Merge pull request #191 from jpoimboe/revert-dynamic

Revert #186 (add dynamic symbol linking support)

Author: jpoimboe

.gitignore

@@ -7,8 +7,9 @@
 *.swp
 .tmp_versions
 Module.symvers
-kpatch-build/lookup
+kpatch-build/add-patches-section
 kpatch-build/create-diff-object
+kpatch-build/link-vmlinux-syms
 man/kpatch.1.gz
 man/kpatch-build.1.gz
 test/integration/test.log

kmod/core/core.c

@@ -40,7 +40,6 @@
 #include <linux/ftrace.h>
 #include <linux/hashtable.h>
 #include <linux/hardirq.h>
-#include <linux/uaccess.h>
 #include <asm/stacktrace.h>
 #include <asm/cacheflush.h>
 #include "kpatch.h"
@@ -425,10 +424,6 @@ int kpatch_register(struct kpatch_module *kpmod, bool replace)
 	int ret, i;
 	struct kpatch_func *funcs, *func;
 	int num_funcs = kpmod->patches_nr;
-	struct kpatch_dynrela *dynrela;
-	void *loc;
-	u64 val;
-	int size;
 
 	if (!kpmod->mod || !kpmod->patches || !num_funcs)
 		return -EINVAL;
@@ -453,34 +448,6 @@ int kpatch_register(struct kpatch_module *kpmod, bool replace)
 		goto err_up;
 	}
 
-	for (i = 0; i < kpmod->dynrelas_nr; i++) {
-		dynrela = &kpmod->dynrelas[i];
-		switch (dynrela->type) {
-			case R_X86_64_PC32:
-				loc = (void *)dynrela->dest;
-				val = (u32)(dynrela->src - dynrela->dest);
-				size = 4;
-				break;
-			case R_X86_64_32S:
-				loc = (void *)dynrela->dest;
-				val = (s32)dynrela->src;
-				size = 4;
-				break;
-			default:
-				printk("unsupported rela type %ld for "
-				       "0x%lx <- 0x%lx at index %d\n",
-				       dynrela->type, dynrela->dest,
-				       dynrela->src, i);
-				ret = -EINVAL;
-				goto err_put;
-		}
-		set_memory_rw((unsigned long)loc & PAGE_MASK, 1);
-		ret = probe_kernel_write(loc, &val, size);
-		set_memory_ro((unsigned long)loc & PAGE_MASK, 1);
-		if (ret)
-			goto err_put;
-	}
-
 	for (i = 0; i < num_funcs; i++) {
 		func = &funcs[i];
 
@@ -597,7 +564,6 @@ int kpatch_register(struct kpatch_module *kpmod, bool replace)
 	kpatch_num_registered--;
 err_rollback:
 	kpatch_remove_funcs_from_filter(funcs, num_funcs);
-err_put:
 	module_put(kpmod->mod);
 err_up:
 	up(&kpatch_mutex);

kmod/core/kpatch.h

@@ -30,12 +30,6 @@ struct kpatch_patch {
 	unsigned long old_size;
 };
 
-struct kpatch_dynrela {
-	unsigned long dest;
-	unsigned long src;
-	unsigned long type;
-};
-
 #ifdef __KERNEL__
 
 #include <linux/types.h>
@@ -46,9 +40,7 @@ struct kpatch_internal;
 struct kpatch_module {
 	struct module *mod;
 	struct kpatch_patch *patches;
-	struct kpatch_dynrela *dynrelas;
 	int patches_nr;
-	int dynrelas_nr;
 	bool enabled;
 	struct kpatch_internal *internal; /* used internally by core module */
 };

kmod/patch/kpatch-patch-hook.c

@@ -29,7 +29,6 @@ module_param(replace, bool, S_IRUGO);
 MODULE_PARM_DESC(replace, "replace all previously loaded patch modules");
 
 extern char __kpatch_patches, __kpatch_patches_end;
-extern char __kpatch_dynrelas, __kpatch_dynrelas_end;
 
 static struct kpatch_module kpmod;
 static struct kobject *patch_kobj;
@@ -72,15 +71,13 @@ static struct kobj_attribute patch_enabled_attr =
 
 static int __init patch_init(void)
 {
+	struct kpatch_patch *patches;
 	int ret;
 
 	kpmod.mod = THIS_MODULE;
 	kpmod.patches = (struct kpatch_patch *)&__kpatch_patches;
 	kpmod.patches_nr = (&__kpatch_patches_end - &__kpatch_patches) /
-			  sizeof(*kpmod.patches);
-	kpmod.dynrelas = (struct kpatch_dynrela *)&__kpatch_dynrelas;
-	kpmod.dynrelas_nr = (&__kpatch_dynrelas_end - &__kpatch_dynrelas) /
-			  sizeof(*kpmod.dynrelas);
+			  sizeof(*patches);
 
 	patch_kobj = kobject_create_and_add(THIS_MODULE->name,
 					    kpatch_patches_kobj);

kmod/patch/kpatch.lds

@@ -1,4 +1,2 @@
-__kpatch_patches = ADDR(.kpatch.patches);
-__kpatch_patches_end = ADDR(.kpatch.patches) + SIZEOF(.kpatch.patches);
-__kpatch_dynrelas = ADDR(.kpatch.dynrelas);
-__kpatch_dynrelas_end = ADDR(.kpatch.dynrelas) + SIZEOF(.kpatch.dynrelas);
+__kpatch_patches = ADDR(.patches);
+__kpatch_patches_end = ADDR(.patches) + SIZEOF(.patches);

kpatch-build/Makefile

@@ -3,12 +3,16 @@ include ../Makefile.inc
 CFLAGS  += -I../kmod/patch -Wall -g
 LDFLAGS = -lelf
 
-TARGETS = create-diff-object
+TARGETS = create-diff-object add-patches-section link-vmlinux-syms
+
 
 all: $(TARGETS)
 
-create-diff-object: create-diff-object.c list.h lookup.c lookup.h
-	$(CC) $(CFLAGS) create-diff-object.c lookup.c -o $@ $(LDFLAGS)
+%: %.c
+	$(CC) $(CFLAGS) $^ -o $@ $(LDFLAGS)
+
+create-diff-object: create-diff-object.c list.h
+	$(CC) $(CFLAGS) create-diff-object.c -o $@ $(LDFLAGS)
 
 install: all
 	$(INSTALL) -d $(LIBEXECDIR)