ARC: Debug/crash-printing Improvements

* Remove the line-break between scratch/callee-regs (sneaked in when we
  converted from printk to pr_*

* Use %pS to print the symbol names of faulting PC (ret pseudo register)
  and BLINK (call return register)

* Don't print user-vma for a kernel crash (only do it for
  print-fatal-signals based regfile dump)

* Verbose print the Interrupt/Exception Enable/Active state

* for main executable link address is 0x10000 based (vs. 0) thus offset
  of faulting PC needs to be adjusted

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

1 files changed, 32 insertions, 18 deletions

diff --git a/arch/arc/kernel/troubleshoot.c b/arch/arc/kernel/troubleshoot.c
index 7c10873c311f..a39d5812cc09 100644
--- a/arch/arc/kernel/troubleshoot.c
+++ b/arch/arc/kernel/troubleshoot.c
@@ -26,7 +26,6 @@ static noinline void print_reg_file(long *reg_rev, int start_num)
         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);
@@ -34,13 +33,18 @@ static noinline void print_reg_file(long *reg_rev, int start_num)
                 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");
 
-        pr_info("%s", buf);
+        /* 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)
@@ -83,6 +87,10 @@ static void show_faulting_vma(unsigned long address, char *buf)
         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
@@ -98,10 +106,13 @@ static void show_faulting_vma(unsigned long address, char *buf)
                         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
+                        "    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)
@@ -110,7 +121,7 @@ static void show_ecr_verbose(struct pt_regs *regs)
         unsigned long address;
 
         cause_reg = current->thread.cause_code;
-        pr_info("\n[ECR]: 0x%08x => ", cause_reg);
+        pr_info("\n[ECR   ]: 0x%08x => ", cause_reg);
 
         /* For Data fault, this is data address not instruction addr */
         address = current->thread.fault_address;
@@ -120,7 +131,7 @@ static void show_ecr_verbose(struct pt_regs *regs)
 
         /* 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",
+                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);
@@ -167,20 +178,23 @@ void show_regs(struct pt_regs *regs)
         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);
+        pr_info("[EFA   ]: 0x%08lx\n[BLINK ]: %pS\n[ERET  ]: %pS\n",
+                current->thread.fault_address,
+                (void *)regs->blink, (void *)regs->ret);
 
-        show_faulting_vma(regs->ret, buf);      /* faulting code, not data */
+        if (user_mode(regs))
+                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
-         */
+        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));
 
-        /* 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("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);