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authorJosh Poimboeuf <jpoimboe@redhat.com>2015-12-03 16:33:26 -0600
committerJiri Kosina <jkosina@suse.cz>2015-12-04 22:51:07 +0100
commitb56b36ee6751abe7fb3890681e86fc8de2122953 (patch)
treeb95a1d26730cf2389214e303199c25bc160134c9 /kernel/livepatch
parentfc284d631894d8673d229fad92762b66c9875cab (diff)
downloadlinux-sh-b56b36ee6751abe7fb3890681e86fc8de2122953.tar.gz
livepatch: Cleanup module page permission changes
Calling set_memory_rw() and set_memory_ro() for every iteration of the loop in klp_write_object_relocations() is messy, inefficient, and error-prone. Change all the read-only pages to read-write before the loop and convert them back to read-only again afterwards. Suggested-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'kernel/livepatch')
-rw-r--r--kernel/livepatch/core.c16
1 files changed, 11 insertions, 5 deletions
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 94893e844e44..bc2c85c064c1 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -28,6 +28,7 @@
#include <linux/list.h>
#include <linux/kallsyms.h>
#include <linux/livepatch.h>
+#include <asm/cacheflush.h>
/**
* struct klp_ops - structure for tracking registered ftrace ops structs
@@ -232,7 +233,7 @@ static int klp_find_external_symbol(struct module *pmod, const char *name,
static int klp_write_object_relocations(struct module *pmod,
struct klp_object *obj)
{
- int ret;
+ int ret = 0;
unsigned long val;
struct klp_reloc *reloc;
@@ -242,13 +243,16 @@ static int klp_write_object_relocations(struct module *pmod,
if (WARN_ON(!obj->relocs))
return -EINVAL;
+ module_disable_ro(pmod);
+
for (reloc = obj->relocs; reloc->name; reloc++) {
/* discover the address of the referenced symbol */
if (reloc->external) {
if (reloc->sympos > 0) {
pr_err("non-zero sympos for external reloc symbol '%s' is not supported\n",
reloc->name);
- return -EINVAL;
+ ret = -EINVAL;
+ goto out;
}
ret = klp_find_external_symbol(pmod, reloc->name, &val);
} else
@@ -257,18 +261,20 @@ static int klp_write_object_relocations(struct module *pmod,
reloc->sympos,
&val);
if (ret)
- return ret;
+ goto out;
ret = klp_write_module_reloc(pmod, reloc->type, reloc->loc,
val + reloc->addend);
if (ret) {
pr_err("relocation failed for symbol '%s' at 0x%016lx (%d)\n",
reloc->name, val, ret);
- return ret;
+ goto out;
}
}
- return 0;
+out:
+ module_enable_ro(pmod);
+ return ret;
}
static void notrace klp_ftrace_handler(unsigned long ip,