This patch add KGDB support to PA-RISC. It also implements
single-stepping utilizing the recovery counter.
Signed-off-by: Sven Schnelle <svens@xxxxxxxxxxxxxx>
---
arch/parisc/Kconfig | 1 +
arch/parisc/include/asm/kgdb.h | 68 +++++++++++
arch/parisc/kernel/Makefile | 1 +
arch/parisc/kernel/kgdb.c | 210 +++++++++++++++++++++++++++++++++
arch/parisc/kernel/traps.c | 15 +++
5 files changed, 295 insertions(+)
create mode 100644 arch/parisc/include/asm/kgdb.h
create mode 100644 arch/parisc/kernel/kgdb.c
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index c8e621296092..a80c19c7fc0e 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -54,6 +54,7 @@ config PARISC
select CPU_NO_EFFICIENT_FFS
select NEED_DMA_MAP_STATE
select NEED_SG_DMA_LENGTH
+ select HAVE_ARCH_KGDB
help
The PA-RISC microprocessor is designed by Hewlett-Packard and used
diff --git a/arch/parisc/include/asm/kgdb.h b/arch/parisc/include/asm/kgdb.h
new file mode 100644
index 000000000000..f23e7f8f13a5
--- /dev/null
+++ b/arch/parisc/include/asm/kgdb.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * PA-RISC KGDB support
+ *
+ * Copyright (c) 2019 Sven Schnelle <svens@xxxxxxxxxxxxxx>
+ *
+ */
+
+#ifndef __PARISC_KGDB_H__
+#define __PARISC_KGDB_H__
+
+#define BREAK_INSTR_SIZE 4
+#define PARISC_KGDB_COMPILED_BREAK_INSN 0x3ffc01f
+#define PARISC_KGDB_BREAK_INSN 0x3ffa01f
+
+
+#define NUMREGBYTES sizeof(struct parisc_gdb_regs)
+#define BUFMAX 4096
+
+#define CACHE_FLUSH_IS_SAFE 1
+
+#ifndef __ASSEMBLY__
+
+static inline void arch_kgdb_breakpoint(void)
+{
+ asm(".word %0" : : "i"(PARISC_KGDB_COMPILED_BREAK_INSN) : "memory");
+}
+
+struct parisc_gdb_regs {
+ unsigned long gpr[32];
+ unsigned long sar;
+ unsigned long iaoq_f;
+ unsigned long iasq_f;
+ unsigned long iaoq_b;
+ unsigned long iasq_b;
+ unsigned long eiem;
+ unsigned long iir;
+ unsigned long isr;
+ unsigned long ior;
+ unsigned long ipsw;
+ unsigned long __unused0;
+ unsigned long sr4;
+ unsigned long sr0;
+ unsigned long sr1;
+ unsigned long sr2;
+ unsigned long sr3;
+ unsigned long sr5;
+ unsigned long sr6;
+ unsigned long sr7;
+ unsigned long cr0;
+ unsigned long pid1;
+ unsigned long pid2;
+ unsigned long scrccr;
+ unsigned long pid3;
+ unsigned long pid4;
+ unsigned long cr24;
+ unsigned long cr25;
+ unsigned long cr26;
+ unsigned long cr27;
+ unsigned long cr28;
+ unsigned long cr29;
+ unsigned long cr30;
+
+ u64 fr[32];
+};
+
+#endif
+#endif
diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile
index d29bbd1a73b2..5012da96c196 100644
--- a/arch/parisc/kernel/Makefile
+++ b/arch/parisc/kernel/Makefile
@@ -33,3 +33,4 @@ obj-$(CONFIG_64BIT) += perf.o perf_asm.o $(obj64-y)
obj-$(CONFIG_PARISC_CPU_TOPOLOGY) += topology.o
obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
+obj-$(CONFIG_KGDB) += kgdb.o
diff --git a/arch/parisc/kernel/kgdb.c b/arch/parisc/kernel/kgdb.c
new file mode 100644
index 000000000000..9836e06d20ab
--- /dev/null
+++ b/arch/parisc/kernel/kgdb.c
@@ -0,0 +1,210 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PA-RISC KGDB support
+ *
+ * Copyright (c) 2019 Sven Schnelle <svens@xxxxxxxxxxxxxx>
+ *
+ */
+
+#include <linux/kgdb.h>
+#include <linux/string.h>
+#include <linux/sched.h>
+#include <linux/notifier.h>
+#include <linux/kdebug.h>
+#include <linux/uaccess.h>
+#include <asm/ptrace.h>
+#include <asm/traps.h>
+#include <asm/processor.h>
+#include <asm/patch.h>
+#include <asm/cacheflush.h>
+
+const struct kgdb_arch arch_kgdb_ops = {
+ .gdb_bpt_instr = { 0x03, 0xff, 0xa0, 0x1f }
+};
+
+static int __kgdb_notify(struct die_args *args, unsigned long cmd)
+{
+ struct pt_regs *regs = args->regs;
+
+ if (kgdb_handle_exception(1, args->signr, cmd, regs))
+ return NOTIFY_DONE;
+ return NOTIFY_STOP;
+}
+
+static int kgdb_notify(struct notifier_block *self,
+ unsigned long cmd, void *ptr)
+{
+ unsigned long flags;
+ int ret;
+
+ local_irq_save(flags);
+ ret = __kgdb_notify(ptr, cmd);
+ local_irq_restore(flags);
+
+ return ret;
+}
+
+static struct notifier_block kgdb_notifier = {
+ .notifier_call = kgdb_notify,
+ .priority = -INT_MAX,
+};
+
+int kgdb_arch_init(void)
+{
+ return register_die_notifier(&kgdb_notifier);
+}
+
+void kgdb_arch_exit(void)
+{
+ unregister_die_notifier(&kgdb_notifier);
+}
+
+void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+ struct parisc_gdb_regs *gr = (struct parisc_gdb_regs *)gdb_regs;
+
+ memset(gr, 0, sizeof(struct parisc_gdb_regs));
+
+ memcpy(gr->gpr, regs->gr, sizeof(gr->gpr));
+ memcpy(gr->fr, regs->fr, sizeof(gr->fr));
+
+ gr->sr0 = regs->sr[0];
+ gr->sr1 = regs->sr[1];
+ gr->sr2 = regs->sr[2];
+ gr->sr3 = regs->sr[3];
+ gr->sr4 = regs->sr[4];
+ gr->sr5 = regs->sr[5];
+ gr->sr6 = regs->sr[6];
+ gr->sr7 = regs->sr[7];
+
+ gr->sar = regs->sar;
+ gr->iir = regs->iir;
+ gr->isr = regs->isr;
+ gr->ior = regs->ior;
+ gr->ipsw = regs->ipsw;
+ gr->cr27 = regs->cr27;
+
+ gr->iaoq_f = regs->iaoq[0];
+ gr->iasq_f = regs->iasq[0];
+
+ gr->iaoq_b = regs->iaoq[1];
+ gr->iasq_b = regs->iasq[1];
+}
+
+void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+ struct parisc_gdb_regs *gr = (struct parisc_gdb_regs *)gdb_regs;
+
+
+ memcpy(regs->gr, gr->gpr, sizeof(regs->gr));
+ memcpy(regs->fr, gr->fr, sizeof(regs->fr));
+
+ regs->sr[0] = gr->sr0;
+ regs->sr[1] = gr->sr1;
+ regs->sr[2] = gr->sr2;
+ regs->sr[3] = gr->sr3;
+ regs->sr[4] = gr->sr4;
+ regs->sr[5] = gr->sr5;
+ regs->sr[6] = gr->sr6;
+ regs->sr[7] = gr->sr7;
+
+ regs->sar = gr->sar;
+ regs->iir = gr->iir;
+ regs->isr = gr->isr;
+ regs->ior = gr->ior;
+ regs->ipsw = gr->ipsw;
+ regs->cr27 = gr->cr27;
+
+ regs->iaoq[0] = gr->iaoq_f;
+ regs->iasq[0] = gr->iasq_f;
+
+ regs->iaoq[1] = gr->iaoq_b;
+ regs->iasq[1] = gr->iasq_b;
+}
+
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,
+ struct task_struct *task)
+{
+ struct pt_regs *regs = task_pt_regs(task);
+ unsigned long gr30, iaoq;
+
+ gr30 = regs->gr[30];
+ iaoq = regs->iaoq[0];
+
+ regs->gr[30] = regs->ksp;
+ regs->iaoq[0] = regs->kpc;
+ pt_regs_to_gdb_regs(gdb_regs, regs);
+
+ regs->gr[30] = gr30;
+ regs->iaoq[0] = iaoq;
+
+}
+
+static void step_instruction_queue(struct pt_regs *regs)
+{
+ regs->iaoq[0] = regs->iaoq[1];
+ regs->iaoq[1] += 4;
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
+{
+ regs->iaoq[0] = ip;
+ regs->iaoq[1] = ip + 4;
+}
+
+int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
+{
+ int ret = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
+ BREAK_INSTR_SIZE);
+ if (ret)
+ return ret;
+
+ patch_text((void *)bpt->bpt_addr,
+ *(unsigned int *)&arch_kgdb_ops.gdb_bpt_instr);
+ return ret;
+}
+
+int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
+{
+ patch_text((void *)bpt->bpt_addr, *(unsigned int *)&bpt->saved_instr);
+ return 0;
+}
+
+int kgdb_arch_handle_exception(int trap, int signo,
+ int err_code, char *inbuf, char *outbuf,
+ struct pt_regs *regs)
+{
+ unsigned long addr;
+ char *p = inbuf + 1;
+
+ switch (inbuf[0]) {
+ case 'D':
+ case 'c':
+ case 'k':
+ kgdb_contthread = NULL;
+ kgdb_single_step = 0;
+
+ if (kgdb_hex2long(&p, &addr))
+ kgdb_arch_set_pc(regs, addr);
+ else if (trap == 9 && regs->iir ==
+ PARISC_KGDB_COMPILED_BREAK_INSN)
+ step_instruction_queue(regs);
+ return 0;
+ case 's':
+ kgdb_single_step = 1;
+ if (kgdb_hex2long(&p, &addr)) {
+ kgdb_arch_set_pc(regs, addr);
+ } else if (trap == 9 && regs->iir ==
+ PARISC_KGDB_COMPILED_BREAK_INSN) {
+ step_instruction_queue(regs);
+ mtctl(-1, 0);
+ } else {
+ mtctl(0, 0);
+ }
+ regs->gr[0] |= PSW_R;
+ return 0;
+
+ }
+ return -1;
+}
+
diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 7e1ccafadf57..91f94fc2abd3 100644
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c
@@ -42,6 +42,7 @@
#include <asm/unwind.h>
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>
+#include <linux/kgdb.h>
#include "../math-emu/math-emu.h" /* for handle_fpe() */
@@ -293,6 +294,14 @@ static void handle_break(struct pt_regs *regs)
(tt == BUG_TRAP_TYPE_NONE) ? 9 : 0);
}
+#ifdef CONFIG_KGDB
+ if (unlikely(iir == PARISC_KGDB_COMPILED_BREAK_INSN ||
+ iir == PARISC_KGDB_BREAK_INSN)) {
+ kgdb_handle_exception(9, SIGTRAP, 0, regs);
+ return;
+ }
+#endif
+
if (unlikely(iir != GDB_BREAK_INSN))
parisc_printk_ratelimited(0, regs,
KERN_DEBUG "break %d,%d: pid=%d command='%s'\n",
@@ -518,6 +527,12 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
case 3:
/* Recovery counter trap */
regs->gr[0] &= ~PSW_R;
+
+ if (kgdb_single_step) {
+ kgdb_handle_exception(0, SIGTRAP, 0, regs);
+ return;
+ }
+
if (user_space(regs))
handle_gdb_break(regs, TRAP_TRACE);
/* else this must be the start of a syscall - just let it run */
--
2.20.1
