The VMA tests need an operation equivalent to atomic_inc_unless_negative() to implement a fake mapping_map_writable(). Adding it will enable them to switch to the shared atomic headers and simplify that fake implementation. In order to add that, also add atomic_try_cmpxchg() which can be used to implement it. This is copied from Documentation/atomic_t.txt. Then, implement atomic_inc_unless_negative() itself based on the raw_atomic_dec_unless_positive() in include/linux/atomic/atomic-arch-fallback.h. There's no present need for a highly-optimised version of this (nor any reason to think this implementation is sub-optimal on x86) so just implement this with generic C, no x86-specifics. Signed-off-by: Brendan Jackman --- tools/include/linux/atomic.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/tools/include/linux/atomic.h b/tools/include/linux/atomic.h index 01907b33537e04c5e860dd2cd61a61dfab6ea8f1..50c66ba9ada58cf05125e2e2472734bf3b0f8595 100644 --- a/tools/include/linux/atomic.h +++ b/tools/include/linux/atomic.h @@ -12,4 +12,26 @@ void atomic_long_set(atomic_long_t *v, long i); #define atomic_cmpxchg_release atomic_cmpxchg #endif /* atomic_cmpxchg_relaxed */ +static inline bool atomic_try_cmpxchg(atomic_t *ptr, int *oldp, int new) +{ + int ret, old = *oldp; + + ret = atomic_cmpxchg(ptr, old, new); + if (ret != old) + *oldp = ret; + return ret == old; +} + +static inline bool atomic_inc_unless_negative(atomic_t *v) +{ + int c = atomic_read(v); + + do { + if (unlikely(c < 0)) + return false; + } while (!atomic_try_cmpxchg(v, &c, c + 1)); + + return true; +} + #endif /* __TOOLS_LINUX_ATOMIC_H */ -- 2.50.1 There is an arch/ tree under tools. This contains some useful stuff, to make that available, add it to the -I flags. This requires $(SRCARCH), which is provided by Makefile.arch, so include that.. There still aren't that many headers so also just smush all of them into SHARED_DEPS instead of starting to do any header dependency hocus pocus. Reviewed-by: Lorenzo Stoakes Reviewed-by: Liam R. Howlett Acked-by: Pedro Falcato Signed-off-by: Brendan Jackman --- tools/testing/shared/shared.mk | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/tools/testing/shared/shared.mk b/tools/testing/shared/shared.mk index 923ee2492256b693c5cf16cc014d9d2410be5457..937aaa7623320da1085a8e0f43f6a728ddd3ab1c 100644 --- a/tools/testing/shared/shared.mk +++ b/tools/testing/shared/shared.mk @@ -1,6 +1,8 @@ # SPDX-License-Identifier: GPL-2.0 +include ../../scripts/Makefile.arch -CFLAGS += -I../shared -I. -I../../include -I../../../lib -g -Og -Wall \ +CFLAGS += -I../shared -I. -I../../include -I../../arch/$(SRCARCH)/include \ + -I../../../lib -g -Og -Wall \ -D_LGPL_SOURCE -fsanitize=address -fsanitize=undefined LDFLAGS += -fsanitize=address -fsanitize=undefined LDLIBS += -lpthread -lurcu @@ -11,6 +13,7 @@ SHARED_DEPS = Makefile ../shared/shared.mk ../shared/*.h generated/map-shift.h \ generated/bit-length.h generated/autoconf.h \ ../../include/linux/*.h \ ../../include/asm/*.h \ + ../../arch/$(SRCARCH)/include/asm/*.h \ ../../../include/linux/xarray.h \ ../../../include/linux/maple_tree.h \ ../../../include/linux/radix-tree.h \ -- 2.50.1 This allows the user to set cflags when building tests that use this shared build infrastructure. For example, it enables building with -Werror so that patch-check scripts will fail: make -C tools/testing/vma -j EXTRA_CFLAGS=-Werror Reviewed-by: Lorenzo Stoakes Reviewed-by: Liam R. Howlett Acked-by: Pedro Falcato Signed-off-by: Brendan Jackman --- tools/testing/shared/shared.mk | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/shared/shared.mk b/tools/testing/shared/shared.mk index 937aaa7623320da1085a8e0f43f6a728ddd3ab1c..5bcdf26c8a9d51ab2cbd264f2f8a7445d7c036e3 100644 --- a/tools/testing/shared/shared.mk +++ b/tools/testing/shared/shared.mk @@ -4,6 +4,7 @@ include ../../scripts/Makefile.arch CFLAGS += -I../shared -I. -I../../include -I../../arch/$(SRCARCH)/include \ -I../../../lib -g -Og -Wall \ -D_LGPL_SOURCE -fsanitize=address -fsanitize=undefined +CFLAGS += $(EXTRA_CFLAGS) LDFLAGS += -fsanitize=address -fsanitize=undefined LDLIBS += -lpthread -lurcu LIBS := slab.o find_bit.o bitmap.o hweight.o vsprintf.o -- 2.50.1 The shared userspace logic used for unit-testing maple tree and VMA code currently has its own replacements for atomics helpers. This is not needed as the necessary APIs already have userspace implementations in the tools tree. Switching over to that allows deleting a bit of code. Note that the implementation is different; while the version being deleted here is implemented using liburcu, the existing version in tools uses either x86 asm or compiler builtins. It's assumed that both are equally likely to be correct. The tools tree's version of atomic_t is a struct type while the version being deleted was just a typedef of an integer. This means it's no longer valid to call __sync_bool_compare_and_swap() directly on it. One option would be to just peek into the struct and call it on the field, but it seems a little cleaner to just use the corresponding atomic.h API whic has been added recently. Now the fake mapping_map_writable() is copied from the real one. Reviewed-by: Lorenzo Stoakes Signed-off-by: Brendan Jackman --- tools/testing/shared/linux/maple_tree.h | 6 ++---- tools/testing/vma/linux/atomic.h | 17 ----------------- tools/testing/vma/vma_internal.h | 12 +++--------- 3 files changed, 5 insertions(+), 30 deletions(-) diff --git a/tools/testing/shared/linux/maple_tree.h b/tools/testing/shared/linux/maple_tree.h index f67d47d32857cee296c2784da57825c9a31cd340..7d0fadef0f11624dbb110ad351aabdc79a19dcd2 100644 --- a/tools/testing/shared/linux/maple_tree.h +++ b/tools/testing/shared/linux/maple_tree.h @@ -1,7 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0+ */ -#define atomic_t int32_t -#define atomic_inc(x) uatomic_inc(x) -#define atomic_read(x) uatomic_read(x) -#define atomic_set(x, y) uatomic_set(x, y) +#include + #define U8_MAX UCHAR_MAX #include "../../../../include/linux/maple_tree.h" diff --git a/tools/testing/vma/linux/atomic.h b/tools/testing/vma/linux/atomic.h deleted file mode 100644 index 788c597c4fdea7392307de93ff4459453b96179b..0000000000000000000000000000000000000000 --- a/tools/testing/vma/linux/atomic.h +++ /dev/null @@ -1,17 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-or-later */ - -#ifndef _LINUX_ATOMIC_H -#define _LINUX_ATOMIC_H - -#define atomic_t int32_t -#define atomic_inc(x) uatomic_inc(x) -#define atomic_read(x) uatomic_read(x) -#define atomic_set(x, y) uatomic_set(x, y) -#define U8_MAX UCHAR_MAX - -#ifndef atomic_cmpxchg_relaxed -#define atomic_cmpxchg_relaxed uatomic_cmpxchg -#define atomic_cmpxchg_release uatomic_cmpxchg -#endif /* atomic_cmpxchg_relaxed */ - -#endif /* _LINUX_ATOMIC_H */ diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h index f13354bf0a1e3839327da7927c4a7da1530a1693..437d2a1013be418c6d3e77534fa19b0ee1518c9b 100644 --- a/tools/testing/vma/vma_internal.h +++ b/tools/testing/vma/vma_internal.h @@ -21,6 +21,7 @@ #include +#include #include #include #include @@ -1398,15 +1399,8 @@ static inline bool map_deny_write_exec(unsigned long old, unsigned long new) static inline int mapping_map_writable(struct address_space *mapping) { - int c = atomic_read(&mapping->i_mmap_writable); - - /* Derived from the raw_atomic_inc_unless_negative() implementation. */ - do { - if (c < 0) - return -EPERM; - } while (!__sync_bool_compare_and_swap(&mapping->i_mmap_writable, c, c+1)); - - return 0; + return atomic_inc_unless_negative(&mapping->i_mmap_writable) ? + 0 : -EPERM; } static inline unsigned long move_page_tables(struct pagetable_move_control *pmc) -- 2.50.1