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arc: fix the bug where regular irq comes out in user mode 

if USERSPACE is configured, it needs to record the user/kernel mode
of interrupted thread, because the switch of aux_sec_k_sp/aux_user_sp
depends on the aux_irq_act's U bit.

Signed-off-by: Watson Zeng <zhiwei@synopsys.com>
This commit is contained in:
Watson Zeng 2020-11-12 13:52:05 +08:00 committed by Anas Nashif
parent 991b0db47e
commit ffd8a91f55
3 changed files with 92 additions and 18 deletions
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52
arch/arc/core/fast_irq.S
View File

@ -222,11 +222,36 @@ _firq_reschedule:
* registers from the interrupted thread.
*/
#if defined(CONFIG_USERSPACE)
/* when USERSPACE is configured, here need to consider the case where firq comes
* out in user mode, according to ARCv2 ISA and nsim, the following micro ops
* will be executed:
* sp<-reg bank1'sp
* switch between sp and _ARC_V2_USER_SP
* then:
* sp is the sp of kernel stack of interrupted thread
* _ARC_V2_USER_SP is reg bank1'sp
* the sp of user stack of interrupted thread is reg bank0'sp
* if firq comes out in kernel mode, the following micro ops will be executed:
* sp<-reg bank'sp
* so, sw needs to do necessary handling to set up the correct sp
*/
lr r0, [_ARC_V2_AUX_IRQ_ACT]
bbit0 r0, 31, _firq_from_kernel
aex sp, [_ARC_V2_USER_SP]
lr r0, [_ARC_V2_STATUS32]
and r0, r0, ~_ARC_V2_STATUS32_RB(7)
kflag r0
aex sp, [_ARC_V2_USER_SP]
b _firq_create_irq_stack_frame
_firq_from_kernel:
#endif
/* chose register bank #0 */
lr r0, [_ARC_V2_STATUS32]
and r0, r0, ~_ARC_V2_STATUS32_RB(7)
kflag r0
_firq_create_irq_stack_frame:
/* we're back on the outgoing thread's stack */
_create_irq_stack_frame
@ -241,6 +266,24 @@ _firq_reschedule:
st ilink, [sp, ___isf_t_pc_OFFSET] /* ilink into pc */
#endif
#if defined(CONFIG_USERSPACE)
/*
* when USERSPACE is enabled, according to ARCv2 ISA, SP will be switched
* if interrupt comes out in user mode, and will be recorded in bit 31
* (U bit) of IRQ_ACT. when interrupt exits, SP will be switched back
* according to U bit.
*
* need to remember the user/kernel status of interrupted thread, will be
* restored when thread switched back
*
*/
lr r4, [_ARC_V2_AUX_IRQ_ACT]
and r3, r4, 0x80000000
push_s r3
bclr r4, r4, 31
sr r4, [_ARC_V2_AUX_IRQ_ACT]
#endif
mov_s r1, _kernel
ld_s r2, [r1, _kernel_offset_to_current]
@ -323,6 +366,15 @@ _firq_return_from_coop:
_firq_return_from_rirq:
_firq_return_from_firq:
#if defined(CONFIG_USERSPACE)
/*
* need to recover the user/kernel status of interrupted thread
*/
pop_s r3
lr r2, [_ARC_V2_AUX_IRQ_ACT]
or r2, r2, r3
sr r2, [_ARC_V2_AUX_IRQ_ACT]
#endif
_pop_irq_stack_frame
ld ilink, [sp, -4] /* status32 into ilink */

46
arch/arc/core/regular_irq.S
View File

@ -152,6 +152,24 @@ SECTION_FUNC(TEXT, _rirq_exit)
.balign 4
_rirq_reschedule:
#if defined(CONFIG_USERSPACE)
/*
* when USERSPACE is enabled, according to ARCv2 ISA, SP will be switched
* if interrupt comes out in user mode, and will be recorded in bit 31
* (U bit) of IRQ_ACT. when interrupt exits, SP will be switched back
* according to U bit.
*
* need to remember the user/kernel status of interrupted thread, will be
* restored when thread switched back
*
*/
lr r4, [_ARC_V2_AUX_IRQ_ACT]
and r3, r4, 0x80000000
push_s r3
bclr r4, r4, 31
sr r4, [_ARC_V2_AUX_IRQ_ACT]
#endif
/* _save_callee_saved_regs expects outgoing thread in r2 */
_save_callee_saved_regs
@ -181,21 +199,6 @@ _rirq_common_interrupt_swap:
pop_s r2
#endif
#if defined(CONFIG_USERSPACE)
/*
* when USERSPACE is enabled, according to ARCv2 ISA, SP will be switched
* if interrupt comes out in user mode, and will be recorded in bit 31
* (U bit) of IRQ_ACT. when interrupt exits, SP will be switched back
* according to U bit.
*
* For the case that context switches in interrupt, the target sp must be
* thread's kernel stack, no need to do hardware sp switch. so, U bit should
* be cleared.
*/
lr r0, [_ARC_V2_AUX_IRQ_ACT]
bclr r0, r0, 31
sr r0, [_ARC_V2_AUX_IRQ_ACT]
#endif
ld r3, [r2, _thread_offset_to_relinquish_cause]
@ -250,11 +253,24 @@ _rirq_return_from_coop:
/* fall through to rtie instruction */
/* stack now has the IRQ stack frame layout, pointing to sp */
/* rtie will pop the rest from the stack */
rtie
#endif /* CONFIG_PREEMPT_ENABLED */
.balign 4
_rirq_return_from_firq:
_rirq_return_from_rirq:
#if defined(CONFIG_USERSPACE)
/*
* need to recover the user/kernel status of interrupted thread
*/
pop_s r3
lr r2, [_ARC_V2_AUX_IRQ_ACT]
or r2, r2, r3
sr r2, [_ARC_V2_AUX_IRQ_ACT]
#endif
#ifdef CONFIG_TRACING
push_s blink

12
arch/arc/core/swap.S
View File

@ -194,6 +194,15 @@ return_loc:
_swap_return_from_rirq:
_swap_return_from_firq:
#if defined(CONFIG_USERSPACE)
/*
* need to recover the user/kernel status of interrupted thread
*/
pop_s r3
lr r2, [_ARC_V2_AUX_IRQ_ACT]
or r2, r2, r3
sr r2, [_ARC_V2_AUX_IRQ_ACT]
#endif
lr r3, [_ARC_V2_STATUS32]
bbit1 r3, _ARC_V2_STATUS32_AE_BIT, _return_from_exc_irq
@ -209,13 +218,10 @@ _swap_return_from_firq:
#endif
lr r3, [_ARC_V2_AUX_IRQ_ACT]
brne r3, 0, _swap_already_in_irq
/* use lowest interrupt priority */
or r3, r3, (1<<(CONFIG_NUM_IRQ_PRIO_LEVELS-1))
sr r3, [_ARC_V2_AUX_IRQ_ACT]
_swap_already_in_irq:
#ifdef CONFIG_TRACING
push_s blink