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powerpc/64e/interrupt: use new interrupt return

Browse source 
Update the new C and asm interrupt return code to account for 64e
specifics, switch over to use it.

The now-unused old ret_from_except code, that was moved to 64e after the
64s conversion, is removed.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316104206.407354-5-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2021-03-16 20:41:58 +10:00 committed by Michael Ellerman
parent dc6231821a
commit 0c2472de23
5 changed files with 25 additions and 404 deletions
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2
arch/powerpc/include/asm/asm-prototypes.h
View file

@ -77,8 +77,6 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
long ppc_fadvise64_64(int fd, int advice, u32 offset_high, u32 offset_low,
u32 len_high, u32 len_low);
long sys_switch_endian(void);
notrace unsigned int __check_irq_replay(void);
void notrace restore_interrupts(void);
/* prom_init (OpenFirmware) */
unsigned long __init prom_init(unsigned long r3, unsigned long r4,

20
arch/powerpc/include/asm/ppc_asm.h
View file

@ -15,26 +15,6 @@
#define SZL (BITS_PER_LONG/8)
/*
* Stuff for accurate CPU time accounting.
* These macros handle transitions between user and system state
* in exception entry and exit and accumulate time to the
* user_time and system_time fields in the paca.
*/
#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
#define ACCOUNT_CPU_USER_EXIT(ptr, ra, rb)
#else
#define ACCOUNT_CPU_USER_EXIT(ptr, ra, rb) \
MFTB(ra); /* get timebase */ \
PPC_LL rb, ACCOUNT_STARTTIME(ptr); \
PPC_STL ra, ACCOUNT_STARTTIME_USER(ptr); \
subf rb,rb,ra; /* subtract start value */ \
PPC_LL ra, ACCOUNT_SYSTEM_TIME(ptr); \
add ra,ra,rb; /* add on to system time */ \
PPC_STL ra, ACCOUNT_SYSTEM_TIME(ptr)
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
/*
* Macros for storing registers into and loading registers from
* exception frames.

10
arch/powerpc/kernel/asm-offsets.c
View file

@ -282,21 +282,11 @@ int main(void)
OFFSET(PACAHWCPUID, paca_struct, hw_cpu_id);
OFFSET(PACAKEXECSTATE, paca_struct, kexec_state);
OFFSET(PACA_DSCR_DEFAULT, paca_struct, dscr_default);
OFFSET(ACCOUNT_STARTTIME, paca_struct, accounting.starttime);
OFFSET(ACCOUNT_STARTTIME_USER, paca_struct, accounting.starttime_user);
OFFSET(ACCOUNT_USER_TIME, paca_struct, accounting.utime);
OFFSET(ACCOUNT_SYSTEM_TIME, paca_struct, accounting.stime);
#ifdef CONFIG_PPC_BOOK3E
OFFSET(PACA_TRAP_SAVE, paca_struct, trap_save);
#endif
OFFSET(PACA_SPRG_VDSO, paca_struct, sprg_vdso);
#else /* CONFIG_PPC64 */
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
OFFSET(ACCOUNT_STARTTIME, thread_info, accounting.starttime);
OFFSET(ACCOUNT_STARTTIME_USER, thread_info, accounting.starttime_user);
OFFSET(ACCOUNT_USER_TIME, thread_info, accounting.utime);
OFFSET(ACCOUNT_SYSTEM_TIME, thread_info, accounting.stime);
#endif
#endif /* CONFIG_PPC64 */
/* RTAS */

321
arch/powerpc/kernel/exceptions-64e.S
View file

@ -139,7 +139,8 @@ ret_from_level_except:
ld r3,_MSR(r1)
andi. r3,r3,MSR_PR
beq 1f
b ret_from_except
REST_NVGPRS(r1)
b interrupt_return
1:
LOAD_REG_ADDR(r11,extlb_level_exc)
@ -208,7 +209,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV)
/*
* Restore PACAIRQHAPPENED rather than setting it based on
* the return MSR[EE], since we could have interrupted
* __check_irq_replay() or other inconsistent transitory
* interrupt replay or other inconsistent transitory
* states that must remain that way.
*/
SPECIAL_EXC_LOAD(r10,IRQHAPPENED)
@ -511,7 +512,7 @@ exc_##n##_bad_stack: \
CHECK_NAPPING(); \
addi r3,r1,STACK_FRAME_OVERHEAD; \
bl hdlr; \
b ret_from_except_lite;
b interrupt_return
/* This value is used to mark exception frames on the stack. */
.section ".toc","aw"
@ -623,7 +624,8 @@ __end_interrupts:
addi r3,r1,STACK_FRAME_OVERHEAD
ld r14,PACA_EXGEN+EX_R14(r13)
bl program_check_exception
b ret_from_except
REST_NVGPRS(r1)
b interrupt_return
/* Floating Point Unavailable Interrupt */
START_EXCEPTION(fp_unavailable);
@ -635,11 +637,11 @@ __end_interrupts:
andi. r0,r12,MSR_PR;
beq- 1f
bl load_up_fpu
b fast_exception_return
b fast_interrupt_return
1: INTS_DISABLE
addi r3,r1,STACK_FRAME_OVERHEAD
bl kernel_fp_unavailable_exception
b ret_from_except
b interrupt_return
/* Altivec Unavailable Interrupt */
START_EXCEPTION(altivec_unavailable);
@ -653,14 +655,14 @@ BEGIN_FTR_SECTION
andi. r0,r12,MSR_PR;
beq- 1f
bl load_up_altivec
b fast_exception_return
b fast_interrupt_return
1:
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
#endif
INTS_DISABLE
addi r3,r1,STACK_FRAME_OVERHEAD
bl altivec_unavailable_exception
b ret_from_except
b interrupt_return
/* AltiVec Assist */
START_EXCEPTION(altivec_assist);
@ -674,10 +676,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
BEGIN_FTR_SECTION
bl altivec_assist_exception
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
REST_NVGPRS(r1)
#else
bl unknown_exception
#endif
b ret_from_except
b interrupt_return
/* Decrementer Interrupt */
@ -719,7 +722,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
INTS_DISABLE
addi r3,r1,STACK_FRAME_OVERHEAD
bl unknown_exception
b ret_from_except
b interrupt_return
/* Debug exception as a critical interrupt*/
START_EXCEPTION(debug_crit);
@ -786,7 +789,8 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
ld r14,PACA_EXCRIT+EX_R14(r13)
ld r15,PACA_EXCRIT+EX_R15(r13)
bl DebugException
b ret_from_except
REST_NVGPRS(r1)
b interrupt_return
kernel_dbg_exc:
b . /* NYI */
@ -857,7 +861,8 @@ kernel_dbg_exc:
ld r14,PACA_EXDBG+EX_R14(r13)
ld r15,PACA_EXDBG+EX_R15(r13)
bl DebugException
b ret_from_except
REST_NVGPRS(r1)
b interrupt_return
START_EXCEPTION(perfmon);
NORMAL_EXCEPTION_PROLOG(0x260, BOOKE_INTERRUPT_PERFORMANCE_MONITOR,
@ -867,7 +872,7 @@ kernel_dbg_exc:
CHECK_NAPPING()
addi r3,r1,STACK_FRAME_OVERHEAD
bl performance_monitor_exception
b ret_from_except_lite
b interrupt_return
/* Doorbell interrupt */
MASKABLE_EXCEPTION(0x280, BOOKE_INTERRUPT_DOORBELL,
@ -895,7 +900,7 @@ kernel_dbg_exc:
addi r3,r1,STACK_FRAME_OVERHEAD
INTS_RESTORE_HARD
bl unknown_exception
b ret_from_except
b interrupt_return
/* Guest Doorbell critical Interrupt */
START_EXCEPTION(guest_doorbell_crit);
@ -916,7 +921,7 @@ kernel_dbg_exc:
addi r3,r1,STACK_FRAME_OVERHEAD
INTS_RESTORE_HARD
bl unknown_exception
b ret_from_except
b interrupt_return
/* Embedded Hypervisor priviledged */
START_EXCEPTION(ehpriv);
@ -926,7 +931,7 @@ kernel_dbg_exc:
addi r3,r1,STACK_FRAME_OVERHEAD
INTS_RESTORE_HARD
bl unknown_exception
b ret_from_except
b interrupt_return
/* LRAT Error interrupt */
START_EXCEPTION(lrat_error);
@ -936,7 +941,7 @@ kernel_dbg_exc:
addi r3,r1,STACK_FRAME_OVERHEAD
INTS_RESTORE_HARD
bl unknown_exception
b ret_from_except
b interrupt_return
/*
* An interrupt came in while soft-disabled; We mark paca->irq_happened
@ -998,11 +1003,11 @@ storage_fault_common:
bl do_page_fault
cmpdi r3,0
bne- 1f
b ret_from_except_lite
b interrupt_return
mr r4,r3
addi r3,r1,STACK_FRAME_OVERHEAD
bl __bad_page_fault
b ret_from_except
b interrupt_return
/*
* Alignment exception doesn't fit entirely in the 0x100 bytes so it
@ -1016,284 +1021,8 @@ alignment_more:
ld r15,PACA_EXGEN+EX_R15(r13)
INTS_RESTORE_HARD
bl alignment_exception
b ret_from_except
.align 7
_GLOBAL(ret_from_except)
REST_NVGPRS(r1)
_GLOBAL(ret_from_except_lite)
/*
* Disable interrupts so that current_thread_info()->flags
* can't change between when we test it and when we return
* from the interrupt.
*/
wrteei 0
ld r9, PACA_THREAD_INFO(r13)
ld r3,_MSR(r1)
ld r10,PACACURRENT(r13)
ld r4,TI_FLAGS(r9)
andi. r3,r3,MSR_PR
beq resume_kernel
lwz r3,(THREAD+THREAD_DBCR0)(r10)
/* Check current_thread_info()->flags */
andi. r0,r4,_TIF_USER_WORK_MASK
bne 1f
/*
* Check to see if the dbcr0 register is set up to debug.
* Use the internal debug mode bit to do this.
*/
andis. r0,r3,DBCR0_IDM@h
beq restore
mfmsr r0
rlwinm r0,r0,0,~MSR_DE /* Clear MSR.DE */
mtmsr r0
mtspr SPRN_DBCR0,r3
li r10, -1
mtspr SPRN_DBSR,r10
b restore
1: andi. r0,r4,_TIF_NEED_RESCHED
beq 2f
bl restore_interrupts
SCHEDULE_USER
b ret_from_except_lite
2:
/*
* Use a non volatile GPR to save and restore our thread_info flags
* across the call to restore_interrupts.
*/
mr r30,r4
bl restore_interrupts
mr r4,r30
addi r3,r1,STACK_FRAME_OVERHEAD
bl do_notify_resume
b ret_from_except
resume_kernel:
/* check current_thread_info, _TIF_EMULATE_STACK_STORE */
andis. r8,r4,_TIF_EMULATE_STACK_STORE@h
beq+ 1f
addi r8,r1,INT_FRAME_SIZE /* Get the kprobed function entry */
ld r3,GPR1(r1)
subi r3,r3,INT_FRAME_SIZE /* dst: Allocate a trampoline exception frame */
mr r4,r1 /* src: current exception frame */
mr r1,r3 /* Reroute the trampoline frame to r1 */
/* Copy from the original to the trampoline. */
li r5,INT_FRAME_SIZE/8 /* size: INT_FRAME_SIZE */
li r6,0 /* start offset: 0 */
mtctr r5
2: ldx r0,r6,r4
stdx r0,r6,r3
addi r6,r6,8
bdnz 2b
/* Do real store operation to complete stdu */
ld r5,GPR1(r1)
std r8,0(r5)
/* Clear _TIF_EMULATE_STACK_STORE flag */
lis r11,_TIF_EMULATE_STACK_STORE@h
addi r5,r9,TI_FLAGS
0: ldarx r4,0,r5
andc r4,r4,r11
stdcx. r4,0,r5
bne- 0b
1:
#ifdef CONFIG_PREEMPT
/* Check if we need to preempt */
andi. r0,r4,_TIF_NEED_RESCHED
beq+ restore
/* Check that preempt_count() == 0 and interrupts are enabled */
lwz r8,TI_PREEMPT(r9)
cmpwi cr0,r8,0
bne restore
ld r0,SOFTE(r1)
andi. r0,r0,IRQS_DISABLED
bne restore
/*
* Here we are preempting the current task. We want to make
* sure we are soft-disabled first and reconcile irq state.
*/
RECONCILE_IRQ_STATE(r3,r4)
bl preempt_schedule_irq
/*
* arch_local_irq_restore() from preempt_schedule_irq above may
* enable hard interrupt but we really should disable interrupts
* when we return from the interrupt, and so that we don't get
* interrupted after loading SRR0/1.
*/
wrteei 0
#endif /* CONFIG_PREEMPT */
restore:
/*
* This is the main kernel exit path. First we check if we
* are about to re-enable interrupts
*/
ld r5,SOFTE(r1)
lbz r6,PACAIRQSOFTMASK(r13)
andi. r5,r5,IRQS_DISABLED
bne .Lrestore_irq_off
/* We are enabling, were we already enabled ? Yes, just return */
andi. r6,r6,IRQS_DISABLED
beq cr0,fast_exception_return
/*
* We are about to soft-enable interrupts (we are hard disabled
* at this point). We check if there's anything that needs to
* be replayed first.
*/
lbz r0,PACAIRQHAPPENED(r13)
cmpwi cr0,r0,0
bne- .Lrestore_check_irq_replay
/*
* Get here when nothing happened while soft-disabled, just
* soft-enable and move-on. We will hard-enable as a side
* effect of rfi
*/
.Lrestore_no_replay:
TRACE_ENABLE_INTS
li r0,IRQS_ENABLED
stb r0,PACAIRQSOFTMASK(r13);
/* This is the return from load_up_fpu fast path which could do with
* less GPR restores in fact, but for now we have a single return path
*/
fast_exception_return:
wrteei 0
1: mr r0,r13
ld r10,_MSR(r1)
REST_4GPRS(2, r1)
andi. r6,r10,MSR_PR
REST_2GPRS(6, r1)
beq 1f
ACCOUNT_CPU_USER_EXIT(r13, r10, r11)
ld r0,GPR13(r1)
1: stdcx. r0,0,r1 /* to clear the reservation */
ld r8,_CCR(r1)
ld r9,_LINK(r1)
ld r10,_CTR(r1)
ld r11,_XER(r1)
mtcr r8
mtlr r9
mtctr r10
mtxer r11
REST_2GPRS(8, r1)
ld r10,GPR10(r1)
ld r11,GPR11(r1)
ld r12,GPR12(r1)
mtspr SPRN_SPRG_GEN_SCRATCH,r0
std r10,PACA_EXGEN+EX_R10(r13);
std r11,PACA_EXGEN+EX_R11(r13);
ld r10,_NIP(r1)
ld r11,_MSR(r1)
ld r0,GPR0(r1)
ld r1,GPR1(r1)
mtspr SPRN_SRR0,r10
mtspr SPRN_SRR1,r11
ld r10,PACA_EXGEN+EX_R10(r13)
ld r11,PACA_EXGEN+EX_R11(r13)
mfspr r13,SPRN_SPRG_GEN_SCRATCH
rfi
/*
* We are returning to a context with interrupts soft disabled.
*
* However, we may also about to hard enable, so we need to
* make sure that in this case, we also clear PACA_IRQ_HARD_DIS
* or that bit can get out of sync and bad things will happen
*/
.Lrestore_irq_off:
ld r3,_MSR(r1)
lbz r7,PACAIRQHAPPENED(r13)
andi. r0,r3,MSR_EE
beq 1f
rlwinm r7,r7,0,~PACA_IRQ_HARD_DIS
stb r7,PACAIRQHAPPENED(r13)
1:
#if defined(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG) && defined(CONFIG_BUG)
/* The interrupt should not have soft enabled. */
lbz r7,PACAIRQSOFTMASK(r13)
1: tdeqi r7,IRQS_ENABLED
EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING
#endif
b fast_exception_return
/*
* Something did happen, check if a re-emit is needed
* (this also clears paca->irq_happened)
*/
.Lrestore_check_irq_replay:
/* XXX: We could implement a fast path here where we check
* for irq_happened being just 0x01, in which case we can
* clear it and return. That means that we would potentially
* miss a decrementer having wrapped all the way around.
*
* Still, this might be useful for things like hash_page
*/
bl __check_irq_replay
cmpwi cr0,r3,0
beq .Lrestore_no_replay
/*
* We need to re-emit an interrupt. We do so by re-using our
* existing exception frame. We first change the trap value,
* but we need to ensure we preserve the low nibble of it
*/
ld r4,_TRAP(r1)
clrldi r4,r4,60
or r4,r4,r3
std r4,_TRAP(r1)
/*
* PACA_IRQ_HARD_DIS won't always be set here, so set it now
* to reconcile the IRQ state. Tracing is already accounted for.
*/
lbz r4,PACAIRQHAPPENED(r13)
ori r4,r4,PACA_IRQ_HARD_DIS
stb r4,PACAIRQHAPPENED(r13)
/*
* Then find the right handler and call it. Interrupts are
* still soft-disabled and we keep them that way.
*/
cmpwi cr0,r3,0x500
bne 1f
addi r3,r1,STACK_FRAME_OVERHEAD;
bl do_IRQ
b ret_from_except
1: cmpwi cr0,r3,0x900
bne 1f
addi r3,r1,STACK_FRAME_OVERHEAD;
bl timer_interrupt
b ret_from_except
#ifdef CONFIG_PPC_DOORBELL
1:
cmpwi cr0,r3,0x280
bne 1f
addi r3,r1,STACK_FRAME_OVERHEAD;
bl doorbell_exception
#endif /* CONFIG_PPC_DOORBELL */
1: b ret_from_except /* What else to do here ? */
_ASM_NOKPROBE_SYMBOL(ret_from_except);
_ASM_NOKPROBE_SYMBOL(ret_from_except_lite);
_ASM_NOKPROBE_SYMBOL(resume_kernel);
_ASM_NOKPROBE_SYMBOL(restore);
_ASM_NOKPROBE_SYMBOL(fast_exception_return);
b interrupt_return
/*
* Trampolines used when spotting a bad kernel stack pointer in

76
arch/powerpc/kernel/irq.c
View file

@ -104,82 +104,6 @@ static inline notrace unsigned long get_irq_happened(void)
return happened;
}
#ifdef CONFIG_PPC_BOOK3E
/* This is called whenever we are re-enabling interrupts
* and returns either 0 (nothing to do) or 500/900/280 if
* there's an EE, DEC or DBELL to generate.
*
* This is called in two contexts: From arch_local_irq_restore()
* before soft-enabling interrupts, and from the exception exit
* path when returning from an interrupt from a soft-disabled to
* a soft enabled context. In both case we have interrupts hard
* disabled.
*
* We take care of only clearing the bits we handled in the
* PACA irq_happened field since we can only re-emit one at a
* time and we don't want to "lose" one.
*/
notrace unsigned int __check_irq_replay(void)
{
/*
* We use local_paca rather than get_paca() to avoid all
* the debug_smp_processor_id() business in this low level
* function
*/
unsigned char happened = local_paca->irq_happened;
/*
* We are responding to the next interrupt, so interrupt-off
* latencies should be reset here.
*/
trace_hardirqs_on();
trace_hardirqs_off();
if (happened & PACA_IRQ_DEC) {
local_paca->irq_happened &= ~PACA_IRQ_DEC;
return 0x900;
}
if (happened & PACA_IRQ_EE) {
local_paca->irq_happened &= ~PACA_IRQ_EE;
return 0x500;
}
if (happened & PACA_IRQ_DBELL) {
local_paca->irq_happened &= ~PACA_IRQ_DBELL;
return 0x280;
}
if (happened & PACA_IRQ_HARD_DIS)
local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
/* There should be nothing left ! */
BUG_ON(local_paca->irq_happened != 0);
return 0;
}
/*
* This is specifically called by assembly code to re-enable interrupts
* if they are currently disabled. This is typically called before
* schedule() or do_signal() when returning to userspace. We do it
* in C to avoid the burden of dealing with lockdep etc...
*
* NOTE: This is called with interrupts hard disabled but not marked
* as such in paca->irq_happened, so we need to resync this.
*/
void notrace restore_interrupts(void)
{
if (irqs_disabled()) {
local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
local_irq_enable();
} else
__hard_irq_enable();
}
#endif /* CONFIG_PPC_BOOK3E */
void replay_soft_interrupts(void)
{
struct pt_regs regs;