[POWERPC] irqtrace support for 64-bit powerpc

This adds the low level irq tracing hooks to the powerpc architecture
needed to enable full lockdep functionality.

This is partly based on Johannes Berg's initial version.  I removed
the asm trampoline that isn't needed (thus improving performance) and
modified all sorts of bits and pieces, reworking most of the assembly,
etc...

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 32 insertions, 15 deletions

diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 44229c3749a..215973a2c8d 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -36,8 +36,7 @@
 #include <asm/firmware.h>
 #include <asm/page_64.h>
 #include <asm/exception.h>
-
-#define DO_SOFT_DISABLE
+#include <asm/irqflags.h>
 
 /*
  * We layout physical memory as follows:
@@ -450,8 +449,8 @@ bad_stack:
  */
 fast_exc_return_irq:			/* restores irq state too */
 	ld	r3,SOFTE(r1)
+	TRACE_AND_RESTORE_IRQ(r3);
 	ld	r12,_MSR(r1)
-	stb	r3,PACASOFTIRQEN(r13)	/* restore paca->soft_enabled */
 	rldicl	r4,r12,49,63		/* get MSR_EE to LSB */
 	stb	r4,PACAHARDIRQEN(r13)	/* restore paca->hard_enabled */
 	b	1f
@@ -824,7 +823,7 @@ _STATIC(load_up_altivec)
  * Hash table stuff
  */
 	.align	7
-_GLOBAL(do_hash_page)
+_STATIC(do_hash_page)
 	std	r3,_DAR(r1)
 	std	r4,_DSISR(r1)
 
@@ -836,6 +835,27 @@ BEGIN_FTR_SECTION
 END_FTR_SECTION_IFCLR(CPU_FTR_SLB)
 
 	/*
+	 * On iSeries, we soft-disable interrupts here, then
+	 * hard-enable interrupts so that the hash_page code can spin on
+	 * the hash_table_lock without problems on a shared processor.
+	 */
+	DISABLE_INTS
+
+	/*
+	 * Currently, trace_hardirqs_off() will be called by DISABLE_INTS
+	 * and will clobber volatile registers when irq tracing is enabled
+	 * so we need to reload them. It may be possible to be smarter here
+	 * and move the irq tracing elsewhere but let's keep it simple for
+	 * now
+	 */
+#ifdef CONFIG_TRACE_IRQFLAGS
+	ld	r3,_DAR(r1)
+	ld	r4,_DSISR(r1)
+	ld	r5,_TRAP(r1)
+	ld	r12,_MSR(r1)
+	clrrdi	r5,r5,4
+#endif /* CONFIG_TRACE_IRQFLAGS */
+	/*
 	 * We need to set the _PAGE_USER bit if MSR_PR is set or if we are
 	 * accessing a userspace segment (even from the kernel). We assume
 	 * kernel addresses always have the high bit set.
@@ -848,13 +868,6 @@ END_FTR_SECTION_IFCLR(CPU_FTR_SLB)
 	rlwimi	r4,r5,22+2,31-2,31-2	/* Set _PAGE_EXEC if trap is 0x400 */
 
 	/*
-	 * On iSeries, we soft-disable interrupts here, then
-	 * hard-enable interrupts so that the hash_page code can spin on
-	 * the hash_table_lock without problems on a shared processor.
-	 */
-	DISABLE_INTS
-
-	/*
 	 * r3 contains the faulting address
 	 * r4 contains the required access permissions
 	 * r5 contains the trap number
@@ -864,7 +877,6 @@ END_FTR_SECTION_IFCLR(CPU_FTR_SLB)
 	bl	.hash_page		/* build HPTE if possible */
 	cmpdi	r3,0			/* see if hash_page succeeded */
 
-#ifdef DO_SOFT_DISABLE
 BEGIN_FW_FTR_SECTION
 	/*
 	 * If we had interrupts soft-enabled at the point where the
@@ -876,7 +888,7 @@ BEGIN_FW_FTR_SECTION
 	 */
 	beq	13f
 END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
-#endif
+
 BEGIN_FW_FTR_SECTION
 	/*
 	 * Here we have interrupts hard-disabled, so it is sufficient
@@ -890,11 +902,12 @@ END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISERIES)
 
 	/*
 	 * hash_page couldn't handle it, set soft interrupt enable back
-	 * to what it was before the trap.  Note that .local_irq_restore
+	 * to what it was before the trap.  Note that .raw_local_irq_restore
 	 * handles any interrupts pending at this point.
 	 */
 	ld	r3,SOFTE(r1)
-	bl	.local_irq_restore
+	TRACE_AND_RESTORE_IRQ_PARTIAL(r3, 11f)
+	bl	.raw_local_irq_restore
 	b	11f
 
 /* Here we have a page fault that hash_page can't handle. */
@@ -1493,6 +1506,10 @@ _INIT_STATIC(start_here_multiplatform)
 	addi	r2,r2,0x4000
 	add	r2,r2,r26
 
+	/* Set initial ptr to current */
+	LOAD_REG_IMMEDIATE(r4, init_task)
+	std	r4,PACACURRENT(r13)
+
 	/* Do very early kernel initializations, including initial hash table,
 	 * stab and slb setup before we turn on relocation.	*/