diff options
Diffstat (limited to 'arch/ia64/kernel/head.S')
| -rw-r--r-- | arch/ia64/kernel/head.S | 89 |
1 files changed, 0 insertions, 89 deletions
diff --git a/arch/ia64/kernel/head.S b/arch/ia64/kernel/head.S index 1a6e44515eb4..696eff28a0c4 100644 --- a/arch/ia64/kernel/head.S +++ b/arch/ia64/kernel/head.S @@ -1130,95 +1130,6 @@ SET_REG(b5); #endif /* CONFIG_IA64_BRL_EMU */ #ifdef CONFIG_SMP - /* - * This routine handles spinlock contention. It uses a non-standard calling - * convention to avoid converting leaf routines into interior routines. Because - * of this special convention, there are several restrictions: - * - * - do not use gp relative variables, this code is called from the kernel - * and from modules, r1 is undefined. - * - do not use stacked registers, the caller owns them. - * - do not use the scratch stack space, the caller owns it. - * - do not use any registers other than the ones listed below - * - * Inputs: - * ar.pfs - saved CFM of caller - * ar.ccv - 0 (and available for use) - * r27 - flags from spin_lock_irqsave or 0. Must be preserved. - * r28 - available for use. - * r29 - available for use. - * r30 - available for use. - * r31 - address of lock, available for use. - * b6 - return address - * p14 - available for use. - * p15 - used to track flag status. - * - * If you patch this code to use more registers, do not forget to update - * the clobber lists for spin_lock() in arch/ia64/include/asm/spinlock.h. - */ - -#if (__GNUC__ == 3 && __GNUC_MINOR__ < 3) - -GLOBAL_ENTRY(ia64_spinlock_contention_pre3_4) - .prologue - .save ar.pfs, r0 // this code effectively has a zero frame size - .save rp, r28 - .body - nop 0 - tbit.nz p15,p0=r27,IA64_PSR_I_BIT - .restore sp // pop existing prologue after next insn - mov b6 = r28 - .prologue - .save ar.pfs, r0 - .altrp b6 - .body - ;; -(p15) ssm psr.i // reenable interrupts if they were on - // DavidM says that srlz.d is slow and is not required in this case -.wait: - // exponential backoff, kdb, lockmeter etc. go in here - hint @pause - ld4 r30=[r31] // don't use ld4.bias; if it's contended, we won't write the word - nop 0 - ;; - cmp4.ne p14,p0=r30,r0 -(p14) br.cond.sptk.few .wait -(p15) rsm psr.i // disable interrupts if we reenabled them - br.cond.sptk.few b6 // lock is now free, try to acquire - .global ia64_spinlock_contention_pre3_4_end // for kernprof -ia64_spinlock_contention_pre3_4_end: -END(ia64_spinlock_contention_pre3_4) - -#else - -GLOBAL_ENTRY(ia64_spinlock_contention) - .prologue - .altrp b6 - .body - tbit.nz p15,p0=r27,IA64_PSR_I_BIT - ;; -.wait: -(p15) ssm psr.i // reenable interrupts if they were on - // DavidM says that srlz.d is slow and is not required in this case -.wait2: - // exponential backoff, kdb, lockmeter etc. go in here - hint @pause - ld4 r30=[r31] // don't use ld4.bias; if it's contended, we won't write the word - ;; - cmp4.ne p14,p0=r30,r0 - mov r30 = 1 -(p14) br.cond.sptk.few .wait2 -(p15) rsm psr.i // disable interrupts if we reenabled them - ;; - cmpxchg4.acq r30=[r31], r30, ar.ccv - ;; - cmp4.ne p14,p0=r0,r30 -(p14) br.cond.sptk.few .wait - - br.ret.sptk.many b6 // lock is now taken -END(ia64_spinlock_contention) - -#endif #ifdef CONFIG_HOTPLUG_CPU GLOBAL_ENTRY(ia64_jump_to_sal) |