[PATCH][PPC32][1/2] 40x and Book E debug: core support
From: Matt Porter
Date: Fri Oct 29 2004 - 20:12:07 EST
This patch updates the 40x and Book E Debug exception handling paths
to handle kernel space debug events. It also fixes up the in-kernel
ppc32 kgdb stub to work properly.
Signed-off-by: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>
diff -Nru a/arch/ppc/kernel/head_44x.S b/arch/ppc/kernel/head_44x.S
--- a/arch/ppc/kernel/head_44x.S 2004-10-29 17:13:29 -07:00
+++ b/arch/ppc/kernel/head_44x.S 2004-10-29 17:13:29 -07:00
@@ -599,64 +599,8 @@
mfspr r10, SPRG0
b InstructionStorage
-/* Check for a single step debug exception while in an exception
- * handler before state has been saved. This is to catch the case
- * where an instruction that we are trying to single step causes
- * an exception (eg ITLB/DTLB miss) and thus the first instruction of
- * the exception handler generates a single step debug exception.
- *
- * If we get a debug trap on the first instruction of an exception handler,
- * we reset the MSR_DE in the _exception handler's_ MSR (the debug trap is
- * a critical exception, so we are using SPRN_CSRR1 to manipulate the MSR).
- * The exception handler was handling a non-critical interrupt, so it will
- * save (and later restore) the MSR via SPRN_SRR1, which will still have
- * the MSR_DE bit set.
- */
/* Debug Interrupt */
- START_EXCEPTION(Debug)
- CRITICAL_EXCEPTION_PROLOG
-
- /*
- * If this is a single step or branch-taken exception in an
- * exception entry sequence, it was probably meant to apply to
- * the code where the exception occurred (since exception entry
- * doesn't turn off DE automatically). We simulate the effect
- * of turning off DE on entry to an exception handler by turning
- * off DE in the CSRR1 value and clearing the debug status.
- */
- mfspr r10,SPRN_DBSR /* check single-step/branch taken */
- andis. r10,r10,(DBSR_IC|DBSR_BT)@h
- beq+ 1f
- andi. r0,r9,MSR_PR /* check supervisor */
- beq 2f /* branch if we need to fix it up... */
-
- /* continue normal handling for a critical exception... */
-1: mfspr r4,SPRN_DBSR
- addi r3,r1,STACK_FRAME_OVERHEAD
- EXC_XFER_TEMPLATE(DebugException, 0x2002, \
- (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
- NOCOPY, crit_transfer_to_handler, ret_from_crit_exc)
-
- /* here it looks like we got an inappropriate debug exception. */
-2: rlwinm r9,r9,0,~MSR_DE /* clear DE in the CSRR1 value */
- mtspr SPRN_DBSR,r10 /* clear the IC/BT debug intr status */
- /* restore state and get out */
- lwz r10,_CCR(r11)
- lwz r0,GPR0(r11)
- lwz r1,GPR1(r11)
- mtcrf 0x80,r10
- mtspr CSRR0,r12
- mtspr CSRR1,r9
- lwz r9,GPR9(r11)
-
- mtspr SPRG2,r8; /* SPRG2 only used in criticals */
- lis r8,crit_save@ha;
- lwz r10,crit_r10@l(r8)
- lwz r11,crit_r11@l(r8)
- mfspr r8,SPRG2
-
- rfci
- b .
+ DEBUG_EXCEPTION
/*
* Local functions
diff -Nru a/arch/ppc/kernel/head_4xx.S b/arch/ppc/kernel/head_4xx.S
--- a/arch/ppc/kernel/head_4xx.S 2004-10-29 17:13:29 -07:00
+++ b/arch/ppc/kernel/head_4xx.S 2004-10-29 17:13:29 -07:00
@@ -709,8 +709,20 @@
EXCEPTION(0x1E00, Trap_1E, UnknownException, EXC_XFER_EE)
EXCEPTION(0x1F00, Trap_1F, UnknownException, EXC_XFER_EE)
-/* 0x2000 - Debug Exception
-*/
+/* Check for a single step debug exception while in an exception
+ * handler before state has been saved. This is to catch the case
+ * where an instruction that we are trying to single step causes
+ * an exception (eg ITLB/DTLB miss) and thus the first instruction of
+ * the exception handler generates a single step debug exception.
+ *
+ * If we get a debug trap on the first instruction of an exception handler,
+ * we reset the MSR_DE in the _exception handler's_ MSR (the debug trap is
+ * a critical exception, so we are using SPRN_CSRR1 to manipulate the MSR).
+ * The exception handler was handling a non-critical interrupt, so it will
+ * save (and later restore) the MSR via SPRN_SRR1, which will still have
+ * the MSR_DE bit set.
+ */
+ /* 0x2000 - Debug Exception */
START_EXCEPTION(0x2000, DebugTrap)
CRITICAL_EXCEPTION_PROLOG
@@ -723,21 +735,20 @@
* off DE in the SRR3 value and clearing the debug status.
*/
mfspr r10,SPRN_DBSR /* check single-step/branch taken */
- andis. r10,r10,(DBSR_IC|DBSR_BT)@h
- beq+ 1f
- andi. r0,r9,MSR_IR|MSR_PR /* check supervisor + MMU off */
- beq 2f /* branch if we need to fix it up... */
+ andis. r10,r10,DBSR_IC@h
+ beq+ 2f
- /* continue normal handling for a critical exception... */
-1: mfspr r4,SPRN_DBSR
- addi r3,r1,STACK_FRAME_OVERHEAD
- EXC_XFER_TEMPLATE(DebugException, 0x2002, \
- (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
- NOCOPY, crit_transfer_to_handler, ret_from_crit_exc)
+ andi. r10,r9,MSR_IR|MSR_PR /* check supervisor + MMU off */
+ beq 1f /* branch and fix it up */
+
+ mfspr r10,SPRN_SRR2 /* Faulting instruction address */
+ cmplwi r10,0x2100
+ bgt+ 2f /* address above exception vectors */
/* here it looks like we got an inappropriate debug exception. */
-2: rlwinm r9,r9,0,~MSR_DE /* clear DE in the SRR3 value */
- mtspr SPRN_DBSR,r10 /* clear the IC/BT debug intr status */
+1: rlwinm r9,r9,0,~MSR_DE /* clear DE in the SRR3 value */
+ lis r10,DBSR_IC@h /* clear the IC event */
+ mtspr SPRN_DBSR,r10
/* restore state and get out */
lwz r10,_CCR(r11)
lwz r0,GPR0(r11)
@@ -752,6 +763,13 @@
PPC405_ERR77_SYNC
rfci
b .
+
+ /* continue normal handling for a critical exception... */
+2: mfspr r4,SPRN_DBSR
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ EXC_XFER_TEMPLATE(DebugException, 0x2002, \
+ (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
+ NOCOPY, crit_transfer_to_handler, ret_from_crit_exc)
/*
* The other Data TLB exceptions bail out to this point
diff -Nru a/arch/ppc/kernel/head_booke.h b/arch/ppc/kernel/head_booke.h
--- a/arch/ppc/kernel/head_booke.h 2004-10-29 17:13:29 -07:00
+++ b/arch/ppc/kernel/head_booke.h 2004-10-29 17:13:29 -07:00
@@ -237,4 +237,70 @@
ret_from_except)
+/* Check for a single step debug exception while in an exception
+ * handler before state has been saved. This is to catch the case
+ * where an instruction that we are trying to single step causes
+ * an exception (eg ITLB/DTLB miss) and thus the first instruction of
+ * the exception handler generates a single step debug exception.
+ *
+ * If we get a debug trap on the first instruction of an exception handler,
+ * we reset the MSR_DE in the _exception handler's_ MSR (the debug trap is
+ * a critical exception, so we are using SPRN_CSRR1 to manipulate the MSR).
+ * The exception handler was handling a non-critical interrupt, so it will
+ * save (and later restore) the MSR via SPRN_CSRR1, which will still have
+ * the MSR_DE bit set.
+ */
+#define DEBUG_EXCEPTION \
+ START_EXCEPTION(Debug); \
+ CRITICAL_EXCEPTION_PROLOG; \
+ \
+ /* \
+ * If there is a single step or branch-taken exception in an \
+ * exception entry sequence, it was probably meant to apply to \
+ * the code where the exception occurred (since exception entry \
+ * doesn't turn off DE automatically). We simulate the effect \
+ * of turning off DE on entry to an exception handler by turning \
+ * off DE in the CSRR1 value and clearing the debug status. \
+ */ \
+ mfspr r10,SPRN_DBSR; /* check single-step/branch taken */ \
+ andis. r10,r10,DBSR_IC@h; \
+ beq+ 2f; \
+ \
+ lis r10,KERNELBASE@h; /* check if exception in vectors */ \
+ ori r10,r10,KERNELBASE@l; \
+ cmplw r12,r10; \
+ blt+ 2f; /* addr below exception vectors */ \
+ \
+ lis r10,Debug@h; \
+ ori r10,r10,Debug@l; \
+ cmplw r12,r10; \
+ bgt+ 2f; /* addr above exception vectors */ \
+ \
+ /* here it looks like we got an inappropriate debug exception. */ \
+1: rlwinm r9,r9,0,~MSR_DE; /* clear DE in the CSRR1 value */ \
+ lis r10,DBSR_IC@h; /* clear the IC event */ \
+ mtspr SPRN_DBSR,r10; \
+ /* restore state and get out */ \
+ lwz r10,_CCR(r11); \
+ lwz r0,GPR0(r11); \
+ lwz r1,GPR1(r11); \
+ mtcrf 0x80,r10; \
+ mtspr CSRR0,r12; \
+ mtspr CSRR1,r9; \
+ lwz r9,GPR9(r11); \
+ lwz r12,GPR12(r11); \
+ mtspr SPRG2,r8; /* SPRG2 only used in criticals */ \
+ lis r8,crit_save@ha; \
+ lwz r10,crit_r10@l(r8); \
+ lwz r11,crit_r11@l(r8); \
+ mfspr r8,SPRG2; \
+ \
+ rfci; \
+ b .; \
+ \
+ /* continue normal handling for a critical exception... */ \
+2: mfspr r4,SPRN_DBSR; \
+ addi r3,r1,STACK_FRAME_OVERHEAD; \
+ EXC_XFER_TEMPLATE(DebugException, 0x2002, (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), NOCOPY, crit_transfer_to_handler, ret_from_crit_exc)
+
#endif /* __HEAD_BOOKE_H__ */
diff -Nru a/arch/ppc/kernel/head_e500.S b/arch/ppc/kernel/head_e500.S
--- a/arch/ppc/kernel/head_e500.S 2004-10-29 17:13:29 -07:00
+++ b/arch/ppc/kernel/head_e500.S 2004-10-29 17:13:29 -07:00
@@ -668,64 +668,8 @@
/* Performance Monitor */
EXCEPTION(0x2060, PerformanceMonitor, UnknownException, EXC_XFER_EE)
-/* Check for a single step debug exception while in an exception
- * handler before state has been saved. This is to catch the case
- * where an instruction that we are trying to single step causes
- * an exception (eg ITLB/DTLB miss) and thus the first instruction of
- * the exception handler generates a single step debug exception.
- *
- * If we get a debug trap on the first instruction of an exception handler,
- * we reset the MSR_DE in the _exception handler's_ MSR (the debug trap is
- * a critical exception, so we are using SPRN_CSRR1 to manipulate the MSR).
- * The exception handler was handling a non-critical interrupt, so it will
- * save (and later restore) the MSR via SPRN_SRR1, which will still have
- * the MSR_DE bit set.
- */
/* Debug Interrupt */
- START_EXCEPTION(Debug)
- CRITICAL_EXCEPTION_PROLOG
-
- /*
- * If this is a single step or branch-taken exception in an
- * exception entry sequence, it was probably meant to apply to
- * the code where the exception occurred (since exception entry
- * doesn't turn off DE automatically). We simulate the effect
- * of turning off DE on entry to an exception handler by turning
- * off DE in the CSRR1 value and clearing the debug status.
- */
- mfspr r10,SPRN_DBSR /* check single-step/branch taken */
- andis. r10,r10,(DBSR_IC|DBSR_BT)@h
- beq+ 1f
- andi. r0,r9,MSR_PR /* check supervisor */
- beq 2f /* branch if we need to fix it up... */
-
- /* continue normal handling for a critical exception... */
-1: mfspr r4,SPRN_DBSR
- addi r3,r1,STACK_FRAME_OVERHEAD
- EXC_XFER_TEMPLATE(DebugException, 0x2002, \
- (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
- NOCOPY, crit_transfer_to_handler, ret_from_crit_exc)
-
- /* here it looks like we got an inappropriate debug exception. */
-2: rlwinm r9,r9,0,~MSR_DE /* clear DE in the CSRR1 value */
- mtspr SPRN_DBSR,r10 /* clear the IC/BT debug intr status */
- /* restore state and get out */
- lwz r10,_CCR(r11)
- lwz r0,GPR0(r11)
- lwz r1,GPR1(r11)
- mtcrf 0x80,r10
- mtspr CSRR0,r12
- mtspr CSRR1,r9
- lwz r9,GPR9(r11)
-
- mtspr SPRG2,r8; /* SPRG2 only used in criticals */
- lis r8,crit_save@ha;
- lwz r10,crit_r10@l(r8)
- lwz r11,crit_r11@l(r8)
- mfspr r8,SPRG2
-
- rfci
- b .
+ DEBUG_EXCEPTION
/*
* Local functions
diff -Nru a/arch/ppc/kernel/ppc-stub.c b/arch/ppc/kernel/ppc-stub.c
--- a/arch/ppc/kernel/ppc-stub.c 2004-10-29 17:13:29 -07:00
+++ b/arch/ppc/kernel/ppc-stub.c 2004-10-29 17:13:29 -07:00
@@ -498,7 +498,7 @@
unsigned int tt; /* Trap type code for powerpc */
unsigned char signo; /* Signal that we map this trap into */
} hard_trap_info[] = {
-#if defined(CONFIG_40x)
+#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
{ 0x100, SIGINT }, /* critical input interrupt */
{ 0x200, SIGSEGV }, /* machine check */
{ 0x300, SIGSEGV }, /* data storage */
@@ -521,7 +521,7 @@
** 0x1100 data TLB miss
** 0x1200 instruction TLB miss
*/
- { 0x2000, SIGTRAP}, /* debug */
+ { 0x2002, SIGTRAP}, /* debug */
#else
{ 0x200, SIGSEGV }, /* machine check */
{ 0x300, SIGSEGV }, /* address error (store) */
@@ -602,11 +602,6 @@
sigval = computeSignal(regs->trap);
ptr = remcomOutBuffer;
-#if defined(CONFIG_40x)
- *ptr++ = 'S';
- *ptr++ = hexchars[sigval >> 4];
- *ptr++ = hexchars[sigval & 0xf];
-#else
*ptr++ = 'T';
*ptr++ = hexchars[sigval >> 4];
*ptr++ = hexchars[sigval & 0xf];
@@ -620,8 +615,6 @@
*ptr++ = ':';
ptr = mem2hex(((char *)regs) + SP_REGNUM*4, ptr, 4);
*ptr++ = ';';
-#endif
-
*ptr++ = 0;
putpacket(remcomOutBuffer);
@@ -774,10 +767,6 @@
* some location may have changed something that is in the instruction cache.
*/
kgdb_flush_cache_all();
-#if defined(CONFIG_40x)
- strcpy(remcomOutBuffer, "OK");
- putpacket(remcomOutBuffer);
-#endif
mtmsr(msr);
kgdb_interruptible(1);
@@ -791,10 +780,9 @@
case 's':
kgdb_flush_cache_all();
-#if defined(CONFIG_40x)
+#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
+ mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) | DBCR0_IC);
regs->msr |= MSR_DE;
- regs->dbcr0 |= (DBCR0_IDM | DBCR0_IC);
- mtmsr(msr);
#else
regs->msr |= MSR_SE;
#endif
diff -Nru a/arch/ppc/kernel/ptrace.c b/arch/ppc/kernel/ptrace.c
--- a/arch/ppc/kernel/ptrace.c 2004-10-29 17:13:29 -07:00
+++ b/arch/ppc/kernel/ptrace.c 2004-10-29 17:13:29 -07:00
@@ -35,7 +35,7 @@
/*
* Set of msr bits that gdb can change on behalf of a process.
*/
-#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
+#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
#define MSR_DEBUGCHANGE 0
#else
#define MSR_DEBUGCHANGE (MSR_SE | MSR_BE)
@@ -201,9 +201,9 @@
struct pt_regs *regs = task->thread.regs;
if (regs != NULL) {
-#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
+#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
task->thread.dbcr0 = DBCR0_IDM | DBCR0_IC;
- /* MSR.DE should already be set */
+ regs->msr |= MSR_DE;
#else
regs->msr |= MSR_SE;
#endif
@@ -216,8 +216,9 @@
struct pt_regs *regs = task->thread.regs;
if (regs != NULL) {
-#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
+#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
task->thread.dbcr0 = 0;
+ regs->msr &= ~MSR_DE;
#else
regs->msr &= ~MSR_SE;
#endif
diff -Nru a/arch/ppc/kernel/traps.c b/arch/ppc/kernel/traps.c
--- a/arch/ppc/kernel/traps.c 2004-10-29 17:13:29 -07:00
+++ b/arch/ppc/kernel/traps.c 2004-10-29 17:13:29 -07:00
@@ -647,22 +647,22 @@
}
#endif /* CONFIG_8xx */
-#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
+#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
void DebugException(struct pt_regs *regs, unsigned long debug_status)
{
-#if 0
- if (debug_status & DBSR_TIE) { /* trap instruction*/
- if (!user_mode(regs) && debugger_bpt(regs))
- return;
- _exception(SIGTRAP, regs, 0, 0);
-
- }
-#endif
if (debug_status & DBSR_IC) { /* instruction completion */
- if (!user_mode(regs) && debugger_sstep(regs))
- return;
- current->thread.dbcr0 &= ~DBCR0_IC;
+ regs->msr &= ~MSR_DE;
+ if (user_mode(regs)) {
+ current->thread.dbcr0 &= ~DBCR0_IC;
+ } else {
+ /* Disable instruction completion */
+ mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
+ /* Clear the instruction completion event */
+ mtspr(SPRN_DBSR, DBSR_IC);
+ if (debugger_sstep(regs))
+ return;
+ }
_exception(SIGTRAP, regs, TRAP_TRACE, 0);
}
}
diff -Nru a/include/asm-ppc/reg_booke.h b/include/asm-ppc/reg_booke.h
--- a/include/asm-ppc/reg_booke.h 2004-10-29 17:13:29 -07:00
+++ b/include/asm-ppc/reg_booke.h 2004-10-29 17:13:29 -07:00
@@ -63,9 +63,9 @@
/* Default MSR for kernel mode. */
#if defined (CONFIG_40x)
-#define MSR_KERNEL (MSR_ME|MSR_RI|MSR_IR|MSR_DR|MSR_CE|MSR_DE)
+#define MSR_KERNEL (MSR_ME|MSR_RI|MSR_IR|MSR_DR|MSR_CE)
#elif defined(CONFIG_BOOKE)
-#define MSR_KERNEL (MSR_ME|MSR_RI|MSR_CE|MSR_DE)
+#define MSR_KERNEL (MSR_ME|MSR_RI|MSR_CE)
#endif
/* Special Purpose Registers (SPRNs)*/
-
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