Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  module: convert to stop_machine_create/destroy.
  stop_machine: introduce stop_machine_create/destroy.
  parisc: fix module loading failure of large kernel modules
  module: fix module loading failure of large kernel modules for parisc
  module: fix warning of unused function when !CONFIG_PROC_FS
  kernel/module.c: compare symbol values when marking symbols as exported in /proc/kallsyms.
  remove CONFIG_KMOD

2 files changed, 139 insertions, 83 deletions

diff --git a/arch/parisc/include/asm/module.h b/arch/parisc/include/asm/module.h
index c2cb49e..1f41234 100644
--- a/arch/parisc/include/asm/module.h
+++ b/arch/parisc/include/asm/module.h
@@ -23,8 +23,10 @@ struct mod_arch_specific
 {
 	unsigned long got_offset, got_count, got_max;
 	unsigned long fdesc_offset, fdesc_count, fdesc_max;
-	unsigned long stub_offset, stub_count, stub_max;
-	unsigned long init_stub_offset, init_stub_count, init_stub_max;
+	struct {
+		unsigned long stub_offset;
+		unsigned int stub_entries;
+		} *section;
 	int unwind_section;
 	struct unwind_table *unwind;
 };
diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index 44138c3..9013243 100644
--- a/arch/parisc/kernel/module.c
+++ b/arch/parisc/kernel/module.c
@@ -6,6 +6,7 @@
  *
  *    Linux/PA-RISC Project (http://www.parisc-linux.org/)
  *    Copyright (C) 2003 Randolph Chung <tausq at debian . org>
+ *    Copyright (C) 2008 Helge Deller <deller@gmx.de>
  *
  *
  *    This program is free software; you can redistribute it and/or modify
@@ -24,6 +25,19 @@
  *
  *
  *    Notes:
+ *    - PLT stub handling
+ *      On 32bit (and sometimes 64bit) and with big kernel modules like xfs or
+ *      ipv6 the relocation types R_PARISC_PCREL17F and R_PARISC_PCREL22F may
+ *      fail to reach their PLT stub if we only create one big stub array for
+ *      all sections at the beginning of the core or init section.
+ *      Instead we now insert individual PLT stub entries directly in front of
+ *      of the code sections where the stubs are actually called.
+ *      This reduces the distance between the PCREL location and the stub entry
+ *      so that the relocations can be fulfilled.
+ *      While calculating the final layout of the kernel module in memory, the
+ *      kernel module loader calls arch_mod_section_prepend() to request the
+ *      to be reserved amount of memory in front of each individual section.
+ *
  *    - SEGREL32 handling
  *      We are not doing SEGREL32 handling correctly. According to the ABI, we
  *      should do a value offset, like this:
@@ -58,9 +72,13 @@
 #define DEBUGP(fmt...)
 #endif
 
+#define RELOC_REACHABLE(val, bits) \
+	(( ( !((val) & (1<<((bits)-1))) && ((val)>>(bits)) != 0 )  ||	\
+	     ( ((val) & (1<<((bits)-1))) && ((val)>>(bits)) != (((__typeof__(val))(~0))>>((bits)+2)))) ? \
+	0 : 1)
+
 #define CHECK_RELOC(val, bits) \
-	if ( ( !((val) & (1<<((bits)-1))) && ((val)>>(bits)) != 0 )  ||	\
-	     ( ((val) & (1<<((bits)-1))) && ((val)>>(bits)) != (((__typeof__(val))(~0))>>((bits)+2)))) { \
+	if (!RELOC_REACHABLE(val, bits)) { \
 		printk(KERN_ERR "module %s relocation of symbol %s is out of range (0x%lx in %d bits)\n", \
 		me->name, strtab + sym->st_name, (unsigned long)val, bits); \
 		return -ENOEXEC;			\
@@ -92,13 +110,6 @@ static inline int in_local(struct module *me, void *loc)
 	return in_init(me, loc) || in_core(me, loc);
 }
 
-static inline int in_local_section(struct module *me, void *loc, void *dot)
-{
-	return (in_init(me, loc) && in_init(me, dot)) ||
-		(in_core(me, loc) && in_core(me, dot));
-}
-
-
 #ifndef CONFIG_64BIT
 struct got_entry {
 	Elf32_Addr addr;
@@ -258,23 +269,42 @@ static inline unsigned long count_stubs(const Elf_Rela *rela, unsigned long n)
 /* Free memory returned from module_alloc */
 void module_free(struct module *mod, void *module_region)
 {
+	kfree(mod->arch.section);
+	mod->arch.section = NULL;
+
 	vfree(module_region);
 	/* FIXME: If module_region == mod->init_region, trim exception
            table entries. */
 }
 
+/* Additional bytes needed in front of individual sections */
+unsigned int arch_mod_section_prepend(struct module *mod,
+				      unsigned int section)
+{
+	/* size needed for all stubs of this section (including
+	 * one additional for correct alignment of the stubs) */
+	return (mod->arch.section[section].stub_entries + 1)
+		* sizeof(struct stub_entry);
+}
+
 #define CONST 
 int module_frob_arch_sections(CONST Elf_Ehdr *hdr,
 			      CONST Elf_Shdr *sechdrs,
 			      CONST char *secstrings,
 			      struct module *me)
 {
-	unsigned long gots = 0, fdescs = 0, stubs = 0, init_stubs = 0;
+	unsigned long gots = 0, fdescs = 0, len;
 	unsigned int i;
 
+	len = hdr->e_shnum * sizeof(me->arch.section[0]);
+	me->arch.section = kzalloc(len, GFP_KERNEL);
+	if (!me->arch.section)
+		return -ENOMEM;
+
 	for (i = 1; i < hdr->e_shnum; i++) {
-		const Elf_Rela *rels = (void *)hdr + sechdrs[i].sh_offset;
+		const Elf_Rela *rels = (void *)sechdrs[i].sh_addr;
 		unsigned long nrels = sechdrs[i].sh_size / sizeof(*rels);
+		unsigned int count, s;
 
 		if (strncmp(secstrings + sechdrs[i].sh_name,
 			    ".PARISC.unwind", 14) == 0)
@@ -290,11 +320,23 @@ int module_frob_arch_sections(CONST Elf_Ehdr *hdr,
 		 */
 		gots += count_gots(rels, nrels);
 		fdescs += count_fdescs(rels, nrels);
-		if(strncmp(secstrings + sechdrs[i].sh_name,
-			   ".rela.init", 10) == 0)
-			init_stubs += count_stubs(rels, nrels);
-		else
-			stubs += count_stubs(rels, nrels);
+
+		/* XXX: By sorting the relocs and finding duplicate entries
+		 *  we could reduce the number of necessary stubs and save
+		 *  some memory. */
+		count = count_stubs(rels, nrels);
+		if (!count)
+			continue;
+
+		/* so we need relocation stubs. reserve necessary memory. */
+		/* sh_info gives the section for which we need to add stubs. */
+		s = sechdrs[i].sh_info;
+
+		/* each code section should only have one relocation section */
+		WARN_ON(me->arch.section[s].stub_entries);
+
+		/* store number of stubs we need for this section */
+		me->arch.section[s].stub_entries += count;
 	}
 
 	/* align things a bit */
@@ -306,18 +348,8 @@ int module_frob_arch_sections(CONST Elf_Ehdr *hdr,
 	me->arch.fdesc_offset = me->core_size;
 	me->core_size += fdescs * sizeof(Elf_Fdesc);
 
-	me->core_size = ALIGN(me->core_size, 16);
-	me->arch.stub_offset = me->core_size;
-	me->core_size += stubs * sizeof(struct stub_entry);
-
-	me->init_size = ALIGN(me->init_size, 16);
-	me->arch.init_stub_offset = me->init_size;
-	me->init_size += init_stubs * sizeof(struct stub_entry);
-
 	me->arch.got_max = gots;
 	me->arch.fdesc_max = fdescs;
-	me->arch.stub_max = stubs;
-	me->arch.init_stub_max = init_stubs;
 
 	return 0;
 }
@@ -380,23 +412,27 @@ enum elf_stub_type {
 };
 
 static Elf_Addr get_stub(struct module *me, unsigned long value, long addend,
-	enum elf_stub_type stub_type, int init_section)
+	enum elf_stub_type stub_type, Elf_Addr loc0, unsigned int targetsec)
 {
-	unsigned long i;
 	struct stub_entry *stub;
 
-	if(init_section) {
-		i = me->arch.init_stub_count++;
-		BUG_ON(me->arch.init_stub_count > me->arch.init_stub_max);
-		stub = me->module_init + me->arch.init_stub_offset + 
-			i * sizeof(struct stub_entry);
-	} else {
-		i = me->arch.stub_count++;
-		BUG_ON(me->arch.stub_count > me->arch.stub_max);
-		stub = me->module_core + me->arch.stub_offset + 
-			i * sizeof(struct stub_entry);
+	/* initialize stub_offset to point in front of the section */
+	if (!me->arch.section[targetsec].stub_offset) {
+		loc0 -= (me->arch.section[targetsec].stub_entries + 1) *
+				sizeof(struct stub_entry);
+		/* get correct alignment for the stubs */
+		loc0 = ALIGN(loc0, sizeof(struct stub_entry));
+		me->arch.section[targetsec].stub_offset = loc0;
 	}
 
+	/* get address of stub entry */
+	stub = (void *) me->arch.section[targetsec].stub_offset;
+	me->arch.section[targetsec].stub_offset += sizeof(struct stub_entry);
+
+	/* do not write outside available stub area */
+	BUG_ON(0 == me->arch.section[targetsec].stub_entries--);
+
+
 #ifndef CONFIG_64BIT
 /* for 32-bit the stub looks like this:
  * 	ldil L'XXX,%r1
@@ -489,15 +525,19 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 	Elf32_Addr val;
 	Elf32_Sword addend;
 	Elf32_Addr dot;
+	Elf_Addr loc0;
+	unsigned int targetsec = sechdrs[relsec].sh_info;
 	//unsigned long dp = (unsigned long)$global$;
 	register unsigned long dp asm ("r27");
 
 	DEBUGP("Applying relocate section %u to %u\n", relsec,
-	       sechdrs[relsec].sh_info);
+	       targetsec);
 	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 		/* This is where to make the change */
-		loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+		loc = (void *)sechdrs[targetsec].sh_addr
 		      + rel[i].r_offset;
+		/* This is the start of the target section */
+		loc0 = sechdrs[targetsec].sh_addr;
 		/* This is the symbol it is referring to */
 		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
 			+ ELF32_R_SYM(rel[i].r_info);
@@ -569,19 +609,32 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 			break;
 		case R_PARISC_PCREL17F:
 			/* 17-bit PC relative address */
-			val = get_stub(me, val, addend, ELF_STUB_GOT, in_init(me, loc));
+			/* calculate direct call offset */
+			val += addend;
 			val = (val - dot - 8)/4;
-			CHECK_RELOC(val, 17)
+			if (!RELOC_REACHABLE(val, 17)) {
+				/* direct distance too far, create
+				 * stub entry instead */
+				val = get_stub(me, sym->st_value, addend,
+					ELF_STUB_DIRECT, loc0, targetsec);
+				val = (val - dot - 8)/4;
+				CHECK_RELOC(val, 17);
+			}
 			*loc = (*loc & ~0x1f1ffd) | reassemble_17(val);
 			break;
 		case R_PARISC_PCREL22F:
 			/* 22-bit PC relative address; only defined for pa20 */
-			val = get_stub(me, val, addend, ELF_STUB_GOT, in_init(me, loc));
-			DEBUGP("STUB FOR %s loc %lx+%lx at %lx\n", 
-			       strtab + sym->st_name, (unsigned long)loc, addend, 
-			       val)
+			/* calculate direct call offset */
+			val += addend;
 			val = (val - dot - 8)/4;
-			CHECK_RELOC(val, 22);
+			if (!RELOC_REACHABLE(val, 22)) {
+				/* direct distance too far, create
+				 * stub entry instead */
+				val = get_stub(me, sym->st_value, addend,
+					ELF_STUB_DIRECT, loc0, targetsec);
+				val = (val - dot - 8)/4;
+				CHECK_RELOC(val, 22);
+			}
 			*loc = (*loc & ~0x3ff1ffd) | reassemble_22(val);
 			break;
 
@@ -610,13 +663,17 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 	Elf64_Addr val;
 	Elf64_Sxword addend;
 	Elf64_Addr dot;
+	Elf_Addr loc0;
+	unsigned int targetsec = sechdrs[relsec].sh_info;
 
 	DEBUGP("Applying relocate section %u to %u\n", relsec,
-	       sechdrs[relsec].sh_info);
+	       targetsec);
 	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 		/* This is where to make the change */
-		loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+		loc = (void *)sechdrs[targetsec].sh_addr
 		      + rel[i].r_offset;
+		/* This is the start of the target section */
+		loc0 = sechdrs[targetsec].sh_addr;
 		/* This is the symbol it is referring to */
 		sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
 			+ ELF64_R_SYM(rel[i].r_info);
@@ -672,42 +729,40 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 			DEBUGP("PCREL22F Symbol %s loc %p val %lx\n",
 			       strtab + sym->st_name,
 			       loc, val);
+			val += addend;
 			/* can we reach it locally? */
-			if(!in_local_section(me, (void *)val, (void *)dot)) {
-
-				if (in_local(me, (void *)val))
-					/* this is the case where the
-					 * symbol is local to the
-					 * module, but in a different
-					 * section, so stub the jump
-					 * in case it's more than 22
-					 * bits away */
-					val = get_stub(me, val, addend, ELF_STUB_DIRECT,
-						       in_init(me, loc));
-				else if (strncmp(strtab + sym->st_name, "$$", 2)
+			if (in_local(me, (void *)val)) {
+				/* this is the case where the symbol is local
+				 * to the module, but in a different section,
+				 * so stub the jump in case it's more than 22
+				 * bits away */
+				val = (val - dot - 8)/4;
+				if (!RELOC_REACHABLE(val, 22)) {
+					/* direct distance too far, create
+					 * stub entry instead */
+					val = get_stub(me, sym->st_value,
+						addend, ELF_STUB_DIRECT,
+						loc0, targetsec);
+				} else {
+					/* Ok, we can reach it directly. */
+					val = sym->st_value;
+					val += addend;
+				}
+			} else {
+				val = sym->st_value;
+				if (strncmp(strtab + sym->st_name, "$$", 2)
 				    == 0)
 					val = get_stub(me, val, addend, ELF_STUB_MILLI,
-						       in_init(me, loc));
+						       loc0, targetsec);
 				else
 					val = get_stub(me, val, addend, ELF_STUB_GOT,
-						       in_init(me, loc));
+						       loc0, targetsec);
 			}
 			DEBUGP("STUB FOR %s loc %lx, val %lx+%lx at %lx\n", 
 			       strtab + sym->st_name, loc, sym->st_value,
 			       addend, val);
-			/* FIXME: local symbols work as long as the
-			 * core and init pieces aren't separated too
-			 * far.  If this is ever broken, you will trip
-			 * the check below.  The way to fix it would
-			 * be to generate local stubs to go between init
-			 * and core */
-			if((Elf64_Sxword)(val - dot - 8) > 0x800000 -1 ||
-			   (Elf64_Sxword)(val - dot - 8) < -0x800000) {
-				printk(KERN_ERR "Module %s, symbol %s is out of range for PCREL22F relocation\n",
-				       me->name, strtab + sym->st_name);
-				return -ENOEXEC;
-			}
 			val = (val - dot - 8)/4;
+			CHECK_RELOC(val, 22);
 			*loc = (*loc & ~0x3ff1ffd) | reassemble_22(val);
 			break;
 		case R_PARISC_DIR64:
@@ -794,12 +849,8 @@ int module_finalize(const Elf_Ehdr *hdr,
 	addr = (u32 *)entry->addr;
 	printk("INSNS: %x %x %x %x\n",
 	       addr[0], addr[1], addr[2], addr[3]);
-	printk("stubs used %ld, stubs max %ld\n"
-	       "init_stubs used %ld, init stubs max %ld\n"
-	       "got entries used %ld, gots max %ld\n"
+	printk("got entries used %ld, gots max %ld\n"
 	       "fdescs used %ld, fdescs max %ld\n",
-	       me->arch.stub_count, me->arch.stub_max,
-	       me->arch.init_stub_count, me->arch.init_stub_max,
 	       me->arch.got_count, me->arch.got_max,
 	       me->arch.fdesc_count, me->arch.fdesc_max);
 #endif
@@ -829,7 +880,10 @@ int module_finalize(const Elf_Ehdr *hdr,
 				me->name, me->arch.got_count, MAX_GOTS);
 		return -EINVAL;
 	}
-	
+
+	kfree(me->arch.section);
+	me->arch.section = NULL;
+
 	/* no symbol table */
 	if(symhdr == NULL)
 		return 0;