Re: [PATCH v4 6/6] x86: change asm/debugger.h to xen/debugger.h

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 28/09/2021 21:30, Bobby Eshleman wrote:
> This commit allows non-x86 architecture to omit the file asm/debugger.h
> if they do not require it.  It changes debugger.h to be a general
> xen/debugger.h which, if CONFIG_CRASH_DEBUG, resolves to include
> asm/debugger.h.
>
> It also changes all asm/debugger.h includes to xen/debugger.h.
>
> Because it is no longer required, arm/debugger.h is removed.
>
> Signed-off-by: Bobby Eshleman <bobby.eshleman@gmail.com>

Julien also acked this patch.

> diff --git a/xen/include/xen/debugger.h b/xen/include/xen/debugger.h
> new file mode 100644
> index 0000000000..ddaa4a938b
> --- /dev/null
> +++ b/xen/include/xen/debugger.h
> @@ -0,0 +1,51 @@
> +/******************************************************************************
> + * Generic hooks into arch-dependent Xen.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; If not, see <http://www.gnu.org/licenses/>.
> + *
> + * Each debugger should define two functions here:
> + *
> + * 1. debugger_trap_fatal():
> + *  Called when Xen is about to give up and crash. Typically you will use this
> + *  hook to drop into a debug session. It can also be used to hook off
> + *  deliberately caused traps (which you then handle and return non-zero).
> + *
> + * 2. debugger_trap_immediate():
> + *  Called if we want to drop into a debugger now.  This is essentially the
> + *  same as debugger_trap_fatal, except that we use the current register state
> + *  rather than the state which was in effect when we took the trap.
> + *  For example: if we're dying because of an unhandled exception, we call
> + *  debugger_trap_fatal; if we're dying because of a panic() we call
> + *  debugger_trap_immediate().

This comment is now duplicated in x86's asm/debugger.h.  The x86 copy
wants deleting as part of this move.

> + */
> +
> +#ifndef __XEN_DEBUGGER_H__
> +#define __XEN_DEBUGGER_H__
> +
> +#ifdef CONFIG_CRASH_DEBUG
> +
> +#include <asm/debugger.h>
> +
> +#else

#include <xen/types.h> because you need bool and false to make this compile.

~Andrew

> +
> +struct cpu_user_regs;
> +
> +static inline bool debugger_trap_fatal(
> +    unsigned int vector, const struct cpu_user_regs *regs)
> +{
> +    return false;
> +}
> +
> +static inline void debugger_trap_immediate(void)
> +{
> +}
> +
> +#endif /* CONFIG_CRASH_DEBUG */
> +
> +#endif /* __XEN_DEBUGGER_H__ */