X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fppc%2Fkernel%2Fhead_booke.h;h=618b469ac83869355f3e2b97009d4989fc71d4ac;hb=6a77f38946aaee1cd85eeec6cf4229b204c15071;hp=6f54039c88737447a690b0a408275fde82211c55;hpb=87fc8d1bb10cd459024a742c6a10961fefcef18f;p=linux-2.6.git

diff --git a/arch/ppc/kernel/head_booke.h b/arch/ppc/kernel/head_booke.h
index 6f54039c8..618b469ac 100644
--- a/arch/ppc/kernel/head_booke.h
+++ b/arch/ppc/kernel/head_booke.h
@@ -237,4 +237,103 @@ label:
 			  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)
+
+#define INSTRUCTION_STORAGE_EXCEPTION					      \
+	START_EXCEPTION(InstructionStorage)				      \
+	NORMAL_EXCEPTION_PROLOG;					      \
+	mfspr	r5,SPRN_ESR;		/* Grab the ESR and save it */	      \
+	stw	r5,_ESR(r11);						      \
+	mr      r4,r12;                 /* Pass SRR0 as arg2 */		      \
+	li      r5,0;                   /* Pass zero as arg3 */		      \
+	EXC_XFER_EE_LITE(0x0400, handle_page_fault)
+
+#define ALIGNMENT_EXCEPTION						      \
+	START_EXCEPTION(Alignment)					      \
+	NORMAL_EXCEPTION_PROLOG;					      \
+	mfspr   r4,SPRN_DEAR;           /* Grab the DEAR and save it */	      \
+	stw     r4,_DEAR(r11);						      \
+	addi    r3,r1,STACK_FRAME_OVERHEAD;				      \
+	EXC_XFER_EE(0x0600, AlignmentException)
+
+#define PROGRAM_EXCEPTION						      \
+	START_EXCEPTION(Program)					      \
+	NORMAL_EXCEPTION_PROLOG;					      \
+	mfspr	r4,SPRN_ESR;		/* Grab the ESR and save it */	      \
+	stw	r4,_ESR(r11);						      \
+	addi	r3,r1,STACK_FRAME_OVERHEAD;				      \
+	EXC_XFER_STD(0x0700, ProgramCheckException)
+
+#define DECREMENTER_EXCEPTION						      \
+	START_EXCEPTION(Decrementer)					      \
+	NORMAL_EXCEPTION_PROLOG;					      \
+	lis     r0,TSR_DIS@h;           /* Setup the DEC interrupt mask */    \
+	mtspr   SPRN_TSR,r0;		/* Clear the DEC interrupt */	      \
+	addi    r3,r1,STACK_FRAME_OVERHEAD;				      \
+	EXC_XFER_LITE(0x0900, timer_interrupt)
+
 #endif /* __HEAD_BOOKE_H__ */