linux-kernel - [PATCH v5 4/9] x86/traps: Enable all exception handler callbacks early

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Date:	Sat,  2 Apr 2016 07:01:35 -0700
From:	Andy Lutomirski <luto@...nel.org>
To:	X86 ML <x86@...nel.org>
Cc:	Paolo Bonzini <pbonzini@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	KVM list <kvm@...r.kernel.org>,
	Arjan van de Ven <arjan@...ux.intel.com>,
	xen-devel <Xen-devel@...ts.xen.org>,
	linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Borislav Petkov <bp@...en8.de>,
	Andy Lutomirski <luto@...nel.org>
Subject: [PATCH v5 4/9] x86/traps: Enable all exception handler callbacks early

Now that early_fixup_exception has pt_regs, we can just call
fixup_exception from it.  This will make fancy exception handlers
work early.

Signed-off-by: Andy Lutomirski <luto@...nel.org>
---
 arch/x86/mm/extable.c | 19 ++-----------------
 1 file changed, 2 insertions(+), 17 deletions(-)

diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 8997022abebc..50dfe438bd91 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -95,10 +95,6 @@ extern unsigned int early_recursion_flag;
 /* Restricted version used during very early boot */
 void __init early_fixup_exception(struct pt_regs *regs, int trapnr)
 {
-	const struct exception_table_entry *e;
-	unsigned long new_ip;
-	ex_handler_t handler;
-
 	/* Ignore early NMIs. */
 	if (trapnr == X86_TRAP_NMI)
 		return;
@@ -109,19 +105,8 @@ void __init early_fixup_exception(struct pt_regs *regs, int trapnr)
 	if (regs->cs != __KERNEL_CS)
 		goto fail;
 
-	e = search_exception_tables(regs->ip);
-	if (!e)
-		goto fail;
-
-	new_ip  = ex_fixup_addr(e);
-	handler = ex_fixup_handler(e);
-
-	/* special handling not supported during early boot */
-	if (handler != ex_handler_default)
-		goto fail;
-
-	regs->ip = new_ip;
-	return;
+	if (fixup_exception(regs, trapnr))
+		return;
 
 fail:
 	early_printk("PANIC: early exception 0x%02x IP %lx:%lx error %lx cr2 0x%lx\n",
-- 
2.5.5