/*
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 */

#include <linux/ptrace.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/kdev_t.h>
#include <linux/fs_struct.h>
#include <linux/proc_fs.h>
#include <linux/file.h>
#include <asm/arcregs.h>

/*
 * Common routine to print scratch regs (r0-r12) or callee regs (r13-r25)
 *   -Prints 3 regs per line and a CR.
 *   -To continue, callee regs right after scratch, special handling of CR
 */
static noinline void print_reg_file(long *reg_rev, int start_num)
{
        unsigned int i;
        char buf[512];
        int n = 0, len = sizeof(buf);

        for (i = start_num; i < start_num + 13; i++) {
                n += scnprintf(buf + n, len - n, "r%02u: 0x%08lx\t",
                               i, (unsigned long)*reg_rev);

                if (((i + 1) % 3) == 0)
                        n += scnprintf(buf + n, len - n, "\n");

                /* because pt_regs has regs reversed: r12..r0, r25..r13 */
                reg_rev--;
        }

        if (start_num != 0)
                n += scnprintf(buf + n, len - n, "\n\n");

        /* To continue printing callee regs on same line as scratch regs */
        if (start_num == 0)
                pr_info("%s", buf);
        else
                pr_cont("%s\n", buf);
}

static void show_callee_regs(struct callee_regs *cregs)
{
        print_reg_file(&(cregs->r13), 13);
}

void print_task_path_n_nm(struct task_struct *tsk, char *buf)
{
        struct path path;
        char *path_nm = NULL;
        struct mm_struct *mm;
        struct file *exe_file;

        mm = get_task_mm(tsk);
        if (!mm)
                goto done;

        exe_file = get_mm_exe_file(mm);
        mmput(mm);

        if (exe_file) {
                path = exe_file->f_path;
                path_get(&exe_file->f_path);
                fput(exe_file);
                path_nm = d_path(&path, buf, 255);
                path_put(&path);
        }

done:
        pr_info("Path: %s\n", path_nm);
}
EXPORT_SYMBOL(print_task_path_n_nm);

static void show_faulting_vma(unsigned long address, char *buf)
{
        struct vm_area_struct *vma;
        struct inode *inode;
        unsigned long ino = 0;
        dev_t dev = 0;
        char *nm = buf;

        /* can't use print_vma_addr() yet as it doesn't check for
         * non-inclusive vma
         */

        vma = find_vma(current->active_mm, address);

        /* check against the find_vma( ) behaviour which returns the next VMA
         * if the container VMA is not found
         */
        if (vma && (vma->vm_start <= address)) {
                struct file *file = vma->vm_file;
                if (file) {
                        struct path *path = &file->f_path;
                        nm = d_path(path, buf, PAGE_SIZE - 1);
                        inode = vma->vm_file->f_path.dentry->d_inode;
                        dev = inode->i_sb->s_dev;
                        ino = inode->i_ino;
                }
                pr_info("    @off 0x%lx in [%s]\n"
                        "    VMA: 0x%08lx to 0x%08lx\n",
                        vma->vm_start < TASK_UNMAPPED_BASE ?
                                address : address - vma->vm_start,
                        nm, vma->vm_start, vma->vm_end);
        } else {
                pr_info("    @No matching VMA found\n");
        }
}

static void show_ecr_verbose(struct pt_regs *regs)
{
        unsigned int vec, cause_code, cause_reg;
        unsigned long address;

        cause_reg = current->thread.cause_code;
        pr_info("\n[ECR   ]: 0x%08x => ", cause_reg);

        /* For Data fault, this is data address not instruction addr */
        address = current->thread.fault_address;

        vec = cause_reg >> 16;
        cause_code = (cause_reg >> 8) & 0xFF;

        /* For DTLB Miss or ProtV, display the memory involved too */
        if (vec == ECR_V_DTLB_MISS) {
                pr_cont("Invalid %s 0x%08lx by insn @ 0x%08lx\n",
                       (cause_code == 0x01) ? "Read From" :
                       ((cause_code == 0x02) ? "Write to" : "EX"),
                       address, regs->ret);
        } else if (vec == ECR_V_ITLB_MISS) {
                pr_cont("Insn could not be fetched\n");
        } else if (vec == ECR_V_MACH_CHK) {
                pr_cont("%s\n", (cause_code == 0x0) ?
                                        "Double Fault" : "Other Fatal Err");

        } else if (vec == ECR_V_PROTV) {
                if (cause_code == ECR_C_PROTV_INST_FETCH)
                        pr_cont("Execute from Non-exec Page\n");
                else if (cause_code == ECR_C_PROTV_LOAD)
                        pr_cont("Read from Non-readable Page\n");
                else if (cause_code == ECR_C_PROTV_STORE)
                        pr_cont("Write to Non-writable Page\n");
                else if (cause_code == ECR_C_PROTV_XCHG)
                        pr_cont("Data exchange protection violation\n");
                else if (cause_code == ECR_C_PROTV_MISALIG_DATA)
                        pr_cont("Misaligned r/w from 0x%08lx\n", address);
        } else if (vec == ECR_V_INSN_ERR) {
                pr_cont("Illegal Insn\n");
        } else {
                pr_cont("Check Programmer's Manual\n");
        }
}

/************************************************************************
 *  API called by rest of kernel
 ***********************************************************************/

void show_regs(struct pt_regs *regs)
{
        struct task_struct *tsk = current;
        struct callee_regs *cregs;
        char *buf;

        buf = (char *)__get_free_page(GFP_TEMPORARY);
        if (!buf)
                return;

        print_task_path_n_nm(tsk, buf);
        show_regs_print_info(KERN_INFO);

        if (current->thread.cause_code)
                show_ecr_verbose(regs);

        pr_info("[EFA   ]: 0x%08lx\n[BLINK ]: %pS\n[ERET  ]: %pS\n",
                current->thread.fault_address,
                (void *)regs->blink, (void *)regs->ret);

        if (user_mode(regs))
                show_faulting_vma(regs->ret, buf); /* faulting code, not data */

        pr_info("[STAT32]: 0x%08lx", regs->status32);

#define STS_BIT(r, bit) r->status32 & STATUS_##bit##_MASK ? #bit : ""
        if (!user_mode(regs))
                pr_cont(" : %2s %2s %2s %2s %2s\n",
                        STS_BIT(regs, AE), STS_BIT(regs, A2), STS_BIT(regs, A1),
                        STS_BIT(regs, E2), STS_BIT(regs, E1));

        pr_info("BTA: 0x%08lx\t SP: 0x%08lx\t FP: 0x%08lx\n",
                regs->bta, regs->sp, regs->fp);
        pr_info("LPS: 0x%08lx\tLPE: 0x%08lx\tLPC: 0x%08lx\n",
               regs->lp_start, regs->lp_end, regs->lp_count);

        /* print regs->r0 thru regs->r12
         * Sequential printing was generating horrible code
         */
        print_reg_file(&(regs->r0), 0);

        /* If Callee regs were saved, display them too */
        cregs = (struct callee_regs *)current->thread.callee_reg;
        if (cregs)
                show_callee_regs(cregs);

        free_page((unsigned long)buf);
}

void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
                            unsigned long address, unsigned long cause_reg)
{
        current->thread.fault_address = address;
        current->thread.cause_code = cause_reg;

        /* Caller and Callee regs */
        show_regs(regs);

        /* Show stack trace if this Fatality happened in kernel mode */
        if (!user_mode(regs))
                show_stacktrace(current, regs);
}

#ifdef CONFIG_DEBUG_FS

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/namei.h>
#include <linux/debugfs.h>

static struct dentry *test_dentry;
static struct dentry *test_dir;
static struct dentry *test_u32_dentry;

static u32 clr_on_read = 1;

#ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT
u32 numitlb, numdtlb, num_pte_not_present;

static int fill_display_data(char *kbuf)
{
        size_t num = 0;
        num += sprintf(kbuf + num, "I-TLB Miss %x\n", numitlb);
        num += sprintf(kbuf + num, "D-TLB Miss %x\n", numdtlb);
        num += sprintf(kbuf + num, "PTE not present %x\n", num_pte_not_present);

        if (clr_on_read)
                numitlb = numdtlb = num_pte_not_present = 0;

        return num;
}

static int tlb_stats_open(struct inode *inode, struct file *file)
{
        file->private_data = (void *)__get_free_page(GFP_KERNEL);
        return 0;
}

/* called on user read(): display the couters */
static ssize_t tlb_stats_output(struct file *file,      /* file descriptor */
                                char __user *user_buf,  /* user buffer */
                                size_t len,             /* length of buffer */
                                loff_t *offset)         /* offset in the file */
{
        size_t num;
        char *kbuf = (char *)file->private_data;

        /* All of the data can he shoved in one iteration */
        if (*offset != 0)
                return 0;

        num = fill_display_data(kbuf);

        /* simple_read_from_buffer() is helper for copy to user space
           It copies up to @2 (num) bytes from kernel buffer @4 (kbuf) at offset
           @3 (offset) into the user space address starting at @1 (user_buf).
           @5 (len) is max size of user buffer
         */
        return simple_read_from_buffer(user_buf, num, offset, kbuf, len);
}

/* called on user write : clears the counters */
static ssize_t tlb_stats_clear(struct file *file, const char __user *user_buf,
                               size_t length, loff_t *offset)
{
        numitlb = numdtlb = num_pte_not_present = 0;
        return length;
}

static int tlb_stats_close(struct inode *inode, struct file *file)
{
        free_page((unsigned long)(file->private_data));
        return 0;
}

static const struct file_operations tlb_stats_file_ops = {
        .read = tlb_stats_output,
        .write = tlb_stats_clear,
        .open = tlb_stats_open,
        .release = tlb_stats_close
};
#endif

static int __init arc_debugfs_init(void)
{
        test_dir = debugfs_create_dir("arc", NULL);

#ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT
        test_dentry = debugfs_create_file("tlb_stats", 0444, test_dir, NULL,
                                          &tlb_stats_file_ops);
#endif

        test_u32_dentry =
            debugfs_create_u32("clr_on_read", 0444, test_dir, &clr_on_read);

        return 0;
}

module_init(arc_debugfs_init);

static void __exit arc_debugfs_exit(void)
{
        debugfs_remove(test_u32_dentry);
        debugfs_remove(test_dentry);
        debugfs_remove(test_dir);
}
module_exit(arc_debugfs_exit);

#endif