Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1270379
| From | Chris J Arges <chris.j.arges@canonical.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 2/3 v7] livepatch: add sympos as disambiguator field to klp_reloc |
| Date | 2015-11-16 18:10 +0100 |
| Message-ID | <qvvrX-1EC-3@gated-at.bofh.it> (permalink) |
| References | <qupoC-ii-19@gated-at.bofh.it> <qvvrX-1EC-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
In cases of duplicate symbols, sympos will be used to disambiguate instead
of val. By default sympos will be 0, and patching will only succeed if
the symbol is unique. Specifying a positive value will ensure that
occurrence of the symbol in kallsyms for the patched object will be used
for patching if it is valid.
Remove klp_verify_callback, klp_verify_args and klp_verify_vmlinux_symbol
as they are no longer used.
From the klp_reloc structure remove val, as it can be refactored as a
local variable in klp_write_object_relocations.
Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
---
include/linux/livepatch.h | 5 ++--
kernel/livepatch/core.c | 75 +++++++++++------------------------------------
2 files changed, 19 insertions(+), 61 deletions(-)
diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index b60e8ab..a882865 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -67,8 +67,7 @@ struct klp_func {
/**
* struct klp_reloc - relocation structure for live patching
* @loc: address where the relocation will be written
- * @val: address of the referenced symbol (optional,
- * vmlinux patches only)
+ * @sympos: position in kallsyms to disambiguate symbols (optional)
* @type: ELF relocation type
* @name: name of the referenced symbol (for lookup/verification)
* @addend: offset from the referenced symbol
@@ -76,7 +75,7 @@ struct klp_func {
*/
struct klp_reloc {
unsigned long loc;
- unsigned long val;
+ unsigned long sympos;
unsigned long type;
const char *name;
int addend;
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 5a53383..9d98c7b 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -203,45 +203,6 @@ static int klp_find_object_symbol(const char *objname, const char *name,
return -EINVAL;
}
-struct klp_verify_args {
- const char *name;
- const unsigned long addr;
-};
-
-static int klp_verify_callback(void *data, const char *name,
- struct module *mod, unsigned long addr)
-{
- struct klp_verify_args *args = data;
-
- if (!mod &&
- !strcmp(args->name, name) &&
- args->addr == addr)
- return 1;
-
- return 0;
-}
-
-static int klp_verify_vmlinux_symbol(const char *name, unsigned long addr)
-{
- struct klp_verify_args args = {
- .name = name,
- .addr = addr,
- };
- int ret;
-
- mutex_lock(&module_mutex);
- ret = kallsyms_on_each_symbol(klp_verify_callback, &args);
- mutex_unlock(&module_mutex);
-
- if (!ret) {
- pr_err("symbol '%s' not found at specified address 0x%016lx, kernel mismatch?\n",
- name, addr);
- return -EINVAL;
- }
-
- return 0;
-}
-
/*
* external symbols are located outside the parent object (where the parent
* object is either vmlinux or the kmod being patched).
@@ -272,6 +233,7 @@ static int klp_write_object_relocations(struct module *pmod,
struct klp_object *obj)
{
int ret;
+ unsigned long val;
struct klp_reloc *reloc;
if (WARN_ON(!klp_is_object_loaded(obj)))
@@ -281,29 +243,26 @@ static int klp_write_object_relocations(struct module *pmod,
return -EINVAL;
for (reloc = obj->relocs; reloc->name; reloc++) {
- if (!klp_is_module(obj)) {
- ret = klp_verify_vmlinux_symbol(reloc->name,
- reloc->val);
- if (ret)
- return ret;
- } else {
- /* module, reloc->val needs to be discovered */
- if (reloc->external)
- ret = klp_find_external_symbol(pmod,
- reloc->name,
- &reloc->val);
- else
- ret = klp_find_object_symbol(obj->mod->name,
- reloc->name,
- 0, &reloc->val);
- if (ret)
- return ret;
+ if (reloc->sympos && (reloc->sympos != 1)) {
+ pr_err("symbol '%s' is external and has sympos %lu\n",
+ reloc->name, reloc->sympos);
+ return -EINVAL;
}
+ /* discover the address of the referenced symbol */
+ if (reloc->external) {
+ ret = klp_find_external_symbol(pmod, reloc->name, &val);
+ } else
+ ret = klp_find_object_symbol(obj->mod->name,
+ reloc->name,
+ reloc->sympos,
+ &val);
+ if (ret)
+ return ret;
ret = klp_write_module_reloc(pmod, reloc->type, reloc->loc,
- reloc->val + reloc->addend);
+ val + reloc->addend);
if (ret) {
pr_err("relocation failed for symbol '%s' at 0x%016lx (%d)\n",
- reloc->name, reloc->val, ret);
+ reloc->name, val, ret);
return ret;
}
}
--
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread
[PATCH 2/3 v7] livepatch: add sympos as disambiguator field to klp_reloc Chris J Arges <chris.j.arges@canonical.com> - 2015-11-16 18:10 +0100
Re: [PATCH 2/3 v7] livepatch: add sympos as disambiguator field to klp_reloc Miroslav Benes <mbenes@suse.cz> - 2015-11-18 11:00 +0100
Re: [PATCH 2/3 v7] livepatch: add sympos as disambiguator field to klp_reloc Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-18 15:10 +0100
Re: [PATCH 2/3 v7] livepatch: add sympos as disambiguator field to klp_reloc Petr Mladek <pmladek@suse.com> - 2015-11-18 17:50 +0100
Re: [PATCH 2/3 v7] livepatch: add sympos as disambiguator field to klp_reloc Petr Mladek <pmladek@suse.com> - 2015-11-18 17:40 +0100
Re: [PATCH 2/3 v7] livepatch: add sympos as disambiguator field to klp_reloc Chris J Arges <chris.j.arges@canonical.com> - 2015-11-18 17:40 +0100
Re: [PATCH 2/3 v7] livepatch: add sympos as disambiguator field to klp_reloc Petr Mladek <pmladek@suse.com> - 2015-11-18 18:00 +0100
Re: [PATCH 2/3 v7] livepatch: add sympos as disambiguator field to klp_reloc Jiri Kosina <jikos@kernel.org> - 2015-11-18 21:40 +0100
csiph-web