[PATCH v4 20/36] nds32: Debugging support

[Greentime Hu]

From: Greentime Hu <greentime@xxxxxxxxxxxxx>

This patch adds ptrace support.

Signed-off-by: Vincent Chen <vincentc@xxxxxxxxxxxxx>
Signed-off-by: Greentime Hu <greentime@xxxxxxxxxxxxx>
---
 arch/nds32/include/uapi/asm/ptrace.h |   25 +++
 arch/nds32/kernel/ptrace.c           |  311 ++++++++++++++++++++++++++++++++++
 2 files changed, 336 insertions(+)
 create mode 100644 arch/nds32/include/uapi/asm/ptrace.h
 create mode 100644 arch/nds32/kernel/ptrace.c

diff --git a/arch/nds32/include/uapi/asm/ptrace.h b/arch/nds32/include/uapi/asm/ptrace.h
new file mode 100644
index 0000000..358c99e
--- /dev/null
+++ b/arch/nds32/include/uapi/asm/ptrace.h
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#ifndef __UAPI_ASM_NDS32_PTRACE_H
+#define __UAPI_ASM_NDS32_PTRACE_H
+
+#ifndef __ASSEMBLY__
+
+/*
+ * User structures for general purpose register.
+ */
+struct user_pt_regs {
+	long uregs[26];
+	long fp;
+	long gp;
+	long lp;
+	long sp;
+	long ipc;
+	long lb;
+	long le;
+	long lc;
+	long syscallno;
+};
+#endif
+#endif
diff --git a/arch/nds32/kernel/ptrace.c b/arch/nds32/kernel/ptrace.c
new file mode 100644
index 0000000..0e18564
--- /dev/null
+++ b/arch/nds32/kernel/ptrace.c
@@ -0,0 +1,311 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/ptrace.h>
+#include <linux/user.h>
+#include <linux/security.h>
+#include <linux/init.h>
+#include <linux/uaccess.h>
+#include <linux/regset.h>
+#include <linux/tracehook.h>
+#include <linux/elf.h>
+#include <linux/sched/task_stack.h>
+
+#include <asm/pgtable.h>
+
+enum nds32_regset {
+	REGSET_GPR,
+};
+
+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 user_pt_regs *uregs = &task_pt_regs(target)->user_regs;
+	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 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 err;
+	struct user_pt_regs newregs = task_pt_regs(target)->user_regs;
+
+	err = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newregs, 0, -1);
+	if (err)
+		return err;
+
+	task_pt_regs(target)->user_regs = newregs;
+	return 0;
+}
+
+static const struct user_regset nds32_regsets[] = {
+	[REGSET_GPR] = {
+			.core_note_type = NT_PRSTATUS,
+			.n = sizeof(struct user_pt_regs) / sizeof(u32),
+			.size = sizeof(u32),
+			.align = sizeof(u32),
+			.get = gpr_get,
+			.set = gpr_set}
+};
+
+static const struct user_regset_view nds32_user_view = {
+	.name = "nds32",.e_machine = EM_NDS32,
+	.regsets = nds32_regsets,.n = ARRAY_SIZE(nds32_regsets)
+};
+
+const struct user_regset_view *task_user_regset_view(struct task_struct *task)
+{
+	return &nds32_user_view;
+}
+
+/* get_user_reg()
+ *
+ * This routine will get a word off of the processes privileged stack.
+ * the offset is how far from the base addr as stored in the THREAD.
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */
+static inline unsigned int get_user_reg(struct task_struct *task, int offset)
+{
+	return task_pt_regs(task)->uregs[offset];
+}
+
+/* put_user_reg()
+ *
+ * this routine will put a word on the processes privileged stack.
+ * the offset is how far from the base addr as stored in the THREAD.
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */
+static inline int put_user_reg(struct task_struct *task, int offset, long data)
+{
+	struct pt_regs newregs, *regs = task_pt_regs(task);
+	int ret = -EINVAL;
+
+	newregs = *regs;
+	newregs.uregs[offset] = data;
+
+	if (valid_user_regs(&newregs)) {
+		regs->uregs[offset] = data;
+		ret = 0;
+	}
+
+	return ret;
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ *
+ * Make sure the single step bit is not set.
+ */
+void ptrace_disable(struct task_struct *child)
+{
+	user_disable_single_step(child);
+}
+
+static void fill_sigtrap_info(struct task_struct *tsk,
+			      struct pt_regs *regs,
+			      int error_code, int si_code, struct siginfo *info)
+{
+	tsk->thread.trap_no = ENTRY_DEBUG_RELATED;
+	tsk->thread.error_code = error_code;
+
+	memset(info, 0, sizeof(*info));
+	info->si_signo = SIGTRAP;
+	info->si_code = si_code;
+	info->si_addr = (void __user *)instruction_pointer(regs);
+}
+
+void user_single_step_siginfo(struct task_struct *tsk,
+			      struct pt_regs *regs, struct siginfo *info)
+{
+	fill_sigtrap_info(tsk, regs, 0, TRAP_BRKPT, info);
+}
+
+/*
+ * Handle hitting a breakpoint.
+ */
+void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
+		  int error_code, int si_code)
+{
+	struct siginfo info;
+
+	fill_sigtrap_info(tsk, regs, error_code, TRAP_BRKPT, &info);
+	/* Send us the fake SIGTRAP */
+	force_sig_info(SIGTRAP, &info, tsk);
+}
+
+/* ptrace_read_user()
+ *
+ * Read the word at offset "off" into the "struct user".  We
+ * actually access the pt_regs stored on the kernel stack.
+ */
+static int
+ptrace_read_user(struct task_struct *tsk, unsigned long off,
+		 unsigned long __user * ret)
+{
+	unsigned long tmp = 0;
+
+	if (off < sizeof(struct pt_regs)) {
+		if (off & 3)
+			return -EIO;
+		tmp = get_user_reg(tsk, off >> 2);
+		return put_user(tmp, ret);
+	} else
+		return -EIO;
+}
+
+/* ptrace_write_user()
+ *
+ * Write the word at offset "off" into "struct user".  We
+ * actually access the pt_regs stored on the kernel stack.
+ */
+static int
+ptrace_write_user(struct task_struct *tsk, unsigned long off, unsigned long val)
+{
+	if (off < sizeof(struct pt_regs)) {
+		if (off & 3)
+			return -EIO;
+		return put_user_reg(tsk, off >> 2, val);
+	} else
+		return -EIO;
+}
+
+/* ptrace_getregs()
+ *
+ * Get all user integer registers.
+ */
+static int ptrace_getregs(struct task_struct *tsk, void __user * uregs)
+{
+	struct pt_regs *regs = task_pt_regs(tsk);
+
+	return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
+}
+
+/* ptrace_setregs()
+ *
+ * Set all user integer registers.
+ */
+static int ptrace_setregs(struct task_struct *tsk, void __user * uregs)
+{
+	struct pt_regs newregs;
+	int ret;
+
+	ret = -EFAULT;
+	if (copy_from_user(&newregs, uregs, sizeof(struct pt_regs)) == 0) {
+		struct pt_regs *regs = task_pt_regs(tsk);
+
+		ret = -EINVAL;
+		if (valid_user_regs(&newregs)) {
+			*regs = newregs;
+			ret = 0;
+		}
+	}
+
+	return ret;
+}
+
+/* ptrace_getfpregs()
+ *
+ * Get the child FPU state.
+ */
+static int ptrace_getfpregs(struct task_struct *tsk, void __user * ufpregs)
+{
+	return -EFAULT;
+}
+
+/*
+ * Set the child FPU state.
+ */
+static int ptrace_setfpregs(struct task_struct *tsk, void __user * ufpregs)
+{
+	return -EFAULT;
+}
+
+/* do_ptrace()
+ *
+ * Provide ptrace defined service.
+ */
+long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
+		 unsigned long data)
+{
+	int ret;
+
+	switch (request) {
+	case PTRACE_PEEKUSR:
+		ret =
+		    ptrace_read_user(child, addr, (unsigned long __user *)data);
+		break;
+
+	case PTRACE_POKEUSR:
+		ret = ptrace_write_user(child, addr, data);
+		break;
+
+	case PTRACE_GETREGS:
+		ret = ptrace_getregs(child, (void __user *)data);
+		break;
+
+	case PTRACE_SETREGS:
+		ret = ptrace_setregs(child, (void __user *)data);
+		break;
+
+	case PTRACE_GETFPREGS:
+		ret = ptrace_getfpregs(child, (void __user *)data);
+		break;
+
+	case PTRACE_SETFPREGS:
+		ret = ptrace_setfpregs(child, (void __user *)data);
+		break;
+
+	default:
+		ret = ptrace_request(child, request, addr, data);
+		break;
+	}
+
+	return ret;
+}
+
+void user_enable_single_step(struct task_struct *child)
+{
+	struct pt_regs *regs;
+	regs = task_pt_regs(child);
+	regs->ipsw |= PSW_mskHSS;
+	set_tsk_thread_flag(child, TIF_SINGLESTEP);
+}
+
+void user_disable_single_step(struct task_struct *child)
+{
+	struct pt_regs *regs;
+	regs = task_pt_regs(child);
+	regs->ipsw &= ~PSW_mskHSS;
+	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
+}
+
+/* sys_trace()
+ *
+ * syscall trace handler.
+ */
+
+asmlinkage int syscall_trace_enter(int syscall, struct pt_regs *regs)
+{
+	if (test_thread_flag(TIF_SYSCALL_TRACE)) {
+		if (tracehook_report_syscall_entry(regs))
+			return -1;
+	}
+	return syscall;
+}
+
+asmlinkage void syscall_trace_leave(struct pt_regs *regs)
+{
+	int step = test_thread_flag(TIF_SINGLESTEP);
+	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall_exit(regs, step);
+
+}
-- 
1.7.9.5