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openrisc: enable LOCKDEP_SUPPORT and irqflags tracing

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Lockdep is needed for proving the spinlocks and rwlocks work fine on our
platform.  It also requires calling the trace_hardirqs_off() and
trace_hardirqs_on() pair of routines when entering and exiting an
interrupt.

For OpenRISC the interrupt stack frame does not support frame pointers,
so to call trace_hardirqs_on() and trace_hardirqs_off() here the macro's
build up a stack frame each time.

There is one necessary small change in _sys_call_handler to move
interrupt enabling later so they can get re-enabled during syscall
restart. This was done to fix lockdep warnings that are now possible due
to this
patch.

Signed-off-by: Stafford Horne <shorne@gmail.com>
This commit is contained in:
Stafford Horne 2017-07-24 21:55:16 +09:00
parent eecac38b04
commit 78cdfb5cf1
2 changed files with 74 additions and 3 deletions
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3
arch/openrisc/Kconfig
View File

@ -64,6 +64,9 @@ config GENERIC_CSUM
config STACKTRACE_SUPPORT
def_bool y
config LOCKDEP_SUPPORT
def_bool y
source "init/Kconfig"
source "kernel/Kconfig.freezer"

74
arch/openrisc/kernel/entry.S
View File

@ -42,6 +42,61 @@
/* =========================================================[ macros ]=== */
#ifdef CONFIG_TRACE_IRQFLAGS
/*
* Trace irq on/off creating a stack frame.
*/
#define TRACE_IRQS_OP(trace_op) \
l.sw -8(r1),r2 /* store frame pointer */ ;\
l.sw -4(r1),r9 /* store return address */ ;\
l.addi r2,r1,0 /* move sp to fp */ ;\
l.jal trace_op ;\
l.addi r1,r1,-8 ;\
l.ori r1,r2,0 /* restore sp */ ;\
l.lwz r9,-4(r1) /* restore return address */ ;\
l.lwz r2,-8(r1) /* restore fp */ ;\
/*
* Trace irq on/off and save registers we need that would otherwise be
* clobbered.
*/
#define TRACE_IRQS_SAVE(t1,trace_op) \
l.sw -12(r1),t1 /* save extra reg */ ;\
l.sw -8(r1),r2 /* store frame pointer */ ;\
l.sw -4(r1),r9 /* store return address */ ;\
l.addi r2,r1,0 /* move sp to fp */ ;\
l.jal trace_op ;\
l.addi r1,r1,-12 ;\
l.ori r1,r2,0 /* restore sp */ ;\
l.lwz r9,-4(r1) /* restore return address */ ;\
l.lwz r2,-8(r1) /* restore fp */ ;\
l.lwz t1,-12(r1) /* restore extra reg */
#define TRACE_IRQS_OFF TRACE_IRQS_OP(trace_hardirqs_off)
#define TRACE_IRQS_ON TRACE_IRQS_OP(trace_hardirqs_on)
#define TRACE_IRQS_ON_SYSCALL \
TRACE_IRQS_SAVE(r10,trace_hardirqs_on) ;\
l.lwz r3,PT_GPR3(r1) ;\
l.lwz r4,PT_GPR4(r1) ;\
l.lwz r5,PT_GPR5(r1) ;\
l.lwz r6,PT_GPR6(r1) ;\
l.lwz r7,PT_GPR7(r1) ;\
l.lwz r8,PT_GPR8(r1) ;\
l.lwz r11,PT_GPR11(r1)
#define TRACE_IRQS_OFF_ENTRY \
l.lwz r5,PT_SR(r1) ;\
l.andi r3,r5,(SPR_SR_IEE|SPR_SR_TEE) ;\
l.sfeq r5,r0 /* skip trace if irqs were already off */;\
l.bf 1f ;\
l.nop ;\
TRACE_IRQS_SAVE(r4,trace_hardirqs_off) ;\
1:
#else
#define TRACE_IRQS_OFF
#define TRACE_IRQS_ON
#define TRACE_IRQS_OFF_ENTRY
#define TRACE_IRQS_ON_SYSCALL
#endif
/*
* We need to disable interrupts at beginning of RESTORE_ALL
* since interrupt might come in after we've loaded EPC return address
@ -124,6 +179,7 @@ handler: ;\
/* r30 already save */ ;\
/* l.sw PT_GPR30(r1),r30*/ ;\
l.sw PT_GPR31(r1),r31 ;\
TRACE_IRQS_OFF_ENTRY ;\
/* Store -1 in orig_gpr11 for non-syscall exceptions */ ;\
l.addi r30,r0,-1 ;\
l.sw PT_ORIG_GPR11(r1),r30
@ -557,9 +613,6 @@ _string_syscall_return:
.align 4
ENTRY(_sys_call_handler)
/* syscalls run with interrupts enabled */
ENABLE_INTERRUPTS(r29) // enable interrupts, r29 is temp
/* r1, EPCR, ESR a already saved */
l.sw PT_GPR2(r1),r2
/* r3-r8 must be saved because syscall restart relies
@ -597,6 +650,10 @@ ENTRY(_sys_call_handler)
/* l.sw PT_GPR30(r1),r30 */
_syscall_check_trace_enter:
/* syscalls run with interrupts enabled */
TRACE_IRQS_ON_SYSCALL
ENABLE_INTERRUPTS(r29) // enable interrupts, r29 is temp
/* If TIF_SYSCALL_TRACE is set, then we want to do syscall tracing */
l.lwz r30,TI_FLAGS(r10)
l.andi r30,r30,_TIF_SYSCALL_TRACE
@ -657,6 +714,7 @@ _syscall_check_trace_leave:
_syscall_check_work:
/* Here we need to disable interrupts */
DISABLE_INTERRUPTS(r27,r29)
TRACE_IRQS_OFF
l.lwz r30,TI_FLAGS(r10)
l.andi r30,r30,_TIF_WORK_MASK
l.sfne r30,r0
@ -871,6 +929,7 @@ UNHANDLED_EXCEPTION(_vector_0x1f00,0x1f00)
_resume_userspace:
DISABLE_INTERRUPTS(r3,r4)
TRACE_IRQS_OFF
l.lwz r4,TI_FLAGS(r10)
l.andi r13,r4,_TIF_WORK_MASK
l.sfeqi r13,0
@ -909,6 +968,15 @@ _work_pending:
l.lwz r8,PT_GPR8(r1)
_restore_all:
#ifdef CONFIG_TRACE_IRQFLAGS
l.lwz r4,PT_SR(r1)
l.andi r3,r4,(SPR_SR_IEE|SPR_SR_TEE)
l.sfeq r3,r0 /* skip trace if irqs were off */
l.bf skip_hardirqs_on
l.nop
TRACE_IRQS_ON
skip_hardirqs_on:
#endif
RESTORE_ALL
/* This returns to userspace code */