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Diffstat (limited to 'arch/arm64/kernel/debug-monitors.c')
-rw-r--r--arch/arm64/kernel/debug-monitors.c130
1 files changed, 110 insertions, 20 deletions
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index cbfacf7fb43..a7fb874b595 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -27,7 +27,6 @@
#include <linux/uaccess.h>
#include <asm/debug-monitors.h>
-#include <asm/local.h>
#include <asm/cputype.h>
#include <asm/system_misc.h>
@@ -89,8 +88,8 @@ early_param("nodebugmon", early_debug_disable);
* Keep track of debug users on each core.
* The ref counts are per-cpu so we use a local_t type.
*/
-static DEFINE_PER_CPU(local_t, mde_ref_count);
-static DEFINE_PER_CPU(local_t, kde_ref_count);
+static DEFINE_PER_CPU(int, mde_ref_count);
+static DEFINE_PER_CPU(int, kde_ref_count);
void enable_debug_monitors(enum debug_el el)
{
@@ -98,11 +97,11 @@ void enable_debug_monitors(enum debug_el el)
WARN_ON(preemptible());
- if (local_inc_return(&__get_cpu_var(mde_ref_count)) == 1)
+ if (this_cpu_inc_return(mde_ref_count) == 1)
enable = DBG_MDSCR_MDE;
if (el == DBG_ACTIVE_EL1 &&
- local_inc_return(&__get_cpu_var(kde_ref_count)) == 1)
+ this_cpu_inc_return(kde_ref_count) == 1)
enable |= DBG_MDSCR_KDE;
if (enable && debug_enabled) {
@@ -118,11 +117,11 @@ void disable_debug_monitors(enum debug_el el)
WARN_ON(preemptible());
- if (local_dec_and_test(&__get_cpu_var(mde_ref_count)))
+ if (this_cpu_dec_return(mde_ref_count) == 0)
disable = ~DBG_MDSCR_MDE;
if (el == DBG_ACTIVE_EL1 &&
- local_dec_and_test(&__get_cpu_var(kde_ref_count)))
+ this_cpu_dec_return(kde_ref_count) == 0)
disable &= ~DBG_MDSCR_KDE;
if (disable) {
@@ -138,7 +137,6 @@ void disable_debug_monitors(enum debug_el el)
static void clear_os_lock(void *unused)
{
asm volatile("msr oslar_el1, %0" : : "r" (0));
- isb();
}
static int os_lock_notify(struct notifier_block *self,
@@ -156,12 +154,17 @@ static struct notifier_block os_lock_nb = {
static int debug_monitors_init(void)
{
+ cpu_notifier_register_begin();
+
/* Clear the OS lock. */
- smp_call_function(clear_os_lock, NULL, 1);
- clear_os_lock(NULL);
+ on_each_cpu(clear_os_lock, NULL, 1);
+ isb();
+ local_dbg_enable();
/* Register hotplug handler. */
- register_cpu_notifier(&os_lock_nb);
+ __register_cpu_notifier(&os_lock_nb);
+
+ cpu_notifier_register_done();
return 0;
}
postcore_initcall(debug_monitors_init);
@@ -188,6 +191,48 @@ static void clear_regs_spsr_ss(struct pt_regs *regs)
regs->pstate = spsr;
}
+/* EL1 Single Step Handler hooks */
+static LIST_HEAD(step_hook);
+static DEFINE_RWLOCK(step_hook_lock);
+
+void register_step_hook(struct step_hook *hook)
+{
+ write_lock(&step_hook_lock);
+ list_add(&hook->node, &step_hook);
+ write_unlock(&step_hook_lock);
+}
+
+void unregister_step_hook(struct step_hook *hook)
+{
+ write_lock(&step_hook_lock);
+ list_del(&hook->node);
+ write_unlock(&step_hook_lock);
+}
+
+/*
+ * Call registered single step handers
+ * There is no Syndrome info to check for determining the handler.
+ * So we call all the registered handlers, until the right handler is
+ * found which returns zero.
+ */
+static int call_step_hook(struct pt_regs *regs, unsigned int esr)
+{
+ struct step_hook *hook;
+ int retval = DBG_HOOK_ERROR;
+
+ read_lock(&step_hook_lock);
+
+ list_for_each_entry(hook, &step_hook, node) {
+ retval = hook->fn(regs, esr);
+ if (retval == DBG_HOOK_HANDLED)
+ break;
+ }
+
+ read_unlock(&step_hook_lock);
+
+ return retval;
+}
+
static int single_step_handler(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
@@ -215,7 +260,9 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
*/
user_rewind_single_step(current);
} else {
- /* TODO: route to KGDB */
+ if (call_step_hook(regs, esr) == DBG_HOOK_HANDLED)
+ return 0;
+
pr_warning("Unexpected kernel single-step exception at EL1\n");
/*
* Re-enable stepping since we know that we will be
@@ -227,11 +274,50 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
return 0;
}
+/*
+ * Breakpoint handler is re-entrant as another breakpoint can
+ * hit within breakpoint handler, especically in kprobes.
+ * Use reader/writer locks instead of plain spinlock.
+ */
+static LIST_HEAD(break_hook);
+static DEFINE_RWLOCK(break_hook_lock);
+
+void register_break_hook(struct break_hook *hook)
+{
+ write_lock(&break_hook_lock);
+ list_add(&hook->node, &break_hook);
+ write_unlock(&break_hook_lock);
+}
+
+void unregister_break_hook(struct break_hook *hook)
+{
+ write_lock(&break_hook_lock);
+ list_del(&hook->node);
+ write_unlock(&break_hook_lock);
+}
+
+static int call_break_hook(struct pt_regs *regs, unsigned int esr)
+{
+ struct break_hook *hook;
+ int (*fn)(struct pt_regs *regs, unsigned int esr) = NULL;
+
+ read_lock(&break_hook_lock);
+ list_for_each_entry(hook, &break_hook, node)
+ if ((esr & hook->esr_mask) == hook->esr_val)
+ fn = hook->fn;
+ read_unlock(&break_hook_lock);
+
+ return fn ? fn(regs, esr) : DBG_HOOK_ERROR;
+}
+
static int brk_handler(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
siginfo_t info;
+ if (call_break_hook(regs, esr) == DBG_HOOK_HANDLED)
+ return 0;
+
if (!user_mode(regs))
return -EFAULT;
@@ -249,7 +335,8 @@ static int brk_handler(unsigned long addr, unsigned int esr,
int aarch32_break_handler(struct pt_regs *regs)
{
siginfo_t info;
- unsigned int instr;
+ u32 arm_instr;
+ u16 thumb_instr;
bool bp = false;
void __user *pc = (void __user *)instruction_pointer(regs);
@@ -258,18 +345,21 @@ int aarch32_break_handler(struct pt_regs *regs)
if (compat_thumb_mode(regs)) {
/* get 16-bit Thumb instruction */
- get_user(instr, (u16 __user *)pc);
- if (instr == AARCH32_BREAK_THUMB2_LO) {
+ get_user(thumb_instr, (u16 __user *)pc);
+ thumb_instr = le16_to_cpu(thumb_instr);
+ if (thumb_instr == AARCH32_BREAK_THUMB2_LO) {
/* get second half of 32-bit Thumb-2 instruction */
- get_user(instr, (u16 __user *)(pc + 2));
- bp = instr == AARCH32_BREAK_THUMB2_HI;
+ get_user(thumb_instr, (u16 __user *)(pc + 2));
+ thumb_instr = le16_to_cpu(thumb_instr);
+ bp = thumb_instr == AARCH32_BREAK_THUMB2_HI;
} else {
- bp = instr == AARCH32_BREAK_THUMB;
+ bp = thumb_instr == AARCH32_BREAK_THUMB;
}
} else {
/* 32-bit ARM instruction */
- get_user(instr, (u32 __user *)pc);
- bp = (instr & ~0xf0000000) == AARCH32_BREAK_ARM;
+ get_user(arm_instr, (u32 __user *)pc);
+ arm_instr = le32_to_cpu(arm_instr);
+ bp = (arm_instr & ~0xf0000000) == AARCH32_BREAK_ARM;
}
if (!bp)
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-03 17:57:25 +0000