On Thu, 2007-07-05 at 00:40 +0200, Johannes Berg wrote:
> On Sat, 2007-06-30 at 10:58 +0200, Christoph Hellwig wrote:
> > On Thu, Jun 28, 2007 at 06:20:42PM +0200, Johannes Berg wrote:
> > > This one doesn't break 32-bit build by simply disabling irqtrace for
> > > 32-bit.
> >
> > This looks really cool to me. I'd love to see this in 2.6.23.
>
> Hmm. Looks like I just found a case where I forgot to trace in some
> place:
>
> [ 241.629380] hardirqs last enabled at (1319): [<c0000000000b3718>]
> .get_page_from_freelist+0x298/0x620
> [ 241.629714] hardirqs last disabled at (1320): [<c000000000033690>]
> .native_hpte_invalidate+0x60/0x320
> [ 241.629732] softirqs last enabled at (1282): [<c000000000059e28>]
> .__do_softirq+0x198/0x1e0
> [ 241.629748] softirqs last disabled at (1273): [<c00000000000c7e4>]
> .do_softirq+0xd4/0xe0
Not sure what that was, but I found one place where it could have come
from (do an interdiff if you want to know). Below patch is a bit nicer,
especially those trace_hardirqs wrappers. However, the presence of those
itself is indication that I haven't given most of the hooks I added much
thought. Though, in case somebody wants to develop it further I'll even
sign it off.
For me it's doing what I want, it allows me to develop with and for
lockdep, take advantage of lockdep and still use my machine (with forced
preemption) as expected; however I don't think I'd be comfortable with
anybody else using it except on test machines unless somebody else gives
it a thorough look first. Especially for say iSeries which is quite
different in the low-level code and I can't even test.
johannes
Subject: powerpc: 64-bit irqtrace support
From: Johannes Berg <[EMAIL PROTECTED]>
This adds irqtrace support to 64-bit powerpc.
Signed-off-by: Johannes Berg <[EMAIL PROTECTED]>
---
arch/powerpc/Kconfig | 9 ++++
arch/powerpc/kernel/Makefile | 1
arch/powerpc/kernel/entry_64.S | 24 +++++++++++
arch/powerpc/kernel/head_64.S | 54 +++++++++++++++++++++-----
arch/powerpc/kernel/irq.c | 2
arch/powerpc/kernel/irqtrace.S | 82 ++++++++++++++++++++++++++++++++++++++++
arch/powerpc/kernel/ppc_ksyms.c | 2
arch/powerpc/kernel/setup_64.c | 6 ++
include/asm-powerpc/hw_irq.h | 14 +++---
include/asm-powerpc/irqflags.h | 13 ------
include/asm-powerpc/rwsem.h | 34 ++++++++++++----
include/asm-powerpc/spinlock.h | 1
12 files changed, 202 insertions(+), 40 deletions(-)
--- linux-2.6-git.orig/arch/powerpc/Kconfig 2007-07-05 23:01:18.001397556
+0200
+++ linux-2.6-git/arch/powerpc/Kconfig 2007-07-05 23:01:18.068397556 +0200
@@ -38,6 +38,15 @@ config STACKTRACE_SUPPORT
bool
default y
+config TRACE_IRQFLAGS_SUPPORT
+ bool
+ depends on PPC64
+ default y
+
+config LOCKDEP_SUPPORT
+ bool
+ default y
+
config RWSEM_GENERIC_SPINLOCK
bool
--- linux-2.6-git.orig/arch/powerpc/kernel/irq.c 2007-07-05
23:01:11.727397556 +0200
+++ linux-2.6-git/arch/powerpc/kernel/irq.c 2007-07-05 23:01:18.084397556
+0200
@@ -114,7 +114,7 @@ static inline void set_soft_enabled(unsi
: : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled)));
}
-void local_irq_restore(unsigned long en)
+void raw_local_irq_restore(unsigned long en)
{
/*
* get_paca()->soft_enabled = en;
--- linux-2.6-git.orig/arch/powerpc/kernel/ppc_ksyms.c 2007-07-05
23:01:11.759397556 +0200
+++ linux-2.6-git/arch/powerpc/kernel/ppc_ksyms.c 2007-07-05
23:01:18.094397556 +0200
@@ -50,7 +50,7 @@
#endif
#ifdef CONFIG_PPC64
-EXPORT_SYMBOL(local_irq_restore);
+EXPORT_SYMBOL(raw_local_irq_restore);
#endif
#ifdef CONFIG_PPC32
--- linux-2.6-git.orig/include/asm-powerpc/hw_irq.h 2007-07-05
23:01:11.985397556 +0200
+++ linux-2.6-git/include/asm-powerpc/hw_irq.h 2007-07-05 23:01:18.108397556
+0200
@@ -27,7 +27,7 @@ static inline unsigned long local_get_fl
return flags;
}
-static inline unsigned long local_irq_disable(void)
+static inline unsigned long raw_local_irq_disable(void)
{
unsigned long flags, zero;
@@ -39,14 +39,15 @@ static inline unsigned long local_irq_di
return flags;
}
-extern void local_irq_restore(unsigned long);
+extern void raw_local_irq_restore(unsigned long);
extern void iseries_handle_interrupts(void);
-#define local_irq_enable() local_irq_restore(1)
-#define local_save_flags(flags) ((flags) = local_get_flags())
-#define local_irq_save(flags) ((flags) = local_irq_disable())
+#define raw_local_irq_enable() raw_local_irq_restore(1)
+#define raw_local_save_flags(flags) ((flags) = local_get_flags())
+#define raw_local_irq_save(flags) ((flags) = raw_local_irq_disable())
-#define irqs_disabled() (local_get_flags() == 0)
+#define raw_irqs_disabled() (local_get_flags() == 0)
+#define raw_irqs_disabled_flags(flags) ((flags) == 0)
#define __hard_irq_enable() __mtmsrd(mfmsr() | MSR_EE, 1)
#define __hard_irq_disable() __mtmsrd(mfmsr() & ~MSR_EE, 1)
@@ -108,6 +109,7 @@ static inline void local_irq_save_ptr(un
#define local_save_flags(flags) ((flags) = mfmsr())
#define local_irq_save(flags) local_irq_save_ptr(&flags)
#define irqs_disabled() ((mfmsr() & MSR_EE) == 0)
+#define irqs_disabled_flags(flags) (((flags) & MSR_EE) == 0)
#define hard_irq_enable() local_irq_enable()
#define hard_irq_disable() local_irq_disable()
--- linux-2.6-git.orig/include/asm-powerpc/irqflags.h 2007-07-05
23:01:12.018397556 +0200
+++ linux-2.6-git/include/asm-powerpc/irqflags.h 2007-07-05
23:01:18.141397556 +0200
@@ -15,17 +15,4 @@
*/
#include <asm-powerpc/hw_irq.h>
-/*
- * Do the CPU's IRQ-state tracing from assembly code. We call a
- * C function, so save all the C-clobbered registers:
- */
-#ifdef CONFIG_TRACE_IRQFLAGS
-
-#error No support on PowerPC yet for CONFIG_TRACE_IRQFLAGS
-
-#else
-# define TRACE_IRQS_ON
-# define TRACE_IRQS_OFF
-#endif
-
#endif
--- linux-2.6-git.orig/include/asm-powerpc/rwsem.h 2007-07-05
23:01:12.050397556 +0200
+++ linux-2.6-git/include/asm-powerpc/rwsem.h 2007-07-05 23:01:18.149397556
+0200
@@ -28,11 +28,21 @@ struct rw_semaphore {
#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS +
RWSEM_ACTIVE_BIAS)
spinlock_t wait_lock;
struct list_head wait_list;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lockdep_map dep_map;
+#endif
};
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname }
+#else
+# define __RWSEM_DEP_MAP_INIT(lockname)
+#endif
+
#define __RWSEM_INITIALIZER(name) \
{ RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \
- LIST_HEAD_INIT((name).wait_list) }
+ LIST_HEAD_INIT((name).wait_list) \
+ __RWSEM_DEP_MAP_INIT(name) }
#define DECLARE_RWSEM(name) \
struct rw_semaphore name = __RWSEM_INITIALIZER(name)
@@ -42,12 +52,15 @@ extern struct rw_semaphore *rwsem_down_w
extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem);
extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem);
-static inline void init_rwsem(struct rw_semaphore *sem)
-{
- sem->count = RWSEM_UNLOCKED_VALUE;
- spin_lock_init(&sem->wait_lock);
- INIT_LIST_HEAD(&sem->wait_list);
-}
+extern void __init_rwsem(struct rw_semaphore *sem, const char *name,
+ struct lock_class_key *key);
+
+#define init_rwsem(sem) \
+ do { \
+ static struct lock_class_key __key; \
+ \
+ __init_rwsem((sem), #sem, &__key); \
+ } while (0)
/*
* lock for reading
@@ -74,7 +87,7 @@ static inline int __down_read_trylock(st
/*
* lock for writing
*/
-static inline void __down_write(struct rw_semaphore *sem)
+static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
{
int tmp;
@@ -84,6 +97,11 @@ static inline void __down_write(struct r
rwsem_down_write_failed(sem);
}
+static inline void __down_write(struct rw_semaphore *sem)
+{
+ __down_write_nested(sem, 0);
+}
+
static inline int __down_write_trylock(struct rw_semaphore *sem)
{
int tmp;
--- linux-2.6-git.orig/include/asm-powerpc/spinlock.h 2007-07-05
23:01:12.097397556 +0200
+++ linux-2.6-git/include/asm-powerpc/spinlock.h 2007-07-05
23:01:18.152397556 +0200
@@ -19,6 +19,7 @@
*
* (the type definitions are in asm/spinlock_types.h)
*/
+#include <linux/irqflags.h>
#ifdef CONFIG_PPC64
#include <asm/paca.h>
#include <asm/hvcall.h>
--- linux-2.6-git.orig/arch/powerpc/kernel/head_64.S 2007-07-05
23:01:11.796397556 +0200
+++ linux-2.6-git/arch/powerpc/kernel/head_64.S 2007-07-05 23:01:18.173397556
+0200
@@ -394,6 +394,12 @@ label##_iSeries:
\
EXCEPTION_PROLOG_ISERIES_2; \
b label##_common; \
+#ifdef CONFIG_TRACE_IRQFLAGS
+#define TRACE_DISABLE_INTS bl .powerpc_trace_hardirqs_off
+#else
+#define TRACE_DISABLE_INTS
+#endif
+
#ifdef CONFIG_PPC_ISERIES
#define DISABLE_INTS \
li r11,0; \
@@ -405,14 +411,15 @@ BEGIN_FW_FTR_SECTION; \
mfmsr r10; \
ori r10,r10,MSR_EE; \
mtmsrd r10,1; \
-END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
+END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES); \
+ TRACE_DISABLE_INTS
#else
#define DISABLE_INTS \
li r11,0; \
stb r11,PACASOFTIRQEN(r13); \
- stb r11,PACAHARDIRQEN(r13)
-
+ stb r11,PACAHARDIRQEN(r13); \
+ TRACE_DISABLE_INTS
#endif /* CONFIG_PPC_ISERIES */
#define ENABLE_INTS \
@@ -965,24 +972,38 @@ bad_stack:
*/
fast_exc_return_irq: /* restores irq state too */
ld r3,SOFTE(r1)
- ld r12,_MSR(r1)
+#ifdef CONFIG_TRACE_IRQFLAGS
+ cmpdi r3,0
+ beq 1f
+ bl .trace_hardirqs_on
+ ld r3,SOFTE(r1)
+1:
stb r3,PACASOFTIRQEN(r13) /* restore paca->soft_enabled */
+ cmpdi r3,0
+ bne 2f
+ bl .trace_hardirqs_off
+ ld r3,SOFTE(r1)
+2:
+#else
+ stb r3,PACASOFTIRQEN(r13) /* restore paca->soft_enabled */
+#endif
+ ld r12,_MSR(r1)
rldicl r4,r12,49,63 /* get MSR_EE to LSB */
stb r4,PACAHARDIRQEN(r13) /* restore paca->hard_enabled */
- b 1f
+ b 3f
.globl fast_exception_return
fast_exception_return:
ld r12,_MSR(r1)
-1: ld r11,_NIP(r1)
+3: ld r11,_NIP(r1)
andi. r3,r12,MSR_RI /* check if RI is set */
beq- unrecov_fer
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
andi. r3,r12,MSR_PR
- beq 2f
+ beq 4f
ACCOUNT_CPU_USER_EXIT(r3, r4)
-2:
+4:
#endif
ld r3,_CCR(r1)
@@ -1387,11 +1408,24 @@ END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISER
/*
* 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
+#ifdef CONFIG_TRACE_IRQFLAGS
+ cmpdi r3,0
+ beq 14f
+ bl .trace_hardirqs_on
+ ld r3,SOFTE(r1)
+14:
+ bl .raw_local_irq_restore
+ cmpdi r3,0
+ bne 15f
+ bl .trace_hardirqs_off
+15:
+#else
+ bl .raw_local_irq_restore
+#endif
b 11f
/* Here we have a page fault that hash_page can't handle. */
--- linux-2.6-git.orig/arch/powerpc/kernel/setup_64.c 2007-07-05
23:01:11.829397556 +0200
+++ linux-2.6-git/arch/powerpc/kernel/setup_64.c 2007-07-05
23:01:18.185397556 +0200
@@ -33,6 +33,7 @@
#include <linux/serial_8250.h>
#include <linux/bootmem.h>
#include <linux/pci.h>
+#include <linux/lockdep.h>
#include <asm/io.h>
#include <asm/kdump.h>
#include <asm/prom.h>
@@ -359,6 +360,11 @@ void __init setup_system(void)
&__start___fw_ftr_fixup, &__stop___fw_ftr_fixup);
/*
+ * start lockdep
+ */
+ lockdep_init();
+
+ /*
* Unflatten the device-tree passed by prom_init or kexec
*/
unflatten_device_tree();
--- linux-2.6-git.orig/arch/powerpc/kernel/entry_64.S 2007-07-05
23:01:11.864397556 +0200
+++ linux-2.6-git/arch/powerpc/kernel/entry_64.S 2007-07-05
23:01:18.211397556 +0200
@@ -88,6 +88,13 @@ system_call_common:
addi r9,r1,STACK_FRAME_OVERHEAD
ld r11,[EMAIL PROTECTED](r2)
std r11,-16(r9) /* "regshere" marker */
+#ifdef CONFIG_TRACE_IRQFLAGS
+ bl .trace_hardirqs_on
+ REST_GPR(0,r1)
+ REST_4GPRS(3,r1)
+ REST_2GPRS(7,r1)
+ addi r9,r1,STACK_FRAME_OVERHEAD
+#endif
li r10,1
stb r10,PACASOFTIRQEN(r13)
stb r10,PACAHARDIRQEN(r13)
@@ -491,8 +498,20 @@ BEGIN_FW_FTR_SECTION
4:
END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
#endif
+#ifdef CONFIG_TRACE_IRQFLAGS
+ cmpdi r5,0
+ beq 5f
+ bl .trace_hardirqs_on
+ ld r5,SOFTE(r1)
stb r5,PACASOFTIRQEN(r13)
-
+ b 6f
+5:
+ stb r5,PACASOFTIRQEN(r13)
+ bl .trace_hardirqs_off
+6:
+#else
+ stb r5,PACASOFTIRQEN(r13)
+#endif
/* extract EE bit and use it to restore paca->hard_enabled */
ld r3,_MSR(r1)
rldicl r4,r3,49,63 /* r0 = (r3 >> 15) & 1 */
@@ -560,6 +579,9 @@ do_work:
bne restore
/* here we are preempting the current task */
1:
+#ifdef CONFIG_TRACE_IRQFLAGS
+ bl .powerpc_trace_hardirqs_on
+#endif
li r0,1
stb r0,PACASOFTIRQEN(r13)
stb r0,PACAHARDIRQEN(r13)
--- linux-2.6-git.orig/arch/powerpc/kernel/Makefile 2007-07-05
23:01:18.002397556 +0200
+++ linux-2.6-git/arch/powerpc/kernel/Makefile 2007-07-05 23:01:18.212397556
+0200
@@ -62,6 +62,7 @@ obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_PPC_UDBG_16550) += legacy_serial.o udbg_16550.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
+obj-$(CONFIG_TRACE_IRQFLAGS) += irqtrace.o
module-$(CONFIG_PPC64) += module_64.o
obj-$(CONFIG_MODULES) += $(module-y)
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-git/arch/powerpc/kernel/irqtrace.S 2007-07-06
02:11:15.110814034 +0200
@@ -0,0 +1,82 @@
+/*
+ * helpers for irq-trace
+ *
+ * We invoke the hardirq trace functions from various inconvenient
+ * places; these helpers save all callee-saved registers.
+ *
+ * Author: Johannes Berg <[EMAIL PROTECTED]>
+ */
+
+#include <asm/ppc_asm.h>
+#include <asm/asm-offsets.h>
+
+#ifdef CONFIG_PPC64
+#define ST std
+#define STU stdu
+#define L ld
+#define WSZ 8
+#define FREE 32
+#else
+#error double-check please
+#define ST stw
+#define STU stwu
+#define L lwz
+#define WSZ 4
+#define FREE 16
+#endif
+
+#define STACKSPACE (FREE + 16*WSZ)
+#define SAVE(n) (FREE + n*WSZ)
+
+_GLOBAL(powerpc_trace_hardirqs_on)
+ ST r3, (SAVE(2)-STACKSPACE)(r1)
+ LOAD_REG_IMMEDIATE(r3, .trace_hardirqs_on)
+ b powerpc_trace_hardirqs
+
+_GLOBAL(powerpc_trace_hardirqs_off)
+ ST r3, (SAVE(2)-STACKSPACE)(r1)
+ LOAD_REG_IMMEDIATE(r3, .trace_hardirqs_off)
+
+powerpc_trace_hardirqs:
+ ST r0, (SAVE(0)-STACKSPACE)(r1)
+ mflr r0
+ ST r0, LRSAVE(r1)
+ STU r1, -STACKSPACE(r1)
+ mfctr r0
+ ST r0, SAVE(14)(r1)
+ mtctr r3
+ ST r2, SAVE(1)(r1)
+ ST r4, SAVE(3)(r1)
+ ST r5, SAVE(4)(r1)
+ ST r6, SAVE(5)(r1)
+ ST r7, SAVE(6)(r1)
+ ST r8, SAVE(7)(r1)
+ ST r9, SAVE(8)(r1)
+ ST r10, SAVE(9)(r1)
+ ST r11, SAVE(10)(r1)
+ ST r12, SAVE(11)(r1)
+ ST r13, SAVE(12)(r1)
+ mfcr r0
+ ST r0, SAVE(13)(r1)
+ bctrl
+ L r2, SAVE(1)(r1)
+ L r3, SAVE(2)(r1)
+ L r4, SAVE(3)(r1)
+ L r5, SAVE(4)(r1)
+ L r6, SAVE(5)(r1)
+ L r7, SAVE(6)(r1)
+ L r8, SAVE(7)(r1)
+ L r9, SAVE(8)(r1)
+ L r10, SAVE(9)(r1)
+ L r11, SAVE(10)(r1)
+ L r12, SAVE(11)(r1)
+ L r13, SAVE(12)(r1)
+ L r0, SAVE(13)(r1)
+ mtcr r0
+ L r0, SAVE(14)(r1)
+ mtctr r0
+ L r1, 0(r1)
+ L r0, LRSAVE(r1)
+ mtlr r0
+ L r0, (SAVE(0)-STACKSPACE)(r1)
+ blr
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