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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/mips/kernel/module.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | arch/mips/kernel/module.c | 453 |
1 files changed, 453 insertions, 0 deletions
diff --git a/arch/mips/kernel/module.c b/arch/mips/kernel/module.c new file mode 100644 index 000000000..0c936cbf2 --- /dev/null +++ b/arch/mips/kernel/module.c @@ -0,0 +1,453 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * + * Copyright (C) 2001 Rusty Russell. + * Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org) + * Copyright (C) 2005 Thiemo Seufer + */ + +#undef DEBUG + +#include <linux/extable.h> +#include <linux/moduleloader.h> +#include <linux/elf.h> +#include <linux/mm.h> +#include <linux/numa.h> +#include <linux/vmalloc.h> +#include <linux/slab.h> +#include <linux/fs.h> +#include <linux/string.h> +#include <linux/kernel.h> +#include <linux/spinlock.h> +#include <linux/jump_label.h> + +extern void jump_label_apply_nops(struct module *mod); + +struct mips_hi16 { + struct mips_hi16 *next; + Elf_Addr *addr; + Elf_Addr value; +}; + +static LIST_HEAD(dbe_list); +static DEFINE_SPINLOCK(dbe_lock); + +#ifdef MODULE_START +void *module_alloc(unsigned long size) +{ + return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END, + GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE, + __builtin_return_address(0)); +} +#endif + +static void apply_r_mips_32(u32 *location, u32 base, Elf_Addr v) +{ + *location = base + v; +} + +static int apply_r_mips_26(struct module *me, u32 *location, u32 base, + Elf_Addr v) +{ + if (v % 4) { + pr_err("module %s: dangerous R_MIPS_26 relocation\n", + me->name); + return -ENOEXEC; + } + + if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { + pr_err("module %s: relocation overflow\n", + me->name); + return -ENOEXEC; + } + + *location = (*location & ~0x03ffffff) | + ((base + (v >> 2)) & 0x03ffffff); + + return 0; +} + +static int apply_r_mips_hi16(struct module *me, u32 *location, Elf_Addr v, + bool rela) +{ + struct mips_hi16 *n; + + if (rela) { + *location = (*location & 0xffff0000) | + ((((long long) v + 0x8000LL) >> 16) & 0xffff); + return 0; + } + + /* + * We cannot relocate this one now because we don't know the value of + * the carry we need to add. Save the information, and let LO16 do the + * actual relocation. + */ + n = kmalloc(sizeof *n, GFP_KERNEL); + if (!n) + return -ENOMEM; + + n->addr = (Elf_Addr *)location; + n->value = v; + n->next = me->arch.r_mips_hi16_list; + me->arch.r_mips_hi16_list = n; + + return 0; +} + +static void free_relocation_chain(struct mips_hi16 *l) +{ + struct mips_hi16 *next; + + while (l) { + next = l->next; + kfree(l); + l = next; + } +} + +static int apply_r_mips_lo16(struct module *me, u32 *location, + u32 base, Elf_Addr v, bool rela) +{ + unsigned long insnlo = base; + struct mips_hi16 *l; + Elf_Addr val, vallo; + + if (rela) { + *location = (*location & 0xffff0000) | (v & 0xffff); + return 0; + } + + /* Sign extend the addend we extract from the lo insn. */ + vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000; + + if (me->arch.r_mips_hi16_list != NULL) { + l = me->arch.r_mips_hi16_list; + while (l != NULL) { + struct mips_hi16 *next; + unsigned long insn; + + /* + * The value for the HI16 had best be the same. + */ + if (v != l->value) + goto out_danger; + + /* + * Do the HI16 relocation. Note that we actually don't + * need to know anything about the LO16 itself, except + * where to find the low 16 bits of the addend needed + * by the LO16. + */ + insn = *l->addr; + val = ((insn & 0xffff) << 16) + vallo; + val += v; + + /* + * Account for the sign extension that will happen in + * the low bits. + */ + val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff; + + insn = (insn & ~0xffff) | val; + *l->addr = insn; + + next = l->next; + kfree(l); + l = next; + } + + me->arch.r_mips_hi16_list = NULL; + } + + /* + * Ok, we're done with the HI16 relocs. Now deal with the LO16. + */ + val = v + vallo; + insnlo = (insnlo & ~0xffff) | (val & 0xffff); + *location = insnlo; + + return 0; + +out_danger: + free_relocation_chain(l); + me->arch.r_mips_hi16_list = NULL; + + pr_err("module %s: dangerous R_MIPS_LO16 relocation\n", me->name); + + return -ENOEXEC; +} + +static int apply_r_mips_pc(struct module *me, u32 *location, u32 base, + Elf_Addr v, unsigned int bits) +{ + unsigned long mask = GENMASK(bits - 1, 0); + unsigned long se_bits; + long offset; + + if (v % 4) { + pr_err("module %s: dangerous R_MIPS_PC%u relocation\n", + me->name, bits); + return -ENOEXEC; + } + + /* retrieve & sign extend implicit addend if any */ + offset = base & mask; + offset |= (offset & BIT(bits - 1)) ? ~mask : 0; + + offset += ((long)v - (long)location) >> 2; + + /* check the sign bit onwards are identical - ie. we didn't overflow */ + se_bits = (offset & BIT(bits - 1)) ? ~0ul : 0; + if ((offset & ~mask) != (se_bits & ~mask)) { + pr_err("module %s: relocation overflow\n", me->name); + return -ENOEXEC; + } + + *location = (*location & ~mask) | (offset & mask); + + return 0; +} + +static int apply_r_mips_pc16(struct module *me, u32 *location, u32 base, + Elf_Addr v) +{ + return apply_r_mips_pc(me, location, base, v, 16); +} + +static int apply_r_mips_pc21(struct module *me, u32 *location, u32 base, + Elf_Addr v) +{ + return apply_r_mips_pc(me, location, base, v, 21); +} + +static int apply_r_mips_pc26(struct module *me, u32 *location, u32 base, + Elf_Addr v) +{ + return apply_r_mips_pc(me, location, base, v, 26); +} + +static int apply_r_mips_64(u32 *location, Elf_Addr v, bool rela) +{ + if (WARN_ON(!rela)) + return -EINVAL; + + *(Elf_Addr *)location = v; + + return 0; +} + +static int apply_r_mips_higher(u32 *location, Elf_Addr v, bool rela) +{ + if (WARN_ON(!rela)) + return -EINVAL; + + *location = (*location & 0xffff0000) | + ((((long long)v + 0x80008000LL) >> 32) & 0xffff); + + return 0; +} + +static int apply_r_mips_highest(u32 *location, Elf_Addr v, bool rela) +{ + if (WARN_ON(!rela)) + return -EINVAL; + + *location = (*location & 0xffff0000) | + ((((long long)v + 0x800080008000LL) >> 48) & 0xffff); + + return 0; +} + +/** + * reloc_handler() - Apply a particular relocation to a module + * @type: type of the relocation to apply + * @me: the module to apply the reloc to + * @location: the address at which the reloc is to be applied + * @base: the existing value at location for REL-style; 0 for RELA-style + * @v: the value of the reloc, with addend for RELA-style + * @rela: indication of is this a RELA (true) or REL (false) relocation + * + * Each implemented relocation function applies a particular type of + * relocation to the module @me. Relocs that may be found in either REL or RELA + * variants can be handled by making use of the @base & @v parameters which are + * set to values which abstract the difference away from the particular reloc + * implementations. + * + * Return: 0 upon success, else -ERRNO + */ +static int reloc_handler(u32 type, struct module *me, u32 *location, u32 base, + Elf_Addr v, bool rela) +{ + switch (type) { + case R_MIPS_NONE: + break; + case R_MIPS_32: + apply_r_mips_32(location, base, v); + break; + case R_MIPS_26: + return apply_r_mips_26(me, location, base, v); + case R_MIPS_HI16: + return apply_r_mips_hi16(me, location, v, rela); + case R_MIPS_LO16: + return apply_r_mips_lo16(me, location, base, v, rela); + case R_MIPS_PC16: + return apply_r_mips_pc16(me, location, base, v); + case R_MIPS_PC21_S2: + return apply_r_mips_pc21(me, location, base, v); + case R_MIPS_PC26_S2: + return apply_r_mips_pc26(me, location, base, v); + case R_MIPS_64: + return apply_r_mips_64(location, v, rela); + case R_MIPS_HIGHER: + return apply_r_mips_higher(location, v, rela); + case R_MIPS_HIGHEST: + return apply_r_mips_highest(location, v, rela); + default: + pr_err("%s: Unknown relocation type %u\n", me->name, type); + return -EINVAL; + } + + return 0; +} + +static int __apply_relocate(Elf_Shdr *sechdrs, const char *strtab, + unsigned int symindex, unsigned int relsec, + struct module *me, bool rela) +{ + union { + Elf_Mips_Rel *rel; + Elf_Mips_Rela *rela; + } r; + Elf_Sym *sym; + u32 *location, base; + unsigned int i, type; + Elf_Addr v; + int err = 0; + size_t reloc_sz; + + pr_debug("Applying relocate section %u to %u\n", relsec, + sechdrs[relsec].sh_info); + + r.rel = (void *)sechdrs[relsec].sh_addr; + reloc_sz = rela ? sizeof(*r.rela) : sizeof(*r.rel); + me->arch.r_mips_hi16_list = NULL; + for (i = 0; i < sechdrs[relsec].sh_size / reloc_sz; i++) { + /* This is where to make the change */ + location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr + + r.rel->r_offset; + /* This is the symbol it is referring to */ + sym = (Elf_Sym *)sechdrs[symindex].sh_addr + + ELF_MIPS_R_SYM(*r.rel); + if (sym->st_value >= -MAX_ERRNO) { + /* Ignore unresolved weak symbol */ + if (ELF_ST_BIND(sym->st_info) == STB_WEAK) + continue; + pr_warn("%s: Unknown symbol %s\n", + me->name, strtab + sym->st_name); + err = -ENOENT; + goto out; + } + + type = ELF_MIPS_R_TYPE(*r.rel); + + if (rela) { + v = sym->st_value + r.rela->r_addend; + base = 0; + r.rela = &r.rela[1]; + } else { + v = sym->st_value; + base = *location; + r.rel = &r.rel[1]; + } + + err = reloc_handler(type, me, location, base, v, rela); + if (err) + goto out; + } + +out: + /* + * Normally the hi16 list should be deallocated at this point. A + * malformed binary however could contain a series of R_MIPS_HI16 + * relocations not followed by a R_MIPS_LO16 relocation, or if we hit + * an error processing a reloc we might have gotten here before + * reaching the R_MIPS_LO16. In either case, free up the list and + * return an error. + */ + if (me->arch.r_mips_hi16_list) { + free_relocation_chain(me->arch.r_mips_hi16_list); + me->arch.r_mips_hi16_list = NULL; + err = err ?: -ENOEXEC; + } + + return err; +} + +int apply_relocate(Elf_Shdr *sechdrs, const char *strtab, + unsigned int symindex, unsigned int relsec, + struct module *me) +{ + return __apply_relocate(sechdrs, strtab, symindex, relsec, me, false); +} + +#ifdef CONFIG_MODULES_USE_ELF_RELA +int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, + unsigned int symindex, unsigned int relsec, + struct module *me) +{ + return __apply_relocate(sechdrs, strtab, symindex, relsec, me, true); +} +#endif /* CONFIG_MODULES_USE_ELF_RELA */ + +/* Given an address, look for it in the module exception tables. */ +const struct exception_table_entry *search_module_dbetables(unsigned long addr) +{ + unsigned long flags; + const struct exception_table_entry *e = NULL; + struct mod_arch_specific *dbe; + + spin_lock_irqsave(&dbe_lock, flags); + list_for_each_entry(dbe, &dbe_list, dbe_list) { + e = search_extable(dbe->dbe_start, + dbe->dbe_end - dbe->dbe_start, addr); + if (e) + break; + } + spin_unlock_irqrestore(&dbe_lock, flags); + + /* Now, if we found one, we are running inside it now, hence + we cannot unload the module, hence no refcnt needed. */ + return e; +} + +/* Put in dbe list if necessary. */ +int module_finalize(const Elf_Ehdr *hdr, + const Elf_Shdr *sechdrs, + struct module *me) +{ + const Elf_Shdr *s; + char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; + + if (IS_ENABLED(CONFIG_JUMP_LABEL)) + jump_label_apply_nops(me); + + INIT_LIST_HEAD(&me->arch.dbe_list); + for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { + if (strcmp("__dbe_table", secstrings + s->sh_name) != 0) + continue; + me->arch.dbe_start = (void *)s->sh_addr; + me->arch.dbe_end = (void *)s->sh_addr + s->sh_size; + spin_lock_irq(&dbe_lock); + list_add(&me->arch.dbe_list, &dbe_list); + spin_unlock_irq(&dbe_lock); + } + return 0; +} + +void module_arch_cleanup(struct module *mod) +{ + spin_lock_irq(&dbe_lock); + list_del(&mod->arch.dbe_list); + spin_unlock_irq(&dbe_lock); +} |