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ARCv2: STAR 9000793984: Handle return from intr to Delay Slot

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Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Vineet Gupta 2014-09-22 16:51:47 +05:30
parent 1f6ccfff63
commit 4255b07f2c
3 changed files with 53 additions and 0 deletions
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1
arch/arc/kernel/asm-offsets.c
View File

@ -56,6 +56,7 @@ int main(void)
DEFINE(PT_r5, offsetof(struct pt_regs, r5));
DEFINE(PT_r6, offsetof(struct pt_regs, r6));
DEFINE(PT_r7, offsetof(struct pt_regs, r7));
DEFINE(PT_ret, offsetof(struct pt_regs, ret));
DEFINE(SZ_CALLEE_REGS, sizeof(struct callee_regs));
DEFINE(SZ_PT_REGS, sizeof(struct pt_regs));

50
arch/arc/kernel/entry-arcv2.S
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@ -163,6 +163,9 @@ END(EV_TLBProtV)
;####### Return from Intr #######
debug_marker_l1:
bbit1.nt r0, STATUS_DE_BIT, .Lintr_ret_to_delay_slot
.Lisr_ret_fast_path:
; Handle special case #1: (Entry via Exception, Return via IRQ)
;
; Exception in U mode, preempted in kernel, Intr taken (K mode), orig
@ -186,4 +189,51 @@ debug_marker_syscall:
EXCEPTION_EPILOGUE
rtie
;####### Return from Intr to insn in delay slot #######
; Handle special case #2: (Entry via Exception in Delay Slot, Return via IRQ)
;
; Intr returning to a Delay Slot (DS) insn
; (since IRQ NOT allowed in DS in ARCv2, this can only happen if orig
; entry was via Exception in DS which got preempted in kernel).
;
; IRQ RTIE won't reliably restore DE bit and/or BTA, needs handling
.Lintr_ret_to_delay_slot:
debug_marker_ds:
ld r2, [@intr_to_DE_cnt]
add r2, r2, 1
st r2, [@intr_to_DE_cnt]
ld r2, [sp, PT_ret]
ld r3, [sp, PT_status32]
bic r0, r3, STATUS_U_MASK|STATUS_DE_MASK|STATUS_IE_MASK|STATUS_L_MASK
st r0, [sp, PT_status32]
mov r1, .Lintr_ret_to_delay_slot_2
st r1, [sp, PT_ret]
st r2, [sp, 0]
st r3, [sp, 4]
b .Lisr_ret_fast_path
.Lintr_ret_to_delay_slot_2:
sub sp, sp, SZ_PT_REGS
st r9, [sp, -4]
ld r9, [sp, 0]
sr r9, [eret]
ld r9, [sp, 4]
sr r9, [erstatus]
ld r9, [sp, 8]
sr r9, [erbta]
ld r9, [sp, -4]
add sp, sp, SZ_PT_REGS
rtie
END(ret_from_exception)

2
arch/arc/kernel/setup.c
View File

@ -30,6 +30,8 @@
#define FIX_PTR(x) __asm__ __volatile__(";" : "+r"(x))
unsigned int intr_to_DE_cnt;
/* Part of U-boot ABI: see head.S */
int __initdata uboot_tag;
char __initdata *uboot_arg;