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[POWERPC] irqtrace support for 64-bit powerpc

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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>
This commit is contained in:
Benjamin Herrenschmidt 2008-04-17 14:35:01 +10:00 • committed by Paul Mackerras
commit 945feb174b
11 changed files with 136 additions and 54 deletions
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27
arch/powerpc/kernel/entry_64.S
View file

@ -30,6 +30,7 @@
#include <asm/firmware.h>
#include <asm/bug.h>
#include <asm/ptrace.h>
#include <asm/irqflags.h>
/*
* System calls.
@ -89,6 +90,14 @@ system_call_common:
addi r9,r1,STACK_FRAME_OVERHEAD
ld r11,exception_marker@toc(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
ld r12,_MSR(r1)
#endif /* CONFIG_TRACE_IRQFLAGS */
li r10,1
stb r10,PACASOFTIRQEN(r13)
stb r10,PACAHARDIRQEN(r13)
@ -103,7 +112,7 @@ BEGIN_FW_FTR_SECTION
b hardware_interrupt_entry
2:
END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
#endif
#endif /* CONFIG_PPC_ISERIES */
mfmsr r11
ori r11,r11,MSR_EE
mtmsrd r11,1
@ -505,6 +514,10 @@ BEGIN_FW_FTR_SECTION
li r3,0
stb r3,PACASOFTIRQEN(r13) /* ensure we are soft-disabled */
#ifdef CONFIG_TRACE_IRQFLAGS
bl .trace_hardirqs_off
mfmsr r10
#endif
ori r10,r10,MSR_EE
mtmsrd r10 /* hard-enable again */
addi r3,r1,STACK_FRAME_OVERHEAD
@ -513,7 +526,7 @@ BEGIN_FW_FTR_SECTION
4:
END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
#endif
stb r5,PACASOFTIRQEN(r13)
TRACE_AND_RESTORE_IRQ(r5);
/* extract EE bit and use it to restore paca->hard_enabled */
ld r3,_MSR(r1)
@ -581,6 +594,16 @@ do_work:
bne restore
/* here we are preempting the current task */
1:
#ifdef CONFIG_TRACE_IRQFLAGS
bl .trace_hardirqs_on
/* Note: we just clobbered r10 which used to contain the previous
* MSR before the hard-disabling done by the caller of do_work.
* We don't have that value anymore, but it doesn't matter as
* we will hard-enable unconditionally, we can just reload the
* current MSR into r10
*/
mfmsr r10
#endif /* CONFIG_TRACE_IRQFLAGS */
li r0,1
stb r0,PACASOFTIRQEN(r13)
stb r0,PACAHARDIRQEN(r13)

47
arch/powerpc/kernel/head_64.S
View file

@ -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)
@ -835,6 +834,27 @@ BEGIN_FTR_SECTION
bne- do_ste_alloc /* If so handle it */
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
@ -847,13 +867,6 @@ END_FTR_SECTION_IFCLR(CPU_FTR_SLB)
ori r4,r4,1 /* add _PAGE_PRESENT */
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
@ -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. */

3
arch/powerpc/kernel/irq.c
View file

@ -114,7 +114,7 @@ static inline void set_soft_enabled(unsigned long enable)
: : "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;
@ -174,6 +174,7 @@ void local_irq_restore(unsigned long en)
__hard_irq_enable();
}
EXPORT_SYMBOL(raw_local_irq_restore);
#endif /* CONFIG_PPC64 */
int show_interrupts(struct seq_file *p, void *v)

4
arch/powerpc/kernel/ppc_ksyms.c
View file

@ -45,10 +45,6 @@
#include <asm/signal.h>
#include <asm/dcr.h>
#ifdef CONFIG_PPC64
EXPORT_SYMBOL(local_irq_restore);
#endif
#ifdef CONFIG_PPC32
extern void transfer_to_handler(void);
extern void do_IRQ(struct pt_regs *regs);

4
arch/powerpc/kernel/setup_64.c
View file

@ -33,6 +33,7 @@
#include <linux/serial_8250.h>
#include <linux/bootmem.h>
#include <linux/pci.h>
#include <linux/lockdep.h>
#include <linux/lmb.h>
#include <asm/io.h>
#include <asm/kdump.h>
@ -178,6 +179,9 @@ void __init early_setup(unsigned long dt_ptr)
/* Enable early debugging if any specified (see udbg.h) */
udbg_early_init();
/* Initialize lockdep early or else spinlocks will blow */
lockdep_init();
DBG(" -> early_setup(), dt_ptr: 0x%lx\n", dt_ptr);
/*