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Diffstat (limited to 'arch/sparc')
-rw-r--r--arch/sparc/kernel/sparc_ksyms.c4
-rw-r--r--arch/sparc/lib/locks.S20
2 files changed, 23 insertions, 1 deletions
diff --git a/arch/sparc/kernel/sparc_ksyms.c b/arch/sparc/kernel/sparc_ksyms.c
index 4d441a554d3..33dadd9f287 100644
--- a/arch/sparc/kernel/sparc_ksyms.c
+++ b/arch/sparc/kernel/sparc_ksyms.c
@@ -87,6 +87,7 @@ extern void ___set_bit(void);
extern void ___clear_bit(void);
extern void ___change_bit(void);
extern void ___rw_read_enter(void);
+extern void ___rw_read_try(void);
extern void ___rw_read_exit(void);
extern void ___rw_write_enter(void);
@@ -104,8 +105,9 @@ extern unsigned _Urem(unsigned, unsigned);
EXPORT_SYMBOL(sparc_cpu_model);
EXPORT_SYMBOL(kernel_thread);
#ifdef CONFIG_SMP
-// XXX find what uses (or used) these.
+// XXX find what uses (or used) these. AV: see asm/spinlock.h
EXPORT_SYMBOL(___rw_read_enter);
+EXPORT_SYMBOL(___rw_read_try);
EXPORT_SYMBOL(___rw_read_exit);
EXPORT_SYMBOL(___rw_write_enter);
#endif
diff --git a/arch/sparc/lib/locks.S b/arch/sparc/lib/locks.S
index 95fa4842496..b1df55cb221 100644
--- a/arch/sparc/lib/locks.S
+++ b/arch/sparc/lib/locks.S
@@ -25,6 +25,15 @@ ___rw_read_enter_spin_on_wlock:
ldstub [%g1 + 3], %g2
b ___rw_read_enter_spin_on_wlock
ldub [%g1 + 3], %g2
+___rw_read_try_spin_on_wlock:
+ andcc %g2, 0xff, %g0
+ be,a ___rw_read_try
+ ldstub [%g1 + 3], %g2
+ xnorcc %g2, 0x0, %o0 /* if g2 is ~0, set o0 to 0 and bugger off */
+ bne,a ___rw_read_enter_spin_on_wlock
+ ld [%g1], %g2
+ retl
+ mov %g4, %o7
___rw_read_exit_spin_on_wlock:
orcc %g2, 0x0, %g0
be,a ___rw_read_exit
@@ -60,6 +69,17 @@ ___rw_read_exit:
retl
mov %g4, %o7
+ .globl ___rw_read_try
+___rw_read_try:
+ orcc %g2, 0x0, %g0
+ bne ___rw_read_try_spin_on_wlock
+ ld [%g1], %g2
+ add %g2, 1, %g2
+ st %g2, [%g1]
+ set 1, %o1
+ retl
+ mov %g4, %o7
+
.globl ___rw_write_enter
___rw_write_enter:
orcc %g2, 0x0, %g0