powerpc/booke: Add support for advanced debug registers

powerpc/booke: Add support for advanced debug registers

From: Dave Kleikamp <shaggy@linux.vnet.ibm.com>

Based on patches originally written by Torez Smith.

This patch defines context switch and trap related functionality
for BookE specific Debug Registers. It adds support to ptrace()
for setting and getting BookE related Debug Registers

Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Torez Smith  <lnxtorez@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Gibson <dwg@au1.ibm.com>
Cc: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Sergio Durigan Junior <sergiodj@br.ibm.com>
Cc: Thiago Jung Bauermann <bauerman@br.ibm.com>
Cc: linuxppc-dev list <Linuxppc-dev@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 404 insertions, 30 deletions

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 8847bd618cec..d9b05866615f 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -738,11 +738,22 @@ void user_disable_single_step(struct task_struct *task)
 
 	if (regs != NULL) {
 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
-		/* If DAC don't clear DBCRO_IDM or MSR_DE */
-		if (task->thread.dabr)
-			task->thread.dbcr0 &= ~(DBCR0_IC | DBCR0_BT);
-		else {
-			task->thread.dbcr0 &= ~(DBCR0_IC | DBCR0_BT | DBCR0_IDM);
+		/*
+		 * The logic to disable single stepping should be as
+		 * simple as turning off the Instruction Complete flag.
+		 * And, after doing so, if all debug flags are off, turn
+		 * off DBCR0(IDM) and MSR(DE) .... Torez
+		 */
+		task->thread.dbcr0 &= ~DBCR0_IC;
+		/*
+		 * Test to see if any of the DBCR_ACTIVE_EVENTS bits are set.
+		 */
+		if (!DBCR_ACTIVE_EVENTS(task->thread.dbcr0,
+					task->thread.dbcr1)) {
+			/*
+			 * All debug events were off.....
+			 */
+			task->thread.dbcr0 &= ~DBCR0_IDM;
 			regs->msr &= ~MSR_DE;
 		}
 #else
@@ -767,7 +778,6 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
 		return -EIO;
 
 #ifndef CONFIG_PPC_ADV_DEBUG_REGS
-
 	/* For processors using DABR (i.e. 970), the bottom 3 bits are flags.
 	 *  It was assumed, on previous implementations, that 3 bits were
 	 *  passed together with the data address, fitting the design of the
@@ -786,20 +796,22 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
 
 	/* Move contents to the DABR register */
 	task->thread.dabr = data;
-
 #else /* CONFIG_PPC_ADV_DEBUG_REGS */
-
 	/* As described above, it was assumed 3 bits were passed with the data
 	 *  address, but we will assume only the mode bits will be passed
 	 *  as to not cause alignment restrictions for DAC-based processors.
 	 */
 
 	/* DAC's hold the whole address without any mode flags */
-	task->thread.dabr = data & ~0x3UL;
-
-	if (task->thread.dabr == 0) {
-		task->thread.dbcr0 &= ~(DBSR_DAC1R | DBSR_DAC1W | DBCR0_IDM);
-		task->thread.regs->msr &= ~MSR_DE;
+	task->thread.dac1 = data & ~0x3UL;
+
+	if (task->thread.dac1 == 0) {
+		dbcr_dac(task) &= ~(DBCR_DAC1R | DBCR_DAC1W);
+		if (!DBCR_ACTIVE_EVENTS(task->thread.dbcr0,
+					task->thread.dbcr1)) {
+			task->thread.regs->msr &= ~MSR_DE;
+			task->thread.dbcr0 &= ~DBCR0_IDM;
+		}
 		return 0;
 	}
 
@@ -810,15 +822,15 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
 
 	/* Set the Internal Debugging flag (IDM bit 1) for the DBCR0
 	   register */
-	task->thread.dbcr0 = DBCR0_IDM;
+	task->thread.dbcr0 |= DBCR0_IDM;
 
 	/* Check for write and read flags and set DBCR0
 	   accordingly */
+	dbcr_dac(task) &= ~(DBCR_DAC1R|DBCR_DAC1W);
 	if (data & 0x1UL)
-		task->thread.dbcr0 |= DBSR_DAC1R;
+		dbcr_dac(task) |= DBCR_DAC1R;
 	if (data & 0x2UL)
-		task->thread.dbcr0 |= DBSR_DAC1W;
-
+		dbcr_dac(task) |= DBCR_DAC1W;
 	task->thread.regs->msr |= MSR_DE;
 #endif /* CONFIG_PPC_ADV_DEBUG_REGS */
 	return 0;
@@ -835,11 +847,344 @@ void ptrace_disable(struct task_struct *child)
 	user_disable_single_step(child);
 }
 
+#ifdef CONFIG_PPC_ADV_DEBUG_REGS
+static long set_intruction_bp(struct task_struct *child,
+			      struct ppc_hw_breakpoint *bp_info)
+{
+	int slot;
+	int slot1_in_use = ((child->thread.dbcr0 & DBCR0_IAC1) != 0);
+	int slot2_in_use = ((child->thread.dbcr0 & DBCR0_IAC2) != 0);
+	int slot3_in_use = ((child->thread.dbcr0 & DBCR0_IAC3) != 0);
+	int slot4_in_use = ((child->thread.dbcr0 & DBCR0_IAC4) != 0);
+
+	if (dbcr_iac_range(child) & DBCR_IAC12MODE)
+		slot2_in_use = 1;
+	if (dbcr_iac_range(child) & DBCR_IAC34MODE)
+		slot4_in_use = 1;
+
+	if (bp_info->addr >= TASK_SIZE)
+		return -EIO;
+
+	if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT) {
+
+		/* Make sure range is valid. */
+		if (bp_info->addr2 >= TASK_SIZE)
+			return -EIO;
+
+		/* We need a pair of IAC regsisters */
+		if ((!slot1_in_use) && (!slot2_in_use)) {
+			slot = 1;
+			child->thread.iac1 = bp_info->addr;
+			child->thread.iac2 = bp_info->addr2;
+			child->thread.dbcr0 |= DBCR0_IAC1;
+			if (bp_info->addr_mode ==
+					PPC_BREAKPOINT_MODE_RANGE_EXCLUSIVE)
+				dbcr_iac_range(child) |= DBCR_IAC12X;
+			else
+				dbcr_iac_range(child) |= DBCR_IAC12I;
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+		} else if ((!slot3_in_use) && (!slot4_in_use)) {
+			slot = 3;
+			child->thread.iac3 = bp_info->addr;
+			child->thread.iac4 = bp_info->addr2;
+			child->thread.dbcr0 |= DBCR0_IAC3;
+			if (bp_info->addr_mode ==
+					PPC_BREAKPOINT_MODE_RANGE_EXCLUSIVE)
+				dbcr_iac_range(child) |= DBCR_IAC34X;
+			else
+				dbcr_iac_range(child) |= DBCR_IAC34I;
+#endif
+		} else
+			return -ENOSPC;
+	} else {
+		/* We only need one.  If possible leave a pair free in
+		 * case a range is needed later
+		 */
+		if (!slot1_in_use) {
+			/*
+			 * Don't use iac1 if iac1-iac2 are free and either
+			 * iac3 or iac4 (but not both) are free
+			 */
+			if (slot2_in_use || (slot3_in_use == slot4_in_use)) {
+				slot = 1;
+				child->thread.iac1 = bp_info->addr;
+				child->thread.dbcr0 |= DBCR0_IAC1;
+				goto out;
+			}
+		}
+		if (!slot2_in_use) {
+			slot = 2;
+			child->thread.iac2 = bp_info->addr;
+			child->thread.dbcr0 |= DBCR0_IAC2;
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+		} else if (!slot3_in_use) {
+			slot = 3;
+			child->thread.iac3 = bp_info->addr;
+			child->thread.dbcr0 |= DBCR0_IAC3;
+		} else if (!slot4_in_use) {
+			slot = 4;
+			child->thread.iac4 = bp_info->addr;
+			child->thread.dbcr0 |= DBCR0_IAC4;
+#endif
+		} else
+			return -ENOSPC;
+	}
+out:
+	child->thread.dbcr0 |= DBCR0_IDM;
+	child->thread.regs->msr |= MSR_DE;
+
+	return slot;
+}
+
+static int del_instruction_bp(struct task_struct *child, int slot)
+{
+	switch (slot) {
+	case 1:
+		if (child->thread.iac1 == 0)
+			return -ENOENT;
+
+		if (dbcr_iac_range(child) & DBCR_IAC12MODE) {
+			/* address range - clear slots 1 & 2 */
+			child->thread.iac2 = 0;
+			dbcr_iac_range(child) &= ~DBCR_IAC12MODE;
+		}
+		child->thread.iac1 = 0;
+		child->thread.dbcr0 &= ~DBCR0_IAC1;
+		break;
+	case 2:
+		if (child->thread.iac2 == 0)
+			return -ENOENT;
+
+		if (dbcr_iac_range(child) & DBCR_IAC12MODE)
+			/* used in a range */
+			return -EINVAL;
+		child->thread.iac2 = 0;
+		child->thread.dbcr0 &= ~DBCR0_IAC2;
+		break;
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+	case 3:
+		if (child->thread.iac3 == 0)
+			return -ENOENT;
+
+		if (dbcr_iac_range(child) & DBCR_IAC34MODE) {
+			/* address range - clear slots 3 & 4 */
+			child->thread.iac4 = 0;
+			dbcr_iac_range(child) &= ~DBCR_IAC34MODE;
+		}
+		child->thread.iac3 = 0;
+		child->thread.dbcr0 &= ~DBCR0_IAC3;
+		break;
+	case 4:
+		if (child->thread.iac4 == 0)
+			return -ENOENT;
+
+		if (dbcr_iac_range(child) & DBCR_IAC34MODE)
+			/* Used in a range */
+			return -EINVAL;
+		child->thread.iac4 = 0;
+		child->thread.dbcr0 &= ~DBCR0_IAC4;
+		break;
+#endif
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int set_dac(struct task_struct *child, struct ppc_hw_breakpoint *bp_info)
+{
+	int byte_enable =
+		(bp_info->condition_mode >> PPC_BREAKPOINT_CONDITION_BE_SHIFT)
+		& 0xf;
+	int condition_mode =
+		bp_info->condition_mode & PPC_BREAKPOINT_CONDITION_MODE;
+	int slot;
+
+	if (byte_enable && (condition_mode == 0))
+		return -EINVAL;
+
+	if (bp_info->addr >= TASK_SIZE)
+		return -EIO;
+
+	if ((dbcr_dac(child) & (DBCR_DAC1R | DBCR_DAC1W)) == 0) {
+		slot = 1;
+		if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_READ)
+			dbcr_dac(child) |= DBCR_DAC1R;
+		if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_WRITE)
+			dbcr_dac(child) |= DBCR_DAC1W;
+		child->thread.dac1 = (unsigned long)bp_info->addr;
+#if CONFIG_PPC_ADV_DEBUG_DVCS > 0
+		if (byte_enable) {
+			child->thread.dvc1 =
+				(unsigned long)bp_info->condition_value;
+			child->thread.dbcr2 |=
+				((byte_enable << DBCR2_DVC1BE_SHIFT) |
+				 (condition_mode << DBCR2_DVC1M_SHIFT));
+		}
+#endif
+#ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
+	} else if (child->thread.dbcr2 & DBCR2_DAC12MODE) {
+		/* Both dac1 and dac2 are part of a range */
+		return -ENOSPC;
+#endif
+	} else if ((dbcr_dac(child) & (DBCR_DAC2R | DBCR_DAC2W)) == 0) {
+		slot = 2;
+		if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_READ)
+			dbcr_dac(child) |= DBCR_DAC2R;
+		if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_WRITE)
+			dbcr_dac(child) |= DBCR_DAC2W;
+		child->thread.dac2 = (unsigned long)bp_info->addr;
+#if CONFIG_PPC_ADV_DEBUG_DVCS > 0
+		if (byte_enable) {
+			child->thread.dvc2 =
+				(unsigned long)bp_info->condition_value;
+			child->thread.dbcr2 |=
+				((byte_enable << DBCR2_DVC2BE_SHIFT) |
+				 (condition_mode << DBCR2_DVC2M_SHIFT));
+		}
+#endif
+	} else
+		return -ENOSPC;
+	child->thread.dbcr0 |= DBCR0_IDM;
+	child->thread.regs->msr |= MSR_DE;
+
+	return slot + 4;
+}
+
+static int del_dac(struct task_struct *child, int slot)
+{
+	if (slot == 1) {
+		if (child->thread.dac1 == 0)
+			return -ENOENT;
+
+		child->thread.dac1 = 0;
+		dbcr_dac(child) &= ~(DBCR_DAC1R | DBCR_DAC1W);
+#ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
+		if (child->thread.dbcr2 & DBCR2_DAC12MODE) {
+			child->thread.dac2 = 0;
+			child->thread.dbcr2 &= ~DBCR2_DAC12MODE;
+		}
+		child->thread.dbcr2 &= ~(DBCR2_DVC1M | DBCR2_DVC1BE);
+#endif
+#if CONFIG_PPC_ADV_DEBUG_DVCS > 0
+		child->thread.dvc1 = 0;
+#endif
+	} else if (slot == 2) {
+		if (child->thread.dac1 == 0)
+			return -ENOENT;
+
+#ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
+		if (child->thread.dbcr2 & DBCR2_DAC12MODE)
+			/* Part of a range */
+			return -EINVAL;
+		child->thread.dbcr2 &= ~(DBCR2_DVC2M | DBCR2_DVC2BE);
+#endif
+#if CONFIG_PPC_ADV_DEBUG_DVCS > 0
+		child->thread.dvc2 = 0;
+#endif
+		child->thread.dac2 = 0;
+		dbcr_dac(child) &= ~(DBCR_DAC2R | DBCR_DAC2W);
+	} else
+		return -EINVAL;
+
+	return 0;
+}
+#endif /* CONFIG_PPC_ADV_DEBUG_REGS */
+
+#ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
+static int set_dac_range(struct task_struct *child,
+			 struct ppc_hw_breakpoint *bp_info)
+{
+	int mode = bp_info->addr_mode & PPC_BREAKPOINT_MODE_MASK;
+
+	/* We don't allow range watchpoints to be used with DVC */
+	if (bp_info->condition_mode)
+		return -EINVAL;
+
+	/*
+	 * Best effort to verify the address range.  The user/supervisor bits
+	 * prevent trapping in kernel space, but let's fail on an obvious bad
+	 * range.  The simple test on the mask is not fool-proof, and any
+	 * exclusive range will spill over into kernel space.
+	 */
+	if (bp_info->addr >= TASK_SIZE)
+		return -EIO;
+	if (mode == PPC_BREAKPOINT_MODE_MASK) {
+		/*
+		 * dac2 is a bitmask.  Don't allow a mask that makes a
+		 * kernel space address from a valid dac1 value
+		 */
+		if (~((unsigned long)bp_info->addr2) >= TASK_SIZE)
+			return -EIO;
+	} else {
+		/*
+		 * For range breakpoints, addr2 must also be a valid address
+		 */
+		if (bp_info->addr2 >= TASK_SIZE)
+			return -EIO;
+	}
+
+	if (child->thread.dbcr0 &
+	    (DBCR0_DAC1R | DBCR0_DAC1W | DBCR0_DAC2R | DBCR0_DAC2W))
+		return -ENOSPC;
+
+	if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_READ)
+		child->thread.dbcr0 |= (DBCR0_DAC1R | DBCR0_IDM);
+	if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_WRITE)
+		child->thread.dbcr0 |= (DBCR0_DAC1W | DBCR0_IDM);
+	child->thread.dac1 = bp_info->addr;
+	child->thread.dac2 = bp_info->addr2;
+	if (mode == PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE)
+		child->thread.dbcr2  |= DBCR2_DAC12M;
+	else if (mode == PPC_BREAKPOINT_MODE_RANGE_EXCLUSIVE)
+		child->thread.dbcr2  |= DBCR2_DAC12MX;
+	else	/* PPC_BREAKPOINT_MODE_MASK */
+		child->thread.dbcr2  |= DBCR2_DAC12MM;
+	child->thread.regs->msr |= MSR_DE;
+
+	return 5;
+}
+#endif /* CONFIG_PPC_ADV_DEBUG_DAC_RANGE */
+
 static long ppc_set_hwdebug(struct task_struct *child,
 		     struct ppc_hw_breakpoint *bp_info)
 {
+	if (bp_info->version != 1)
+		return -ENOTSUPP;
+#ifdef CONFIG_PPC_ADV_DEBUG_REGS
+	/*
+	 * Check for invalid flags and combinations
+	 */
+	if ((bp_info->trigger_type == 0) ||
+	    (bp_info->trigger_type & ~(PPC_BREAKPOINT_TRIGGER_EXECUTE |
+				       PPC_BREAKPOINT_TRIGGER_RW)) ||
+	    (bp_info->addr_mode & ~PPC_BREAKPOINT_MODE_MASK) ||
+	    (bp_info->condition_mode &
+	     ~(PPC_BREAKPOINT_CONDITION_MODE |
+	       PPC_BREAKPOINT_CONDITION_BE_ALL)))
+		return -EINVAL;
+#if CONFIG_PPC_ADV_DEBUG_DVCS == 0
+	if (bp_info->condition_mode != PPC_BREAKPOINT_CONDITION_NONE)
+		return -EINVAL;
+#endif
+
+	if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_EXECUTE) {
+		if ((bp_info->trigger_type != PPC_BREAKPOINT_TRIGGER_EXECUTE) ||
+		    (bp_info->condition_mode != PPC_BREAKPOINT_CONDITION_NONE))
+			return -EINVAL;
+		return set_intruction_bp(child, bp_info);
+	}
+	if (bp_info->addr_mode == PPC_BREAKPOINT_MODE_EXACT)
+		return set_dac(child, bp_info);
+
+#ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
+	return set_dac_range(child, bp_info);
+#else
+	return -EINVAL;
+#endif
+#else /* !CONFIG_PPC_ADV_DEBUG_DVCS */
 	/*
-	 * We currently support one data breakpoint
+	 * We only support one data breakpoint
 	 */
 	if (((bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_RW) == 0) ||
 	    ((bp_info->trigger_type & ~PPC_BREAKPOINT_TRIGGER_RW) != 0) ||
@@ -855,30 +1200,39 @@ static long ppc_set_hwdebug(struct task_struct *child,
 		return -EIO;
 
 	child->thread.dabr = (unsigned long)bp_info->addr;
-#ifdef CONFIG_PPC_ADV_DEBUG_REGS
-	child->thread.dbcr0 = DBCR0_IDM;
-	if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_READ)
-		child->thread.dbcr0 |= DBSR_DAC1R;
-	if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_WRITE)
-		child->thread.dbcr0 |= DBSR_DAC1W;
-	child->thread.regs->msr |= MSR_DE;
-#endif
+
 	return 1;
+#endif /* !CONFIG_PPC_ADV_DEBUG_DVCS */
 }
 
 static long ppc_del_hwdebug(struct task_struct *child, long addr, long data)
 {
+#ifdef CONFIG_PPC_ADV_DEBUG_REGS
+	int rc;
+
+	if (data <= 4)
+		rc = del_instruction_bp(child, (int)data);
+	else
+		rc = del_dac(child, (int)data - 4);
+
+	if (!rc) {
+		if (!DBCR_ACTIVE_EVENTS(child->thread.dbcr0,
+					child->thread.dbcr1)) {
+			child->thread.dbcr0 &= ~DBCR0_IDM;
+			child->thread.regs->msr &= ~MSR_DE;
+		}
+	}
+	return rc;
+#else
 	if (data != 1)
 		return -EINVAL;
 	if (child->thread.dabr == 0)
 		return -ENOENT;
 
 	child->thread.dabr = 0;
-#ifdef CONFIG_PPC_ADV_DEBUG_REGS
-	child->thread.dbcr0 &= ~(DBSR_DAC1R | DBSR_DAC1W | DBCR0_IDM);
-	child->thread.regs->msr &= ~MSR_DE;
-#endif
+
 	return 0;
+#endif
 }
 
 /*
@@ -978,6 +1332,20 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 		struct ppc_debug_info dbginfo;
 
 		dbginfo.version = 1;
+#ifdef CONFIG_PPC_ADV_DEBUG_REGS
+		dbginfo.num_instruction_bps = CONFIG_PPC_ADV_DEBUG_IACS;
+		dbginfo.num_data_bps = CONFIG_PPC_ADV_DEBUG_DACS;
+		dbginfo.num_condition_regs = CONFIG_PPC_ADV_DEBUG_DVCS;
+		dbginfo.data_bp_alignment = 4;
+		dbginfo.sizeof_condition = 4;
+		dbginfo.features = PPC_DEBUG_FEATURE_INSN_BP_RANGE |
+				   PPC_DEBUG_FEATURE_INSN_BP_MASK;
+#ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
+		dbginfo.features |=
+				   PPC_DEBUG_FEATURE_DATA_BP_RANGE |
+				   PPC_DEBUG_FEATURE_DATA_BP_MASK;
+#endif
+#else /* !CONFIG_PPC_ADV_DEBUG_REGS */
 		dbginfo.num_instruction_bps = 0;
 		dbginfo.num_data_bps = 1;
 		dbginfo.num_condition_regs = 0;
@@ -988,6 +1356,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 #endif
 		dbginfo.sizeof_condition = 0;
 		dbginfo.features = 0;
+#endif /* CONFIG_PPC_ADV_DEBUG_REGS */
 
 		if (!access_ok(VERIFY_WRITE, data,
 			       sizeof(struct ppc_debug_info)))
@@ -1023,8 +1392,13 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 		/* We only support one DABR and no IABRS at the moment */
 		if (addr > 0)
 			break;
+#ifdef CONFIG_PPC_ADV_DEBUG_REGS
+		ret = put_user(child->thread.dac1,
+			       (unsigned long __user *)data);
+#else
 		ret = put_user(child->thread.dabr,
 			       (unsigned long __user *)data);
+#endif
 		break;
 	}