[RFC:PATCH 01/03] powerpc: Extended ptrace interface

Dave Kleikamp
2009-12-10T15:57:15Z

powerpc: Extended ptrace interface

From: Torez Smith <lnxtorez@linux.vnet.ibm.com>

Add a new extended ptrace interface so that user-space has a single
interface for powerpc, without having to know the specific layout
of the debug registers.

Implement:
PPC_PTRACE_GETHWDEBUGINFO
PPC_PTRACE_SETHWDEBUG
PPC_PTRACE_DELHWDEBUG

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

arch/powerpc/include/asm/ptrace.h | 75 ++++++++++++++++++++++++++++++++
arch/powerpc/kernel/ptrace.c | 88 +++++++++++++++++++++++++++++++++++++
2 files changed, 163 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index 8c34149..7ae887b 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -24,6 +24,12 @@
* 2 of the License, or (at your option) any later version.
*/

+#ifdef __KERNEL__
+#include <linux/types.h>
+#else
+#include <stdint.h>
+#endif
+
#ifndef __ASSEMBLY__

struct pt_regs {
@@ -292,4 +298,73 @@ extern void user_disable_single_step(struct task_struct *);

#define PTRACE_SINGLEBLOCK 0x100 /* resume execution until next branch */

+#define PPC_PTRACE_GETHWDBGINFO 0x89
+#define PPC_PTRACE_SETHWDEBUG 0x88
+#define PPC_PTRACE_DELHWDEBUG 0x87
+
+#ifndef __ASSEMBLY__
+
+struct ppc_debug_info {
+ uint32_t version; /* Only version 1 exists to date */
+ uint32_t num_instruction_bps;
+ uint32_t num_data_bps;
+ uint32_t num_condition_regs;
+ uint32_t data_bp_alignment;
+ uint32_t sizeof_condition; /* size of the DVC register */
+ uint64_t features;
+};
+
+#endif /* __ASSEMBLY__ */
+
+/*
+ * features will have bits indication whether there is support for:
+ */
+#define PPC_DEBUG_FEATURE_INSN_BP_RANGE 0x1
+#define PPC_DEBUG_FEATURE_INSN_BP_MASK 0x2
+#define PPC_DEBUG_FEATURE_DATA_BP_RANGE 0x4
+#define PPC_DEBUG_FEATURE_DATA_BP_MASK 0x8
+
+#ifndef __ASSEMBLY__
+
+struct ppc_hw_breakpoint {
+ uint32_t version; /* currently, version must be 1 */
+ uint32_t trigger_type; /* only some combinations allowed */
+ uint32_t addr_mode; /* address match mode */
+ uint32_t condition_mode; /* break/watchpoint condition flags */
+ uint64_t addr; /* break/watchpoint address */
+ uint64_t addr2; /* range end or mask */
+ uint64_t condition_value; /* contents of the DVC register */
+};
+
+#endif /* __ASSEMBLY__ */
+
+/*
+ * Trigger Type
+ */
+#define PPC_BREAKPOINT_TRIGGER_EXECUTE 0x1
+#define PPC_BREAKPOINT_TRIGGER_READ 0x2
+#define PPC_BREAKPOINT_TRIGGER_WRITE 0x4
+#define PPC_BREAKPOINT_TRIGGER_RW 0x6
+
+/*
+ * Address Mode
+ */
+#define PPC_BREAKPOINT_MODE_EXACT 0x0
+#define PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE 0x1
+#define PPC_BREAKPOINT_MODE_RANGE_EXCLUSIVE 0x2
+#define PPC_BREAKPOINT_MODE_MASK 0x3
+
+/*
+ * Condition Mode
+ */
+#define PPC_BREAKPOINT_CONDITION_NONE 0x0
+#define PPC_BREAKPOINT_CONDITION_AND 0x1
+#define PPC_BREAKPOINT_CONDITION_EXACT 0x1
+#define PPC_BREAKPOINT_CONDITION_OR 0x2
+#define PPC_BREAKPOINT_CONDITION_AND_OR 0x3
+#define PPC_BREAKPOINT_CONDITION_BE_ALL 0x00ff0000
+#define PPC_BREAKPOINT_CONDITION_BE_SHIFT 16
+#define PPC_BREAKPOINT_CONDITION_BE(n) \
+ (1<<((n)+PPC_BREAKPOINT_CONDITION_BE_SHIFT))
+
#endif /* _ASM_POWERPC_PTRACE_H */
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index ef14988..6be2ce0 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -839,6 +839,50 @@ void ptrace_disable(struct task_struct *child)
user_disable_single_step(child);
}

+static long ppc_set_hwdebug(struct task_struct *child,
+ struct ppc_hw_breakpoint *bp_info)
+{
+ /*
+ * We currently support one data breakpoint
+ */
+ if (((bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_RW) == 0) ||
+ ((bp_info->trigger_type & ~PPC_BREAKPOINT_TRIGGER_RW) != 0) ||
+ (bp_info->trigger_type != PPC_BREAKPOINT_TRIGGER_WRITE) ||
+ (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT) ||
+ (bp_info->condition_mode != PPC_BREAKPOINT_CONDITION_NONE))
+ return -EINVAL;
+
+ if (child->thread.dabr)
+ return -ENOSPC;
+
+ if ((unsigned long)bp_info->addr >= TASK_SIZE)
+ return -EIO;
+
+ child->thread.dabr = (unsigned long)bp_info->addr;
+#ifdef CONFIG_BOOKE
+ 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;
+}
+
+static long ppc_del_hwdebug(struct task_struct *child, long addr, long data)
+{
+ if ((data != 1) || (child->thread.dabr == 0))
+ return -EINVAL;
+
+ child->thread.dabr = 0;
+#ifdef CONFIG_BOOKE
+ child->thread.dbcr0 &= ~(DBSR_DAC1R | DBSR_DAC1W | DBCR0_IDM);
+ child->thread.regs->msr &= ~MSR_DE;
+#endif
+ return 0;
+}
+
/*
* Here are the old "legacy" powerpc specific getregs/setregs ptrace calls,
* we mark them as obsolete now, they will be removed in a future version
@@ -932,6 +976,50 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
break;
}

+ case PPC_PTRACE_GETHWDBGINFO: {
+ struct ppc_debug_info dbginfo;
+
+ dbginfo.version = 1;
+ dbginfo.num_instruction_bps = 0;
+ dbginfo.num_data_bps = 1;
+ dbginfo.num_condition_regs = 0;
+#ifdef CONFIG_PPC64
+ dbginfo.data_bp_alignment = 8;
+#else
+ dbginfo.data_bp_alignment = 0;
+#endif
+ dbginfo.sizeof_condition = 0;
+ dbginfo.features = 0;
+
+ if (!access_ok(VERIFY_WRITE, data,
+ sizeof(struct ppc_debug_info)))
+ return -EFAULT;
+ ret = __copy_to_user((struct ppc_debug_info __user *)data,
+ &dbginfo, sizeof(struct ppc_debug_info)) ?
+ -EFAULT : 0;
+ break;
+ }
+
+ case PPC_PTRACE_SETHWDEBUG: {
+ struct ppc_hw_breakpoint bp_info;
+
+ if (!access_ok(VERIFY_READ, data,
+ sizeof(struct ppc_hw_breakpoint)))
+ return -EFAULT;
+ ret = __copy_from_user(&bp_info,
+ (struct ppc_hw_breakpoint __user *)data,
+ sizeof(struct ppc_hw_breakpoint)) ?
+ -EFAULT : 0;
+ if (!ret)
+ ret = ppc_set_hwdebug(child, &bp_info);
+ break;
+ }
+
+ case PPC_PTRACE_DELHWDEBUG: {
+ ret = ppc_del_hwdebug(child, addr, data);
+ break;
+ }
+
case PTRACE_GET_DEBUGREG: {
ret = -EINVAL;
/* We only support one DABR and no IABRS at the moment */

--
Dave Kleikamp
IBM Linux Technology Center