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| 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 /kernel/livepatch | |
| parent | fc284d631894d8673d229fad92762b66c9875cab (diff) | |
| download | linux-rt-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.c | 16 |
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, |