[PATCH v4 20/36] nds32: Debugging support

From: Greentime Hu
Date: Mon Dec 18 2017 - 02:13:38 EST


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