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

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 579455c..eb9d6c0 100644 (file)
--- 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");
 }