[PATCH 12/19] csky: Debug and Ptrace GDB

[Guo Ren <ren_guo@c-sky.com>]

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
---
 arch/csky/include/uapi/asm/ptrace.h |  97 +++++++++++
 arch/csky/kernel/dumpstack.c        |  65 +++++++
 arch/csky/kernel/ptrace.c           | 339 ++++++++++++++++++++++++++++++++++++
 3 files changed, 501 insertions(+)
 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/uapi/asm/ptrace.h b/arch/csky/include/uapi/asm/ptrace.h
new file mode 100644
index 0000000..b8516b2
--- /dev/null
+++ b/arch/csky/include/uapi/asm/ptrace.h
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+#ifndef _CSKY_PTRACE_H
+#define _CSKY_PTRACE_H
+
+#define REGNO_SR   	32
+#define REGNO_PC   	33
+
+#ifndef __ASSEMBLY__
+
+/* this struct defines the way the registers are stored on the
+   stack during a system call. */
+struct  pt_regs {
+	unsigned long    pc;
+	long             orig_a0;
+	unsigned long    sr;
+	long             a0;  // ABIV2: r0, ABIV1: r2
+	long             a1;  // ABIV2: r1, ABIV1: r3
+	long             a2;  // ABIV2: r2, ABIV1: r4
+	long             a3;  // ABIV2: r3, ABIV1: r5
+	// ABIV2: r4 ~ r13,  ABIV1: r6 ~ r14, r1.
+	long             regs[10];
+	long             r15;
+#if defined(__CSKYABIV2__)
+	// r16~r31;
+	long             exregs[16];
+	long             rhi;
+	long             rlo;
+#endif
+};
+
+/*
+ * 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
+};
+
+#define PTRACE_GETREGS            12
+#define PTRACE_SETREGS            13
+#define PTRACE_GETFPREGS          14
+#define PTRACE_SETFPREGS          15
+#define PTRACE_GET_THREAD_AREA    25
+
+#define CSKY_GREG_NUM             35
+#define CSKY_FREG_NUM_HI          72
+#define CSKY_FREG_NUM_LO          40
+#define CSKY_FCR_NUM              74
+
+#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 current_user_stack_pointer() rdusp()
+
+#define user_mode(regs) (!((regs)->sr & PS_S))
+#define instruction_pointer(regs) ((regs)->pc)
+#define profile_pc(regs) instruction_pointer(regs)
+
+void show_regs(struct pt_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..d4be08a
--- /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:");
+	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..9aee8b5
--- /dev/null
+++ b/arch/csky/kernel/ptrace.c
@@ -0,0 +1,339 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/user.h>
+#include <linux/signal.h>
+#include <linux/uaccess.h>
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/processor.h>
+#include <asm/asm-offsets.h>
+
+#include <abi/regdef.h>
+
+/*
+ * does not yet catch signals sent when the child dies.
+ * in exit.c or in signal.c.
+ */
+
+/* sets the trace bits. */
+#define TRACE_MODE_SI      1 << 14
+#define TRACE_MODE_RUN     0
+#define TRACE_MODE_JMP     0x3 << 14
+#define TRACE_MODE_MASK    ~(0x3 << 14)
+
+/*
+ * PT_xxx is the stack offset at which the register is  saved.
+ * Notice that usp has no stack-slot and needs to be treated
+ * specially (see get_reg/put_reg below).
+ */
+static int regoff[] = PTRACE_REGOFF_ABI;
+
+/*
+ * Get contents of register REGNO in task TASK.
+ */
+static long get_reg(struct task_struct *task, int regno)
+{
+	unsigned long *addr;
+
+	if (regno == REGNO_USP)
+		addr = &task->thread.usp;
+	else if ((regno < sizeof(regoff)/sizeof(regoff[0])) && (regoff[regno] != -1))
+		addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
+	else
+		return 0;
+	return *addr;
+}
+
+/*
+ * Write contents of register REGNO in task TASK.
+ */
+static int put_reg(struct task_struct *task, int regno,
+		unsigned long data)
+{
+	unsigned long *addr;
+
+	if (regno == REGNO_USP)
+		addr = &task->thread.usp;
+	else if ((regno < sizeof(regoff) / sizeof(regoff[0])) && (regoff[regno] != -1))
+		addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
+	else
+		return -1;
+	*addr = data;
+	return 0;
+}
+/*
+ * Make sure the single step bit is not set.
+ */
+static void singlestep_disable(struct task_struct *child)
+{
+	unsigned long tmp;
+	tmp = (get_reg(child, REGNO_SR) & TRACE_MODE_MASK) | TRACE_MODE_RUN;
+	put_reg(child, REGNO_SR, tmp);
+}
+
+
+static void singlestep_enable(struct task_struct *child)
+{
+	unsigned long tmp;
+	tmp = (get_reg(child, REGNO_SR) & TRACE_MODE_MASK) | TRACE_MODE_SI;
+	put_reg(child, REGNO_SR, tmp);
+}
+
+/*
+ * 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);
+}
+
+int ptrace_getfpregs(struct task_struct *child, void __user *data)
+{
+
+	if (!access_ok(VERIFY_WRITE, data, sizeof(struct user_cskyfp_struct)))
+		return -EIO;
+
+	if(raw_copy_to_user(data, &child->thread.fcr,
+				sizeof(struct user_cskyfp_struct)))
+		return -EFAULT;
+
+	return 0;
+}
+
+int ptrace_setfpregs(struct task_struct *child, void __user *data)
+{
+	if (!access_ok(VERIFY_READ, data, sizeof(struct user_cskyfp_struct)))
+		return -EIO;
+
+	if(raw_copy_from_user(&child->thread.fcr, data,
+				sizeof(struct user_cskyfp_struct)))
+		return -EFAULT;
+	return 0;
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ *
+ * Make sure the single step bit is not set.
+ */
+void ptrace_disable(struct task_struct *child)
+{
+	singlestep_disable(child);
+}
+
+/*
+ * Handle the requests of ptrace system call.
+ *
+ * INPUT:
+ * child   - process being traced.
+ * request - request type.
+ * addr    - address of data that this request to read from or write to.
+ * data    - address of data that this request to read to or write from.
+ *
+ * RETURN:
+ * 0       - success
+ * others  - fail
+ */
+long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
+		unsigned long data)
+{
+	unsigned long tmp = 0, ret = 0;
+	int i;
+
+	switch (request) {
+		/* read the word at location addr in the USER area. */
+	case PTRACE_PEEKUSR:
+		if (addr & 3)
+			goto out_eio;
+		addr >>= 2;     /* temporary hack. */
+
+		if (addr >= 0 && addr <= CSKY_GREG_NUM) {
+			tmp = get_reg(child, addr);
+		}else if(addr >= CSKY_FREG_NUM_LO && addr < CSKY_FREG_NUM_HI) {
+			tmp = child->thread.fp[addr - CSKY_FREG_NUM_LO];
+		}else if(addr >= CSKY_FREG_NUM_HI && addr < CSKY_FCR_NUM) {
+			tmp = (&(child->thread.fcr))[addr - CSKY_FREG_NUM_HI];
+		} else
+			break;
+		ret = put_user(tmp,(long unsigned int *) data);
+		break;
+
+	case PTRACE_POKEUSR:  /* write the word at location addr in the USER area */
+		if (addr & 3)
+			goto out_eio;
+		addr >>= 2;     /* temporary hack. */
+
+		if (addr >= 0 && addr <= CSKY_GREG_NUM) {
+			if (put_reg(child, addr, data)) /*** should protect 'psr'? ***/
+				goto out_eio;
+		}else if(addr >= CSKY_FREG_NUM_LO && addr < CSKY_FREG_NUM_HI) {
+			child->thread.fp[addr - CSKY_FREG_NUM_LO] = data;
+		}else if(addr >= CSKY_FREG_NUM_HI && addr <= CSKY_FCR_NUM) {
+			(&(child->thread.fcr))[addr - CSKY_FREG_NUM_HI] = data;
+		}else
+			goto out_eio;
+		break;
+	case PTRACE_GETREGS:    /* Get all gp regs from the child. */
+		for (i = 0; i <= CSKY_GREG_NUM; i++) {
+			tmp = get_reg(child, i);
+			ret = put_user(tmp, (unsigned long *)data);
+			if (ret)
+				break;
+			data += sizeof(long);
+		}
+		break;
+	case PTRACE_SETREGS:    /* Set all gp regs in the child. */
+		for (i = 0; i <= CSKY_GREG_NUM; i++) {
+			ret = get_user(tmp, (unsigned long *)data);
+			if (ret)
+				break;
+			put_reg(child, i, tmp);
+			data += sizeof(long);
+		}
+		break;
+
+	case PTRACE_GETFPREGS:
+		ret = ptrace_getfpregs(child, (void  __user *) data);
+		break;
+
+	case PTRACE_SETFPREGS:
+		ret = ptrace_setfpregs(child, (void __user *) data);
+		break;
+
+	case PTRACE_GET_THREAD_AREA:
+		ret = put_user(task_thread_info(child)->tp_value,
+				(long unsigned int *) data);
+		break;
+	default:
+		ret = ptrace_request(child, request, addr, data);
+		break;
+	}
+
+	return ret;
+out_eio:
+	return -EIO;
+}
+
+/*
+ * 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->r15);
+	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    r31: 0x%08lx\n",
+	       fp->exregs[12], fp->exregs[13], fp->exregs[14], fp->exregs[15]);
+	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->r15);
+#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