit, op, init, ret, expect, args...) \
do { \
atomic##bit##_set(&v, init); \
BUG_ON(atomic##bit##_##op(&v, ##args) != ret); \
BUG_ON(atomic##bit##_read(&v) != expect); \
} while (0)
#define XCHG_FAMILY_TEST(bit, init, new) \
do { \
FAMILY_TEST(TEST_ARGS, bit, xchg, init, init, new, new); \
} while (0)
#define CMPXCHG_FAMILY_TEST(bit, init, new, wrong) \
do { \
FAMILY_TEST(TEST_ARGS, bit, cmpxchg, \
init, init, new, init, new); \
FAMILY_TEST(TEST_ARGS, bit, cmpxchg, \
init, init, init, wrong, new); \
} while (0)
#define INC_RETURN_FAMILY_TEST(bit, i) \
do { \
FAMILY_TEST(TEST_ARGS, bit, inc_return, \
i, (i) + one, (i) + one); \
} while (0)
#define DEC_RETURN_FAMILY_TEST(bit, i) \
do { \
FAMILY_TEST(TEST_ARGS, bit, dec_return, \
i, (i) - one, (i) - one); \
} while (0)
static __init void test_atomic(void)
{
int v0 = 0xaaa31337;
int v1 = 0xdeadbeef;
int onestwos = 0x11112222;
int one = 1;
atomic_t v;
int r;
TEST(, add, +=, onestwos);
TEST(, add, +=, -one);
TEST(, sub, -=, onestwos);
TEST(, sub, -=, -one);
TEST(, or, |=, v1);
TEST(, and, &=, v1);
TEST(, xor, ^=, v1);
TEST(, andnot, &= ~, v1);
RETURN_FAMILY_TEST(, add_return, +=, onestwos);
RETURN_FAMILY_TEST(, add_return, +=, -one);
RETURN_FAMILY_TEST(, sub_return, -=, onestwos);
RETURN_FAMILY_TEST(, sub_return, -=, -one);
FETCH_FAMILY_TEST(, fetch_add, +=, onestwos);
FETCH_FAMILY_TEST(, fetch_add, +=, -one);
FETCH_FAMILY_TEST(, fetch_sub, -=, onestwos);
FETCH_FAMILY_TEST(, fetch_sub, -=, -one);
FETCH_FAMILY_TEST(, fetch_or, |=, v1);
FETCH_FAMILY_TEST(, fetch_and, &=, v1);
FETCH_FAMILY_TEST(, fetch_andnot, &= ~, v1);
FETCH_FAMILY_TEST(, fetch_xor, ^=, v1);
INC_RETURN_FAMILY_TEST(, v0);
DEC_RETURN_FAMILY_TEST(, v0);
XCHG_FAMILY_TEST(, v0, v1);
CMPXCHG_FAMILY_TEST(, v0, v1, onestwos);
}
#define INIT(c) do { atomic64_set(&v, c); r = c; } while (0)
static __init void test_atomic64(void)
{
long long v0 = 0xaaa31337c001d00dLL;
long long v1 = 0xdeadbeefdeafcafeLL;
long long v2 = 0xfaceabadf00df001LL;
long long v3 = 0x8000000000000000LL;
long long onestwos = 0x1111111122222222LL;
long long one = 1LL;
int r_int;
atomic64_t v = ATOMIC64_INIT(v0);
long long r = v0;
BUG_ON(v.counter != r);
atomic64_set(&v, v1);
r = v1;
BUG_ON(v.counter != r);
BUG_ON(atomic64_read(&v) != r);
TEST(64, add, +=, onestwos);
TEST(64, add, +=, -one);
TEST(64, sub, -=, onestwos);
TEST(64, sub, -=, -one);
TEST(64, or, |=, v1);
TEST(64, and, &=, v1);
TEST(64, xor, ^=, v1);
TEST(64, andnot, &= ~, v1);
RETURN_FAMILY_TEST(64, add_return, +=, onestwos);
RETURN_FAMILY_TEST(64, add_return, +=, -one);
RETURN_FAMILY_TEST(64, sub_return, -=, onestwos);
RETURN_FAMILY_TEST(64, sub_return, -=, -one);
FETCH_FAMILY_TEST(64, fetch_add, +=, onestwos);
FETCH_FAMILY_TEST(64, fetch_add, +=, -one);
FETCH_FAMILY_TEST(64, fetch_sub, -=, onestwos);
FETCH_FAMILY_TEST(64, fetch_sub, -=, -one);
FETCH_FAMILY_TEST(64, fetch_or, |=, v1);
FETCH_FAMILY_TEST(64, fetch_and, &=, v1);
FETCH_FAMILY_TEST(64, fetch_andnot, &= ~, v1);
FETCH_FAMILY_TEST(64, fetch_xor, ^=, v1);
INIT(v0);
atomic64_inc(&v);
r += one;
BUG_ON(v.counter != r);
INIT(v0);
atomic64_dec(&v);
r -= one;
BUG_ON(v.counter != r);
INC_RETURN_FAMILY_TEST(64, v0);
DEC_RETURN_FAMILY_TEST(64, v0);
XCHG_FAMILY_TEST(64, v0, v1);
CMPXCHG_FAMILY_TEST(64, v0, v1, v2);
INIT(v0);
BUG_ON(atomic64_add_unless(&v, one, v0));
BUG_ON(v.counter != r);
INIT(v0);
BUG_ON(!atomic64_add_unless(&v, one, v1));
r += one;
BUG_ON(v.counter != r);
INIT(onestwos);
BUG_ON(atomic64_dec_if_positive(&v) != (onestwos - 1));
r -= one;
BUG_ON(v.counter != r);
INIT(0);
BUG_ON(atomic64_dec_if_positive(&v) != -one);
BUG_ON(v.counter != r);
INIT(-one);
BUG_ON(atomic64_dec_if_positive(&v) != (-one - one));
BUG_ON(v.counter != r);
INIT(onestwos);
BUG_ON(!atomic64_inc_not_zero(&v));
r += one;
BUG_ON(v.counter != r);
INIT(0);
BUG_ON(atomic64_inc_not_zero(&v));
BUG_ON(v.counter != r);
INIT(-one);
BUG_ON(!atomic64_inc_not_zero(&v));
r += one;
BUG_ON(v.counter != r);
/* Confirm the return value fits in an int, even if the value doesn't */
INIT(v3);
r_int = atomic64_inc_not_zero(&v);
BUG_ON(!r_int);
}
static __init int test_atomics_init(void)
{
test_atomic();
test_atomic64();
#ifdef CONFIG_X86
pr_info("passed for %s platform %s CX8 and %s SSE\n",
#ifdef CONFIG_X86_64
"x86-64",
#elif defined(CONFIG_X86_CMPXCHG64)
"i586+",
#else
"i386+",
#endif
boot_cpu_has(X86_FEATURE_CX8) ? "with" : "without",
boot_cpu_has(X86_FEATURE_XMM) ? "with" : "without");
#else
pr_info("passed\n");
#endif
return 0;
}
static __exit void test_atomics_exit(void) {}
module_init(test_atomics_init);
module_exit(test_atomics_exit);
MODULE_LICENSE("GPL");
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