On Fri, 26 Aug 2022, Geert Uytterhoeven wrote: > Hi Mikulas, > > noreply@xxxxxxxxxxxxxx reports lots of build failures on m68k: > > include/asm-generic/bitops/non-instrumented-non-atomic.h:15:33: > error: implicit declaration of function 'arch_test_bit_acquire'; did > you mean '_test_bit_acquire'? [-Werror=implicit-function-declaration] > > which I've bisected to this commit. > > http://kisskb.ellerman.id.au/kisskb/head/3e5c673f0d75bc22b3c26eade87e4db4f374cd34 Does this patch fix it? It is untested. I'm not sure about the hexagon architecture, it is presumably in-order so that test_bit and test_bit_acquire are equivalent, but I am not sure about that - I'm adding hexagon maintainer to the recipient field. Mikulas provide arch_test_bit_acquire for architectures that define test_bit Some architectures define their own arch_test_bit and they also need arch_test_bit_acquire, otherwise they won't compile. Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Fixes: 8238b4579866 ("wait_on_bit: add an acquire memory barrier") --- arch/alpha/include/asm/bitops.h | 7 +++++++ arch/hexagon/include/asm/bitops.h | 15 +++++++++++++++ arch/ia64/include/asm/bitops.h | 7 +++++++ arch/m68k/include/asm/bitops.h | 7 +++++++ arch/s390/include/asm/bitops.h | 7 +++++++ 5 files changed, 43 insertions(+) Index: linux-2.6/arch/m68k/include/asm/bitops.h =================================================================== --- linux-2.6.orig/arch/m68k/include/asm/bitops.h +++ linux-2.6/arch/m68k/include/asm/bitops.h @@ -163,6 +163,13 @@ arch_test_bit(unsigned long nr, const vo return (addr[nr >> 5] & (1UL << (nr & 31))) != 0; } +static __always_inline bool +arch_test_bit_acquire(unsigned long nr, const volatile unsigned long *addr) +{ + unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); + return 1UL & (smp_load_acquire(p) >> (nr & (BITS_PER_LONG-1))); +} + static inline int bset_reg_test_and_set_bit(int nr, volatile unsigned long *vaddr) { Index: linux-2.6/arch/alpha/include/asm/bitops.h =================================================================== --- linux-2.6.orig/arch/alpha/include/asm/bitops.h +++ linux-2.6/arch/alpha/include/asm/bitops.h @@ -289,6 +289,13 @@ arch_test_bit(unsigned long nr, const vo return (1UL & (((const int *) addr)[nr >> 5] >> (nr & 31))) != 0UL; } +static __always_inline bool +arch_test_bit_acquire(unsigned long nr, const volatile unsigned long *addr) +{ + unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); + return 1UL & (smp_load_acquire(p) >> (nr & (BITS_PER_LONG-1))); +} + /* * ffz = Find First Zero in word. Undefined if no zero exists, * so code should check against ~0UL first.. Index: linux-2.6/arch/hexagon/include/asm/bitops.h =================================================================== --- linux-2.6.orig/arch/hexagon/include/asm/bitops.h +++ linux-2.6/arch/hexagon/include/asm/bitops.h @@ -179,6 +179,21 @@ arch_test_bit(unsigned long nr, const vo return retval; } +static __always_inline bool +arch_test_bit_acquire(unsigned long nr, const volatile unsigned long *addr) +{ + int retval; + + asm volatile( + "{P0 = tstbit(%1,%2); if (P0.new) %0 = #1; if (!P0.new) %0 = #0;}\n" + : "=&r" (retval) + : "r" (addr[BIT_WORD(nr)]), "r" (nr % BITS_PER_LONG) + : "p0", "memory" + ); + + return retval; +} + /* * ffz - find first zero in word. * @word: The word to search Index: linux-2.6/arch/ia64/include/asm/bitops.h =================================================================== --- linux-2.6.orig/arch/ia64/include/asm/bitops.h +++ linux-2.6/arch/ia64/include/asm/bitops.h @@ -337,6 +337,13 @@ arch_test_bit(unsigned long nr, const vo return 1 & (((const volatile __u32 *) addr)[nr >> 5] >> (nr & 31)); } +static __always_inline bool +arch_test_bit_acquire(unsigned long nr, const volatile unsigned long *addr) +{ + unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); + return 1UL & (smp_load_acquire(p) >> (nr & (BITS_PER_LONG-1))); +} + /** * ffz - find the first zero bit in a long word * @x: The long word to find the bit in Index: linux-2.6/arch/s390/include/asm/bitops.h =================================================================== --- linux-2.6.orig/arch/s390/include/asm/bitops.h +++ linux-2.6/arch/s390/include/asm/bitops.h @@ -185,6 +185,13 @@ arch_test_bit(unsigned long nr, const vo return *p & mask; } +static __always_inline bool +arch_test_bit_acquire(unsigned long nr, const volatile unsigned long *addr) +{ + unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); + return 1UL & (smp_load_acquire(p) >> (nr & (BITS_PER_LONG-1))); +} + static inline bool arch_test_and_set_bit_lock(unsigned long nr, volatile unsigned long *ptr) {
