ARM: 6357/1: hw-breakpoint: add new ptrace requests for hw-breakpoint interaction
For debuggers to take advantage of the hw-breakpoint framework in the kernel, it is necessary to expose the API calls via a ptrace interface. This patch exposes the hardware breakpoints framework as a collection of virtual registers, accesible using PTRACE_SETHBPREGS and PTRACE_GETHBPREGS requests. The breakpoints are stored in the debug_info struct of the running thread. Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: S. Karthikeyan <informkarthik@gmail.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>hifive-unleashed-5.1
Will Deacon
Russell King
parent
f81ef4a920
commit
864232fa1a
|
|
@ -2,6 +2,11 @@
|
|||
#define _ARM_HW_BREAKPOINT_H
|
||||
|
||||
#ifdef __KERNEL__
|
||||
|
||||
struct task_struct;
|
||||
|
||||
#ifdef CONFIG_HAVE_HW_BREAKPOINT
|
||||
|
||||
struct arch_hw_breakpoint_ctrl {
|
||||
u32 __reserved : 9,
|
||||
mismatch : 1,
|
||||
|
|
@ -102,7 +107,6 @@ static inline void decode_ctrl_reg(u32 reg,
|
|||
struct notifier_block;
|
||||
struct perf_event;
|
||||
struct pmu;
|
||||
struct task_struct;
|
||||
|
||||
extern struct pmu perf_ops_bp;
|
||||
extern int arch_bp_generic_fields(struct arch_hw_breakpoint_ctrl ctrl,
|
||||
|
|
@ -111,13 +115,19 @@ extern int arch_check_bp_in_kernelspace(struct perf_event *bp);
|
|||
extern int arch_validate_hwbkpt_settings(struct perf_event *bp);
|
||||
extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
|
||||
unsigned long val, void *data);
|
||||
|
||||
extern u8 arch_get_debug_arch(void);
|
||||
extern u8 arch_get_max_wp_len(void);
|
||||
extern void clear_ptrace_hw_breakpoint(struct task_struct *tsk);
|
||||
|
||||
int arch_install_hw_breakpoint(struct perf_event *bp);
|
||||
void arch_uninstall_hw_breakpoint(struct perf_event *bp);
|
||||
void hw_breakpoint_pmu_read(struct perf_event *bp);
|
||||
int hw_breakpoint_slots(int type);
|
||||
|
||||
#else
|
||||
static inline void clear_ptrace_hw_breakpoint(struct task_struct *tsk) {}
|
||||
|
||||
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
|
||||
#endif /* __KERNEL__ */
|
||||
#endif /* _ARM_HW_BREAKPOINT_H */
|
||||
|
|
|
|||
|
|
@ -19,6 +19,7 @@
|
|||
|
||||
#ifdef __KERNEL__
|
||||
|
||||
#include <asm/hw_breakpoint.h>
|
||||
#include <asm/ptrace.h>
|
||||
#include <asm/types.h>
|
||||
|
||||
|
|
@ -41,6 +42,9 @@ struct debug_entry {
|
|||
struct debug_info {
|
||||
int nsaved;
|
||||
struct debug_entry bp[2];
|
||||
#ifdef CONFIG_HAVE_HW_BREAKPOINT
|
||||
struct perf_event *hbp[ARM_MAX_HBP_SLOTS];
|
||||
#endif
|
||||
};
|
||||
|
||||
struct thread_struct {
|
||||
|
|
|
|||
|
|
@ -29,6 +29,8 @@
|
|||
#define PTRACE_SETCRUNCHREGS 26
|
||||
#define PTRACE_GETVFPREGS 27
|
||||
#define PTRACE_SETVFPREGS 28
|
||||
#define PTRACE_GETHBPREGS 29
|
||||
#define PTRACE_SETHBPREGS 30
|
||||
|
||||
/*
|
||||
* PSR bits
|
||||
|
|
|
|||
|
|
@ -29,6 +29,7 @@
|
|||
#include <linux/utsname.h>
|
||||
#include <linux/uaccess.h>
|
||||
#include <linux/random.h>
|
||||
#include <linux/hw_breakpoint.h>
|
||||
|
||||
#include <asm/cacheflush.h>
|
||||
#include <asm/leds.h>
|
||||
|
|
@ -317,6 +318,8 @@ void flush_thread(void)
|
|||
struct thread_info *thread = current_thread_info();
|
||||
struct task_struct *tsk = current;
|
||||
|
||||
flush_ptrace_hw_breakpoint(tsk);
|
||||
|
||||
memset(thread->used_cp, 0, sizeof(thread->used_cp));
|
||||
memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
|
||||
memset(&thread->fpstate, 0, sizeof(union fp_state));
|
||||
|
|
@ -345,6 +348,8 @@ copy_thread(unsigned long clone_flags, unsigned long stack_start,
|
|||
thread->cpu_context.sp = (unsigned long)childregs;
|
||||
thread->cpu_context.pc = (unsigned long)ret_from_fork;
|
||||
|
||||
clear_ptrace_hw_breakpoint(p);
|
||||
|
||||
if (clone_flags & CLONE_SETTLS)
|
||||
thread->tp_value = regs->ARM_r3;
|
||||
|
||||
|
|
|
|||
|
|
@ -19,6 +19,8 @@
|
|||
#include <linux/init.h>
|
||||
#include <linux/signal.h>
|
||||
#include <linux/uaccess.h>
|
||||
#include <linux/perf_event.h>
|
||||
#include <linux/hw_breakpoint.h>
|
||||
|
||||
#include <asm/pgtable.h>
|
||||
#include <asm/system.h>
|
||||
|
|
@ -847,6 +849,232 @@ static int ptrace_setvfpregs(struct task_struct *tsk, void __user *data)
|
|||
}
|
||||
#endif
|
||||
|
||||
#ifdef CONFIG_HAVE_HW_BREAKPOINT
|
||||
/*
|
||||
* Convert a virtual register number into an index for a thread_info
|
||||
* breakpoint array. Breakpoints are identified using positive numbers
|
||||
* whilst watchpoints are negative. The registers are laid out as pairs
|
||||
* of (address, control), each pair mapping to a unique hw_breakpoint struct.
|
||||
* Register 0 is reserved for describing resource information.
|
||||
*/
|
||||
static int ptrace_hbp_num_to_idx(long num)
|
||||
{
|
||||
if (num < 0)
|
||||
num = (ARM_MAX_BRP << 1) - num;
|
||||
return (num - 1) >> 1;
|
||||
}
|
||||
|
||||
/*
|
||||
* Returns the virtual register number for the address of the
|
||||
* breakpoint at index idx.
|
||||
*/
|
||||
static long ptrace_hbp_idx_to_num(int idx)
|
||||
{
|
||||
long mid = ARM_MAX_BRP << 1;
|
||||
long num = (idx << 1) + 1;
|
||||
return num > mid ? mid - num : num;
|
||||
}
|
||||
|
||||
/*
|
||||
* Handle hitting a HW-breakpoint.
|
||||
*/
|
||||
static void ptrace_hbptriggered(struct perf_event *bp, int unused,
|
||||
struct perf_sample_data *data,
|
||||
struct pt_regs *regs)
|
||||
{
|
||||
struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
|
||||
long num;
|
||||
int i;
|
||||
siginfo_t info;
|
||||
|
||||
for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
|
||||
if (current->thread.debug.hbp[i] == bp)
|
||||
break;
|
||||
|
||||
num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
|
||||
|
||||
info.si_signo = SIGTRAP;
|
||||
info.si_errno = (int)num;
|
||||
info.si_code = TRAP_HWBKPT;
|
||||
info.si_addr = (void __user *)(bkpt->trigger);
|
||||
|
||||
force_sig_info(SIGTRAP, &info, current);
|
||||
}
|
||||
|
||||
/*
|
||||
* Set ptrace breakpoint pointers to zero for this task.
|
||||
* This is required in order to prevent child processes from unregistering
|
||||
* breakpoints held by their parent.
|
||||
*/
|
||||
void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
|
||||
{
|
||||
memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
|
||||
}
|
||||
|
||||
/*
|
||||
* Unregister breakpoints from this task and reset the pointers in
|
||||
* the thread_struct.
|
||||
*/
|
||||
void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
|
||||
{
|
||||
int i;
|
||||
struct thread_struct *t = &tsk->thread;
|
||||
|
||||
for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
|
||||
if (t->debug.hbp[i]) {
|
||||
unregister_hw_breakpoint(t->debug.hbp[i]);
|
||||
t->debug.hbp[i] = NULL;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
static u32 ptrace_get_hbp_resource_info(void)
|
||||
{
|
||||
u8 num_brps, num_wrps, debug_arch, wp_len;
|
||||
u32 reg = 0;
|
||||
|
||||
num_brps = hw_breakpoint_slots(TYPE_INST);
|
||||
num_wrps = hw_breakpoint_slots(TYPE_DATA);
|
||||
debug_arch = arch_get_debug_arch();
|
||||
wp_len = arch_get_max_wp_len();
|
||||
|
||||
reg |= debug_arch;
|
||||
reg <<= 8;
|
||||
reg |= wp_len;
|
||||
reg <<= 8;
|
||||
reg |= num_wrps;
|
||||
reg <<= 8;
|
||||
reg |= num_brps;
|
||||
|
||||
return reg;
|
||||
}
|
||||
|
||||
static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
|
||||
{
|
||||
struct perf_event_attr attr;
|
||||
|
||||
ptrace_breakpoint_init(&attr);
|
||||
|
||||
/* Initialise fields to sane defaults. */
|
||||
attr.bp_addr = 0;
|
||||
attr.bp_len = HW_BREAKPOINT_LEN_4;
|
||||
attr.bp_type = type;
|
||||
attr.disabled = 1;
|
||||
|
||||
return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, tsk);
|
||||
}
|
||||
|
||||
static int ptrace_gethbpregs(struct task_struct *tsk, long num,
|
||||
unsigned long __user *data)
|
||||
{
|
||||
u32 reg;
|
||||
int idx, ret = 0;
|
||||
struct perf_event *bp;
|
||||
struct arch_hw_breakpoint_ctrl arch_ctrl;
|
||||
|
||||
if (num == 0) {
|
||||
reg = ptrace_get_hbp_resource_info();
|
||||
} else {
|
||||
idx = ptrace_hbp_num_to_idx(num);
|
||||
if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
|
||||
ret = -EINVAL;
|
||||
goto out;
|
||||
}
|
||||
|
||||
bp = tsk->thread.debug.hbp[idx];
|
||||
if (!bp) {
|
||||
reg = 0;
|
||||
goto put;
|
||||
}
|
||||
|
||||
arch_ctrl = counter_arch_bp(bp)->ctrl;
|
||||
|
||||
/*
|
||||
* Fix up the len because we may have adjusted it
|
||||
* to compensate for an unaligned address.
|
||||
*/
|
||||
while (!(arch_ctrl.len & 0x1))
|
||||
arch_ctrl.len >>= 1;
|
||||
|
||||
if (idx & 0x1)
|
||||
reg = encode_ctrl_reg(arch_ctrl);
|
||||
else
|
||||
reg = bp->attr.bp_addr;
|
||||
}
|
||||
|
||||
put:
|
||||
if (put_user(reg, data))
|
||||
ret = -EFAULT;
|
||||
|
||||
out:
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int ptrace_sethbpregs(struct task_struct *tsk, long num,
|
||||
unsigned long __user *data)
|
||||
{
|
||||
int idx, gen_len, gen_type, implied_type, ret = 0;
|
||||
u32 user_val;
|
||||
struct perf_event *bp;
|
||||
struct arch_hw_breakpoint_ctrl ctrl;
|
||||
struct perf_event_attr attr;
|
||||
|
||||
if (num == 0)
|
||||
goto out;
|
||||
else if (num < 0)
|
||||
implied_type = HW_BREAKPOINT_RW;
|
||||
else
|
||||
implied_type = HW_BREAKPOINT_X;
|
||||
|
||||
idx = ptrace_hbp_num_to_idx(num);
|
||||
if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
|
||||
ret = -EINVAL;
|
||||
goto out;
|
||||
}
|
||||
|
||||
if (get_user(user_val, data)) {
|
||||
ret = -EFAULT;
|
||||
goto out;
|
||||
}
|
||||
|
||||
bp = tsk->thread.debug.hbp[idx];
|
||||
if (!bp) {
|
||||
bp = ptrace_hbp_create(tsk, implied_type);
|
||||
if (IS_ERR(bp)) {
|
||||
ret = PTR_ERR(bp);
|
||||
goto out;
|
||||
}
|
||||
tsk->thread.debug.hbp[idx] = bp;
|
||||
}
|
||||
|
||||
attr = bp->attr;
|
||||
|
||||
if (num & 0x1) {
|
||||
/* Address */
|
||||
attr.bp_addr = user_val;
|
||||
} else {
|
||||
/* Control */
|
||||
decode_ctrl_reg(user_val, &ctrl);
|
||||
ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
|
||||
if (ret)
|
||||
goto out;
|
||||
|
||||
if ((gen_type & implied_type) != gen_type) {
|
||||
ret = -EINVAL;
|
||||
goto out;
|
||||
}
|
||||
|
||||
attr.bp_len = gen_len;
|
||||
attr.bp_type = gen_type;
|
||||
attr.disabled = !ctrl.enabled;
|
||||
}
|
||||
|
||||
ret = modify_user_hw_breakpoint(bp, &attr);
|
||||
out:
|
||||
return ret;
|
||||
}
|
||||
#endif
|
||||
|
||||
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
|
||||
{
|
||||
int ret;
|
||||
|
|
@ -916,6 +1144,17 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
|
|||
break;
|
||||
#endif
|
||||
|
||||
#ifdef CONFIG_HAVE_HW_BREAKPOINT
|
||||
case PTRACE_GETHBPREGS:
|
||||
ret = ptrace_gethbpregs(child, addr,
|
||||
(unsigned long __user *)data);
|
||||
break;
|
||||
case PTRACE_SETHBPREGS:
|
||||
ret = ptrace_sethbpregs(child, addr,
|
||||
(unsigned long __user *)data);
|
||||
break;
|
||||
#endif
|
||||
|
||||
default:
|
||||
ret = ptrace_request(child, request, addr, data);
|
||||
break;
|
||||
|
|
|
|||
Loading…
Reference in New Issue