x86/dumpstack: Carve out code-dumping into a function

No functionality change, carve it out into a separate function for later
changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Link: https://lkml.kernel.org/r/20180417161124.5294-4-bp@alien8.de

1 files changed, 30 insertions, 27 deletions

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 579455c2b91e..eb9d6c00a52f 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -70,6 +70,35 @@ static void printk_stack_address(unsigned long address, int reliable,
         printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address);
 }
 
+static void show_opcodes(u8 *rip)
+{
+        unsigned int code_prologue = OPCODE_BUFSIZE * 43 / 64;
+        unsigned int code_len = OPCODE_BUFSIZE;
+        unsigned char c;
+        u8 *ip;
+        int i;
+
+        printk(KERN_DEFAULT "Code: ");
+
+        ip = (u8 *)rip - code_prologue;
+        if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
+                /* try starting at IP */
+                ip = (u8 *)rip;
+                code_len = code_len - code_prologue + 1;
+        }
+        for (i = 0; i < code_len; i++, ip++) {
+                if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
+                        pr_cont(" Bad RIP value.");
+                        break;
+                }
+                if (ip == (u8 *)rip)
+                        pr_cont("<%02x> ", c);
+                else
+                        pr_cont("%02x ", c);
+        }
+        pr_cont("\n");
+}
+
 void show_iret_regs(struct pt_regs *regs)
 {
         printk(KERN_DEFAULT "RIP: %04x:%pS\n", (int)regs->cs, (void *)regs->ip);
@@ -359,7 +388,6 @@ void die(const char *str, struct pt_regs *regs, long err)
 void show_regs(struct pt_regs *regs)
 {
         bool all = true;
-        int i;
 
         show_regs_print_info(KERN_DEFAULT);
 
@@ -373,32 +401,7 @@ void show_regs(struct pt_regs *regs)
          * time of the fault..
          */
         if (!user_mode(regs)) {
-                unsigned int code_prologue = OPCODE_BUFSIZE * 43 / 64;
-                unsigned int code_len = OPCODE_BUFSIZE;
-                unsigned char c;
-                u8 *ip;
-
                 show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
-
-                printk(KERN_DEFAULT "Code: ");
-
-                ip = (u8 *)regs->ip - code_prologue;
-                if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
-                        /* try starting at IP */
-                        ip = (u8 *)regs->ip;
-                        code_len = code_len - code_prologue + 1;
-                }
-                for (i = 0; i < code_len; i++, ip++) {
-                        if (ip < (u8 *)PAGE_OFFSET ||
-                                        probe_kernel_address(ip, c)) {
-                                pr_cont(" Bad RIP value.");
-                                break;
-                        }
-                        if (ip == (u8 *)regs->ip)
-                                pr_cont("<%02x> ", c);
-                        else
-                                pr_cont("%02x ", c);
-                }
+                show_opcodes((u8 *)regs->ip);
         }
-        pr_cont("\n");
 }