From 09b4ad9fcbb1a946df939adeb373d1be0e701694 Mon Sep 17 00:00:00 2001 From: Ulrich Weigand Date: Wed, 21 Sep 2011 12:39:50 +0000 Subject: [PATCH] * linux-arm-low.c: Include . (PTRACE_GETHBPREGS, PTRACE_SETHBPREGS): Define if necessary. (struct arm_linux_hwbp_cap): New data type. (arm_hwbp_type, arm_hwbp_control_t): New typedefs. (struct arm_linux_hw_breakpoint): New data type. (MAX_BPTS, MAX_WPTS): Define. (struct arch_process_info, struct arch_lwp_info): New data types. (arm_linux_get_hwbp_cap): New function. (arm_linux_get_hw_breakpoint_count): Likewise. (arm_linux_get_hw_watchpoint_count): Likewise. (arm_linux_get_hw_watchpoint_max_length): Likewise. (arm_hwbp_control_initialize): Likewise. (arm_hwbp_control_is_enabled): Likewise. (arm_hwbp_control_is_initialized): Likewise. (arm_hwbp_control_disable): Likewise. (arm_linux_hw_breakpoint_equal): Likewise. (arm_linux_hw_point_initialize): Likewise. (struct update_registers_data): New data structure. (update_registers_callback: New function. (arm_insert_point): Likewise. (arm_remove_point): Likewise. (arm_stopped_by_watchpoint): Likewise. (arm_stopped_data_address): Likewise. (arm_new_process): Likewise. (arm_new_thread): Likewise. (arm_prepare_to_resume): Likewise. (the_low_target): Register arm_insert_point, arm_remove_point, arm_stopped_by_watchpoint, arm_stopped_data_address, arm_new_process, arm_new_thread, and arm_prepare_to_resume. --- gdb/gdbserver/ChangeLog | 32 +++ gdb/gdbserver/linux-arm-low.c | 495 ++++++++++++++++++++++++++++++++++ 2 files changed, 527 insertions(+) diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index b634f5f667b..60eb8113ee5 100644 --- a/gdb/gdbserver/ChangeLog +++ b/gdb/gdbserver/ChangeLog @@ -1,3 +1,35 @@ +2011-11-15 Ulrich Weigand + + * linux-arm-low.c: Include . + (PTRACE_GETHBPREGS, PTRACE_SETHBPREGS): Define if necessary. + (struct arm_linux_hwbp_cap): New data type. + (arm_hwbp_type, arm_hwbp_control_t): New typedefs. + (struct arm_linux_hw_breakpoint): New data type. + (MAX_BPTS, MAX_WPTS): Define. + (struct arch_process_info, struct arch_lwp_info): New data types. + (arm_linux_get_hwbp_cap): New function. + (arm_linux_get_hw_breakpoint_count): Likewise. + (arm_linux_get_hw_watchpoint_count): Likewise. + (arm_linux_get_hw_watchpoint_max_length): Likewise. + (arm_hwbp_control_initialize): Likewise. + (arm_hwbp_control_is_enabled): Likewise. + (arm_hwbp_control_is_initialized): Likewise. + (arm_hwbp_control_disable): Likewise. + (arm_linux_hw_breakpoint_equal): Likewise. + (arm_linux_hw_point_initialize): Likewise. + (struct update_registers_data): New data structure. + (update_registers_callback: New function. + (arm_insert_point): Likewise. + (arm_remove_point): Likewise. + (arm_stopped_by_watchpoint): Likewise. + (arm_stopped_data_address): Likewise. + (arm_new_process): Likewise. + (arm_new_thread): Likewise. + (arm_prepare_to_resume): Likewise. + (the_low_target): Register arm_insert_point, arm_remove_point, + arm_stopped_by_watchpoint, arm_stopped_data_address, arm_new_process, + arm_new_thread, and arm_prepare_to_resume. + 2011-09-15 Stan Shebs * server.h (struct emit_ops): Add compare-goto fields. diff --git a/gdb/gdbserver/linux-arm-low.c b/gdb/gdbserver/linux-arm-low.c index babb20c8c64..f5365c7c8ad 100644 --- a/gdb/gdbserver/linux-arm-low.c +++ b/gdb/gdbserver/linux-arm-low.c @@ -26,6 +26,7 @@ #include #endif #include +#include /* Defined in auto-generated files. */ void init_registers_arm (void); @@ -48,6 +49,65 @@ void init_registers_arm_with_neon (void); # define PTRACE_SETVFPREGS 28 #endif +#ifndef PTRACE_GETHBPREGS +#define PTRACE_GETHBPREGS 29 +#define PTRACE_SETHBPREGS 30 +#endif + +/* Information describing the hardware breakpoint capabilities. */ +struct arm_linux_hwbp_cap +{ + unsigned char arch; + unsigned char max_wp_length; + unsigned char wp_count; + unsigned char bp_count; +}; + +/* Enum describing the different types of ARM hardware break-/watch-points. */ +typedef enum +{ + arm_hwbp_break = 0, + arm_hwbp_load = 1, + arm_hwbp_store = 2, + arm_hwbp_access = 3 +} arm_hwbp_type; + +/* Type describing an ARM Hardware Breakpoint Control register value. */ +typedef unsigned int arm_hwbp_control_t; + +/* Structure used to keep track of hardware break-/watch-points. */ +struct arm_linux_hw_breakpoint +{ + /* Address to break on, or being watched. */ + unsigned int address; + /* Control register for break-/watch- point. */ + arm_hwbp_control_t control; +}; + +/* Since we cannot dynamically allocate subfields of arch_process_info, + assume a maximum number of supported break-/watchpoints. */ +#define MAX_BPTS 32 +#define MAX_WPTS 32 + +/* Per-process arch-specific data we want to keep. */ +struct arch_process_info +{ + /* Hardware breakpoints for this process. */ + struct arm_linux_hw_breakpoint bpts[MAX_BPTS]; + /* Hardware watchpoints for this process. */ + struct arm_linux_hw_breakpoint wpts[MAX_WPTS]; +}; + +/* Per-thread arch-specific data we want to keep. */ +struct arch_lwp_info +{ + /* Non-zero if our copy differs from what's recorded in the thread. */ + char bpts_changed[MAX_BPTS]; + char wpts_changed[MAX_WPTS]; + /* Cached stopped data address. */ + CORE_ADDR stopped_data_address; +}; + static unsigned long arm_hwcap; /* These are in in current kernels. */ @@ -280,6 +340,431 @@ ps_get_thread_area (const struct ps_prochandle *ph, return PS_OK; } + +/* Get hold of the Hardware Breakpoint information for the target we are + attached to. Returns NULL if the kernel doesn't support Hardware + breakpoints at all, or a pointer to the information structure. */ +static const struct arm_linux_hwbp_cap * +arm_linux_get_hwbp_cap (void) +{ + /* The info structure we return. */ + static struct arm_linux_hwbp_cap info; + + /* Is INFO in a good state? -1 means that no attempt has been made to + initialize INFO; 0 means an attempt has been made, but it failed; 1 + means INFO is in an initialized state. */ + static int available = -1; + + if (available == -1) + { + int pid = lwpid_of (get_thread_lwp (current_inferior)); + unsigned int val; + + if (ptrace (PTRACE_GETHBPREGS, pid, 0, &val) < 0) + available = 0; + else + { + info.arch = (unsigned char)((val >> 24) & 0xff); + info.max_wp_length = (unsigned char)((val >> 16) & 0xff); + info.wp_count = (unsigned char)((val >> 8) & 0xff); + info.bp_count = (unsigned char)(val & 0xff); + available = (info.arch != 0); + } + + if (available) + { + if (info.wp_count > MAX_WPTS) + internal_error (__FILE__, __LINE__, + "Unsupported number of watchpoints"); + if (info.bp_count > MAX_BPTS) + internal_error (__FILE__, __LINE__, + "Unsupported number of breakpoints"); + } + } + + return available == 1 ? &info : NULL; +} + +/* How many hardware breakpoints are available? */ +static int +arm_linux_get_hw_breakpoint_count (void) +{ + const struct arm_linux_hwbp_cap *cap = arm_linux_get_hwbp_cap (); + return cap != NULL ? cap->bp_count : 0; +} + +/* How many hardware watchpoints are available? */ +static int +arm_linux_get_hw_watchpoint_count (void) +{ + const struct arm_linux_hwbp_cap *cap = arm_linux_get_hwbp_cap (); + return cap != NULL ? cap->wp_count : 0; +} + +/* Maximum length of area watched by hardware watchpoint. */ +static int +arm_linux_get_hw_watchpoint_max_length (void) +{ + const struct arm_linux_hwbp_cap *cap = arm_linux_get_hwbp_cap (); + return cap != NULL ? cap->max_wp_length : 0; +} + +/* Initialize an ARM hardware break-/watch-point control register value. + BYTE_ADDRESS_SELECT is the mask of bytes to trigger on; HWBP_TYPE is the + type of break-/watch-point; ENABLE indicates whether the point is enabled. + */ +static arm_hwbp_control_t +arm_hwbp_control_initialize (unsigned byte_address_select, + arm_hwbp_type hwbp_type, + int enable) +{ + gdb_assert ((byte_address_select & ~0xffU) == 0); + gdb_assert (hwbp_type != arm_hwbp_break + || ((byte_address_select & 0xfU) != 0)); + + return (byte_address_select << 5) | (hwbp_type << 3) | (3 << 1) | enable; +} + +/* Does the breakpoint control value CONTROL have the enable bit set? */ +static int +arm_hwbp_control_is_enabled (arm_hwbp_control_t control) +{ + return control & 0x1; +} + +/* Is the breakpoint control value CONTROL initialized? */ +static int +arm_hwbp_control_is_initialized (arm_hwbp_control_t control) +{ + return control != 0; +} + +/* Change a breakpoint control word so that it is in the disabled state. */ +static arm_hwbp_control_t +arm_hwbp_control_disable (arm_hwbp_control_t control) +{ + return control & ~0x1; +} + +/* Are two break-/watch-points equal? */ +static int +arm_linux_hw_breakpoint_equal (const struct arm_linux_hw_breakpoint *p1, + const struct arm_linux_hw_breakpoint *p2) +{ + return p1->address == p2->address && p1->control == p2->control; +} + +/* Initialize the hardware breakpoint structure P for a breakpoint or + watchpoint at ADDR to LEN. The type of watchpoint is given in TYPE. + Returns -1 if TYPE is unsupported, 0 if TYPE represents a breakpoint, + and 1 if type represents a watchpoint. */ +static int +arm_linux_hw_point_initialize (char type, CORE_ADDR addr, int len, + struct arm_linux_hw_breakpoint *p) +{ + arm_hwbp_type hwbp_type; + unsigned mask; + + /* Breakpoint/watchpoint types (GDB terminology): + 0 = memory breakpoint for instructions + (not supported; done via memory write instead) + 1 = hardware breakpoint for instructions (supported) + 2 = write watchpoint (supported) + 3 = read watchpoint (supported) + 4 = access watchpoint (supported). */ + switch (type) + { + case '1': + hwbp_type = arm_hwbp_break; + break; + case '2': + hwbp_type = arm_hwbp_store; + break; + case '3': + hwbp_type = arm_hwbp_load; + break; + case '4': + hwbp_type = arm_hwbp_access; + break; + default: + /* Unsupported. */ + return -1; + } + + if (hwbp_type == arm_hwbp_break) + { + /* For breakpoints, the length field encodes the mode. */ + switch (len) + { + case 2: /* 16-bit Thumb mode breakpoint */ + case 3: /* 32-bit Thumb mode breakpoint */ + mask = 0x3 << (addr & 2); + break; + case 4: /* 32-bit ARM mode breakpoint */ + mask = 0xf; + break; + default: + /* Unsupported. */ + return -1; + } + + addr &= ~3; + } + else + { + CORE_ADDR max_wp_length = arm_linux_get_hw_watchpoint_max_length (); + CORE_ADDR aligned_addr; + + /* Can not set watchpoints for zero or negative lengths. */ + if (len <= 0) + return -1; + /* The current ptrace interface can only handle watchpoints that are a + power of 2. */ + if ((len & (len - 1)) != 0) + return -1; + + /* Test that the range [ADDR, ADDR + LEN) fits into the largest address + range covered by a watchpoint. */ + aligned_addr = addr & ~(max_wp_length - 1); + if (aligned_addr + max_wp_length < addr + len) + return -1; + + mask = (1 << len) - 1; + } + + p->address = (unsigned int) addr; + p->control = arm_hwbp_control_initialize (mask, hwbp_type, 1); + + return hwbp_type != arm_hwbp_break; +} + +/* Callback to mark a watch-/breakpoint to be updated in all threads of + the current process. */ + +struct update_registers_data +{ + int watch; + int i; +}; + +static int +update_registers_callback (struct inferior_list_entry *entry, void *arg) +{ + struct lwp_info *lwp = (struct lwp_info *) entry; + struct update_registers_data *data = (struct update_registers_data *) arg; + + /* Only update the threads of the current process. */ + if (pid_of (lwp) == pid_of (get_thread_lwp (current_inferior))) + { + /* The actual update is done later just before resuming the lwp, + we just mark that the registers need updating. */ + if (data->watch) + lwp->arch_private->wpts_changed[data->i] = 1; + else + lwp->arch_private->bpts_changed[data->i] = 1; + + /* If the lwp isn't stopped, force it to momentarily pause, so + we can update its breakpoint registers. */ + if (!lwp->stopped) + linux_stop_lwp (lwp); + } + + return 0; +} + +/* Insert hardware break-/watchpoint. */ +static int +arm_insert_point (char type, CORE_ADDR addr, int len) +{ + struct process_info *proc = current_process (); + struct arm_linux_hw_breakpoint p, *pts; + int watch, i, count; + + watch = arm_linux_hw_point_initialize (type, addr, len, &p); + if (watch < 0) + { + /* Unsupported. */ + return 1; + } + + if (watch) + { + count = arm_linux_get_hw_watchpoint_count (); + pts = proc->private->arch_private->wpts; + } + else + { + count = arm_linux_get_hw_breakpoint_count (); + pts = proc->private->arch_private->bpts; + } + + for (i = 0; i < count; i++) + if (!arm_hwbp_control_is_enabled (pts[i].control)) + { + struct update_registers_data data = { watch, i }; + pts[i] = p; + find_inferior (&all_lwps, update_registers_callback, &data); + return 0; + } + + /* We're out of watchpoints. */ + return -1; +} + +/* Remove hardware break-/watchpoint. */ +static int +arm_remove_point (char type, CORE_ADDR addr, int len) +{ + struct process_info *proc = current_process (); + struct arm_linux_hw_breakpoint p, *pts; + int watch, i, count; + + watch = arm_linux_hw_point_initialize (type, addr, len, &p); + if (watch < 0) + { + /* Unsupported. */ + return -1; + } + + if (watch) + { + count = arm_linux_get_hw_watchpoint_count (); + pts = proc->private->arch_private->wpts; + } + else + { + count = arm_linux_get_hw_breakpoint_count (); + pts = proc->private->arch_private->bpts; + } + + for (i = 0; i < count; i++) + if (arm_linux_hw_breakpoint_equal (&p, pts + i)) + { + struct update_registers_data data = { watch, i }; + pts[i].control = arm_hwbp_control_disable (pts[i].control); + find_inferior (&all_lwps, update_registers_callback, &data); + return 0; + } + + /* No watchpoint matched. */ + return -1; +} + +/* Return whether current thread is stopped due to a watchpoint. */ +static int +arm_stopped_by_watchpoint (void) +{ + struct lwp_info *lwp = get_thread_lwp (current_inferior); + struct siginfo siginfo; + + /* We must be able to set hardware watchpoints. */ + if (arm_linux_get_hw_watchpoint_count () == 0) + return 0; + + /* Retrieve siginfo. */ + errno = 0; + ptrace (PTRACE_GETSIGINFO, lwpid_of (lwp), 0, &siginfo); + if (errno != 0) + return 0; + + /* This must be a hardware breakpoint. */ + if (siginfo.si_signo != SIGTRAP + || (siginfo.si_code & 0xffff) != 0x0004 /* TRAP_HWBKPT */) + return 0; + + /* If we are in a positive slot then we're looking at a breakpoint and not + a watchpoint. */ + if (siginfo.si_errno >= 0) + return 0; + + /* Cache stopped data address for use by arm_stopped_data_address. */ + lwp->arch_private->stopped_data_address + = (CORE_ADDR) (uintptr_t) siginfo.si_addr; + + return 1; +} + +/* Return data address that triggered watchpoint. Called only if + arm_stopped_by_watchpoint returned true. */ +static CORE_ADDR +arm_stopped_data_address (void) +{ + struct lwp_info *lwp = get_thread_lwp (current_inferior); + return lwp->arch_private->stopped_data_address; +} + +/* Called when a new process is created. */ +static struct arch_process_info * +arm_new_process (void) +{ + struct arch_process_info *info = xcalloc (1, sizeof (*info)); + return info; +} + +/* Called when a new thread is detected. */ +static struct arch_lwp_info * +arm_new_thread (void) +{ + struct arch_lwp_info *info = xcalloc (1, sizeof (*info)); + int i; + + for (i = 0; i < MAX_BPTS; i++) + info->bpts_changed[i] = 1; + for (i = 0; i < MAX_WPTS; i++) + info->wpts_changed[i] = 1; + + return info; +} + +/* Called when resuming a thread. + If the debug regs have changed, update the thread's copies. */ +static void +arm_prepare_to_resume (struct lwp_info *lwp) +{ + int pid = lwpid_of (lwp); + struct process_info *proc = find_process_pid (pid_of (lwp)); + struct arch_process_info *proc_info = proc->private->arch_private; + struct arch_lwp_info *lwp_info = lwp->arch_private; + int i; + + for (i = 0; i < arm_linux_get_hw_breakpoint_count (); i++) + if (lwp_info->bpts_changed[i]) + { + errno = 0; + + if (arm_hwbp_control_is_enabled (proc_info->bpts[i].control)) + if (ptrace (PTRACE_SETHBPREGS, pid, ((i << 1) + 1), + &proc_info->bpts[i].address) < 0) + error (_("Unexpected error setting breakpoint address")); + + if (arm_hwbp_control_is_initialized (proc_info->bpts[i].control)) + if (ptrace (PTRACE_SETHBPREGS, pid, ((i << 1) + 2), + &proc_info->bpts[i].control) < 0) + error (_("Unexpected error setting breakpoint")); + + lwp_info->bpts_changed[i] = 0; + } + + for (i = 0; i < arm_linux_get_hw_watchpoint_count (); i++) + if (lwp_info->wpts_changed[i]) + { + errno = 0; + + if (arm_hwbp_control_is_enabled (proc_info->wpts[i].control)) + if (ptrace (PTRACE_SETHBPREGS, pid, -((i << 1) + 1), + &proc_info->wpts[i].address) < 0) + error (_("Unexpected error setting watchpoint address")); + + if (arm_hwbp_control_is_initialized (proc_info->wpts[i].control)) + if (ptrace (PTRACE_SETHBPREGS, pid, -((i << 1) + 2), + &proc_info->wpts[i].control) < 0) + error (_("Unexpected error setting watchpoint")); + + lwp_info->wpts_changed[i] = 0; + } +} + + static int arm_get_hwcap (unsigned long *valp) { @@ -389,4 +874,14 @@ struct linux_target_ops the_low_target = { arm_reinsert_addr, 0, arm_breakpoint_at, + arm_insert_point, + arm_remove_point, + arm_stopped_by_watchpoint, + arm_stopped_data_address, + NULL, /* collect_ptrace_register */ + NULL, /* supply_ptrace_register */ + NULL, /* siginfo_fixup */ + arm_new_process, + arm_new_thread, + arm_prepare_to_resume, }; -- 2.39.2