9a0b26e6bc
- Move the slow path fallbacks to their own assembly files This makes them much easier to read and is needed for the next change. - Add CFI annotations for unwinding (XXX need review) - Remove constant case which can never happen with out of line spinlocks - Use patchable LOCK prefixes - Don't use lock sections anymore for inline code because they can't be expressed by the unwinder (this adds one taken jump to the lock fast path) Cc: jbeulich@novell.com Signed-off-by: Andi Kleen <ak@suse.de>
39 lines
646 B
ArmAsm
39 lines
646 B
ArmAsm
/* Slow paths of read/write spinlocks. */
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#include <linux/linkage.h>
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#include <asm/rwlock.h>
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#include <asm/alternative-asm.i>
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#include <asm/dwarf2.h>
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/* rdi: pointer to rwlock_t */
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ENTRY(__write_lock_failed)
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CFI_STARTPROC
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LOCK_PREFIX
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addl $RW_LOCK_BIAS,(%rdi)
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1: rep
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nop
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cmpl $RW_LOCK_BIAS,(%rdi)
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jne 1b
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LOCK_PREFIX
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subl $RW_LOCK_BIAS,(%rdi)
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jnz __write_lock_failed
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ret
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CFI_ENDPROC
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END(__write_lock_failed)
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/* rdi: pointer to rwlock_t */
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ENTRY(__read_lock_failed)
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CFI_STARTPROC
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LOCK_PREFIX
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incl (%rdi)
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1: rep
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nop
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cmpl $1,(%rdi)
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js 1b
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LOCK_PREFIX
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decl (%rdi)
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js __read_lock_failed
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ret
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CFI_ENDPROC
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END(__read_lock_failed)
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