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Diffstat (limited to 'arch/x86/mm/extable.c')
-rw-r--r--arch/x86/mm/extable.c100
1 files changed, 72 insertions, 28 deletions
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 903ec1e9c326..9dd7e4b7fcde 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -3,6 +3,9 @@
#include <linux/sort.h>
#include <asm/uaccess.h>
+typedef bool (*ex_handler_t)(const struct exception_table_entry *,
+ struct pt_regs *, int);
+
static inline unsigned long
ex_insn_addr(const struct exception_table_entry *x)
{
@@ -13,11 +16,56 @@ ex_fixup_addr(const struct exception_table_entry *x)
{
return (unsigned long)&x->fixup + x->fixup;
}
+static inline ex_handler_t
+ex_fixup_handler(const struct exception_table_entry *x)
+{
+ return (ex_handler_t)((unsigned long)&x->handler + x->handler);
+}
-int fixup_exception(struct pt_regs *regs)
+bool ex_handler_default(const struct exception_table_entry *fixup,
+ struct pt_regs *regs, int trapnr)
{
- const struct exception_table_entry *fixup;
- unsigned long new_ip;
+ 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)
+{
+ regs->ip = ex_fixup_addr(fixup);
+ regs->ax = trapnr;
+ return true;
+}
+EXPORT_SYMBOL_GPL(ex_handler_fault);
+
+bool ex_handler_ext(const struct exception_table_entry *fixup,
+ struct pt_regs *regs, int trapnr)
+{
+ /* Special hack for uaccess_err */
+ current_thread_info()->uaccess_err = 1;
+ regs->ip = ex_fixup_addr(fixup);
+ return true;
+}
+EXPORT_SYMBOL(ex_handler_ext);
+
+bool ex_has_fault_handler(unsigned long ip)
+{
+ const struct exception_table_entry *e;
+ ex_handler_t handler;
+
+ e = search_exception_tables(ip);
+ if (!e)
+ return false;
+ handler = ex_fixup_handler(e);
+
+ return handler == ex_handler_fault;
+}
+
+int fixup_exception(struct pt_regs *regs, int trapnr)
+{
+ const struct exception_table_entry *e;
+ ex_handler_t handler;
#ifdef CONFIG_PNPBIOS
if (unlikely(SEGMENT_IS_PNP_CODE(regs->cs))) {
@@ -33,42 +81,34 @@ int fixup_exception(struct pt_regs *regs)
}
#endif
- fixup = search_exception_tables(regs->ip);
- if (fixup) {
- new_ip = ex_fixup_addr(fixup);
-
- if (fixup->fixup - fixup->insn >= 0x7ffffff0 - 4) {
- /* Special hack for uaccess_err */
- current_thread_info()->uaccess_err = 1;
- new_ip -= 0x7ffffff0;
- }
- regs->ip = new_ip;
- return 1;
- }
+ e = search_exception_tables(regs->ip);
+ if (!e)
+ return 0;
- return 0;
+ handler = ex_fixup_handler(e);
+ return handler(e, regs, trapnr);
}
/* Restricted version used during very early boot */
int __init early_fixup_exception(unsigned long *ip)
{
- const struct exception_table_entry *fixup;
+ const struct exception_table_entry *e;
unsigned long new_ip;
+ ex_handler_t handler;
- fixup = search_exception_tables(*ip);
- if (fixup) {
- new_ip = ex_fixup_addr(fixup);
+ e = search_exception_tables(*ip);
+ if (!e)
+ return 0;
- if (fixup->fixup - fixup->insn >= 0x7ffffff0 - 4) {
- /* uaccess handling not supported during early boot */
- return 0;
- }
+ new_ip = ex_fixup_addr(e);
+ handler = ex_fixup_handler(e);
- *ip = new_ip;
- return 1;
- }
+ /* special handling not supported during early boot */
+ if (handler != ex_handler_default)
+ return 0;
- return 0;
+ *ip = new_ip;
+ return 1;
}
/*
@@ -133,6 +173,8 @@ void sort_extable(struct exception_table_entry *start,
i += 4;
p->fixup += i;
i += 4;
+ p->handler += i;
+ i += 4;
}
sort(start, finish - start, sizeof(struct exception_table_entry),
@@ -145,6 +187,8 @@ void sort_extable(struct exception_table_entry *start,
i += 4;
p->fixup -= i;
i += 4;
+ p->handler -= i;
+ i += 4;
}
}