Commit 78cdfb5c authored by Stafford Horne's avatar Stafford Horne
Browse files

openrisc: enable LOCKDEP_SUPPORT and irqflags tracing 



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: default avatarStafford Horne <shorne@gmail.com>
parent eecac38b

arch/openrisc/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -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"

arch/openrisc/kernel/entry.S

+71 −3
Original line number Diff line number Diff line
@@ -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 */

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