extable: Add function to search only kernel exception table

Certain architecture specific operating modes (e.g., in powerpc machine
check handler that is unable to access vmalloc memory), the
search_exception_tables cannot be called because it also searches the
module exception tables if entry is not found in the kernel exception
table.

Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190820081352.8641-5-santosh@fossix.org

diff --git a/include/linux/extable.h b/include/linux/extable.h
index 41c5b3a..81ecfaa 100644 (file)
--- a/include/linux/extable.h
+++ b/include/linux/extable.h
@@ -19,6 +19,8 @@ void trim_init_extable(struct module *m);
 
 /* Given an address, look for it in the exception tables */
 const struct exception_table_entry *search_exception_tables(unsigned long add);
+const struct exception_table_entry *
+search_kernel_exception_table(unsigned long addr);
 
 #ifdef CONFIG_MODULES
 /* For extable.c to search modules' exception tables. */

diff --git a/kernel/extable.c b/kernel/extable.c
index e23cce6..f6c9406 100644 (file)
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -40,13 +40,20 @@ void __init sort_main_extable(void)
        }
 }
 
+/* Given an address, look for it in the kernel exception table */
+const
+struct exception_table_entry *search_kernel_exception_table(unsigned long addr)
+{
+       return search_extable(__start___ex_table,
+                             __stop___ex_table - __start___ex_table, addr);
+}
+
 /* Given an address, look for it in the exception tables. */
 const struct exception_table_entry *search_exception_tables(unsigned long addr)
 {
        const struct exception_table_entry *e;
 
-       e = search_extable(__start___ex_table,
-                          __stop___ex_table - __start___ex_table, addr);
+       e = search_kernel_exception_table(addr);
        if (!e)
                e = search_module_extables(addr);
        return e;