[PATCH] x86-64: make trap information available to die notification handlers

["Jan Beulich" <JBeulich@novell.com>]

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This adjusts things so that handlers of the die() notifier will have
sufficient information about the trap currently being handled. It also
adjusts the notify_die() prototype to (again) match that of i386.

From: Jan Beulich <jbeulich@novell.com>

(actual patch attached)


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This adjusts things so that handlers of the die() notifier will have
sufficient information about the trap currently being handled. It also
adjusts the notify_die() prototype to (again) match that of i386.

From: Jan Beulich <jbeulich@novell.com>

--- 2.6.14/arch/x86_64/kernel/traps.c	2005-10-28 02:02:08.000000000 +0200
+++ 2.6.14-x86_64-die-trap-info/arch/x86_64/kernel/traps.c	2005-11-07 09:33:53.000000000 +0100
@@ -382,7 +382,7 @@ void __die(const char * str, struct pt_r
 	printk("DEBUG_PAGEALLOC");
 #endif
 	printk("\n");
-	notify_die(DIE_OOPS, (char *)str, regs, err, 255, SIGSEGV);
+	notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV);
 	show_registers(regs);
 	/* Executive summary in case the oops scrolled away */
 	printk(KERN_ALERT "RIP ");
@@ -426,6 +426,8 @@ static void __kprobes do_trap(int trapnr
 			      struct pt_regs * regs, long error_code,
 			      siginfo_t *info)
 {
+	struct task_struct *tsk = current;
+
 	conditional_sti(regs);
 
 #ifdef CONFIG_CHECKING
@@ -441,17 +443,16 @@ static void __kprobes do_trap(int trapnr
        }
 #endif
 
-	if (user_mode(regs)) {
-		struct task_struct *tsk = current;
+	tsk->thread.error_code = error_code;
+	tsk->thread.trap_no = trapnr;
 
+	if (user_mode(regs)) {
 		if (exception_trace && unhandled_signal(tsk, signr))
 			printk(KERN_INFO
 			       "%s[%d] trap %s rip:%lx rsp:%lx error:%lx\n",
 			       tsk->comm, tsk->pid, str,
 			       regs->rip,regs->rsp,error_code); 
 
-		tsk->thread.error_code = error_code;
-		tsk->thread.trap_no = trapnr;
 		if (info)
 			force_sig_info(signr, info, tsk);
 		else
@@ -511,6 +512,8 @@ DO_ERROR( 8, SIGSEGV, "double fault", do
 asmlinkage void __kprobes do_general_protection(struct pt_regs * regs,
 						long error_code)
 {
+	struct task_struct *tsk = current;
+
 	conditional_sti(regs);
 
 #ifdef CONFIG_CHECKING
@@ -527,17 +530,16 @@ asmlinkage void __kprobes do_general_pro
        }
 #endif
 
-	if (user_mode(regs)) {
-		struct task_struct *tsk = current;
+	tsk->thread.error_code = error_code;
+	tsk->thread.trap_no = 13;
 
+	if (user_mode(regs)) {
 		if (exception_trace && unhandled_signal(tsk, SIGSEGV))
 			printk(KERN_INFO
 		       "%s[%d] general protection rip:%lx rsp:%lx error:%lx\n",
 			       tsk->comm, tsk->pid,
 			       regs->rip,regs->rsp,error_code); 
 
-		tsk->thread.error_code = error_code;
-		tsk->thread.trap_no = 13;
 		force_sig(SIGSEGV, tsk);
 		return;
 	} 
@@ -748,6 +750,7 @@ static int kernel_math_error(struct pt_r
 	}
 	notify_die(DIE_GPF, str, regs, 0, 16, SIGFPE);
 	/* Illegal floating point operation in the kernel */
+	current->thread.trap_no = 16;
 	die(str, regs, 0);
 	return 0;
 }
--- 2.6.14/arch/x86_64/mm/fault.c	2005-10-28 02:02:08.000000000 +0200
+++ 2.6.14-x86_64-die-trap-info/arch/x86_64/mm/fault.c	2005-11-07 14:27:42.000000000 +0100
@@ -222,10 +222,15 @@ static noinline void pgtable_bad(unsigne
 				 unsigned long error_code)
 {
 	unsigned long flags = oops_begin();
+	struct task_struct *tsk;
 
 	printk(KERN_ALERT "%s: Corrupted page table at address %lx\n",
 	       current->comm, address);
 	dump_pagetable(address);
+	tsk = current;
+	tsk->thread.cr2 = address;
+	tsk->thread.trap_no = 14;
+	tsk->thread.error_code = error_code;
 	__die("Bad pagetable", regs, error_code);
 	oops_end(flags);
 	do_exit(SIGKILL);
@@ -533,6 +538,9 @@ no_context:
 	printk_address(regs->rip);
 	printk("\n");
 	dump_pagetable(address);
+	tsk->thread.cr2 = address;
+	tsk->thread.trap_no = 14;
+	tsk->thread.error_code = error_code;
 	__die("Oops", regs, error_code);
 	/* Executive summary in case the body of the oops scrolled away */
 	printk(KERN_EMERG "CR2: %016lx\n", address);
--- 2.6.14/include/asm-x86_64/kdebug.h	2005-10-28 02:02:08.000000000 +0200
+++ 2.6.14-x86_64-die-trap-info/include/asm-x86_64/kdebug.h	2005-11-07 10:31:52.000000000 +0100
@@ -35,9 +35,16 @@ enum die_val { 
 	DIE_PAGE_FAULT,
 }; 
 	
-static inline int notify_die(enum die_val val,char *str,struct pt_regs *regs,long err,int trap, int sig)
-{ 
-	struct die_args args = { .regs=regs, .str=str, .err=err, .trapnr=trap,.signr=sig }; 
+static inline int notify_die(enum die_val val, const char *str,
+			struct pt_regs *regs, long err, int trap, int sig)
+{
+	struct die_args args = {
+		.regs = regs,
+		.str = str,
+		.err = err,
+		.trapnr = trap,
+		.signr = sig
+	};
 	return notifier_call_chain(&die_chain, val, &args); 
 }