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Diffstat (limited to 'arch/arm64/kernel/hw_breakpoint.c')
-rw-r--r--arch/arm64/kernel/hw_breakpoint.c123
1 files changed, 56 insertions, 67 deletions
diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c
index 0b727edf4104..ab76b36dce82 100644
--- a/arch/arm64/kernel/hw_breakpoint.c
+++ b/arch/arm64/kernel/hw_breakpoint.c
@@ -21,6 +21,8 @@
#include <asm/current.h>
#include <asm/debug-monitors.h>
+#include <asm/esr.h>
+#include <asm/exception.h>
#include <asm/hw_breakpoint.h>
#include <asm/traps.h>
#include <asm/cputype.h>
@@ -257,7 +259,7 @@ static int hw_breakpoint_control(struct perf_event *bp,
* level.
*/
enable_debug_monitors(dbg_el);
- /* Fall through */
+ fallthrough;
case HW_BREAKPOINT_RESTORE:
/* Setup the address register. */
write_wb_reg(val_reg, i, info->address);
@@ -541,13 +543,13 @@ int hw_breakpoint_arch_parse(struct perf_event *bp,
if (hw->ctrl.len == ARM_BREAKPOINT_LEN_2)
break;
- /* Fallthrough */
+ fallthrough;
case 3:
/* Allow single byte watchpoint. */
if (hw->ctrl.len == ARM_BREAKPOINT_LEN_1)
break;
- /* Fallthrough */
+ fallthrough;
default:
return -EINVAL;
}
@@ -617,8 +619,7 @@ NOKPROBE_SYMBOL(toggle_bp_registers);
/*
* Debug exception handlers.
*/
-static int breakpoint_handler(unsigned long unused, unsigned int esr,
- struct pt_regs *regs)
+void do_breakpoint(unsigned long esr, struct pt_regs *regs)
{
int i, step = 0, *kernel_step;
u32 ctrl_reg;
@@ -661,7 +662,7 @@ unlock:
}
if (!step)
- return 0;
+ return;
if (user_mode(regs)) {
debug_info->bps_disabled = 1;
@@ -669,7 +670,7 @@ unlock:
/* If we're already stepping a watchpoint, just return. */
if (debug_info->wps_disabled)
- return 0;
+ return;
if (test_thread_flag(TIF_SINGLESTEP))
debug_info->suspended_step = 1;
@@ -680,7 +681,7 @@ unlock:
kernel_step = this_cpu_ptr(&stepping_kernel_bp);
if (*kernel_step != ARM_KERNEL_STEP_NONE)
- return 0;
+ return;
if (kernel_active_single_step()) {
*kernel_step = ARM_KERNEL_STEP_SUSPEND;
@@ -689,10 +690,8 @@ unlock:
kernel_enable_single_step(regs);
}
}
-
- return 0;
}
-NOKPROBE_SYMBOL(breakpoint_handler);
+NOKPROBE_SYMBOL(do_breakpoint);
/*
* Arm64 hardware does not always report a watchpoint hit address that matches
@@ -701,7 +700,7 @@ NOKPROBE_SYMBOL(breakpoint_handler);
* addresses. There is no straight-forward way, short of disassembling the
* offending instruction, to map that address back to the watchpoint. This
* function computes the distance of the memory access from the watchpoint as a
- * heuristic for the likelyhood that a given access triggered the watchpoint.
+ * heuristic for the likelihood that a given access triggered the watchpoint.
*
* See Section D2.10.5 "Determining the memory location that caused a Watchpoint
* exception" of ARMv8 Architecture Reference Manual for details.
@@ -730,8 +729,28 @@ static u64 get_distance_from_watchpoint(unsigned long addr, u64 val,
return 0;
}
-static int watchpoint_handler(unsigned long addr, unsigned int esr,
- struct pt_regs *regs)
+static int watchpoint_report(struct perf_event *wp, unsigned long addr,
+ struct pt_regs *regs)
+{
+ int step = is_default_overflow_handler(wp);
+ struct arch_hw_breakpoint *info = counter_arch_bp(wp);
+
+ info->trigger = addr;
+
+ /*
+ * If we triggered a user watchpoint from a uaccess routine, then
+ * handle the stepping ourselves since userspace really can't help
+ * us with this.
+ */
+ if (!user_mode(regs) && info->ctrl.privilege == AARCH64_BREAKPOINT_EL0)
+ step = 1;
+ else
+ perf_bp_event(wp, regs);
+
+ return step;
+}
+
+void do_watchpoint(unsigned long addr, unsigned long esr, struct pt_regs *regs)
{
int i, step = 0, *kernel_step, access, closest_match = 0;
u64 min_dist = -1, dist;
@@ -739,7 +758,6 @@ static int watchpoint_handler(unsigned long addr, unsigned int esr,
u64 val;
struct perf_event *wp, **slots;
struct debug_info *debug_info;
- struct arch_hw_breakpoint *info;
struct arch_hw_breakpoint_ctrl ctrl;
slots = this_cpu_ptr(wp_on_reg);
@@ -759,7 +777,7 @@ static int watchpoint_handler(unsigned long addr, unsigned int esr,
* Check that the access type matches.
* 0 => load, otherwise => store
*/
- access = (esr & AARCH64_ESR_ACCESS_MASK) ? HW_BREAKPOINT_W :
+ access = (esr & ESR_ELx_WNR) ? HW_BREAKPOINT_W :
HW_BREAKPOINT_R;
if (!(access & hw_breakpoint_type(wp)))
continue;
@@ -777,29 +795,17 @@ static int watchpoint_handler(unsigned long addr, unsigned int esr,
if (dist != 0)
continue;
- info = counter_arch_bp(wp);
- info->trigger = addr;
- perf_bp_event(wp, regs);
-
- /* Do we need to handle the stepping? */
- if (is_default_overflow_handler(wp))
- step = 1;
+ step = watchpoint_report(wp, addr, regs);
}
- if (min_dist > 0 && min_dist != -1) {
- /* No exact match found. */
- wp = slots[closest_match];
- info = counter_arch_bp(wp);
- info->trigger = addr;
- perf_bp_event(wp, regs);
- /* Do we need to handle the stepping? */
- if (is_default_overflow_handler(wp))
- step = 1;
- }
+ /* No exact match found? */
+ if (min_dist > 0 && min_dist != -1)
+ step = watchpoint_report(slots[closest_match], addr, regs);
+
rcu_read_unlock();
if (!step)
- return 0;
+ return;
/*
* We always disable EL0 watchpoints because the kernel can
@@ -812,7 +818,7 @@ static int watchpoint_handler(unsigned long addr, unsigned int esr,
/* If we're already stepping a breakpoint, just return. */
if (debug_info->bps_disabled)
- return 0;
+ return;
if (test_thread_flag(TIF_SINGLESTEP))
debug_info->suspended_step = 1;
@@ -823,7 +829,7 @@ static int watchpoint_handler(unsigned long addr, unsigned int esr,
kernel_step = this_cpu_ptr(&stepping_kernel_bp);
if (*kernel_step != ARM_KERNEL_STEP_NONE)
- return 0;
+ return;
if (kernel_active_single_step()) {
*kernel_step = ARM_KERNEL_STEP_SUSPEND;
@@ -832,44 +838,41 @@ static int watchpoint_handler(unsigned long addr, unsigned int esr,
kernel_enable_single_step(regs);
}
}
-
- return 0;
}
-NOKPROBE_SYMBOL(watchpoint_handler);
+NOKPROBE_SYMBOL(do_watchpoint);
/*
* Handle single-step exception.
*/
-int reinstall_suspended_bps(struct pt_regs *regs)
+bool try_step_suspended_breakpoints(struct pt_regs *regs)
{
struct debug_info *debug_info = &current->thread.debug;
- int handled_exception = 0, *kernel_step;
-
- kernel_step = this_cpu_ptr(&stepping_kernel_bp);
+ int *kernel_step = this_cpu_ptr(&stepping_kernel_bp);
+ bool handled_exception = false;
/*
- * Called from single-step exception handler.
- * Return 0 if execution can resume, 1 if a SIGTRAP should be
- * reported.
+ * Called from single-step exception entry.
+ * Return true if we stepped a breakpoint and can resume execution,
+ * false if we need to handle a single-step.
*/
if (user_mode(regs)) {
if (debug_info->bps_disabled) {
debug_info->bps_disabled = 0;
toggle_bp_registers(AARCH64_DBG_REG_BCR, DBG_ACTIVE_EL0, 1);
- handled_exception = 1;
+ handled_exception = true;
}
if (debug_info->wps_disabled) {
debug_info->wps_disabled = 0;
toggle_bp_registers(AARCH64_DBG_REG_WCR, DBG_ACTIVE_EL0, 1);
- handled_exception = 1;
+ handled_exception = true;
}
if (handled_exception) {
if (debug_info->suspended_step) {
debug_info->suspended_step = 0;
/* Allow exception handling to fall-through. */
- handled_exception = 0;
+ handled_exception = false;
} else {
user_disable_single_step(current);
}
@@ -883,17 +886,17 @@ int reinstall_suspended_bps(struct pt_regs *regs)
if (*kernel_step != ARM_KERNEL_STEP_SUSPEND) {
kernel_disable_single_step();
- handled_exception = 1;
+ handled_exception = true;
} else {
- handled_exception = 0;
+ handled_exception = false;
}
*kernel_step = ARM_KERNEL_STEP_NONE;
}
- return !handled_exception;
+ return handled_exception;
}
-NOKPROBE_SYMBOL(reinstall_suspended_bps);
+NOKPROBE_SYMBOL(try_step_suspended_breakpoints);
/*
* Context-switcher for restoring suspended breakpoints.
@@ -965,14 +968,6 @@ static int hw_breakpoint_reset(unsigned int cpu)
return 0;
}
-#ifdef CONFIG_CPU_PM
-extern void cpu_suspend_set_dbg_restorer(int (*hw_bp_restore)(unsigned int));
-#else
-static inline void cpu_suspend_set_dbg_restorer(int (*hw_bp_restore)(unsigned int))
-{
-}
-#endif
-
/*
* One-time initialisation.
*/
@@ -986,12 +981,6 @@ static int __init arch_hw_breakpoint_init(void)
pr_info("found %d breakpoint and %d watchpoint registers.\n",
core_num_brps, core_num_wrps);
- /* Register debug fault handlers. */
- hook_debug_fault_code(DBG_ESR_EVT_HWBP, breakpoint_handler, SIGTRAP,
- TRAP_HWBKPT, "hw-breakpoint handler");
- hook_debug_fault_code(DBG_ESR_EVT_HWWP, watchpoint_handler, SIGTRAP,
- TRAP_HWBKPT, "hw-watchpoint handler");
-
/*
* Reset the breakpoint resources. We assume that a halting
* debugger will leave the world in a nice state for us.
generated by cgit (git 2.34.1) at 2025-12-25 22:55:17 +0000