Re: [patch 7/8] KGDB support for x86_64

[Andi Kleen]

On Fri, Oct 29, 2004 at 11:34:21AM -0700, Tom Rini wrote:
> 
> Cc: Andi Kleen <ak@xxxxxxx>
> This adds KGDB support for x86_64.

Can you please explain what the additional hooks are good for? 


> +++ linux-2.6.10-rc1-trini/arch/x86_64/kernel/Makefile	2004-10-29 11:26:45.757144605 -0700
> @@ -10,6 +10,8 @@ obj-y	:= process.o semaphore.o signal.o 
>  		setup64.o bootflag.o e820.o reboot.o warmreboot.o
>  obj-y += mce.o
>  
> +CFLAGS_vsyscall.o := -g0
> +

What's this? 


> +#include <linux/kgdb.h>
>  #include <asm/uaccess.h>
>  #include <asm/io_apic.h>
>  
> @@ -103,6 +104,13 @@ asmlinkage unsigned int do_IRQ(struct pt
>  	__do_IRQ(irq, regs);
>  	irq_exit();
>  
> +	/*
> +	 * Do not call breakpoint as on the x86_64 architecture if the
> +	 * exception tables are not set.
> +	 */
> +	if(CHECK_EXCEPTION_STACK())
> +		kgdb_process_breakpoint();
> +

And that?   Why do you need to check breakpoints in interrupts?

>  #include <linux/moduleparam.h>
> +#include <linux/debugger.h>
>  
>  #include <asm/system.h>
>  #include <asm/uaccess.h>
> @@ -642,7 +643,7 @@ asmlinkage void *do_debug(struct pt_regs
>  	tsk->thread.debugreg6 = condition;
>  
>  	/* Mask out spurious TF errors due to lazy TF clearing */
> -	if (condition & DR_STEP) {
> +	if (condition & DR_STEP && !debugger_step) {

This also looks bogus. What is this exactly for and why is it not
handled through the debug chain? 


-Andi
-
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