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authorJesper Nilsson <jesper.nilsson@axis.com>2010-08-02 18:09:56 +0200
committerJesper Nilsson <jesper.nilsson@axis.com>2010-08-04 13:00:00 +0200
commit43f6cdd7693ddddb4db17a1ab591d506cb1fc110 (patch)
treef05f9e14364b4ea9b82feb37b83538adaee943cf /arch/cris/arch-v32/kernel
parenta80a635f3d60e4aa61f96d22a122071cb061be93 (diff)
CRIS: Simple insn reschedule to avoid interlocks.
Brings down the CPI from ~1.5 to ~1.1. Signed-off-by: Edgar Iglesias <Edgar.Iglesias@axis.com> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Diffstat (limited to 'arch/cris/arch-v32/kernel')
-rw-r--r--arch/cris/arch-v32/kernel/entry.S18
1 files changed, 9 insertions, 9 deletions
diff --git a/arch/cris/arch-v32/kernel/entry.S b/arch/cris/arch-v32/kernel/entry.S
index 7c14acb754a..ce121df3aae 100644
--- a/arch/cris/arch-v32/kernel/entry.S
+++ b/arch/cris/arch-v32/kernel/entry.S
@@ -348,40 +348,40 @@ _syscall_trace_entry:
.type resume,@function
resume:
- subq 4, $sp
- move $srp, [$sp] ; Keep old/new PC on the stack.
+ subq 4, $sp ; Make space for srp.
+
add.d $r12, $r10 ; R10 = current tasks tss.
addoq +THREAD_ccs, $r10, $acr
+ move $srp, [$sp] ; Keep old/new PC on the stack.
move $ccs, [$acr] ; Save IRQ enable state.
di
addoq +THREAD_usp, $r10, $acr
+ subq 10*4, $sp ; Make room for R9.
move $usp, [$acr] ; Save user-mode stackpointer.
;; See copy_thread for the reason why register R9 is saved.
- subq 10*4, $sp
movem $r9, [$sp] ; Save non-scratch registers and R9.
addoq +THREAD_ksp, $r10, $acr
+ move.d $sp, $r10 ; Return last running task in R10.
move.d $sp, [$acr] ; Save kernel SP for old task.
- move.d $sp, $r10 ; Return last running task in R10.
and.d -8192, $r10 ; Get thread_info from stackpointer.
addoq +TI_task, $r10, $acr
- move.d [$acr], $r10 ; Get task.
add.d $r12, $r11 ; Find the new tasks tss.
+ move.d [$acr], $r10 ; Get task.
addoq +THREAD_ksp, $r11, $acr
move.d [$acr], $sp ; Switch to new stackframe.
+ addoq +THREAD_usp, $r11, $acr
movem [$sp+], $r9 ; Restore non-scratch registers and R9.
- addoq +THREAD_usp, $r11, $acr
move [$acr], $usp ; Restore user-mode stackpointer.
addoq +THREAD_ccs, $r11, $acr
+ move.d [$sp+], $r11
+ jump $r11 ; Restore PC.
move [$acr], $ccs ; Restore IRQ enable status.
- move.d [$sp+], $acr
- jump $acr ; Restore PC.
- nop
.size resume, . - resume
nmi_interrupt: