Messages in this thread Patch in this message |  | | Date | Fri, 12 Oct 2001 16:35:59 +0400 | From | Ivan Kokshaysky <> | Subject | Re: [patch 2.4.11-pre5] atomic_dec_and_lock() for alpha |
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On Thu, Oct 11, 2001 at 11:28:10AM -0700, Richard Henderson wrote: > Hmm. What about a mixture:
...
> 2: lda $27, atomic_dec_and_lock_1"); > > /* FALLTHRU */ > > static int > atomic_dec_and_lock_1(atomic_t *atomic, spinlock_t *lock)
Oh cool. I've made a patch of the above (with some minor changes), but are you certain that these two will be linked in proper order under any circumstances? Or "br atomic_dec_and_lock_1" is needed?
Ivan.
--- 2.4.13p1/arch/alpha/lib/dec_and_lock.c Thu Jan 1 00:00:00 1970 +++ linux/arch/alpha/lib/dec_and_lock.c Fri Oct 12 14:48:57 2001 @@ -0,0 +1,41 @@ +/* + * arch/alpha/lib/dec_and_lock.c + * + * ll/sc version of atomic_dec_and_lock() and nice example + * of mixing C and assembly. + * + */ + +#include <linux/spinlock.h> +#include <asm/atomic.h> + + asm (".text \n\ + .global atomic_dec_and_lock \n\ + .ent atomic_dec_and_lock \n\ + .align 4 \n\ +atomic_dec_and_lock: \n\ + .prologue 0 \n\ +1: ldl_l $1, 0($16) \n\ + subl $1, 1, $1 \n\ + beq $1, 2f \n\ + stl_c $1, 0($16) \n\ + beq $1, 3f \n\ + mb \n\ + clr $0 \n\ + ret \n\ +3: br 1b \n\ +2: lda $27, atomic_dec_and_lock_1 \n\ + .end atomic_dec_and_lock"); + + /* FALLTHRU */ + +static int __attribute__((unused)) +atomic_dec_and_lock_1(atomic_t *atomic, spinlock_t *lock) +{ + /* Slow path */ + spin_lock(lock); + if (atomic_dec_and_test(atomic)) + return 1; + spin_unlock(lock); + return 0; +} --- 2.4.13p1/arch/alpha/lib/Makefile Wed Jun 20 22:10:27 2001 +++ linux/arch/alpha/lib/Makefile Fri Oct 5 17:37:20 2001 @@ -49,6 +49,10 @@ OBJS = __divqu.o __remqu.o __divlu.o __r fpreg.o \ callback_srm.o srm_puts.o srm_printk.o +ifeq ($(CONFIG_SMP),y) + OBJS += dec_and_lock.o +endif + lib.a: $(OBJS) $(AR) rcs lib.a $(OBJS) --- 2.4.13p1/arch/alpha/kernel/alpha_ksyms.c Fri Sep 14 02:21:32 2001 +++ linux/arch/alpha/kernel/alpha_ksyms.c Fri Oct 5 19:56:39 2001 @@ -215,6 +215,7 @@ EXPORT_SYMBOL(__global_cli); EXPORT_SYMBOL(__global_sti); EXPORT_SYMBOL(__global_save_flags); EXPORT_SYMBOL(__global_restore_flags); +EXPORT_SYMBOL(atomic_dec_and_lock); #if DEBUG_SPINLOCK EXPORT_SYMBOL(spin_unlock); EXPORT_SYMBOL(debug_spin_lock); --- 2.4.13p1/arch/alpha/config.in Fri Oct 5 17:27:50 2001 +++ linux/arch/alpha/config.in Fri Oct 5 17:37:20 2001 @@ -217,6 +217,10 @@ then bool 'Symmetric multi-processing support' CONFIG_SMP fi +if [ "$CONFIG_SMP" = "y" ]; then + define_bool CONFIG_HAVE_DEC_LOCK y +fi + if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then bool 'Discontiguous Memory Support' CONFIG_DISCONTIGMEM if [ "$CONFIG_DISCONTIGMEM" = "y" ]; then - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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