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authorDavid Howells <dhowells@redhat.com>2008-04-10 16:10:55 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-10 13:41:29 -0700
commite31c243f984628d02f045dc4b622f1e2827860dc (patch)
treecd2ac2f33c7da86b515087260d93179b31fd1671 /arch/frv/kernel/entry.S
parent0c93d8e4d342b1b5cda1037f2527fcf443c80fbc (diff)
FRV: Add support for emulation of userspace atomic ops [try #2]
Use traps 120-126 to emulate atomic cmpxchg32, xchg32, and XOR-, OR-, AND-, SUB- and ADD-to-memory operations for userspace. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/frv/kernel/entry.S')
-rw-r--r--arch/frv/kernel/entry.S20
1 files changed, 20 insertions, 0 deletions
diff --git a/arch/frv/kernel/entry.S b/arch/frv/kernel/entry.S
index f36d7f4a7c25..b8a4b94779b1 100644
--- a/arch/frv/kernel/entry.S
+++ b/arch/frv/kernel/entry.S
@@ -656,6 +656,26 @@ __entry_debug_exception:
###############################################################################
#
+# handle atomic operation emulation for userspace
+#
+###############################################################################
+ .globl __entry_atomic_op
+__entry_atomic_op:
+ LEDS 0x6012
+ sethi.p %hi(atomic_operation),gr5
+ setlo %lo(atomic_operation),gr5
+ movsg esfr1,gr8
+ movsg epcr0,gr9
+ movsg esr0,gr10
+
+ # now that we've accessed the exception regs, we can enable exceptions
+ movsg psr,gr4
+ ori gr4,#PSR_ET,gr4
+ movgs gr4,psr
+ jmpl @(gr5,gr0) ; call atomic_operation(esfr1,epcr0,esr0)
+
+###############################################################################
+#
# handle media exception
#
###############################################################################