[PATCH V6 15/33] csky: Debug and Ptrace GDB

From: Guo Ren
Date: Thu Sep 27 2018 - 10:51:36 EST

This patch adds arch ptrace implementation, stack dump and bug.h.

Signed-off-by: Guo Ren <ren_guo@xxxxxxxxx>
---
arch/csky/include/asm/bug.h | 26 +++
arch/csky/include/uapi/asm/ptrace.h | 104 ++++++++++++
arch/csky/kernel/dumpstack.c | 65 ++++++++
arch/csky/kernel/ptrace.c | 318 ++++++++++++++++++++++++++++++++++++
4 files changed, 513 insertions(+)
create mode 100644 arch/csky/include/asm/bug.h
create mode 100644 arch/csky/include/uapi/asm/ptrace.h
create mode 100644 arch/csky/kernel/dumpstack.c
create mode 100644 arch/csky/kernel/ptrace.c

diff --git a/arch/csky/include/asm/bug.h b/arch/csky/include/asm/bug.h
new file mode 100644
index 0000000..10b9028
--- /dev/null
+++ b/arch/csky/include/asm/bug.h
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#ifndef __ASM_CSKY_BUG_H
+#define __ASM_CSKY_BUG_H
+
+#include <linux/compiler.h>
+#include <linux/const.h>
+#include <linux/types.h>
+
+#define BUG() \
+do { \
+ asm volatile ("bkpt\n"); \
+ unreachable(); \
+} while (0)
+
+#define HAVE_ARCH_BUG
+
+#include <asm-generic/bug.h>
+
+struct pt_regs;
+
+void die_if_kernel (char *str, struct pt_regs *regs, int nr);
+void show_regs(struct pt_regs *);
+
+#endif /* __ASM_CSKY_BUG_H */
diff --git a/arch/csky/include/uapi/asm/ptrace.h b/arch/csky/include/uapi/asm/ptrace.h
new file mode 100644
index 0000000..688c6fd
--- /dev/null
+++ b/arch/csky/include/uapi/asm/ptrace.h
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#ifndef _CSKY_PTRACE_H
+#define _CSKY_PTRACE_H
+
+#ifndef __ASSEMBLY__
+
+struct pt_regs {
+ unsigned long tls;
+ unsigned long lr;
+ unsigned long pc;
+ unsigned long sr;
+ unsigned long usp;
+
+ /*
+ * a0, a1, a2, a3:
+ * abiv1: r2, r3, r4, r5
+ * abiv2: r0, r1, r2, r3
+ */
+ unsigned long orig_a0;
+ unsigned long a0;
+ unsigned long a1;
+ unsigned long a2;
+ unsigned long a3;
+
+ /*
+ * ABIV2: r4 ~ r13
+ * ABIV1: r6 ~ r14, r1
+ */
+ unsigned long regs[10];
+
+#if defined(__CSKYABIV2__)
+ /* r16 ~ r30 */
+ unsigned long exregs[15];
+
+ unsigned long rhi;
+ unsigned long rlo;
+ unsigned long pad; /* reserved */
+#endif
+};
+
+struct user_fp {
+ unsigned long vr[96];
+ unsigned long fcr;
+ unsigned long fesr;
+ unsigned long fid;
+ unsigned long reserved;
+};
+
+/*
+ * Switch stack for switch_to after push pt_regs.
+ *
+ * ABI_CSKYV2: r4 ~ r11, r15 ~ r17, r26 ~ r30;
+ * ABI_CSKYV1: r8 ~ r14, r15;
+ */
+struct switch_stack {
+#if defined(__CSKYABIV2__)
+ unsigned long r4;
+ unsigned long r5;
+ unsigned long r6;
+ unsigned long r7;
+ unsigned long r8;
+ unsigned long r9;
+ unsigned long r10;
+ unsigned long r11;
+#else
+ unsigned long r8;
+ unsigned long r9;
+ unsigned long r10;
+ unsigned long r11;
+ unsigned long r12;
+ unsigned long r13;
+ unsigned long r14;
+#endif
+ unsigned long r15;
+#if defined(__CSKYABIV2__)
+ unsigned long r16;
+ unsigned long r17;
+ unsigned long r26;
+ unsigned long r27;
+ unsigned long r28;
+ unsigned long r29;
+ unsigned long r30;
+#endif
+};
+
+#ifdef __KERNEL__
+
+#define PS_S 0x80000000 /* Supervisor Mode */
+
+#define arch_has_single_step() (1)
+#define current_pt_regs() \
+ (struct pt_regs *)((char *)current_thread_info() + THREAD_SIZE) - 1
+
+#define user_stack_pointer(regs) ((regs)->usp)
+
+#define user_mode(regs) (!((regs)->sr & PS_S))
+#define instruction_pointer(regs) ((regs)->pc)
+#define profile_pc(regs) instruction_pointer(regs)
+
+#endif /* __KERNEL__ */
+#endif /* __ASSEMBLY__ */
+#endif /* _CSKY_PTRACE_H */
diff --git a/arch/csky/kernel/dumpstack.c b/arch/csky/kernel/dumpstack.c
new file mode 100644
index 0000000..c7e46d8
--- /dev/null
+++ b/arch/csky/kernel/dumpstack.c
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/ptrace.h>
+
+int kstack_depth_to_print = 48;
+
+void show_trace(unsigned long *stack)
+{
+ unsigned long *endstack;
+ unsigned long addr;
+ int i;
+
+ pr_info("Call Trace:\n");
+ addr = (unsigned long)stack + THREAD_SIZE - 1;
+ endstack = (unsigned long *)(addr & -THREAD_SIZE);
+ i = 0;
+ while (stack + 1 <= endstack) {
+ addr = *stack++;
+ /*
+ * If the address is either in the text segment of the
+ * kernel, or in the region which contains vmalloc'ed
+ * memory, it *may* be the address of a calling
+ * routine; if so, print it so that someone tracing
+ * down the cause of the crash will be able to figure
+ * out the call path that was taken.
+ */
+ if (__kernel_text_address(addr)) {
+#ifndef CONFIG_KALLSYMS
+ if (i % 5 == 0)
+ pr_cont("\n ");
+#endif
+ pr_cont(" [<%08lx>] %pS\n", addr, (void *)addr);
+ i++;
+ }
+ }
+ pr_cont("\n");
+}
+
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+ unsigned long *p;
+ unsigned long *endstack;
+ int i;
+
+ if (!stack) {
+ if (task)
+ stack = (unsigned long *)task->thread.esp0;
+ else
+ stack = (unsigned long *)&stack;
+ }
+ endstack = (unsigned long *)(((unsigned long)stack + THREAD_SIZE - 1) & -THREAD_SIZE);
+
+ pr_info("Stack from %08lx:", (unsigned long)stack);
+ p = stack;
+ for (i = 0; i < kstack_depth_to_print; i++) {
+ if (p + 1 > endstack)
+ break;
+ if (i % 8 == 0)
+ pr_cont("\n ");
+ pr_cont(" %08lx", *p++);
+ }
+ pr_cont("\n");
+ show_trace(stack);
+}
diff --git a/arch/csky/kernel/ptrace.c b/arch/csky/kernel/ptrace.c
new file mode 100644
index 0000000..23c6ef2
--- /dev/null
+++ b/arch/csky/kernel/ptrace.c
@@ -0,0 +1,318 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/elf.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/ptrace.h>
+#include <linux/regset.h>
+#include <linux/sched.h>
+#include <linux/signal.h>
+#include <linux/smp.h>
+#include <linux/uaccess.h>
+#include <linux/user.h>
+
+#include <asm/thread_info.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/processor.h>
+#include <asm/asm-offsets.h>
+
+#include <abi/regdef.h>
+
+/* sets the trace bits. */
+#define TRACE_MODE_SI 1 << 14
+#define TRACE_MODE_RUN 0
+#define TRACE_MODE_MASK ~(0x3 << 14)
+
+/*
+ * Make sure the single step bit is not set.
+ */
+static void singlestep_disable(struct task_struct *tsk)
+{
+ struct pt_regs *regs;
+
+ regs = task_pt_regs(tsk);
+ regs->sr = (regs->sr & TRACE_MODE_MASK) | TRACE_MODE_RUN;
+}
+
+static void singlestep_enable(struct task_struct *tsk)
+{
+ struct pt_regs *regs;
+
+ regs = task_pt_regs(tsk);
+ regs->sr = (regs->sr & TRACE_MODE_MASK) | TRACE_MODE_SI;
+}
+
+/*
+ * Make sure the single step bit is set.
+ */
+void user_enable_single_step(struct task_struct *child)
+{
+ if (child->thread.esp0 == 0) return;
+ singlestep_enable(child);
+}
+
+void user_disable_single_step(struct task_struct *child)
+{
+ if (child->thread.esp0 == 0) return;
+ singlestep_disable(child);
+}
+
+enum csky_regset {
+ REGSET_GPR,
+ REGSET_FPR,
+};
+
+static int gpr_get(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ void *kbuf, void __user *ubuf)
+{
+ struct pt_regs *regs;
+
+ regs = task_pt_regs(target);
+
+ /* Abiv1 regs->tls is fake and we need sync here. */
+ regs->tls = task_thread_info(target)->tp_value;
+
+ return user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
+}
+
+static int gpr_set(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, const void __user *ubuf)
+{
+ int ret;
+ struct pt_regs regs;
+
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &regs, 0, -1);
+ if (ret)
+ return ret;
+
+ regs.sr = task_pt_regs(target)->sr;
+
+ task_thread_info(target)->tp_value = regs.tls;
+
+ *task_pt_regs(target) = regs;
+
+ return 0;
+}
+
+static int fpr_get(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ void *kbuf, void __user *ubuf)
+{
+ struct user_fp *regs = (struct user_fp *)&target->thread.user_fp;
+
+#if defined(CONFIG_CPU_HAS_FPUV2) && !defined(CONFIG_CPU_HAS_VDSP)
+ int i;
+ struct user_fp tmp = *regs;
+
+ for (i = 0; i < 16; i++) {
+ tmp.vr[i*4] = regs->vr[i*2];
+ tmp.vr[i*4 + 1] = regs->vr[i*2 + 1];
+ }
+
+ for (i = 0; i < 32; i++) {
+ tmp.vr[64 + i] = regs->vr[32 + i];
+ }
+
+ return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &tmp, 0, -1);
+#else
+ return user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
+#endif
+}
+
+static int fpr_set(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, const void __user *ubuf)
+{
+ int ret;
+ struct user_fp *regs = (struct user_fp *)&target->thread.user_fp;
+
+#if defined(CONFIG_CPU_HAS_FPUV2) && !defined(CONFIG_CPU_HAS_VDSP)
+ int i;
+ struct user_fp tmp;
+
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tmp, 0, -1);
+
+ *regs = tmp;
+
+ for (i = 0; i < 16; i++) {
+ regs->vr[i*2] = tmp.vr[i*4];
+ regs->vr[i*2 + 1] = tmp.vr[i*4 + 1];
+ }
+
+ for (i = 0; i < 32; i++) {
+ regs->vr[32 + i] = tmp.vr[64 + i];
+ }
+#else
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
+#endif
+
+ return ret;
+}
+
+static const struct user_regset csky_regsets[] = {
+ [REGSET_GPR] = {
+ .core_note_type = NT_PRSTATUS,
+ .n = ELF_NGREG,
+ .size = sizeof(u32),
+ .align = sizeof(u32),
+ .get = &gpr_get,
+ .set = &gpr_set,
+ },
+ [REGSET_FPR] = {
+ .core_note_type = NT_PRFPREG,
+ .n = sizeof(struct user_fp) / sizeof(u32),
+ .size = sizeof(u32),
+ .align = sizeof(u32),
+ .get = &fpr_get,
+ .set = &fpr_set,
+ },
+};
+
+static const struct user_regset_view user_csky_view = {
+ .name = "csky",
+ .e_machine = ELF_ARCH,
+ .regsets = csky_regsets,
+ .n = ARRAY_SIZE(csky_regsets),
+};
+
+const struct user_regset_view *task_user_regset_view(struct task_struct *task)
+{
+ return &user_csky_view;
+}
+
+void ptrace_disable(struct task_struct *child)
+{
+ singlestep_disable(child);
+}
+
+long arch_ptrace(struct task_struct *child, long request,
+ unsigned long addr, unsigned long data)
+{
+ long ret = -EIO;
+
+ switch (request) {
+ default:
+ ret = ptrace_request(child, request, addr, data);
+ break;
+ }
+
+ return ret;
+}
+
+/*
+ * If process's system calls is traces, do some corresponding handles in this
+ * fuction before entering system call function and after exiting system call
+ * fuction.
+ */
+asmlinkage void syscall_trace(int why, struct pt_regs * regs)
+{
+ long saved_why;
+ /*
+ * Save saved_why, why is used to denote syscall entry/exit;
+ * why = 0:entry, why = 1: exit
+ */
+ saved_why = regs->regs[SYSTRACE_SAVENUM];
+ regs->regs[SYSTRACE_SAVENUM] = why;
+
+ /* the 0x80 provides a way for the tracing parent to distinguish
+ between a syscall stop and SIGTRAP delivery */
+ ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+ ? 0x80 : 0));
+ /*
+ * this isn't the same as continuing with a signal, but it will do
+ * for normal use. strace only continues with a signal if the
+ * stopping signal is not SIGTRAP. -brl
+ */
+ if (current->exit_code) {
+ send_sig(current->exit_code, current, 1);
+ current->exit_code = 0;
+ }
+
+ regs->regs[SYSTRACE_SAVENUM] = saved_why;
+ return;
+}
+
+void show_regs(struct pt_regs *fp)
+{
+ unsigned long *sp;
+ unsigned char *tp;
+ int i;
+
+ pr_info("\nCURRENT PROCESS:\n\n");
+ pr_info("COMM=%s PID=%d\n", current->comm, current->pid);
+
+ if (current->mm) {
+ pr_info("TEXT=%08x-%08x DATA=%08x-%08x BSS=%08x-%08x\n",
+ (int) current->mm->start_code,
+ (int) current->mm->end_code,
+ (int) current->mm->start_data,
+ (int) current->mm->end_data,
+ (int) current->mm->end_data,
+ (int) current->mm->brk);
+ pr_info("USER-STACK=%08x KERNEL-STACK=%08x\n\n",
+ (int) current->mm->start_stack,
+ (int) (((unsigned long) current) + 2 * PAGE_SIZE));
+ }
+
+ pr_info("PC: 0x%08lx\n", (long)fp->pc);
+ pr_info("orig_a0: 0x%08lx\n", fp->orig_a0);
+ pr_info("PSR: 0x%08lx\n", (long)fp->sr);
+
+ pr_info("a0: 0x%08lx a1: 0x%08lx a2: 0x%08lx a3: 0x%08lx\n",
+ fp->a0, fp->a1, fp->a2, fp->a3);
+#if defined(__CSKYABIV2__)
+ pr_info("r4: 0x%08lx r5: 0x%08lx r6: 0x%08lx r7: 0x%08lx\n",
+ fp->regs[0], fp->regs[1], fp->regs[2], fp->regs[3]);
+ pr_info("r8: 0x%08lx r9: 0x%08lx r10: 0x%08lx r11: 0x%08lx\n",
+ fp->regs[4], fp->regs[5], fp->regs[6], fp->regs[7]);
+ pr_info("r12 0x%08lx r13: 0x%08lx r15: 0x%08lx\n",
+ fp->regs[8], fp->regs[9], fp->lr);
+ pr_info("r16:0x%08lx r17: 0x%08lx r18: 0x%08lx r19: 0x%08lx\n",
+ fp->exregs[0], fp->exregs[1], fp->exregs[2], fp->exregs[3]);
+ pr_info("r20 0x%08lx r21: 0x%08lx r22: 0x%08lx r23: 0x%08lx\n",
+ fp->exregs[4], fp->exregs[5], fp->exregs[6], fp->exregs[7]);
+ pr_info("r24 0x%08lx r25: 0x%08lx r26: 0x%08lx r27: 0x%08lx\n",
+ fp->exregs[8], fp->exregs[9], fp->exregs[10], fp->exregs[11]);
+ pr_info("r28 0x%08lx r29: 0x%08lx r30: 0x%08lx tls: 0x%08lx\n",
+ fp->exregs[12], fp->exregs[13], fp->exregs[14], fp->tls);
+ pr_info("hi 0x%08lx lo: 0x%08lx \n",
+ fp->rhi, fp->rlo);
+#else
+ pr_info("r6: 0x%08lx r7: 0x%08lx r8: 0x%08lx r9: 0x%08lx\n",
+ fp->regs[0], fp->regs[1], fp->regs[2], fp->regs[3]);
+ pr_info("r10: 0x%08lx r11: 0x%08lx r12: 0x%08lx r13: 0x%08lx\n",
+ fp->regs[4], fp->regs[5], fp->regs[6], fp->regs[7]);
+ pr_info("r14 0x%08lx r1: 0x%08lx r15: 0x%08lx\n",
+ fp->regs[8], fp->regs[9], fp->lr);
+#endif
+
+ pr_info("\nCODE:");
+ tp = ((unsigned char *) fp->pc) - 0x20;
+ tp += ((int)tp % 4) ? 2 : 0;
+ for (sp = (unsigned long *) tp, i = 0; (i < 0x40); i += 4) {
+ if ((i % 0x10) == 0)
+ pr_cont("\n%08x: ", (int) (tp + i));
+ pr_cont("%08x ", (int) *sp++);
+ }
+ pr_cont("\n");
+
+ pr_info("\nKERNEL STACK:");
+ tp = ((unsigned char *) fp) - 0x40;
+ for (sp = (unsigned long *) tp, i = 0; (i < 0xc0); i += 4) {
+ if ((i % 0x10) == 0)
+ pr_cont("\n%08x: ", (int) (tp + i));
+ pr_cont("%08x ", (int) *sp++);
+ }
+ pr_cont("\n");
+
+ return;
+}
--
2.7.4