Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching

Pull livepatching updates from Jiri Kosina:

 - RO/NX attribute fixes for patch module relocations from Josh
   Poimboeuf.  As part of this effort, module.c has been cleaned up as
   well and livepatching is piggy-backing on this cleanup.  Rusty is OK
   with this whole lot going through livepatching tree.

 - symbol disambiguation support from Chris J Arges.  That series is
   also
Reviewed-by: Miroslav Benes <mbenes@suse.cz>

   but this came in only after I've alredy pushed out.  Didn't want to
   rebase because of that, hence I am mentioning it here.

 - symbol lookup fix from Miroslav Benes

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  livepatch: Cleanup module page permission changes
  module: keep percpu symbols in module's symtab
  module: clean up RO/NX handling.
  module: use a structure to encapsulate layout.
  gcov: use within_module() helper.
  module: Use the same logic for setting and unsetting RO/NX
  livepatch: function,sympos scheme in livepatch sysfs directory
  livepatch: add sympos as disambiguator field to klp_reloc
  livepatch: add old_sympos as disambiguator field to klp_func

Documentation/ABI/testing/sysfs-kernel-livepatch

@@ -33,7 +33,7 @@ Description:
 		The object directory contains subdirectories for each function
 		that is patched within the object.
 
-What:		/sys/kernel/livepatch/<patch>/<object>/<function>
+What:		/sys/kernel/livepatch/<patch>/<object>/<function,sympos>
 Date:		Nov 2014
 KernelVersion:	3.19.0
 Contact:	live-patching@vger.kernel.org
@@ -41,4 +41,8 @@ Description:
 		The function directory contains attributes regarding the
 		properties and state of the patched function.
 
+		The directory name contains the patched function name and a
+		sympos number corresponding to the nth occurrence of the symbol
+		name in kallsyms for the patched object.
+
 		There are currently no such attributes.

arch/alpha/kernel/module.c

@@ -160,7 +160,7 @@ apply_relocate_add(Elf64_Shdr *sechdrs, const char *strtab,
 
 	/* The small sections were sorted to the end of the segment.
 	   The following should definitely cover them.  */
-	gp = (u64)me->module_core + me->core_size - 0x8000;
+	gp = (u64)me->core_layout.base + me->core_layout.size - 0x8000;
 	got = sechdrs[me->arch.gotsecindex].sh_addr;
 
 	for (i = 0; i < n; i++) {

arch/arc/kernel/unwind.c

@@ -385,8 +385,8 @@ void *unwind_add_table(struct module *module, const void *table_start,
 		return NULL;
 
 	init_unwind_table(table, module->name,
-			  module->module_core, module->core_size,
-			  module->module_init, module->init_size,
+			  module->core_layout.base, module->core_layout.size,
+			  module->init_layout.base, module->init_layout.size,
 			  table_start, table_size,
 			  NULL, 0);
 

arch/arm/kernel/module-plts.c

@@ -32,7 +32,7 @@ struct plt_entries {
 
 static bool in_init(const struct module *mod, u32 addr)
 {
-	return addr - (u32)mod->module_init < mod->init_size;
+	return addr - (u32)mod->init_layout.base < mod->init_layout.size;
 }
 
 u32 get_module_plt(struct module *mod, unsigned long loc, Elf32_Addr val)

arch/avr32/kernel/module.c

@@ -118,9 +118,9 @@ int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 	 * Increase core size to make room for GOT and set start
 	 * offset for GOT.
 	 */
-	module->core_size = ALIGN(module->core_size, 4);
-	module->arch.got_offset = module->core_size;
-	module->core_size += module->arch.got_size;
+	module->core_layout.size = ALIGN(module->core_layout.size, 4);
+	module->arch.got_offset = module->core_layout.size;
+	module->core_layout.size += module->arch.got_size;
 
 	return 0;
 
@@ -177,7 +177,7 @@ int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
 			if (!info->got_initialized) {
 				Elf32_Addr *gotent;
 
-				gotent = (module->module_core
+				gotent = (module->core_layout.base
 					  + module->arch.got_offset
 					  + info->got_offset);
 				*gotent = relocation;
@@ -255,8 +255,8 @@ int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
 			 */
 			pr_debug("GOTPC: PC=0x%x, got_offset=0x%lx, core=0x%p\n",
 				 relocation, module->arch.got_offset,
-				 module->module_core);
-			relocation -= ((unsigned long)module->module_core
+				 module->core_layout.base);
+			relocation -= ((unsigned long)module->core_layout.base
 				       + module->arch.got_offset);
 			*location = relocation;
 			break;

arch/ia64/kernel/module.c

@@ -486,13 +486,13 @@ module_frob_arch_sections (Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, char *secstrings,
 static inline int
 in_init (const struct module *mod, uint64_t addr)
 {
-	return addr - (uint64_t) mod->module_init < mod->init_size;
+	return addr - (uint64_t) mod->init_layout.base < mod->init_layout.size;
 }
 
 static inline int
 in_core (const struct module *mod, uint64_t addr)
 {
-	return addr - (uint64_t) mod->module_core < mod->core_size;
+	return addr - (uint64_t) mod->core_layout.base < mod->core_layout.size;
 }
 
 static inline int
@@ -675,7 +675,7 @@ do_reloc (struct module *mod, uint8_t r_type, Elf64_Sym *sym, uint64_t addend,
 		break;
 
 	      case RV_BDREL:
-		val -= (uint64_t) (in_init(mod, val) ? mod->module_init : mod->module_core);
+		val -= (uint64_t) (in_init(mod, val) ? mod->init_layout.base : mod->core_layout.base);
 		break;
 
 	      case RV_LTV:
@@ -810,15 +810,15 @@ apply_relocate_add (Elf64_Shdr *sechdrs, const char *strtab, unsigned int symind
 		 *     addresses have been selected...
 		 */
 		uint64_t gp;
-		if (mod->core_size > MAX_LTOFF)
+		if (mod->core_layout.size > MAX_LTOFF)
 			/*
 			 * This takes advantage of fact that SHF_ARCH_SMALL gets allocated
 			 * at the end of the module.
 			 */
-			gp = mod->core_size - MAX_LTOFF / 2;
+			gp = mod->core_layout.size - MAX_LTOFF / 2;
 		else
-			gp = mod->core_size / 2;
-		gp = (uint64_t) mod->module_core + ((gp + 7) & -8);
+			gp = mod->core_layout.size / 2;
+		gp = (uint64_t) mod->core_layout.base + ((gp + 7) & -8);
 		mod->arch.gp = gp;
 		DEBUGP("%s: placing gp at 0x%lx\n", __func__, gp);
 	}

arch/metag/kernel/module.c

@@ -176,8 +176,8 @@ static uint32_t do_plt_call(void *location, Elf32_Addr val,
 	tramp[1] = 0xac000001 | ((val & 0x0000ffff) << 3);
 
 	/* Init, or core PLT? */
-	if (location >= mod->module_core
-	    && location < mod->module_core + mod->core_size)
+	if (location >= mod->core_layout.base
+	    && location < mod->core_layout.base + mod->core_layout.size)
 		entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr;
 	else
 		entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr;

arch/mips/kernel/vpe.c

@@ -205,11 +205,11 @@ static void layout_sections(struct module *mod, const Elf_Ehdr *hdr,
 			    || s->sh_entsize != ~0UL)
 				continue;
 			s->sh_entsize =
-				get_offset((unsigned long *)&mod->core_size, s);
+				get_offset((unsigned long *)&mod->core_layout.size, s);
 		}
 
 		if (m == 0)
-			mod->core_text_size = mod->core_size;
+			mod->core_layout.text_size = mod->core_layout.size;
 
 	}
 }
@@ -641,7 +641,7 @@ static int vpe_elfload(struct vpe *v)
 		layout_sections(&mod, hdr, sechdrs, secstrings);
 	}
 
-	v->load_addr = alloc_progmem(mod.core_size);
+	v->load_addr = alloc_progmem(mod.core_layout.size);
 	if (!v->load_addr)
 		return -ENOMEM;
 

arch/parisc/kernel/module.c

@@ -42,9 +42,9 @@
  *      We are not doing SEGREL32 handling correctly. According to the ABI, we
  *      should do a value offset, like this:
  *			if (in_init(me, (void *)val))
- *				val -= (uint32_t)me->module_init;
+ *				val -= (uint32_t)me->init_layout.base;
  *			else
- *				val -= (uint32_t)me->module_core;
+ *				val -= (uint32_t)me->core_layout.base;
  *	However, SEGREL32 is used only for PARISC unwind entries, and we want
  *	those entries to have an absolute address, and not just an offset.
  *
@@ -100,14 +100,14 @@
  * or init pieces the location is */
 static inline int in_init(struct module *me, void *loc)
 {
-	return (loc >= me->module_init &&
-		loc <= (me->module_init + me->init_size));
+	return (loc >= me->init_layout.base &&
+		loc <= (me->init_layout.base + me->init_layout.size));
 }
 
 static inline int in_core(struct module *me, void *loc)
 {
-	return (loc >= me->module_core &&
-		loc <= (me->module_core + me->core_size));
+	return (loc >= me->core_layout.base &&
+		loc <= (me->core_layout.base + me->core_layout.size));
 }
 
 static inline int in_local(struct module *me, void *loc)
@@ -367,13 +367,13 @@ int module_frob_arch_sections(CONST Elf_Ehdr *hdr,
 	}
 
 	/* align things a bit */
-	me->core_size = ALIGN(me->core_size, 16);
-	me->arch.got_offset = me->core_size;
-	me->core_size += gots * sizeof(struct got_entry);
+	me->core_layout.size = ALIGN(me->core_layout.size, 16);
+	me->arch.got_offset = me->core_layout.size;
+	me->core_layout.size += gots * sizeof(struct got_entry);
 
-	me->core_size = ALIGN(me->core_size, 16);
-	me->arch.fdesc_offset = me->core_size;
-	me->core_size += fdescs * sizeof(Elf_Fdesc);
+	me->core_layout.size = ALIGN(me->core_layout.size, 16);
+	me->arch.fdesc_offset = me->core_layout.size;
+	me->core_layout.size += fdescs * sizeof(Elf_Fdesc);
 
 	me->arch.got_max = gots;
 	me->arch.fdesc_max = fdescs;
@@ -391,7 +391,7 @@ static Elf64_Word get_got(struct module *me, unsigned long value, long addend)
 
 	BUG_ON(value == 0);
 
-	got = me->module_core + me->arch.got_offset;
+	got = me->core_layout.base + me->arch.got_offset;
 	for (i = 0; got[i].addr; i++)
 		if (got[i].addr == value)
 			goto out;
@@ -409,7 +409,7 @@ static Elf64_Word get_got(struct module *me, unsigned long value, long addend)
 #ifdef CONFIG_64BIT
 static Elf_Addr get_fdesc(struct module *me, unsigned long value)
 {
-	Elf_Fdesc *fdesc = me->module_core + me->arch.fdesc_offset;
+	Elf_Fdesc *fdesc = me->core_layout.base + me->arch.fdesc_offset;
 
 	if (!value) {
 		printk(KERN_ERR "%s: zero OPD requested!\n", me->name);
@@ -427,7 +427,7 @@ static Elf_Addr get_fdesc(struct module *me, unsigned long value)
 
 	/* Create new one */
 	fdesc->addr = value;
-	fdesc->gp = (Elf_Addr)me->module_core + me->arch.got_offset;
+	fdesc->gp = (Elf_Addr)me->core_layout.base + me->arch.got_offset;
 	return (Elf_Addr)fdesc;
 }
 #endif /* CONFIG_64BIT */
@@ -839,7 +839,7 @@ register_unwind_table(struct module *me,
 
 	table = (unsigned char *)sechdrs[me->arch.unwind_section].sh_addr;
 	end = table + sechdrs[me->arch.unwind_section].sh_size;
-	gp = (Elf_Addr)me->module_core + me->arch.got_offset;
+	gp = (Elf_Addr)me->core_layout.base + me->arch.got_offset;
 
 	DEBUGP("register_unwind_table(), sect = %d at 0x%p - 0x%p (gp=0x%lx)\n",
 	       me->arch.unwind_section, table, end, gp);

arch/powerpc/kernel/module_32.c

@@ -188,8 +188,8 @@ static uint32_t do_plt_call(void *location,
 
 	pr_debug("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location);
 	/* Init, or core PLT? */
-	if (location >= mod->module_core
-	    && location < mod->module_core + mod->core_size)
+	if (location >= mod->core_layout.base
+	    && location < mod->core_layout.base + mod->core_layout.size)
 		entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr;
 	else
 		entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr;
@@ -296,7 +296,7 @@ int apply_relocate_add(Elf32_Shdr *sechdrs,
 	}
 #ifdef CONFIG_DYNAMIC_FTRACE
 	module->arch.tramp =
-		do_plt_call(module->module_core,
+		do_plt_call(module->core_layout.base,
 			    (unsigned long)ftrace_caller,
 			    sechdrs, module);
 #endif

arch/s390/kernel/module.c

@@ -159,11 +159,11 @@ int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 
 	/* Increase core size by size of got & plt and set start
 	   offsets for got and plt. */
-	me->core_size = ALIGN(me->core_size, 4);
-	me->arch.got_offset = me->core_size;
-	me->core_size += me->arch.got_size;
-	me->arch.plt_offset = me->core_size;
-	me->core_size += me->arch.plt_size;
+	me->core_layout.size = ALIGN(me->core_layout.size, 4);
+	me->arch.got_offset = me->core_layout.size;
+	me->core_layout.size += me->arch.got_size;
+	me->arch.plt_offset = me->core_layout.size;
+	me->core_layout.size += me->arch.plt_size;
 	return 0;
 }
 
@@ -279,7 +279,7 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
 		if (info->got_initialized == 0) {
 			Elf_Addr *gotent;
 
-			gotent = me->module_core + me->arch.got_offset +
+			gotent = me->core_layout.base + me->arch.got_offset +
 				info->got_offset;
 			*gotent = val;
 			info->got_initialized = 1;
@@ -302,7 +302,7 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
 			rc = apply_rela_bits(loc, val, 0, 64, 0);
 		else if (r_type == R_390_GOTENT ||
 			 r_type == R_390_GOTPLTENT) {
-			val += (Elf_Addr) me->module_core - loc;
+			val += (Elf_Addr) me->core_layout.base - loc;
 			rc = apply_rela_bits(loc, val, 1, 32, 1);
 		}
 		break;
@@ -315,7 +315,7 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
 	case R_390_PLTOFF64:	/* 16 bit offset from GOT to PLT. */
 		if (info->plt_initialized == 0) {
 			unsigned int *ip;
-			ip = me->module_core + me->arch.plt_offset +
+			ip = me->core_layout.base + me->arch.plt_offset +
 				info->plt_offset;
 			ip[0] = 0x0d10e310; /* basr 1,0; lg 1,10(1); br 1 */
 			ip[1] = 0x100a0004;
@@ -334,7 +334,7 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
 			       val - loc + 0xffffUL < 0x1ffffeUL) ||
 			      (r_type == R_390_PLT32DBL &&
 			       val - loc + 0xffffffffULL < 0x1fffffffeULL)))
-				val = (Elf_Addr) me->module_core +
+				val = (Elf_Addr) me->core_layout.base +
 					me->arch.plt_offset +
 					info->plt_offset;
 			val += rela->r_addend - loc;
@@ -356,7 +356,7 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
 	case R_390_GOTOFF32:	/* 32 bit offset to GOT.  */
 	case R_390_GOTOFF64:	/* 64 bit offset to GOT. */
 		val = val + rela->r_addend -
-			((Elf_Addr) me->module_core + me->arch.got_offset);
+			((Elf_Addr) me->core_layout.base + me->arch.got_offset);
 		if (r_type == R_390_GOTOFF16)
 			rc = apply_rela_bits(loc, val, 0, 16, 0);
 		else if (r_type == R_390_GOTOFF32)
@@ -366,7 +366,7 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
 		break;
 	case R_390_GOTPC:	/* 32 bit PC relative offset to GOT. */
 	case R_390_GOTPCDBL:	/* 32 bit PC rel. off. to GOT shifted by 1. */
-		val = (Elf_Addr) me->module_core + me->arch.got_offset +
+		val = (Elf_Addr) me->core_layout.base + me->arch.got_offset +
 			rela->r_addend - loc;
 		if (r_type == R_390_GOTPC)
 			rc = apply_rela_bits(loc, val, 1, 32, 0);

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>
 
@@ -38,11 +36,10 @@
 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->module_core;
-	unsigned long core_size = mod->core_size;
+	unsigned long core = (unsigned long)mod->core_layout.base;
+	unsigned long core_size = mod->core_layout.size;
 
 	switch (type) {
 	case R_X86_64_NONE:
@@ -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_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);
 }

include/linux/livepatch.h

@@ -37,8 +37,9 @@ enum klp_state {
  * struct klp_func - function structure for live patching
  * @old_name:	name of the function to be patched
  * @new_func:	pointer to the patched function code
- * @old_addr:	a hint conveying at what address the old function
- *		can be found (optional, vmlinux patches only)
+ * @old_sympos: a hint indicating which symbol position the old function
+ *		can be found (optional)
+ * @old_addr:	the address of the function being patched
  * @kobj:	kobject for sysfs resources
  * @state:	tracks function-level patch application state
  * @stack_node:	list node for klp_ops func_stack list
@@ -48,16 +49,16 @@ struct klp_func {
 	const char *old_name;
 	void *new_func;
 	/*
-	 * The old_addr field is optional and can be used to resolve
-	 * duplicate symbol names in the vmlinux object.  If this
-	 * information is not present, the symbol is located by name
-	 * with kallsyms. If the name is not unique and old_addr is
-	 * not provided, the patch application fails as there is no
-	 * way to resolve the ambiguity.
+	 * The old_sympos field is optional and can be used to resolve
+	 * duplicate symbol names in livepatch objects. If this field is zero,
+	 * it is expected the symbol is unique, otherwise patching fails. If
+	 * this value is greater than zero then that occurrence of the symbol
+	 * in kallsyms for the given object is used.
 	 */
-	unsigned long old_addr;
+	unsigned long old_sympos;
 
 	/* internal */
+	unsigned long old_addr;
 	struct kobject kobj;
 	enum klp_state state;
 	struct list_head stack_node;
@@ -66,8 +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
@@ -75,7 +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;

include/linux/module.h

@@ -302,6 +302,28 @@ struct mod_tree_node {
 	struct latch_tree_node node;
 };
 
+struct module_layout {
+	/* The actual code + data. */
+	void *base;
+	/* Total size. */
+	unsigned int size;
+	/* The size of the executable code.  */
+	unsigned int text_size;
+	/* Size of RO section of the module (text+rodata) */
+	unsigned int ro_size;
+
+#ifdef CONFIG_MODULES_TREE_LOOKUP
+	struct mod_tree_node mtn;
+#endif
+};
+
+#ifdef CONFIG_MODULES_TREE_LOOKUP
+/* Only touch one cacheline for common rbtree-for-core-layout case. */
+#define __module_layout_align ____cacheline_aligned
+#else
+#define __module_layout_align
+#endif
+
 struct module {
 	enum module_state state;
 
@@ -366,37 +388,9 @@ struct module {
 	/* Startup function. */
 	int (*init)(void);
 
-	/*
-	 * If this is non-NULL, vfree() after init() returns.
-	 *
-	 * Cacheline align here, such that:
-	 *   module_init, module_core, init_size, core_size,
-	 *   init_text_size, core_text_size and mtn_core::{mod,node[0]}
-	 * are on the same cacheline.
-	 */
-	void *module_init	____cacheline_aligned;
-
-	/* Here is the actual code + data, vfree'd on unload. */
-	void *module_core;
-
-	/* Here are the sizes of the init and core sections */
-	unsigned int init_size, core_size;
-
-	/* The size of the executable code in each section.  */
-	unsigned int init_text_size, core_text_size;
-
-#ifdef CONFIG_MODULES_TREE_LOOKUP
-	/*
-	 * We want mtn_core::{mod,node[0]} to be in the same cacheline as the
-	 * above entries such that a regular lookup will only touch one
-	 * cacheline.
-	 */
-	struct mod_tree_node	mtn_core;
-	struct mod_tree_node	mtn_init;
-#endif
-
-	/* Size of RO sections of the module (text+rodata) */
-	unsigned int init_ro_size, core_ro_size;
+	/* Core layout: rbtree is accessed frequently, so keep together. */
+	struct module_layout core_layout __module_layout_align;
+	struct module_layout init_layout;
 
 	/* Arch-specific module values */
 	struct mod_arch_specific arch;
@@ -505,15 +499,15 @@ bool is_module_text_address(unsigned long addr);
 static inline bool within_module_core(unsigned long addr,
 				      const struct module *mod)
 {
-	return (unsigned long)mod->module_core <= addr &&
-	       addr < (unsigned long)mod->module_core + mod->core_size;
+	return (unsigned long)mod->core_layout.base <= addr &&
+	       addr < (unsigned long)mod->core_layout.base + mod->core_layout.size;
 }
 
 static inline bool within_module_init(unsigned long addr,
 				      const struct module *mod)
 {
-	return (unsigned long)mod->module_init <= addr &&
-	       addr < (unsigned long)mod->module_init + mod->init_size;
+	return (unsigned long)mod->init_layout.base <= addr &&
+	       addr < (unsigned long)mod->init_layout.base + mod->init_layout.size;
 }
 
 static inline bool within_module(unsigned long addr, const struct module *mod)
@@ -768,9 +762,13 @@ extern int module_sysfs_initialized;
 #ifdef CONFIG_DEBUG_SET_MODULE_RONX
 extern void set_all_modules_text_rw(void);
 extern void set_all_modules_text_ro(void);
+extern void module_enable_ro(const struct module *mod);
+extern void module_disable_ro(const struct module *mod);
 #else
 static inline void set_all_modules_text_rw(void) { }
 static inline void set_all_modules_text_ro(void) { }
+static inline void module_enable_ro(const struct module *mod) { }
+static inline void module_disable_ro(const struct module *mod) { }
 #endif
 
 #ifdef CONFIG_GENERIC_BUG

kernel/debug/kdb/kdb_main.c

@@ -2021,7 +2021,7 @@ static int kdb_lsmod(int argc, const char **argv)
 			continue;
 
 		kdb_printf("%-20s%8u  0x%p ", mod->name,
-			   mod->core_size, (void *)mod);
+			   mod->core_layout.size, (void *)mod);
 #ifdef CONFIG_MODULE_UNLOAD
 		kdb_printf("%4d ", module_refcount(mod));
 #endif
@@ -2031,7 +2031,7 @@ static int kdb_lsmod(int argc, const char **argv)
 			kdb_printf(" (Loading)");
 		else
 			kdb_printf(" (Live)");
-		kdb_printf(" 0x%p", mod->module_core);
+		kdb_printf(" 0x%p", mod->core_layout.base);
 
 #ifdef CONFIG_MODULE_UNLOAD
 		{

kernel/gcov/base.c

@@ -123,11 +123,6 @@ void gcov_enable_events(void)
 }
 
 #ifdef CONFIG_MODULES
-static inline int within(void *addr, void *start, unsigned long size)
-{
-	return ((addr >= start) && (addr < start + size));
-}
-
 /* Update list and generate events when modules are unloaded. */
 static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
 				void *data)
@@ -142,7 +137,7 @@ static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
 
 	/* Remove entries located in module from linked list. */
 	while ((info = gcov_info_next(info))) {
-		if (within(info, mod->module_core, mod->core_size)) {
+		if (within_module((unsigned long)info, mod)) {
 			gcov_info_unlink(prev, info);
 			if (gcov_events_enabled)
 				gcov_event(GCOV_REMOVE, info);

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
@@ -135,13 +136,8 @@ struct klp_find_arg {
 	const char *objname;
 	const char *name;
 	unsigned long addr;
-	/*
-	 * If count == 0, the symbol was not found. If count == 1, a unique
-	 * match was found and addr is set.  If count > 1, there is
-	 * unresolvable ambiguity among "count" number of symbols with the same
-	 * name in the same object.
-	 */
 	unsigned long count;
+	unsigned long pos;
 };
 
 static int klp_find_callback(void *data, const char *name,
@@ -158,37 +154,48 @@ static int klp_find_callback(void *data, const char *name,
 	if (args->objname && strcmp(args->objname, mod->name))
 		return 0;
 
-	/*
-	 * args->addr might be overwritten if another match is found
-	 * but klp_find_object_symbol() handles this and only returns the
-	 * addr if count == 1.
-	 */
 	args->addr = addr;
 	args->count++;
 
+	/*
+	 * Finish the search when the symbol is found for the desired position
+	 * or the position is not defined for a non-unique symbol.
+	 */
+	if ((args->pos && (args->count == args->pos)) ||
+	    (!args->pos && (args->count > 1)))
+		return 1;
+
 	return 0;
 }
 
 static int klp_find_object_symbol(const char *objname, const char *name,
-				  unsigned long *addr)
+				  unsigned long sympos, unsigned long *addr)
 {
 	struct klp_find_arg args = {
 		.objname = objname,
 		.name = name,
 		.addr = 0,
-		.count = 0
+		.count = 0,
+		.pos = sympos,
 	};
 
 	mutex_lock(&module_mutex);
 	kallsyms_on_each_symbol(klp_find_callback, &args);
 	mutex_unlock(&module_mutex);
 
-	if (args.count == 0)
+	/*
+	 * Ensure an address was found. If sympos is 0, ensure symbol is unique;
+	 * otherwise ensure the symbol position count matches sympos.
+	 */
+	if (args.addr == 0)
 		pr_err("symbol '%s' not found in symbol table\n", name);
-	else if (args.count > 1)
+	else if (args.count > 1 && sympos == 0) {
 		pr_err("unresolvable ambiguity (%lu matches) on symbol '%s' in object '%s'\n",
 		       args.count, name, objname);
-	else {
+	} else if (sympos != args.count && sympos > 0) {
+		pr_err("symbol position %lu for symbol '%s' in object '%s' not found\n",
+		       sympos, name, objname ? objname : "vmlinux");
+	} else {
 		*addr = args.addr;
 		return 0;
 	}
@@ -197,66 +204,6 @@ 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;
-}
-
-static int klp_find_verify_func_addr(struct klp_object *obj,
-				     struct klp_func *func)
-{
-	int ret;
-
-#if defined(CONFIG_RANDOMIZE_BASE)
-	/* If KASLR has been enabled, adjust old_addr accordingly */
-	if (kaslr_enabled() && func->old_addr)
-		func->old_addr += kaslr_offset();
-#endif
-
-	if (!func->old_addr || klp_is_module(obj))
-		ret = klp_find_object_symbol(obj->name, func->old_name,
-					     &func->old_addr);
-	else
-		ret = klp_verify_vmlinux_symbol(func->old_name,
-						func->old_addr);
-
-	return ret;
-}
-
 /*
  * external symbols are located outside the parent object (where the parent
  * object is either vmlinux or the kmod being patched).
@@ -276,14 +223,18 @@ static int klp_find_external_symbol(struct module *pmod, const char *name,
 	}
 	preempt_enable();
 
-	/* otherwise check if it's in another .o within the patch module */
-	return klp_find_object_symbol(pmod->name, name, addr);
+	/*
+	 * Check if it's in another .o within the patch module. This also
+	 * checks that the external symbol is unique.
+	 */
+	return klp_find_object_symbol(pmod->name, name, 0, addr);
 }
 
 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;
 
 	if (WARN_ON(!klp_is_object_loaded(obj)))
@@ -292,41 +243,38 @@ 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++) {
-		if (!klp_is_module(obj)) {
-
-#if defined(CONFIG_RANDOMIZE_BASE)
-			/* If KASLR has been enabled, adjust old value accordingly */
-			if (kaslr_enabled())
-				reloc->val += kaslr_offset();
-#endif
-			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,
-							     &reloc->val);
-			if (ret)
-				return ret;
-		}
+		/* 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);
+				ret = -EINVAL;
+				goto out;
+			}
+			ret = klp_find_external_symbol(pmod, reloc->name, &val);
+		} else
+			ret = klp_find_object_symbol(obj->name,
+						     reloc->name,
+						     reloc->sympos,
+						     &val);
+		if (ret)
+			goto out;
+
 		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);
-			return ret;
+			       reloc->name, val, ret);
+			goto out;
 		}
 	}
 
-	return 0;
+out:
+	module_enable_ro(pmod);
+	return ret;
 }
 
 static void notrace klp_ftrace_handler(unsigned long ip,
@@ -593,7 +541,7 @@ EXPORT_SYMBOL_GPL(klp_enable_patch);
  * /sys/kernel/livepatch/<patch>
  * /sys/kernel/livepatch/<patch>/enabled
  * /sys/kernel/livepatch/<patch>/<object>
- * /sys/kernel/livepatch/<patch>/<object>/<func>
+ * /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
  */
 
 static ssize_t enabled_store(struct kobject *kobj, struct kobj_attribute *attr,
@@ -738,8 +686,14 @@ static int klp_init_func(struct klp_object *obj, struct klp_func *func)
 	INIT_LIST_HEAD(&func->stack_node);
 	func->state = KLP_DISABLED;
 
+	/* The format for the sysfs directory is <function,sympos> where sympos
+	 * is the nth occurrence of this symbol in kallsyms for the patched
+	 * object. If the user selects 0 for old_sympos, then 1 will be used
+	 * since a unique symbol will be the first occurrence.
+	 */
 	return kobject_init_and_add(&func->kobj, &klp_ktype_func,
-				    &obj->kobj, "%s", func->old_name);
+				    &obj->kobj, "%s,%lu", func->old_name,
+				    func->old_sympos ? func->old_sympos : 1);
 }
 
 /* parts of the initialization that is done only when the object is loaded */
@@ -756,7 +710,9 @@ static int klp_init_object_loaded(struct klp_patch *patch,
 	}
 
 	klp_for_each_func(obj, func) {
-		ret = klp_find_verify_func_addr(obj, func);
+		ret = klp_find_object_symbol(obj->name, func->old_name,
+					     func->old_sympos,
+					     &func->old_addr);
 		if (ret)
 			return ret;
 	}