x86: Make Alt-SysRq-p display the debug register contents

This patch (as921) adds code to the show_regs() routine in i386 and x86_64
to print the contents of the debug registers along with all the others.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/i386/kernel/process.c

@@ -300,6 +300,7 @@ early_param("idle", idle_setup);
 void show_regs(struct pt_regs * regs)
 {
 	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
+	unsigned long d0, d1, d2, d3, d6, d7;
 
 	printk("\n");
 	printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
@@ -324,6 +325,17 @@ void show_regs(struct pt_regs * regs)
 	cr3 = read_cr3();
 	cr4 = read_cr4_safe();
 	printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4);
+
+	get_debugreg(d0, 0);
+	get_debugreg(d1, 1);
+	get_debugreg(d2, 2);
+	get_debugreg(d3, 3);
+	printk("DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
+			d0, d1, d2, d3);
+	get_debugreg(d6, 6);
+	get_debugreg(d7, 7);
+	printk("DR6: %08lx DR7: %08lx\n", d6, d7);
+
 	show_trace(NULL, regs, &regs->esp);
 }
 

arch/x86_64/kernel/process.c

@@ -306,6 +306,7 @@ early_param("idle", idle_setup);
 void __show_regs(struct pt_regs * regs)
 {
 	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs;
+	unsigned long d0, d1, d2, d3, d6, d7;
 	unsigned int fsindex,gsindex;
 	unsigned int ds,cs,es; 
 
@@ -350,6 +351,15 @@ void __show_regs(struct pt_regs * regs)
 	       fs,fsindex,gs,gsindex,shadowgs); 
 	printk("CS:  %04x DS: %04x ES: %04x CR0: %016lx\n", cs, ds, es, cr0); 
 	printk("CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2, cr3, cr4);
+
+	get_debugreg(d0, 0);
+	get_debugreg(d1, 1);
+	get_debugreg(d2, 2);
+	printk("DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2);
+	get_debugreg(d3, 3);
+	get_debugreg(d6, 6);
+	get_debugreg(d7, 7);
+	printk("DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7);
 }
 
 void show_regs(struct pt_regs *regs)