csky: Debug and Ptrace GDB

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

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

4 files changed, 510 insertions, 0 deletions

diff --git a/arch/csky/include/asm/bug.h b/arch/csky/include/asm/bug.h
new file mode 100644
index 000000000000..bd7b3235bb84
--- /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 *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 000000000000..f10d02c8b09e
--- /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 000000000000..a9a03ac57ec5
--- /dev/null
+++ b/arch/csky/kernel/dumpstack.c
@@ -0,0 +1,66 @@
+// 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 000000000000..34b30257298f
--- /dev/null
+++ b/arch/csky/kernel/ptrace.c
@@ -0,0 +1,314 @@
+// 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
+ * function before entering system call function and after exiting system call
+ * function.
+ */
+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;
+
+        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;
+}
+
+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");
+}