x86/debug: Only print out DR registers if they are not power-on defaults

[firefly-linux-kernel-4.4.55.git] / arch / x86 / kernel / process_32.c

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 7305f7dfc7abe7ef46875a9028556de99f73e79e..f84cfd1b0c0bb4ef21c63bbedd27f499c059a9e1 100644 (file)
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -110,11 +110,16 @@ void __show_regs(struct pt_regs *regs, int all)
        get_debugreg(d1, 1);
        get_debugreg(d2, 2);
        get_debugreg(d3, 3);
-       printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
-                       d0, d1, d2, d3);
-
        get_debugreg(d6, 6);
        get_debugreg(d7, 7);
+
+       /* Only print out debug registers if they are in their non-default state. */
+       if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) &&
+           (d6 == DR6_RESERVED) && (d7 == 0x400))
+               return;
+
+       printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
+                       d0, d1, d2, d3);
        printk(KERN_DEFAULT "DR6: %08lx DR7: %08lx\n",
                        d6, d7);
 }