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