Import necessary atomic functions used by qspinlock. Copied x86
implementation verbatim, and used compiler builtin for generic
implementation.
Signed-off-by: Yuzhuo Jing <yuzhuo@google.com>
---
tools/arch/x86/include/asm/atomic.h | 14 +++
tools/arch/x86/include/asm/cmpxchg.h | 113 +++++++++++++++++++++++++
tools/include/asm-generic/atomic-gcc.h | 47 ++++++++++
tools/include/linux/atomic.h | 24 ++++++
tools/include/linux/compiler_types.h | 24 ++++++
5 files changed, 222 insertions(+)
diff --git a/tools/arch/x86/include/asm/atomic.h b/tools/arch/x86/include/asm/atomic.h
index 365cf182df12..a55ffd4eb5f1 100644
--- a/tools/arch/x86/include/asm/atomic.h
+++ b/tools/arch/x86/include/asm/atomic.h
@@ -71,6 +71,20 @@ static __always_inline int atomic_cmpxchg(atomic_t *v, int old, int new)
return cmpxchg(&v->counter, old, new);
}
+static __always_inline bool atomic_try_cmpxchg(atomic_t *v, int *old, int new)
+{
+ return try_cmpxchg(&v->counter, old, new);
+}
+
+static __always_inline int atomic_fetch_or(int i, atomic_t *v)
+{
+ int val = atomic_read(v);
+
+ do { } while (!atomic_try_cmpxchg(v, &val, val | i));
+
+ return val;
+}
+
static inline int test_and_set_bit(long nr, unsigned long *addr)
{
GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(bts), *addr, "Ir", nr, "%0", "c");
diff --git a/tools/arch/x86/include/asm/cmpxchg.h b/tools/arch/x86/include/asm/cmpxchg.h
index 0ed9ca2766ad..5372da8b27fc 100644
--- a/tools/arch/x86/include/asm/cmpxchg.h
+++ b/tools/arch/x86/include/asm/cmpxchg.h
@@ -8,6 +8,8 @@
* Non-existant functions to indicate usage errors at link time
* (or compile-time if the compiler implements __compiletime_error().
*/
+extern void __xchg_wrong_size(void)
+ __compiletime_error("Bad argument size for xchg");
extern void __cmpxchg_wrong_size(void)
__compiletime_error("Bad argument size for cmpxchg");
@@ -27,6 +29,49 @@ extern void __cmpxchg_wrong_size(void)
#define __X86_CASE_Q -1 /* sizeof will never return -1 */
#endif
+/*
+ * An exchange-type operation, which takes a value and a pointer, and
+ * returns the old value.
+ */
+#define __xchg_op(ptr, arg, op, lock) \
+ ({ \
+ __typeof__ (*(ptr)) __ret = (arg); \
+ switch (sizeof(*(ptr))) { \
+ case __X86_CASE_B: \
+ asm_inline volatile (lock #op "b %b0, %1" \
+ : "+q" (__ret), "+m" (*(ptr)) \
+ : : "memory", "cc"); \
+ break; \
+ case __X86_CASE_W: \
+ asm_inline volatile (lock #op "w %w0, %1" \
+ : "+r" (__ret), "+m" (*(ptr)) \
+ : : "memory", "cc"); \
+ break; \
+ case __X86_CASE_L: \
+ asm_inline volatile (lock #op "l %0, %1" \
+ : "+r" (__ret), "+m" (*(ptr)) \
+ : : "memory", "cc"); \
+ break; \
+ case __X86_CASE_Q: \
+ asm_inline volatile (lock #op "q %q0, %1" \
+ : "+r" (__ret), "+m" (*(ptr)) \
+ : : "memory", "cc"); \
+ break; \
+ default: \
+ __ ## op ## _wrong_size(); \
+ __cmpxchg_wrong_size(); \
+ } \
+ __ret; \
+ })
+
+/*
+ * Note: no "lock" prefix even on SMP: xchg always implies lock anyway.
+ * Since this is generally used to protect other memory information, we
+ * use "asm volatile" and "memory" clobbers to prevent gcc from moving
+ * information around.
+ */
+#define xchg(ptr, v) __xchg_op((ptr), (v), xchg, "")
+
/*
* Atomic compare and exchange. Compare OLD with MEM, if identical,
* store NEW in MEM. Return the initial value in MEM. Success is
@@ -86,5 +131,73 @@ extern void __cmpxchg_wrong_size(void)
#define cmpxchg(ptr, old, new) \
__cmpxchg(ptr, old, new, sizeof(*(ptr)))
+#define __raw_try_cmpxchg(_ptr, _pold, _new, size, lock) \
+({ \
+ bool success; \
+ __typeof__(_ptr) _old = (__typeof__(_ptr))(_pold); \
+ __typeof__(*(_ptr)) __old = *_old; \
+ __typeof__(*(_ptr)) __new = (_new); \
+ switch (size) { \
+ case __X86_CASE_B: \
+ { \
+ volatile u8 *__ptr = (volatile u8 *)(_ptr); \
+ asm_inline volatile(lock "cmpxchgb %[new], %[ptr]" \
+ CC_SET(z) \
+ : CC_OUT(z) (success), \
+ [ptr] "+m" (*__ptr), \
+ [old] "+a" (__old) \
+ : [new] "q" (__new) \
+ : "memory"); \
+ break; \
+ } \
+ case __X86_CASE_W: \
+ { \
+ volatile u16 *__ptr = (volatile u16 *)(_ptr); \
+ asm_inline volatile(lock "cmpxchgw %[new], %[ptr]" \
+ CC_SET(z) \
+ : CC_OUT(z) (success), \
+ [ptr] "+m" (*__ptr), \
+ [old] "+a" (__old) \
+ : [new] "r" (__new) \
+ : "memory"); \
+ break; \
+ } \
+ case __X86_CASE_L: \
+ { \
+ volatile u32 *__ptr = (volatile u32 *)(_ptr); \
+ asm_inline volatile(lock "cmpxchgl %[new], %[ptr]" \
+ CC_SET(z) \
+ : CC_OUT(z) (success), \
+ [ptr] "+m" (*__ptr), \
+ [old] "+a" (__old) \
+ : [new] "r" (__new) \
+ : "memory"); \
+ break; \
+ } \
+ case __X86_CASE_Q: \
+ { \
+ volatile u64 *__ptr = (volatile u64 *)(_ptr); \
+ asm_inline volatile(lock "cmpxchgq %[new], %[ptr]" \
+ CC_SET(z) \
+ : CC_OUT(z) (success), \
+ [ptr] "+m" (*__ptr), \
+ [old] "+a" (__old) \
+ : [new] "r" (__new) \
+ : "memory"); \
+ break; \
+ } \
+ default: \
+ __cmpxchg_wrong_size(); \
+ } \
+ if (unlikely(!success)) \
+ *_old = __old; \
+ likely(success); \
+})
+
+#define __try_cmpxchg(ptr, pold, new, size) \
+ __raw_try_cmpxchg((ptr), (pold), (new), (size), LOCK_PREFIX)
+
+#define try_cmpxchg(ptr, pold, new) \
+ __try_cmpxchg((ptr), (pold), (new), sizeof(*(ptr)))
#endif /* TOOLS_ASM_X86_CMPXCHG_H */
diff --git a/tools/include/asm-generic/atomic-gcc.h b/tools/include/asm-generic/atomic-gcc.h
index 9b3c528bab92..08b7b3b36873 100644
--- a/tools/include/asm-generic/atomic-gcc.h
+++ b/tools/include/asm-generic/atomic-gcc.h
@@ -62,6 +62,12 @@ static inline int atomic_dec_and_test(atomic_t *v)
return __sync_sub_and_fetch(&v->counter, 1) == 0;
}
+#define xchg(ptr, v) \
+ __atomic_exchange_n(ptr, v, __ATOMIC_SEQ_CST)
+
+#define xchg_relaxed(ptr, v) \
+ __atomic_exchange_n(ptr, v, __ATOMIC_RELAXED)
+
#define cmpxchg(ptr, oldval, newval) \
__sync_val_compare_and_swap(ptr, oldval, newval)
@@ -70,6 +76,47 @@ static inline int atomic_cmpxchg(atomic_t *v, int oldval, int newval)
return cmpxchg(&(v)->counter, oldval, newval);
}
+/**
+ * atomic_try_cmpxchg() - atomic compare and exchange with full ordering
+ * @v: pointer to atomic_t
+ * @old: pointer to int value to compare with
+ * @new: int value to assign
+ *
+ * If (@v == @old), atomically updates @v to @new with full ordering.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
+ *
+ * Unsafe to use in noinstr code; use raw_atomic_try_cmpxchg() there.
+ *
+ * Return: @true if the exchange occured, @false otherwise.
+ */
+static __always_inline bool
+atomic_try_cmpxchg(atomic_t *v, int *old, int new)
+{
+ int r, o = *old;
+ r = atomic_cmpxchg(v, o, new);
+ if (unlikely(r != o))
+ *old = r;
+ return likely(r == o);
+}
+
+/**
+ * atomic_fetch_or() - atomic bitwise OR with full ordering
+ * @i: int value
+ * @v: pointer to atomic_t
+ *
+ * Atomically updates @v to (@v | @i) with full ordering.
+ *
+ * Unsafe to use in noinstr code; use raw_atomic_fetch_or() there.
+ *
+ * Return: The original value of @v.
+ */
+static __always_inline int
+atomic_fetch_or(int i, atomic_t *v)
+{
+ return __sync_fetch_and_or(&v->counter, i);
+}
+
static inline int test_and_set_bit(long nr, unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
diff --git a/tools/include/linux/atomic.h b/tools/include/linux/atomic.h
index 01907b33537e..332a34177995 100644
--- a/tools/include/linux/atomic.h
+++ b/tools/include/linux/atomic.h
@@ -12,4 +12,28 @@ void atomic_long_set(atomic_long_t *v, long i);
#define atomic_cmpxchg_release atomic_cmpxchg
#endif /* atomic_cmpxchg_relaxed */
+#ifndef atomic_cmpxchg_acquire
+#define atomic_cmpxchg_acquire atomic_cmpxchg
+#endif
+
+#ifndef atomic_try_cmpxchg_acquire
+#define atomic_try_cmpxchg_acquire atomic_try_cmpxchg
+#endif
+
+#ifndef atomic_try_cmpxchg_relaxed
+#define atomic_try_cmpxchg_relaxed atomic_try_cmpxchg
+#endif
+
+#ifndef atomic_fetch_or_acquire
+#define atomic_fetch_or_acquire atomic_fetch_or
+#endif
+
+#ifndef xchg_relaxed
+#define xchg_relaxed xchg
+#endif
+
+#ifndef cmpxchg_release
+#define cmpxchg_release cmpxchg
+#endif
+
#endif /* __TOOLS_LINUX_ATOMIC_H */
diff --git a/tools/include/linux/compiler_types.h b/tools/include/linux/compiler_types.h
index d09f9dc172a4..9a2a2f8d7b6c 100644
--- a/tools/include/linux/compiler_types.h
+++ b/tools/include/linux/compiler_types.h
@@ -31,6 +31,28 @@
# define __cond_lock(x,c) (c)
#endif /* __CHECKER__ */
+/*
+ * __unqual_scalar_typeof(x) - Declare an unqualified scalar type, leaving
+ * non-scalar types unchanged.
+ */
+/*
+ * Prefer C11 _Generic for better compile-times and simpler code. Note: 'char'
+ * is not type-compatible with 'signed char', and we define a separate case.
+ */
+#define __scalar_type_to_expr_cases(type) \
+ unsigned type: (unsigned type)0, \
+ signed type: (signed type)0
+
+#define __unqual_scalar_typeof(x) typeof( \
+ _Generic((x), \
+ char: (char)0, \
+ __scalar_type_to_expr_cases(char), \
+ __scalar_type_to_expr_cases(short), \
+ __scalar_type_to_expr_cases(int), \
+ __scalar_type_to_expr_cases(long), \
+ __scalar_type_to_expr_cases(long long), \
+ default: (x)))
+
/* Compiler specific macros. */
#ifdef __GNUC__
#include <linux/compiler-gcc.h>
@@ -40,4 +62,6 @@
#define asm_goto_output(x...) asm goto(x)
#endif
+#define asm_inline asm
+
#endif /* __LINUX_COMPILER_TYPES_H */
--
2.50.1.487.gc89ff58d15-goog
Hello,
kernel test robot noticed "kernel-selftests.kvm.make.fail" on:
commit: 108c296547f3e749d89c270aa6319894f014f01c ("[PATCH v1 1/7] tools: Import cmpxchg and xchg functions")
url: https://github.com/intel-lab-lkp/linux/commits/Yuzhuo-Jing/tools-Import-cmpxchg-and-xchg-functions/20250729-102940
base: https://git.kernel.org/cgit/linux/kernel/git/perf/perf-tools-next.git perf-tools-next
patch link: https://lore.kernel.org/all/20250729022640.3134066-2-yuzhuo@google.com/
patch subject: [PATCH v1 1/7] tools: Import cmpxchg and xchg functions
in testcase: kernel-selftests
version: kernel-selftests-x86_64-186f3edfdd41-1_20250803
with following parameters:
group: kvm
config: x86_64-rhel-9.4-kselftests
compiler: gcc-12
test machine: 224 threads 2 sockets Intel(R) Xeon(R) Platinum 8480+ (Sapphire Rapids) with 256G memory
(please refer to attached dmesg/kmsg for entire log/backtrace)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202508080716.5744484-lkp@intel.com
KERNEL SELFTESTS: linux_headers_dir is /usr/src/linux-headers-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c
2025-08-05 10:05:53 sed -i s/default_timeout=45/default_timeout=300/ kselftest/runner.sh
2025-08-05 10:05:53 make -j224 TARGETS=kvm
make[1]: Entering directory '/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/kvm'
gcc -D_GNU_SOURCE= -I/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/cgroup/lib/include -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 -Wno-gnu-variable-sized-type-not-at-end -MD -MP -DCONFIG_64BIT -fno-builtin-memcmp -fno-builtin-memcpy -fno-builtin-memset -fno-builtin-strnlen -fno-stack-protector -fno-PIE -fno-strict-aliasing -I/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include -I/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/arch/x86/include -I/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../usr/include/ -Iinclude -I. -Iinclude/x86 -I ../rseq -I.. -isystem /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/usr/include -march=x86-64-v2 -c demand_paging_test.c -o /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/kvm/demand_paging_test.o
...
gcc -D_GNU_SOURCE= -I/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/cgroup/lib/include -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 -Wno-gnu-variable-sized-type-not-at-end -MD -MP -DCONFIG_64BIT -fno-builtin-memcmp -fno-builtin-memcpy -fno-builtin-memset -fno-builtin-strnlen -fno-stack-protector -fno-PIE -fno-strict-aliasing -I/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include -I/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/arch/x86/include -I/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../usr/include/ -Iinclude -I. -Iinclude/x86 -I ../rseq -I.. -isystem /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/usr/include -march=x86-64-v2 -c pre_fault_memory_test.c -o /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/kvm/pre_fault_memory_test.o
gcc -D_GNU_SOURCE= -I/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/cgroup/lib/include -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 -Wno-gnu-variable-sized-type-not-at-end -MD -MP -DCONFIG_64BIT -fno-builtin-memcmp -fno-builtin-memcpy -fno-builtin-memset -fno-builtin-strnlen -fno-stack-protector -fno-PIE -fno-strict-aliasing -I/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include -I/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/arch/x86/include -I/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../usr/include/ -Iinclude -Ix86 -Iinclude/x86 -I ../rseq -I.. -isystem /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/usr/include -march=x86-64-v2 -c x86/nx_huge_pages_test.c -o /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/kvm/x86/nx_huge_pages_test.o
In file included from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/bits.h:34,
from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/arch/x86/include/asm/msr-index.h:5,
from include/x86/processor.h:13,
from include/x86/apic.h:11,
from x86/fix_hypercall_test.c:13:
/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/overflow.h:31: warning: "is_signed_type" redefined
31 | #define is_signed_type(type) (((type)(-1)) < (type)1)
|
In file included from include/kvm_test_harness.h:11,
from x86/fix_hypercall_test.c:12:
../kselftest_harness.h:754: note: this is the location of the previous definition
754 | #define is_signed_type(var) (!!(((__typeof__(var))(-1)) < (__typeof__(var))1))
|
In file included from x86/svm_nested_soft_inject_test.c:11:
/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/asm/../../arch/x86/include/asm/atomic.h:79:28: error: expected declaration specifiers or ‘...’ before ‘(’ token
79 | static __always_inline int atomic_fetch_or(int i, atomic_t *v)
| ^~~~~~~~~~~~~~~
/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/asm/../../arch/x86/include/asm/atomic.h:79:28: error: expected declaration specifiers or ‘...’ before ‘(’ token
79 | static __always_inline int atomic_fetch_or(int i, atomic_t *v)
| ^~~~~~~~~~~~~~~
/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/asm/../../arch/x86/include/asm/atomic.h:79:28: error: expected declaration specifiers or ‘...’ before numeric constant
79 | static __always_inline int atomic_fetch_or(int i, atomic_t *v)
| ^~~~~~~~~~~~~~~
In file included from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/bits.h:34,
from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/bitops.h:14,
from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/hashtable.h:13,
from include/kvm_util.h:11,
from x86/userspace_msr_exit_test.c:11:
/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/overflow.h:31: warning: "is_signed_type" redefined
31 | #define is_signed_type(type) (((type)(-1)) < (type)1)
|
In file included from include/kvm_test_harness.h:11,
from x86/userspace_msr_exit_test.c:9:
../kselftest_harness.h:754: note: this is the location of the previous definition
754 | #define is_signed_type(var) (!!(((__typeof__(var))(-1)) < (__typeof__(var))1))
|
cc1: note: unrecognized command-line option ‘-Wno-gnu-variable-sized-type-not-at-end’ may have been intended to silence earlier diagnostics
make[1]: *** [Makefile.kvm:299: /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/kvm/x86/svm_nested_soft_inject_test.o] Error 1
make[1]: *** Waiting for unfinished jobs....
In file included from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/bits.h:34,
from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/bitops.h:14,
from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/hashtable.h:13,
from include/kvm_util.h:11,
from x86/sync_regs_test.c:20:
/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/overflow.h:31: warning: "is_signed_type" redefined
31 | #define is_signed_type(type) (((type)(-1)) < (type)1)
|
In file included from include/kvm_test_harness.h:11,
from x86/sync_regs_test.c:18:
../kselftest_harness.h:754: note: this is the location of the previous definition
754 | #define is_signed_type(var) (!!(((__typeof__(var))(-1)) < (__typeof__(var))1))
|
In file included from include/kvm_test_harness.h:11,
from x86/vmx_pmu_caps_test.c:17:
../kselftest_harness.h:754: warning: "is_signed_type" redefined
754 | #define is_signed_type(var) (!!(((__typeof__(var))(-1)) < (__typeof__(var))1))
|
In file included from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/bits.h:34,
from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/bitops.h:14,
from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/bitmap.h:7,
from x86/vmx_pmu_caps_test.c:15:
/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/linux/overflow.h:31: note: this is the location of the previous definition
31 | #define is_signed_type(type) (((type)(-1)) < (type)1)
|
In file included from memslot_perf_test.c:12:
/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/asm/../../arch/x86/include/asm/atomic.h:79:28: error: expected declaration specifiers or ‘...’ before ‘(’ token
79 | static __always_inline int atomic_fetch_or(int i, atomic_t *v)
| ^~~~~~~~~~~~~~~
/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/asm/../../arch/x86/include/asm/atomic.h:79:28: error: expected declaration specifiers or ‘...’ before ‘(’ token
79 | static __always_inline int atomic_fetch_or(int i, atomic_t *v)
| ^~~~~~~~~~~~~~~
/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/../../../tools/include/asm/../../arch/x86/include/asm/atomic.h:79:28: error: expected declaration specifiers or ‘...’ before numeric constant
79 | static __always_inline int atomic_fetch_or(int i, atomic_t *v)
| ^~~~~~~~~~~~~~~
cc1: note: unrecognized command-line option ‘-Wno-gnu-variable-sized-type-not-at-end’ may have been intended to silence earlier diagnostics
make[1]: *** [Makefile.kvm:299: /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/kvm/memslot_perf_test.o] Error 1
cc1: note: unrecognized command-line option ‘-Wno-gnu-variable-sized-type-not-at-end’ may have been intended to silence earlier diagnostics
cc1: note: unrecognized command-line option ‘-Wno-gnu-variable-sized-type-not-at-end’ may have been intended to silence earlier diagnostics
cc1: note: unrecognized command-line option ‘-Wno-gnu-variable-sized-type-not-at-end’ may have been intended to silence earlier diagnostics
cc1: note: unrecognized command-line option ‘-Wno-gnu-variable-sized-type-not-at-end’ may have been intended to silence earlier diagnostics
make[1]: Leaving directory '/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-108c296547f3e749d89c270aa6319894f014f01c/tools/testing/selftests/kvm'
make: *** [Makefile:207: all] Error 2
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20250808/202508080716.5744484-lkp@intel.com
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On Mon, Jul 28, 2025 at 07:26:34PM -0700, Yuzhuo Jing wrote:
> Import necessary atomic functions used by qspinlock. Copied x86
> implementation verbatim, and used compiler builtin for generic
> implementation.
Why x86 only? Can we just use the generic version always?
Thanks,
Namhyung
>
> Signed-off-by: Yuzhuo Jing <yuzhuo@google.com>
> ---
> tools/arch/x86/include/asm/atomic.h | 14 +++
> tools/arch/x86/include/asm/cmpxchg.h | 113 +++++++++++++++++++++++++
> tools/include/asm-generic/atomic-gcc.h | 47 ++++++++++
> tools/include/linux/atomic.h | 24 ++++++
> tools/include/linux/compiler_types.h | 24 ++++++
> 5 files changed, 222 insertions(+)
>
> diff --git a/tools/arch/x86/include/asm/atomic.h b/tools/arch/x86/include/asm/atomic.h
> index 365cf182df12..a55ffd4eb5f1 100644
> --- a/tools/arch/x86/include/asm/atomic.h
> +++ b/tools/arch/x86/include/asm/atomic.h
> @@ -71,6 +71,20 @@ static __always_inline int atomic_cmpxchg(atomic_t *v, int old, int new)
> return cmpxchg(&v->counter, old, new);
> }
>
> +static __always_inline bool atomic_try_cmpxchg(atomic_t *v, int *old, int new)
> +{
> + return try_cmpxchg(&v->counter, old, new);
> +}
> +
> +static __always_inline int atomic_fetch_or(int i, atomic_t *v)
> +{
> + int val = atomic_read(v);
> +
> + do { } while (!atomic_try_cmpxchg(v, &val, val | i));
> +
> + return val;
> +}
> +
> static inline int test_and_set_bit(long nr, unsigned long *addr)
> {
> GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(bts), *addr, "Ir", nr, "%0", "c");
> diff --git a/tools/arch/x86/include/asm/cmpxchg.h b/tools/arch/x86/include/asm/cmpxchg.h
> index 0ed9ca2766ad..5372da8b27fc 100644
> --- a/tools/arch/x86/include/asm/cmpxchg.h
> +++ b/tools/arch/x86/include/asm/cmpxchg.h
> @@ -8,6 +8,8 @@
> * Non-existant functions to indicate usage errors at link time
> * (or compile-time if the compiler implements __compiletime_error().
> */
> +extern void __xchg_wrong_size(void)
> + __compiletime_error("Bad argument size for xchg");
> extern void __cmpxchg_wrong_size(void)
> __compiletime_error("Bad argument size for cmpxchg");
>
> @@ -27,6 +29,49 @@ extern void __cmpxchg_wrong_size(void)
> #define __X86_CASE_Q -1 /* sizeof will never return -1 */
> #endif
>
> +/*
> + * An exchange-type operation, which takes a value and a pointer, and
> + * returns the old value.
> + */
> +#define __xchg_op(ptr, arg, op, lock) \
> + ({ \
> + __typeof__ (*(ptr)) __ret = (arg); \
> + switch (sizeof(*(ptr))) { \
> + case __X86_CASE_B: \
> + asm_inline volatile (lock #op "b %b0, %1" \
> + : "+q" (__ret), "+m" (*(ptr)) \
> + : : "memory", "cc"); \
> + break; \
> + case __X86_CASE_W: \
> + asm_inline volatile (lock #op "w %w0, %1" \
> + : "+r" (__ret), "+m" (*(ptr)) \
> + : : "memory", "cc"); \
> + break; \
> + case __X86_CASE_L: \
> + asm_inline volatile (lock #op "l %0, %1" \
> + : "+r" (__ret), "+m" (*(ptr)) \
> + : : "memory", "cc"); \
> + break; \
> + case __X86_CASE_Q: \
> + asm_inline volatile (lock #op "q %q0, %1" \
> + : "+r" (__ret), "+m" (*(ptr)) \
> + : : "memory", "cc"); \
> + break; \
> + default: \
> + __ ## op ## _wrong_size(); \
> + __cmpxchg_wrong_size(); \
> + } \
> + __ret; \
> + })
> +
> +/*
> + * Note: no "lock" prefix even on SMP: xchg always implies lock anyway.
> + * Since this is generally used to protect other memory information, we
> + * use "asm volatile" and "memory" clobbers to prevent gcc from moving
> + * information around.
> + */
> +#define xchg(ptr, v) __xchg_op((ptr), (v), xchg, "")
> +
> /*
> * Atomic compare and exchange. Compare OLD with MEM, if identical,
> * store NEW in MEM. Return the initial value in MEM. Success is
> @@ -86,5 +131,73 @@ extern void __cmpxchg_wrong_size(void)
> #define cmpxchg(ptr, old, new) \
> __cmpxchg(ptr, old, new, sizeof(*(ptr)))
>
> +#define __raw_try_cmpxchg(_ptr, _pold, _new, size, lock) \
> +({ \
> + bool success; \
> + __typeof__(_ptr) _old = (__typeof__(_ptr))(_pold); \
> + __typeof__(*(_ptr)) __old = *_old; \
> + __typeof__(*(_ptr)) __new = (_new); \
> + switch (size) { \
> + case __X86_CASE_B: \
> + { \
> + volatile u8 *__ptr = (volatile u8 *)(_ptr); \
> + asm_inline volatile(lock "cmpxchgb %[new], %[ptr]" \
> + CC_SET(z) \
> + : CC_OUT(z) (success), \
> + [ptr] "+m" (*__ptr), \
> + [old] "+a" (__old) \
> + : [new] "q" (__new) \
> + : "memory"); \
> + break; \
> + } \
> + case __X86_CASE_W: \
> + { \
> + volatile u16 *__ptr = (volatile u16 *)(_ptr); \
> + asm_inline volatile(lock "cmpxchgw %[new], %[ptr]" \
> + CC_SET(z) \
> + : CC_OUT(z) (success), \
> + [ptr] "+m" (*__ptr), \
> + [old] "+a" (__old) \
> + : [new] "r" (__new) \
> + : "memory"); \
> + break; \
> + } \
> + case __X86_CASE_L: \
> + { \
> + volatile u32 *__ptr = (volatile u32 *)(_ptr); \
> + asm_inline volatile(lock "cmpxchgl %[new], %[ptr]" \
> + CC_SET(z) \
> + : CC_OUT(z) (success), \
> + [ptr] "+m" (*__ptr), \
> + [old] "+a" (__old) \
> + : [new] "r" (__new) \
> + : "memory"); \
> + break; \
> + } \
> + case __X86_CASE_Q: \
> + { \
> + volatile u64 *__ptr = (volatile u64 *)(_ptr); \
> + asm_inline volatile(lock "cmpxchgq %[new], %[ptr]" \
> + CC_SET(z) \
> + : CC_OUT(z) (success), \
> + [ptr] "+m" (*__ptr), \
> + [old] "+a" (__old) \
> + : [new] "r" (__new) \
> + : "memory"); \
> + break; \
> + } \
> + default: \
> + __cmpxchg_wrong_size(); \
> + } \
> + if (unlikely(!success)) \
> + *_old = __old; \
> + likely(success); \
> +})
> +
> +#define __try_cmpxchg(ptr, pold, new, size) \
> + __raw_try_cmpxchg((ptr), (pold), (new), (size), LOCK_PREFIX)
> +
> +#define try_cmpxchg(ptr, pold, new) \
> + __try_cmpxchg((ptr), (pold), (new), sizeof(*(ptr)))
>
> #endif /* TOOLS_ASM_X86_CMPXCHG_H */
> diff --git a/tools/include/asm-generic/atomic-gcc.h b/tools/include/asm-generic/atomic-gcc.h
> index 9b3c528bab92..08b7b3b36873 100644
> --- a/tools/include/asm-generic/atomic-gcc.h
> +++ b/tools/include/asm-generic/atomic-gcc.h
> @@ -62,6 +62,12 @@ static inline int atomic_dec_and_test(atomic_t *v)
> return __sync_sub_and_fetch(&v->counter, 1) == 0;
> }
>
> +#define xchg(ptr, v) \
> + __atomic_exchange_n(ptr, v, __ATOMIC_SEQ_CST)
> +
> +#define xchg_relaxed(ptr, v) \
> + __atomic_exchange_n(ptr, v, __ATOMIC_RELAXED)
> +
> #define cmpxchg(ptr, oldval, newval) \
> __sync_val_compare_and_swap(ptr, oldval, newval)
>
> @@ -70,6 +76,47 @@ static inline int atomic_cmpxchg(atomic_t *v, int oldval, int newval)
> return cmpxchg(&(v)->counter, oldval, newval);
> }
>
> +/**
> + * atomic_try_cmpxchg() - atomic compare and exchange with full ordering
> + * @v: pointer to atomic_t
> + * @old: pointer to int value to compare with
> + * @new: int value to assign
> + *
> + * If (@v == @old), atomically updates @v to @new with full ordering.
> + * Otherwise, @v is not modified, @old is updated to the current value of @v,
> + * and relaxed ordering is provided.
> + *
> + * Unsafe to use in noinstr code; use raw_atomic_try_cmpxchg() there.
> + *
> + * Return: @true if the exchange occured, @false otherwise.
> + */
> +static __always_inline bool
> +atomic_try_cmpxchg(atomic_t *v, int *old, int new)
> +{
> + int r, o = *old;
> + r = atomic_cmpxchg(v, o, new);
> + if (unlikely(r != o))
> + *old = r;
> + return likely(r == o);
> +}
> +
> +/**
> + * atomic_fetch_or() - atomic bitwise OR with full ordering
> + * @i: int value
> + * @v: pointer to atomic_t
> + *
> + * Atomically updates @v to (@v | @i) with full ordering.
> + *
> + * Unsafe to use in noinstr code; use raw_atomic_fetch_or() there.
> + *
> + * Return: The original value of @v.
> + */
> +static __always_inline int
> +atomic_fetch_or(int i, atomic_t *v)
> +{
> + return __sync_fetch_and_or(&v->counter, i);
> +}
> +
> static inline int test_and_set_bit(long nr, unsigned long *addr)
> {
> unsigned long mask = BIT_MASK(nr);
> diff --git a/tools/include/linux/atomic.h b/tools/include/linux/atomic.h
> index 01907b33537e..332a34177995 100644
> --- a/tools/include/linux/atomic.h
> +++ b/tools/include/linux/atomic.h
> @@ -12,4 +12,28 @@ void atomic_long_set(atomic_long_t *v, long i);
> #define atomic_cmpxchg_release atomic_cmpxchg
> #endif /* atomic_cmpxchg_relaxed */
>
> +#ifndef atomic_cmpxchg_acquire
> +#define atomic_cmpxchg_acquire atomic_cmpxchg
> +#endif
> +
> +#ifndef atomic_try_cmpxchg_acquire
> +#define atomic_try_cmpxchg_acquire atomic_try_cmpxchg
> +#endif
> +
> +#ifndef atomic_try_cmpxchg_relaxed
> +#define atomic_try_cmpxchg_relaxed atomic_try_cmpxchg
> +#endif
> +
> +#ifndef atomic_fetch_or_acquire
> +#define atomic_fetch_or_acquire atomic_fetch_or
> +#endif
> +
> +#ifndef xchg_relaxed
> +#define xchg_relaxed xchg
> +#endif
> +
> +#ifndef cmpxchg_release
> +#define cmpxchg_release cmpxchg
> +#endif
> +
> #endif /* __TOOLS_LINUX_ATOMIC_H */
> diff --git a/tools/include/linux/compiler_types.h b/tools/include/linux/compiler_types.h
> index d09f9dc172a4..9a2a2f8d7b6c 100644
> --- a/tools/include/linux/compiler_types.h
> +++ b/tools/include/linux/compiler_types.h
> @@ -31,6 +31,28 @@
> # define __cond_lock(x,c) (c)
> #endif /* __CHECKER__ */
>
> +/*
> + * __unqual_scalar_typeof(x) - Declare an unqualified scalar type, leaving
> + * non-scalar types unchanged.
> + */
> +/*
> + * Prefer C11 _Generic for better compile-times and simpler code. Note: 'char'
> + * is not type-compatible with 'signed char', and we define a separate case.
> + */
> +#define __scalar_type_to_expr_cases(type) \
> + unsigned type: (unsigned type)0, \
> + signed type: (signed type)0
> +
> +#define __unqual_scalar_typeof(x) typeof( \
> + _Generic((x), \
> + char: (char)0, \
> + __scalar_type_to_expr_cases(char), \
> + __scalar_type_to_expr_cases(short), \
> + __scalar_type_to_expr_cases(int), \
> + __scalar_type_to_expr_cases(long), \
> + __scalar_type_to_expr_cases(long long), \
> + default: (x)))
> +
> /* Compiler specific macros. */
> #ifdef __GNUC__
> #include <linux/compiler-gcc.h>
> @@ -40,4 +62,6 @@
> #define asm_goto_output(x...) asm goto(x)
> #endif
>
> +#define asm_inline asm
> +
> #endif /* __LINUX_COMPILER_TYPES_H */
> --
> 2.50.1.487.gc89ff58d15-goog
>
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