redonkable/remarkable-linux
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CRIS: Simple insn reschedule to avoid interlocks.

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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>
This commit is contained in:
Jesper Nilsson 2010-08-02 18:09:56 +02:00
parent a80a635f3d
commit 43f6cdd769
1 changed files with 9 additions and 9 deletions
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18
arch/cris/arch-v32/kernel/entry.S
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@ -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: