Hi Will I have used Takahiro's patch to fix the single stepping problem of KGDB on arm64. We had real hardware called Hi1610. The problem I had is exactly the same as the description of Takahiro. We are working on kernel4.1.
But It seems that the single stepping with kgdb doesn’t work correctly, 'stepi' moves forward and stops at the next instruction just after enable_dbg in el1_dbg, and never goes beyond that.
I want to know if anyone fix the issues already ?
The patch is like follows:
Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.orghttp://lists.infradead.org/mailman/listinfo/linux-arm-kernel>
arch/arm64/kernel/kgdb.c | 60
+++++++++++++++++++++++++++++++++++-----------
1 file changed, 46 insertions(+), 14 deletions(-)
diff --git a/arch/arm64/kernel/kgdb.c b/arch/arm64/kernel/kgdb.c
index a0d10c5..81b5910 100644
--- a/arch/arm64/kernel/kgdb.c
+++ b/arch/arm64/kernel/kgdb.c
@@ -19,9 +19,13 @@
- along with this program. If not, see
*/
+#include <linux/cpumask.h>
#include <linux/irq.h>
+#include <linux/irq_work.h>
#include <linux/kdebug.h>
#include <linux/kgdb.h>
+#include <linux/percpu.h>
+#include <asm/ptrace.h>
#include <asm/traps.h>
struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
@@ -95,6 +99,9 @@ struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
{ "fpcr", 4, -1 },
};
+static DEFINE_PER_CPU(unsigned int, kgdb_pstate);
+static DEFINE_PER_CPU(struct irq_work, kgdb_irq_work);
char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
{
if (regno >= DBG_MAX_REG_NUM || regno < 0)
@@ -176,18 +183,14 @@ int kgdb_arch_handle_exception(int
exception_vector, int signo,
* over and over again.
*/
kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
atomic_set(&kgdb_cpu_doing_single_step, -1);
kgdb_single_step = 0;
/*
* Received continue command, disable single step
*/
if (kernel_active_single_step())
kernel_disable_single_step();
err = 0;
break;
case 's':
/* mask interrupts while single stepping */
__this_cpu_write(kgdb_pstate, linux_regs->pstate);
linux_regs->pstate |= PSR_I_BIT;
/*
* Update step address value with address passed
* with step packet.
@@ -198,8 +201,6 @@ int kgdb_arch_handle_exception(int
exception_vector, int signo,
*/
kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
atomic_set(&kgdb_cpu_doing_single_step,
raw_smp_processor_id());
kgdb_single_step = 1;
/*
* Enable single step handling
*/
@@ -229,6 +230,18 @@ static int kgdb_compiled_brk_fn(struct pt_regs
*regs, unsigned int esr)
static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned int esr)
{
- unsigned int pstate;
- kernel_disable_single_step();
- atomic_set(&kgdb_cpu_doing_single_step, -1);
- /* restore interrupt mask status */
- pstate = __this_cpu_read(kgdb_pstate);
- if (pstate & PSR_I_BIT)
regs->pstate |= PSR_I_BIT;
- else
regs->pstate &= ~PSR_I_BIT;
kgdb_handle_exception(1, SIGTRAP, 0, regs);
return 0;
}
@@ -249,16 +262,27 @@ static struct step_hook kgdb_step_hook = {
.fn = kgdb_step_brk_fn
};
-static void kgdb_call_nmi_hook(void *ignored)
+static void kgdb_roundup_hook(struct irq_work *work)
{
kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
}
void kgdb_roundup_cpus(unsigned long flags)
{
- local_irq_enable();
- smp_call_function(kgdb_call_nmi_hook, NULL, 0);
- local_irq_disable();
- int cpu;
- struct cpumask mask;
- struct irq_work *work;
- mask = *cpu_online_mask;
- cpumask_clear_cpu(smp_processor_id(), &mask);
- cpu = cpumask_first(&mask);
- if (cpu >= nr_cpu_ids)
return;
- for_each_cpu(cpu, &mask) {
work = per_cpu_ptr(&kgdb_irq_work, cpu);
irq_work_queue_on(work, cpu);
- }
}
static int __kgdb_notify(struct die_args *args, unsigned long cmd)
@@ -299,6 +323,8 @@ static struct notifier_block kgdb_notifier = {
int kgdb_arch_init(void)
{
int ret = register_die_notifier(&kgdb_notifier);
- int cpu;
- struct irq_work *work;
if (ret != 0)
return ret;
@@ -306,6 +332,12 @@ int kgdb_arch_init(void)
register_break_hook(&kgdb_brkpt_hook);
register_break_hook(&kgdb_compiled_brkpt_hook);
register_step_hook(&kgdb_step_hook);
- for_each_possible_cpu(cpu) {
work = per_cpu_ptr(&kgdb_irq_work, cpu);
init_irq_work(work, kgdb_roundup_hook);
- }
return 0;
}
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Gong Huan 00194563 2012 Lab-Euler Dept 6 （Programming Technologies Lab）
Mobile：15372050534 Tel.：057163165 Seat No.：Hangzhou Research Center Z9-3-B01
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