diff options
Diffstat (limited to 'arch/sparc/lib/atomic.S')
| -rw-r--r-- | arch/sparc/lib/atomic.S | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/arch/sparc/lib/atomic.S b/arch/sparc/lib/atomic.S new file mode 100644 index 0000000..f48ad0c --- /dev/null +++ b/arch/sparc/lib/atomic.S @@ -0,0 +1,100 @@ +/* atomic.S: Move this stuff here for better ICACHE hit rates. + * + * Copyright (C) 1996 David S. Miller (davem@caipfs.rutgers.edu) + */ + +#include <linux/config.h> +#include <asm/ptrace.h> +#include <asm/psr.h> + + .text + .align 4 + + .globl __atomic_begin +__atomic_begin: + +#ifndef CONFIG_SMP + .globl ___xchg32_sun4c +___xchg32_sun4c: + rd %psr, %g3 + andcc %g3, PSR_PIL, %g0 + bne 1f + nop + wr %g3, PSR_PIL, %psr + nop; nop; nop +1: + andcc %g3, PSR_PIL, %g0 + ld [%g1], %g7 + bne 1f + st %g2, [%g1] + wr %g3, 0x0, %psr + nop; nop; nop +1: + mov %g7, %g2 + jmpl %o7 + 8, %g0 + mov %g4, %o7 + + .globl ___xchg32_sun4md +___xchg32_sun4md: + swap [%g1], %g2 + jmpl %o7 + 8, %g0 + mov %g4, %o7 +#endif + + /* Read asm-sparc/atomic.h carefully to understand how this works for SMP. + * Really, some things here for SMP are overly clever, go read the header. + */ + .globl ___atomic24_add +___atomic24_add: + rd %psr, %g3 ! Keep the code small, old way was stupid + nop; nop; nop; ! Let the bits set + or %g3, PSR_PIL, %g7 ! Disable interrupts + wr %g7, 0x0, %psr ! Set %psr + nop; nop; nop; ! Let the bits set +#ifdef CONFIG_SMP +1: ldstub [%g1 + 3], %g7 ! Spin on the byte lock for SMP. + orcc %g7, 0x0, %g0 ! Did we get it? + bne 1b ! Nope... + ld [%g1], %g7 ! Load locked atomic24_t + sra %g7, 8, %g7 ! Get signed 24-bit integer + add %g7, %g2, %g2 ! Add in argument + sll %g2, 8, %g7 ! Transpose back to atomic24_t + st %g7, [%g1] ! Clever: This releases the lock as well. +#else + ld [%g1], %g7 ! Load locked atomic24_t + add %g7, %g2, %g2 ! Add in argument + st %g2, [%g1] ! Store it back +#endif + wr %g3, 0x0, %psr ! Restore original PSR_PIL + nop; nop; nop; ! Let the bits set + jmpl %o7, %g0 ! NOTE: not + 8, see callers in atomic.h + mov %g4, %o7 ! Restore %o7 + + .globl ___atomic24_sub +___atomic24_sub: + rd %psr, %g3 ! Keep the code small, old way was stupid + nop; nop; nop; ! Let the bits set + or %g3, PSR_PIL, %g7 ! Disable interrupts + wr %g7, 0x0, %psr ! Set %psr + nop; nop; nop; ! Let the bits set +#ifdef CONFIG_SMP +1: ldstub [%g1 + 3], %g7 ! Spin on the byte lock for SMP. + orcc %g7, 0x0, %g0 ! Did we get it? + bne 1b ! Nope... + ld [%g1], %g7 ! Load locked atomic24_t + sra %g7, 8, %g7 ! Get signed 24-bit integer + sub %g7, %g2, %g2 ! Subtract argument + sll %g2, 8, %g7 ! Transpose back to atomic24_t + st %g7, [%g1] ! Clever: This releases the lock as well +#else + ld [%g1], %g7 ! Load locked atomic24_t + sub %g7, %g2, %g2 ! Subtract argument + st %g2, [%g1] ! Store it back +#endif + wr %g3, 0x0, %psr ! Restore original PSR_PIL + nop; nop; nop; ! Let the bits set + jmpl %o7, %g0 ! NOTE: not + 8, see callers in atomic.h + mov %g4, %o7 ! Restore %o7 + + .globl __atomic_end +__atomic_end: |
