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Diffstat (limited to 'arch/x86/kernel/kgdb.c')
-rw-r--r--arch/x86/kernel/kgdb.c172
1 files changed, 128 insertions, 44 deletions
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index ec592caac4b..7ec1d5f8d28 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -39,15 +39,16 @@
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/kgdb.h>
-#include <linux/init.h>
#include <linux/smp.h>
#include <linux/nmi.h>
#include <linux/hw_breakpoint.h>
+#include <linux/uaccess.h>
+#include <linux/memory.h>
#include <asm/debugreg.h>
#include <asm/apicdef.h>
-#include <asm/system.h>
#include <asm/apic.h>
+#include <asm/nmi.h>
struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
{
@@ -66,8 +67,6 @@ struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
{ "ss", 4, offsetof(struct pt_regs, ss) },
{ "ds", 4, offsetof(struct pt_regs, ds) },
{ "es", 4, offsetof(struct pt_regs, es) },
- { "fs", 4, -1 },
- { "gs", 4, -1 },
#else
{ "ax", 8, offsetof(struct pt_regs, ax) },
{ "bx", 8, offsetof(struct pt_regs, bx) },
@@ -89,7 +88,11 @@ struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
{ "flags", 4, offsetof(struct pt_regs, flags) },
{ "cs", 4, offsetof(struct pt_regs, cs) },
{ "ss", 4, offsetof(struct pt_regs, ss) },
+ { "ds", 4, -1 },
+ { "es", 4, -1 },
#endif
+ { "fs", 4, -1 },
+ { "gs", 4, -1 },
};
int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
@@ -120,8 +123,8 @@ char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
dbg_reg_def[regno].size);
- switch (regno) {
#ifdef CONFIG_X86_32
+ switch (regno) {
case GDB_SS:
if (!user_mode_vm(regs))
*(unsigned long *)mem = __KERNEL_DS;
@@ -134,8 +137,8 @@ char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
case GDB_FS:
*(unsigned long *)mem = 0xFFFF;
break;
-#endif
}
+#endif
return dbg_reg_def[regno].name;
}
@@ -277,7 +280,7 @@ static int hw_break_release_slot(int breakno)
pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
if (dbg_release_bp_slot(*pevent))
/*
- * The debugger is responisble for handing the retry on
+ * The debugger is responsible for handing the retry on
* remove failure.
*/
return -1;
@@ -315,14 +318,18 @@ static void kgdb_remove_all_hw_break(void)
if (!breakinfo[i].enabled)
continue;
bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
- if (bp->attr.disabled == 1)
+ if (!bp->attr.disabled) {
+ arch_uninstall_hw_breakpoint(bp);
+ bp->attr.disabled = 1;
continue;
+ }
if (dbg_is_early)
early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
breakinfo[i].type);
- else
- arch_uninstall_hw_breakpoint(bp);
- bp->attr.disabled = 1;
+ else if (hw_break_release_slot(i))
+ printk(KERN_ERR "KGDB: hw bpt remove failed %lx\n",
+ breakinfo[i].addr);
+ breakinfo[i].enabled = 0;
}
}
@@ -436,12 +443,12 @@ void kgdb_roundup_cpus(unsigned long flags)
/**
* kgdb_arch_handle_exception - Handle architecture specific GDB packets.
- * @vector: The error vector of the exception that happened.
+ * @e_vector: The error vector of the exception that happened.
* @signo: The signal number of the exception that happened.
* @err_code: The error code of the exception that happened.
- * @remcom_in_buffer: The buffer of the packet we have read.
- * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
- * @regs: The &struct pt_regs of the current process.
+ * @remcomInBuffer: The buffer of the packet we have read.
+ * @remcomOutBuffer: The buffer of %BUFMAX bytes to write a packet into.
+ * @linux_regs: The &struct pt_regs of the current process.
*
* This function MUST handle the 'c' and 's' command packets,
* as well packets to set / remove a hardware breakpoint, if used.
@@ -506,41 +513,37 @@ single_step_cont(struct pt_regs *regs, struct die_args *args)
static int was_in_debug_nmi[NR_CPUS];
-static int __kgdb_notify(struct die_args *args, unsigned long cmd)
+static int kgdb_nmi_handler(unsigned int cmd, struct pt_regs *regs)
{
- struct pt_regs *regs = args->regs;
-
switch (cmd) {
- case DIE_NMI:
+ case NMI_LOCAL:
if (atomic_read(&kgdb_active) != -1) {
/* KGDB CPU roundup */
kgdb_nmicallback(raw_smp_processor_id(), regs);
was_in_debug_nmi[raw_smp_processor_id()] = 1;
touch_nmi_watchdog();
- return NOTIFY_STOP;
+ return NMI_HANDLED;
}
- return NOTIFY_DONE;
-
- case DIE_NMI_IPI:
- /* Just ignore, we will handle the roundup on DIE_NMI. */
- return NOTIFY_DONE;
+ break;
- case DIE_NMIUNKNOWN:
+ case NMI_UNKNOWN:
if (was_in_debug_nmi[raw_smp_processor_id()]) {
was_in_debug_nmi[raw_smp_processor_id()] = 0;
- return NOTIFY_STOP;
- }
- return NOTIFY_DONE;
-
- case DIE_NMIWATCHDOG:
- if (atomic_read(&kgdb_active) != -1) {
- /* KGDB CPU roundup: */
- kgdb_nmicallback(raw_smp_processor_id(), regs);
- return NOTIFY_STOP;
+ return NMI_HANDLED;
}
- /* Enter debugger: */
break;
+ default:
+ /* do nothing */
+ break;
+ }
+ return NMI_DONE;
+}
+static int __kgdb_notify(struct die_args *args, unsigned long cmd)
+{
+ struct pt_regs *regs = args->regs;
+
+ switch (cmd) {
case DIE_DEBUG:
if (atomic_read(&kgdb_cpu_doing_single_step) != -1) {
if (user_mode(regs))
@@ -598,11 +601,6 @@ kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
static struct notifier_block kgdb_notifier = {
.notifier_call = kgdb_notify,
-
- /*
- * Lowest-prio notifier priority, we want to be notified last:
- */
- .priority = -INT_MAX,
};
/**
@@ -613,10 +611,34 @@ static struct notifier_block kgdb_notifier = {
*/
int kgdb_arch_init(void)
{
- return register_die_notifier(&kgdb_notifier);
+ int retval;
+
+ retval = register_die_notifier(&kgdb_notifier);
+ if (retval)
+ goto out;
+
+ retval = register_nmi_handler(NMI_LOCAL, kgdb_nmi_handler,
+ 0, "kgdb");
+ if (retval)
+ goto out1;
+
+ retval = register_nmi_handler(NMI_UNKNOWN, kgdb_nmi_handler,
+ 0, "kgdb");
+
+ if (retval)
+ goto out2;
+
+ return retval;
+
+out2:
+ unregister_nmi_handler(NMI_LOCAL, "kgdb");
+out1:
+ unregister_die_notifier(&kgdb_notifier);
+out:
+ return retval;
}
-static void kgdb_hw_overflow_handler(struct perf_event *event, int nmi,
+static void kgdb_hw_overflow_handler(struct perf_event *event,
struct perf_sample_data *data, struct pt_regs *regs)
{
struct task_struct *tsk = current;
@@ -646,7 +668,7 @@ void kgdb_arch_late(void)
for (i = 0; i < HBP_NUM; i++) {
if (breakinfo[i].pev)
continue;
- breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL);
+ breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL, NULL);
if (IS_ERR((void * __force)breakinfo[i].pev)) {
printk(KERN_ERR "kgdb: Could not allocate hw"
"breakpoints\nDisabling the kernel debugger\n");
@@ -681,6 +703,8 @@ void kgdb_arch_exit(void)
breakinfo[i].pev = NULL;
}
}
+ unregister_nmi_handler(NMI_UNKNOWN, "kgdb");
+ unregister_nmi_handler(NMI_LOCAL, "kgdb");
unregister_die_notifier(&kgdb_notifier);
}
@@ -718,6 +742,66 @@ void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
regs->ip = ip;
}
+int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
+{
+ int err;
+#ifdef CONFIG_DEBUG_RODATA
+ char opc[BREAK_INSTR_SIZE];
+#endif /* CONFIG_DEBUG_RODATA */
+
+ bpt->type = BP_BREAKPOINT;
+ err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
+ BREAK_INSTR_SIZE);
+ if (err)
+ return err;
+ err = probe_kernel_write((char *)bpt->bpt_addr,
+ arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
+#ifdef CONFIG_DEBUG_RODATA
+ if (!err)
+ return err;
+ /*
+ * It is safe to call text_poke() because normal kernel execution
+ * is stopped on all cores, so long as the text_mutex is not locked.
+ */
+ if (mutex_is_locked(&text_mutex))
+ return -EBUSY;
+ text_poke((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr,
+ BREAK_INSTR_SIZE);
+ err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
+ if (err)
+ return err;
+ if (memcmp(opc, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE))
+ return -EINVAL;
+ bpt->type = BP_POKE_BREAKPOINT;
+#endif /* CONFIG_DEBUG_RODATA */
+ return err;
+}
+
+int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
+{
+#ifdef CONFIG_DEBUG_RODATA
+ int err;
+ char opc[BREAK_INSTR_SIZE];
+
+ if (bpt->type != BP_POKE_BREAKPOINT)
+ goto knl_write;
+ /*
+ * It is safe to call text_poke() because normal kernel execution
+ * is stopped on all cores, so long as the text_mutex is not locked.
+ */
+ if (mutex_is_locked(&text_mutex))
+ goto knl_write;
+ text_poke((void *)bpt->bpt_addr, bpt->saved_instr, BREAK_INSTR_SIZE);
+ err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
+ if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE))
+ goto knl_write;
+ return err;
+knl_write:
+#endif /* CONFIG_DEBUG_RODATA */
+ return probe_kernel_write((char *)bpt->bpt_addr,
+ (char *)bpt->saved_instr, BREAK_INSTR_SIZE);
+}
+
struct kgdb_arch arch_kgdb_ops = {
/* Breakpoint instruction: */
.gdb_bpt_instr = { 0xcc },
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-04 01:24:13 +0000