diff options
| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2015-12-03 16:33:26 -0600 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2015-12-04 22:51:07 +0100 |
| commit | b56b36ee6751abe7fb3890681e86fc8de2122953 (patch) | |
| tree | b95a1d26730cf2389214e303199c25bc160134c9 /arch | |
| parent | fc284d631894d8673d229fad92762b66c9875cab (diff) | |
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 'arch')
| -rw-r--r-- | arch/x86/kernel/livepatch.c | 25 |
1 files changed, 2 insertions, 23 deletions
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 <linux/module.h> #include <linux/uaccess.h> -#include <asm/cacheflush.h> -#include <asm/page_types.h> #include <asm/elf.h> #include <asm/livepatch.h> @@ -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); } |