From 80a3e3949b8f3a3efa853d8752fd7ed5ec02de2d Mon Sep 17 00:00:00 2001
From: Andi Kleen <ak@linux.intel.com>
Date: Thu, 21 Dec 2017 16:18:20 -0800
Subject: [PATCH] x86/extable: Mark exception handler functions visible

Mark the C exception handler functions that are directly called through
exception tables visible. LTO needs to know they are accessed from assembler.

[ tglx: Mopped up the wrecked argument alignment. Sigh.... ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20171222001821.2157-6-andi@firstfloor.org
---
 arch/x86/mm/extable.c | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 9fe656c42aa5..45f5d6cf65ae 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -21,16 +21,16 @@ ex_fixup_handler(const struct exception_table_entry *x)
 	return (ex_handler_t)((unsigned long)&x->handler + x->handler);
 }
 
-bool ex_handler_default(const struct exception_table_entry *fixup,
-		       struct pt_regs *regs, int trapnr)
+__visible bool ex_handler_default(const struct exception_table_entry *fixup,
+				  struct pt_regs *regs, int trapnr)
 {
 	regs->ip = ex_fixup_addr(fixup);
 	return true;
 }
 EXPORT_SYMBOL(ex_handler_default);
 
-bool ex_handler_fault(const struct exception_table_entry *fixup,
-		     struct pt_regs *regs, int trapnr)
+__visible bool ex_handler_fault(const struct exception_table_entry *fixup,
+				struct pt_regs *regs, int trapnr)
 {
 	regs->ip = ex_fixup_addr(fixup);
 	regs->ax = trapnr;
@@ -42,8 +42,8 @@ EXPORT_SYMBOL_GPL(ex_handler_fault);
  * Handler for UD0 exception following a failed test against the
  * result of a refcount inc/dec/add/sub.
  */
-bool ex_handler_refcount(const struct exception_table_entry *fixup,
-			 struct pt_regs *regs, int trapnr)
+__visible bool ex_handler_refcount(const struct exception_table_entry *fixup,
+				   struct pt_regs *regs, int trapnr)
 {
 	/* First unconditionally saturate the refcount. */
 	*(int *)regs->cx = INT_MIN / 2;
@@ -95,8 +95,8 @@ EXPORT_SYMBOL(ex_handler_refcount);
  * of vulnerability by restoring from the initial state (essentially, zeroing
  * out all the FPU registers) if we can't restore from the task's FPU state.
  */
-bool ex_handler_fprestore(const struct exception_table_entry *fixup,
-			  struct pt_regs *regs, int trapnr)
+__visible bool ex_handler_fprestore(const struct exception_table_entry *fixup,
+				    struct pt_regs *regs, int trapnr)
 {
 	regs->ip = ex_fixup_addr(fixup);
 
@@ -108,8 +108,8 @@ bool ex_handler_fprestore(const struct exception_table_entry *fixup,
 }
 EXPORT_SYMBOL_GPL(ex_handler_fprestore);
 
-bool ex_handler_ext(const struct exception_table_entry *fixup,
-		   struct pt_regs *regs, int trapnr)
+__visible bool ex_handler_ext(const struct exception_table_entry *fixup,
+			      struct pt_regs *regs, int trapnr)
 {
 	/* Special hack for uaccess_err */
 	current->thread.uaccess_err = 1;
@@ -118,8 +118,8 @@ bool ex_handler_ext(const struct exception_table_entry *fixup,
 }
 EXPORT_SYMBOL(ex_handler_ext);
 
-bool ex_handler_rdmsr_unsafe(const struct exception_table_entry *fixup,
-			     struct pt_regs *regs, int trapnr)
+__visible bool ex_handler_rdmsr_unsafe(const struct exception_table_entry *fixup,
+				       struct pt_regs *regs, int trapnr)
 {
 	if (pr_warn_once("unchecked MSR access error: RDMSR from 0x%x at rIP: 0x%lx (%pF)\n",
 			 (unsigned int)regs->cx, regs->ip, (void *)regs->ip))
@@ -133,8 +133,8 @@ bool ex_handler_rdmsr_unsafe(const struct exception_table_entry *fixup,
 }
 EXPORT_SYMBOL(ex_handler_rdmsr_unsafe);
 
-bool ex_handler_wrmsr_unsafe(const struct exception_table_entry *fixup,
-			     struct pt_regs *regs, int trapnr)
+__visible bool ex_handler_wrmsr_unsafe(const struct exception_table_entry *fixup,
+				       struct pt_regs *regs, int trapnr)
 {
 	if (pr_warn_once("unchecked MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x) at rIP: 0x%lx (%pF)\n",
 			 (unsigned int)regs->cx, (unsigned int)regs->dx,
@@ -147,8 +147,8 @@ bool ex_handler_wrmsr_unsafe(const struct exception_table_entry *fixup,
 }
 EXPORT_SYMBOL(ex_handler_wrmsr_unsafe);
 
-bool ex_handler_clear_fs(const struct exception_table_entry *fixup,
-			 struct pt_regs *regs, int trapnr)
+__visible bool ex_handler_clear_fs(const struct exception_table_entry *fixup,
+				   struct pt_regs *regs, int trapnr)
 {
 	if (static_cpu_has(X86_BUG_NULL_SEG))
 		asm volatile ("mov %0, %%fs" : : "rm" (__USER_DS));
@@ -157,7 +157,7 @@ bool ex_handler_clear_fs(const struct exception_table_entry *fixup,
 }
 EXPORT_SYMBOL(ex_handler_clear_fs);
 
-bool ex_has_fault_handler(unsigned long ip)
+__visible bool ex_has_fault_handler(unsigned long ip)
 {
 	const struct exception_table_entry *e;
 	ex_handler_t handler;
-- 
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