[PATCH 5/6] x86: Make exception handler functions visible

Andi Kleen
2017-12-22T00:27:14Z

From: Andi Kleen <ak@linux.intel.com>

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

Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
arch/x86/mm/extable.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 9fe656c42aa5..8bd4b864e681 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -21,7 +21,7 @@ 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,
+__visible bool ex_handler_default(const struct exception_table_entry *fixup,
struct pt_regs *regs, int trapnr)
{
regs->ip = ex_fixup_addr(fixup);
@@ -29,7 +29,7 @@ bool ex_handler_default(const struct exception_table_entry *fixup,
}
EXPORT_SYMBOL(ex_handler_default);

-bool ex_handler_fault(const struct exception_table_entry *fixup,
+__visible bool ex_handler_fault(const struct exception_table_entry *fixup,
struct pt_regs *regs, int trapnr)
{
regs->ip = ex_fixup_addr(fixup);
@@ -42,7 +42,7 @@ 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,
+__visible bool ex_handler_refcount(const struct exception_table_entry *fixup,
struct pt_regs *regs, int trapnr)
{
/* First unconditionally saturate the refcount. */
@@ -95,6 +95,7 @@ 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.
*/
+__visible
bool ex_handler_fprestore(const struct exception_table_entry *fixup,
struct pt_regs *regs, int trapnr)
{
@@ -108,7 +109,7 @@ 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,
+__visible bool ex_handler_ext(const struct exception_table_entry *fixup,
struct pt_regs *regs, int trapnr)
{
/* Special hack for uaccess_err */
@@ -118,7 +119,7 @@ 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,
+__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",
@@ -133,7 +134,7 @@ 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,
+__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",
@@ -147,7 +148,7 @@ 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,
+__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))
@@ -157,7 +158,7 @@ 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;
--
2.15.0