ARC: Diagnostics: show_regs() etc

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

1 files changed, 305 insertions, 0 deletions

diff --git a/arch/arc/kernel/troubleshoot.c b/arch/arc/kernel/troubleshoot.c
index 80bfe2a15a98..7c10873c311f 100644
--- a/arch/arc/kernel/troubleshoot.c
+++ b/arch/arc/kernel/troubleshoot.c
@@ -6,12 +6,317 @@
  */
 
 #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);
+
+        /* weird loop because pt_regs regs rev r12..r0, r25..r13 */
+        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");
+
+                reg_rev--;
+        }
+
+        if (start_num != 0)
+                n += scnprintf(buf + n, len - n, "\n\n");
+
+        pr_info("%s", 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("%s, TGID %u\n", path_nm, tsk->tgid);
+}
+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;
+
+        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\n",
+                       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);
+
+        if (current->thread.cause_code)
+                show_ecr_verbose(regs);
+
+        pr_info("[EFA]: 0x%08lx\n", current->thread.fault_address);
+        pr_info("[ERET]: 0x%08lx (PC of Faulting Instr)\n", regs->ret);
+
+        show_faulting_vma(regs->ret, buf);      /* faulting code, not data */
+
+        /* can't use print_vma_addr() yet as it doesn't check for
+         * non-inclusive vma
+         */
+
+        /* print special regs */
+        pr_info("status32: 0x%08lx\n", regs->status32);
+        pr_info(" SP: 0x%08lx\tFP: 0x%08lx\n", regs->sp, regs->fp);
+        pr_info("BTA: 0x%08lx\tBLINK: 0x%08lx\n",
+                regs->bta, regs->blink);
+        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