diff options
| -rw-r--r-- | Documentation/powerpc/ptrace.txt | 134 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/ptrace.h | 77 | ||||
| -rw-r--r-- | arch/powerpc/kernel/ptrace.c | 90 |
3 files changed, 301 insertions, 0 deletions
diff --git a/Documentation/powerpc/ptrace.txt b/Documentation/powerpc/ptrace.txt new file mode 100644 index 0000000..f4a5499 --- /dev/null +++ b/Documentation/powerpc/ptrace.txt @@ -0,0 +1,134 @@ +GDB intends to support the following hardware debug features of BookE +processors: + +4 hardware breakpoints (IAC) +2 hardware watchpoints (read, write and read-write) (DAC) +2 value conditions for the hardware watchpoints (DVC) + +For that, we need to extend ptrace so that GDB can query and set these +resources. Since we're extending, we're trying to create an interface +that's extendable and that covers both BookE and server processors, so +that GDB doesn't need to special-case each of them. We added the +following 3 new ptrace requests. + +1. PTRACE_PPC_GETHWDEBUGINFO + +Query for GDB to discover the hardware debug features. The main info to +be returned here is the minimum alignment for the hardware watchpoints. +BookE processors don't have restrictions here, but server processors have +an 8-byte alignment restriction for hardware watchpoints. We'd like to avoid +adding special cases to GDB based on what it sees in AUXV. + +Since we're at it, we added other useful info that the kernel can return to +GDB: this query will return the number of hardware breakpoints, hardware +watchpoints and whether it supports a range of addresses and a condition. +The query will fill the following structure provided by the requesting process: + +struct ppc_debug_info { + unit32_t version; + unit32_t num_instruction_bps; + unit32_t num_data_bps; + unit32_t num_condition_regs; + unit32_t data_bp_alignment; + unit32_t sizeof_condition; /* size of the DVC register */ + uint64_t features; /* bitmask of the individual flags */ +}; + +features will have bits indicating 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 + +2. PTRACE_SETHWDEBUG + +Sets a hardware breakpoint or watchpoint, according to the provided structure: + +struct ppc_hw_breakpoint { + uint32_t version; +#define PPC_BREAKPOINT_TRIGGER_EXECUTE 0x1 +#define PPC_BREAKPOINT_TRIGGER_READ 0x2 +#define PPC_BREAKPOINT_TRIGGER_WRITE 0x4 + uint32_t trigger_type; /* only some combinations allowed */ +#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 + uint32_t addr_mode; /* address match mode */ + +#define PPC_BREAKPOINT_CONDITION_MODE 0x3 +#define PPC_BREAKPOINT_CONDITION_NONE 0x0 +#define PPC_BREAKPOINT_CONDITION_AND 0x1 +#define PPC_BREAKPOINT_CONDITION_EXACT 0x1 /* different name for the same thing as above */ +#define PPC_BREAKPOINT_CONDITION_OR 0x2 +#define PPC_BREAKPOINT_CONDITION_AND_OR 0x3 +#define PPC_BREAKPOINT_CONDITION_BE_ALL 0x00ff0000 /* byte enable bits */ +#define PPC_BREAKPOINT_CONDITION_BE(n) (1<<((n)+16)) + uint32_t condition_mode; /* break/watchpoint condition flags */ + + uint64_t addr; + uint64_t addr2; + uint64_t condition_value; +}; + +A request specifies one event, not necessarily just one register to be set. +For instance, if the request is for a watchpoint with a condition, both the +DAC and DVC registers will be set in the same request. + +With this GDB can ask for all kinds of hardware breakpoints and watchpoints +that the BookE supports. COMEFROM breakpoints available in server processors +are not contemplated, but that is out of the scope of this work. + +ptrace will return an integer (handle) uniquely identifying the breakpoint or +watchpoint just created. This integer will be used in the PTRACE_DELHWDEBUG +request to ask for its removal. Return -ENOSPC if the requested breakpoint +can't be allocated on the registers. + +Some examples of using the structure to: + +- set a breakpoint in the first breakpoint register + + p.version = PPC_DEBUG_CURRENT_VERSION; + p.trigger_type = PPC_BREAKPOINT_TRIGGER_EXECUTE; + p.addr_mode = PPC_BREAKPOINT_MODE_EXACT; + p.condition_mode = PPC_BREAKPOINT_CONDITION_NONE; + p.addr = (uint64_t) address; + p.addr2 = 0; + p.condition_value = 0; + +- set a watchpoint which triggers on reads in the second watchpoint register + + p.version = PPC_DEBUG_CURRENT_VERSION; + p.trigger_type = PPC_BREAKPOINT_TRIGGER_READ; + p.addr_mode = PPC_BREAKPOINT_MODE_EXACT; + p.condition_mode = PPC_BREAKPOINT_CONDITION_NONE; + p.addr = (uint64_t) address; + p.addr2 = 0; + p.condition_value = 0; + +- set a watchpoint which triggers only with a specific value + + p.version = PPC_DEBUG_CURRENT_VERSION; + p.trigger_type = PPC_BREAKPOINT_TRIGGER_READ; + p.addr_mode = PPC_BREAKPOINT_MODE_EXACT; + p.condition_mode = PPC_BREAKPOINT_CONDITION_AND | PPC_BREAKPOINT_CONDITION_BE_ALL; + p.addr = (uint64_t) address; + p.addr2 = 0; + p.condition_value = (uint64_t) condition; + +- set a ranged hardware breakpoint + + p.version = PPC_DEBUG_CURRENT_VERSION; + p.trigger_type = PPC_BREAKPOINT_TRIGGER_EXECUTE; + p.addr_mode = PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE; + p.condition_mode = PPC_BREAKPOINT_CONDITION_NONE; + p.addr = (uint64_t) begin_range; + p.addr2 = (uint64_t) end_range; + p.condition_value = 0; + +3. PTRACE_DELHWDEBUG + +Takes an integer which identifies an existing breakpoint or watchpoint +(i.e., the value returned from PTRACE_SETHWDEBUG), and deletes the +corresponding breakpoint or watchpoint.. diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h index cbd759e..b451081 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 { @@ -294,4 +300,75 @@ 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 0x0000000000000001 +#define PPC_DEBUG_FEATURE_INSN_BP_MASK 0x0000000000000002 +#define PPC_DEBUG_FEATURE_DATA_BP_RANGE 0x0000000000000004 +#define PPC_DEBUG_FEATURE_DATA_BP_MASK 0x0000000000000008 + +#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 0x00000001 +#define PPC_BREAKPOINT_TRIGGER_READ 0x00000002 +#define PPC_BREAKPOINT_TRIGGER_WRITE 0x00000004 +#define PPC_BREAKPOINT_TRIGGER_RW \ + (PPC_BREAKPOINT_TRIGGER_READ | PPC_BREAKPOINT_TRIGGER_WRITE) + +/* + * Address Mode + */ +#define PPC_BREAKPOINT_MODE_EXACT 0x00000000 +#define PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE 0x00000001 +#define PPC_BREAKPOINT_MODE_RANGE_EXCLUSIVE 0x00000002 +#define PPC_BREAKPOINT_MODE_MASK 0x00000003 + +/* + * Condition Mode + */ +#define PPC_BREAKPOINT_CONDITION_MODE 0x00000003 +#define PPC_BREAKPOINT_CONDITION_NONE 0x00000000 +#define PPC_BREAKPOINT_CONDITION_AND 0x00000001 +#define PPC_BREAKPOINT_CONDITION_EXACT PPC_BREAKPOINT_CONDITION_AND +#define PPC_BREAKPOINT_CONDITION_OR 0x00000002 +#define PPC_BREAKPOINT_CONDITION_AND_OR 0x00000003 +#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 292c814..8847bd6 100644 --- a/arch/powerpc/kernel/ptrace.c +++ b/arch/powerpc/kernel/ptrace.c @@ -835,6 +835,52 @@ 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_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; +} + +static long ppc_del_hwdebug(struct task_struct *child, long addr, long data) +{ + 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; +} + /* * 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 @@ -928,6 +974,50 @@ 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 = 4; +#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 */ |
