From b56b36ee6751abe7fb3890681e86fc8de2122953 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 3 Dec 2015 16:33:26 -0600 Subject: 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 Signed-off-by: Josh Poimboeuf Reviewed-by: Petr Mladek Signed-off-by: Jiri Kosina --- arch/x86/kernel/livepatch.c | 25 ++----------------------- 1 file changed, 2 insertions(+), 23 deletions(-) (limited to 'arch') diff --git a/arch/x86/kernel/livepatch.c b/arch/x86/kernel/livepatch.c index bcc06e82a593..92fc1a51f994 100644 --- a/arch/x86/kernel/livepatch.c +++ b/arch/x86/kernel/livepatch.c @@ -20,8 +20,6 @@ #include #include -#include -#include #include #include @@ -38,8 +36,7 @@ int klp_write_module_reloc(struct module *mod, unsigned long type, unsigned long loc, unsigned long value) { - int ret, numpages, size = 4; - bool readonly; + size_t size = 4; unsigned long val; unsigned long core = (unsigned long)mod->core_layout.base; unsigned long core_size = mod->core_layout.size; @@ -69,23 +66,5 @@ int klp_write_module_reloc(struct module *mod, unsigned long type, /* loc does not point to any symbol inside the module */ return -EINVAL; - readonly = false; - -#ifdef CONFIG_DEBUG_SET_MODULE_RONX - if (loc < core + mod->core_layout.ro_size) - readonly = true; -#endif - - /* determine if the relocation spans a page boundary */ - numpages = ((loc & PAGE_MASK) == ((loc + size) & PAGE_MASK)) ? 1 : 2; - - if (readonly) - set_memory_rw(loc & PAGE_MASK, numpages); - - ret = probe_kernel_write((void *)loc, &val, size); - - if (readonly) - set_memory_ro(loc & PAGE_MASK, numpages); - - return ret; + return probe_kernel_write((void *)loc, &val, size); } -- cgit v1.2.3