Commit 775acc82 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Dave Hansen
Browse files

x86/traps: Refactor exc_general_protection() 



TDX brings a new exception -- Virtualization Exception (#VE). Handling
of #VE structurally very similar to handling #GP.

Extract two helpers from exc_general_protection() that can be reused for
handling #VE.

No functional changes.

Suggested-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20220405232939.73860-7-kirill.shutemov@linux.intel.com
parent 65fab5bc

arch/x86/kernel/traps.c

+31 −26
Original line number Diff line number Diff line
@@ -686,13 +686,40 @@ static bool try_fixup_enqcmd_gp(void) 
#endif

}



static bool gp_try_fixup_and_notify(struct pt_regs *regs, int trapnr,

				    unsigned long error_code, const char *str)

{

	if (fixup_exception(regs, trapnr, error_code, 0))

		return true;



	current->thread.error_code = error_code;

	current->thread.trap_nr = trapnr;



	/*

	 * To be potentially processing a kprobe fault and to trust the result

	 * from kprobe_running(), we have to be non-preemptible.

	 */

	if (!preemptible() && kprobe_running() &&

	    kprobe_fault_handler(regs, trapnr))

		return true;



	return notify_die(DIE_GPF, str, regs, error_code, trapnr, SIGSEGV) == NOTIFY_STOP;

}



static void gp_user_force_sig_segv(struct pt_regs *regs, int trapnr,

				   unsigned long error_code, const char *str)

{

	current->thread.error_code = error_code;

	current->thread.trap_nr = trapnr;

	show_signal(current, SIGSEGV, "", str, regs, error_code);

	force_sig(SIGSEGV);

}



DEFINE_IDTENTRY_ERRORCODE(exc_general_protection)

{

	char desc[sizeof(GPFSTR) + 50 + 2*sizeof(unsigned long) + 1] = GPFSTR;

	enum kernel_gp_hint hint = GP_NO_HINT;

	struct task_struct *tsk;

	unsigned long gp_addr;

	int ret;



	if (user_mode(regs) && try_fixup_enqcmd_gp())

		return;
@@ -711,40 +738,18 @@ DEFINE_IDTENTRY_ERRORCODE(exc_general_protection) 
		return;

	}



	tsk = current;



	if (user_mode(regs)) {

		if (fixup_iopl_exception(regs))

			goto exit;



		tsk->thread.error_code = error_code;

		tsk->thread.trap_nr = X86_TRAP_GP;



		if (fixup_vdso_exception(regs, X86_TRAP_GP, error_code, 0))

			goto exit;



		show_signal(tsk, SIGSEGV, "", desc, regs, error_code);

		force_sig(SIGSEGV);

		gp_user_force_sig_segv(regs, X86_TRAP_GP, error_code, desc);

		goto exit;

	}



	if (fixup_exception(regs, X86_TRAP_GP, error_code, 0))

		goto exit;



	tsk->thread.error_code = error_code;

	tsk->thread.trap_nr = X86_TRAP_GP;



	/*

	 * To be potentially processing a kprobe fault and to trust the result

	 * from kprobe_running(), we have to be non-preemptible.

	 */

	if (!preemptible() &&

	    kprobe_running() &&

	    kprobe_fault_handler(regs, X86_TRAP_GP))

		goto exit;



	ret = notify_die(DIE_GPF, desc, regs, error_code, X86_TRAP_GP, SIGSEGV);

	if (ret == NOTIFY_STOP)

	if (gp_try_fixup_and_notify(regs, X86_TRAP_GP, error_code, desc))

		goto exit;



	if (error_code)