diff options
Diffstat (limited to 'arch/parisc/kernel')
| -rw-r--r-- | arch/parisc/kernel/module.c | 216 |
1 files changed, 135 insertions, 81 deletions
diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c index 44138c3e6ea7..9013243cecca 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; |
