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957 lines
27 KiB
957 lines
27 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* IA-64-specific support for kernel module loader. |
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* |
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* Copyright (C) 2003 Hewlett-Packard Co |
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* David Mosberger-Tang <[email protected]> |
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* |
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* Loosely based on patch by Rusty Russell. |
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*/ |
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|
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/* relocs tested so far: |
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DIR64LSB |
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FPTR64LSB |
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GPREL22 |
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LDXMOV |
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LDXMOV |
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LTOFF22 |
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LTOFF22X |
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LTOFF22X |
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LTOFF_FPTR22 |
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PCREL21B (for br.call only; br.cond is not supported out of modules!) |
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PCREL60B (for brl.cond only; brl.call is not supported for modules!) |
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PCREL64LSB |
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SECREL32LSB |
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SEGREL64LSB |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/sched.h> |
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#include <linux/elf.h> |
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#include <linux/moduleloader.h> |
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#include <linux/string.h> |
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#include <linux/vmalloc.h> |
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#include <asm/patch.h> |
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#include <asm/unaligned.h> |
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#include <asm/sections.h> |
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#define ARCH_MODULE_DEBUG 0 |
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#if ARCH_MODULE_DEBUG |
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# define DEBUGP printk |
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# define inline |
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#else |
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# define DEBUGP(fmt , a...) |
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#endif |
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#ifdef CONFIG_ITANIUM |
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# define USE_BRL 0 |
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#else |
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# define USE_BRL 1 |
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#endif |
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#define MAX_LTOFF ((uint64_t) (1 << 22)) /* max. allowable linkage-table offset */ |
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/* Define some relocation helper macros/types: */ |
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#define FORMAT_SHIFT 0 |
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#define FORMAT_BITS 3 |
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#define FORMAT_MASK ((1 << FORMAT_BITS) - 1) |
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#define VALUE_SHIFT 3 |
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#define VALUE_BITS 5 |
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#define VALUE_MASK ((1 << VALUE_BITS) - 1) |
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enum reloc_target_format { |
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/* direct encoded formats: */ |
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RF_NONE = 0, |
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RF_INSN14 = 1, |
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RF_INSN22 = 2, |
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RF_INSN64 = 3, |
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RF_32MSB = 4, |
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RF_32LSB = 5, |
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RF_64MSB = 6, |
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RF_64LSB = 7, |
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|
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/* formats that cannot be directly decoded: */ |
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RF_INSN60, |
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RF_INSN21B, /* imm21 form 1 */ |
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RF_INSN21M, /* imm21 form 2 */ |
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RF_INSN21F /* imm21 form 3 */ |
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}; |
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enum reloc_value_formula { |
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RV_DIRECT = 4, /* S + A */ |
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RV_GPREL = 5, /* @gprel(S + A) */ |
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RV_LTREL = 6, /* @ltoff(S + A) */ |
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RV_PLTREL = 7, /* @pltoff(S + A) */ |
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RV_FPTR = 8, /* @fptr(S + A) */ |
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RV_PCREL = 9, /* S + A - P */ |
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RV_LTREL_FPTR = 10, /* @ltoff(@fptr(S + A)) */ |
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RV_SEGREL = 11, /* @segrel(S + A) */ |
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RV_SECREL = 12, /* @secrel(S + A) */ |
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RV_BDREL = 13, /* BD + A */ |
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RV_LTV = 14, /* S + A (like RV_DIRECT, except frozen at static link-time) */ |
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RV_PCREL2 = 15, /* S + A - P */ |
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RV_SPECIAL = 16, /* various (see below) */ |
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RV_RSVD17 = 17, |
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RV_TPREL = 18, /* @tprel(S + A) */ |
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RV_LTREL_TPREL = 19, /* @ltoff(@tprel(S + A)) */ |
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RV_DTPMOD = 20, /* @dtpmod(S + A) */ |
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RV_LTREL_DTPMOD = 21, /* @ltoff(@dtpmod(S + A)) */ |
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RV_DTPREL = 22, /* @dtprel(S + A) */ |
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RV_LTREL_DTPREL = 23, /* @ltoff(@dtprel(S + A)) */ |
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RV_RSVD24 = 24, |
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RV_RSVD25 = 25, |
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RV_RSVD26 = 26, |
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RV_RSVD27 = 27 |
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/* 28-31 reserved for implementation-specific purposes. */ |
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}; |
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#define N(reloc) [R_IA64_##reloc] = #reloc |
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static const char *reloc_name[256] = { |
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N(NONE), N(IMM14), N(IMM22), N(IMM64), |
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N(DIR32MSB), N(DIR32LSB), N(DIR64MSB), N(DIR64LSB), |
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N(GPREL22), N(GPREL64I), N(GPREL32MSB), N(GPREL32LSB), |
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N(GPREL64MSB), N(GPREL64LSB), N(LTOFF22), N(LTOFF64I), |
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N(PLTOFF22), N(PLTOFF64I), N(PLTOFF64MSB), N(PLTOFF64LSB), |
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N(FPTR64I), N(FPTR32MSB), N(FPTR32LSB), N(FPTR64MSB), |
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N(FPTR64LSB), N(PCREL60B), N(PCREL21B), N(PCREL21M), |
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N(PCREL21F), N(PCREL32MSB), N(PCREL32LSB), N(PCREL64MSB), |
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N(PCREL64LSB), N(LTOFF_FPTR22), N(LTOFF_FPTR64I), N(LTOFF_FPTR32MSB), |
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N(LTOFF_FPTR32LSB), N(LTOFF_FPTR64MSB), N(LTOFF_FPTR64LSB), N(SEGREL32MSB), |
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N(SEGREL32LSB), N(SEGREL64MSB), N(SEGREL64LSB), N(SECREL32MSB), |
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N(SECREL32LSB), N(SECREL64MSB), N(SECREL64LSB), N(REL32MSB), |
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N(REL32LSB), N(REL64MSB), N(REL64LSB), N(LTV32MSB), |
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N(LTV32LSB), N(LTV64MSB), N(LTV64LSB), N(PCREL21BI), |
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N(PCREL22), N(PCREL64I), N(IPLTMSB), N(IPLTLSB), |
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N(COPY), N(LTOFF22X), N(LDXMOV), N(TPREL14), |
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N(TPREL22), N(TPREL64I), N(TPREL64MSB), N(TPREL64LSB), |
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N(LTOFF_TPREL22), N(DTPMOD64MSB), N(DTPMOD64LSB), N(LTOFF_DTPMOD22), |
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N(DTPREL14), N(DTPREL22), N(DTPREL64I), N(DTPREL32MSB), |
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N(DTPREL32LSB), N(DTPREL64MSB), N(DTPREL64LSB), N(LTOFF_DTPREL22) |
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}; |
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#undef N |
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/* Opaque struct for insns, to protect against derefs. */ |
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struct insn; |
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static inline uint64_t |
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bundle (const struct insn *insn) |
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{ |
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return (uint64_t) insn & ~0xfUL; |
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} |
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static inline int |
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slot (const struct insn *insn) |
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{ |
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return (uint64_t) insn & 0x3; |
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} |
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static int |
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apply_imm64 (struct module *mod, struct insn *insn, uint64_t val) |
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{ |
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if (slot(insn) != 1 && slot(insn) != 2) { |
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printk(KERN_ERR "%s: invalid slot number %d for IMM64\n", |
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mod->name, slot(insn)); |
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return 0; |
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} |
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ia64_patch_imm64((u64) insn, val); |
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return 1; |
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} |
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static int |
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apply_imm60 (struct module *mod, struct insn *insn, uint64_t val) |
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{ |
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if (slot(insn) != 1 && slot(insn) != 2) { |
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printk(KERN_ERR "%s: invalid slot number %d for IMM60\n", |
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mod->name, slot(insn)); |
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return 0; |
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} |
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if (val + ((uint64_t) 1 << 59) >= (1UL << 60)) { |
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printk(KERN_ERR "%s: value %ld out of IMM60 range\n", |
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mod->name, (long) val); |
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return 0; |
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} |
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ia64_patch_imm60((u64) insn, val); |
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return 1; |
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} |
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static int |
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apply_imm22 (struct module *mod, struct insn *insn, uint64_t val) |
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{ |
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if (val + (1 << 21) >= (1 << 22)) { |
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printk(KERN_ERR "%s: value %li out of IMM22 range\n", |
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mod->name, (long)val); |
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return 0; |
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} |
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ia64_patch((u64) insn, 0x01fffcfe000UL, ( ((val & 0x200000UL) << 15) /* bit 21 -> 36 */ |
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| ((val & 0x1f0000UL) << 6) /* bit 16 -> 22 */ |
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| ((val & 0x00ff80UL) << 20) /* bit 7 -> 27 */ |
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| ((val & 0x00007fUL) << 13) /* bit 0 -> 13 */)); |
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return 1; |
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} |
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static int |
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apply_imm21b (struct module *mod, struct insn *insn, uint64_t val) |
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{ |
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if (val + (1 << 20) >= (1 << 21)) { |
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printk(KERN_ERR "%s: value %li out of IMM21b range\n", |
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mod->name, (long)val); |
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return 0; |
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} |
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ia64_patch((u64) insn, 0x11ffffe000UL, ( ((val & 0x100000UL) << 16) /* bit 20 -> 36 */ |
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| ((val & 0x0fffffUL) << 13) /* bit 0 -> 13 */)); |
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return 1; |
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} |
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#if USE_BRL |
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struct plt_entry { |
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/* Three instruction bundles in PLT. */ |
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unsigned char bundle[2][16]; |
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}; |
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static const struct plt_entry ia64_plt_template = { |
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{ |
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{ |
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0x04, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */ |
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0x00, 0x00, 0x00, 0x00, 0x00, 0x20, /* movl gp=TARGET_GP */ |
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0x00, 0x00, 0x00, 0x60 |
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}, |
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{ |
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0x05, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */ |
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* brl.many gp=TARGET_GP */ |
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0x08, 0x00, 0x00, 0xc0 |
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} |
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} |
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}; |
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static int |
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patch_plt (struct module *mod, struct plt_entry *plt, long target_ip, unsigned long target_gp) |
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{ |
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if (apply_imm64(mod, (struct insn *) (plt->bundle[0] + 2), target_gp) |
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&& apply_imm60(mod, (struct insn *) (plt->bundle[1] + 2), |
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(target_ip - (int64_t) plt->bundle[1]) / 16)) |
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return 1; |
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return 0; |
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} |
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unsigned long |
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plt_target (struct plt_entry *plt) |
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{ |
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uint64_t b0, b1, *b = (uint64_t *) plt->bundle[1]; |
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long off; |
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b0 = b[0]; b1 = b[1]; |
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off = ( ((b1 & 0x00fffff000000000UL) >> 36) /* imm20b -> bit 0 */ |
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| ((b0 >> 48) << 20) | ((b1 & 0x7fffffUL) << 36) /* imm39 -> bit 20 */ |
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| ((b1 & 0x0800000000000000UL) << 0)); /* i -> bit 59 */ |
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return (long) plt->bundle[1] + 16*off; |
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} |
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#else /* !USE_BRL */ |
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struct plt_entry { |
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/* Three instruction bundles in PLT. */ |
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unsigned char bundle[3][16]; |
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}; |
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static const struct plt_entry ia64_plt_template = { |
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{ |
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{ |
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0x05, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */ |
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* movl r16=TARGET_IP */ |
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0x02, 0x00, 0x00, 0x60 |
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}, |
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{ |
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0x04, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */ |
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0x00, 0x00, 0x00, 0x00, 0x00, 0x20, /* movl gp=TARGET_GP */ |
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0x00, 0x00, 0x00, 0x60 |
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}, |
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{ |
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0x11, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MIB] nop.m 0 */ |
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0x60, 0x80, 0x04, 0x80, 0x03, 0x00, /* mov b6=r16 */ |
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0x60, 0x00, 0x80, 0x00 /* br.few b6 */ |
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} |
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} |
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}; |
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static int |
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patch_plt (struct module *mod, struct plt_entry *plt, long target_ip, unsigned long target_gp) |
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{ |
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if (apply_imm64(mod, (struct insn *) (plt->bundle[0] + 2), target_ip) |
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&& apply_imm64(mod, (struct insn *) (plt->bundle[1] + 2), target_gp)) |
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return 1; |
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return 0; |
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} |
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unsigned long |
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plt_target (struct plt_entry *plt) |
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{ |
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uint64_t b0, b1, *b = (uint64_t *) plt->bundle[0]; |
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b0 = b[0]; b1 = b[1]; |
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return ( ((b1 & 0x000007f000000000) >> 36) /* imm7b -> bit 0 */ |
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| ((b1 & 0x07fc000000000000) >> 43) /* imm9d -> bit 7 */ |
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| ((b1 & 0x0003e00000000000) >> 29) /* imm5c -> bit 16 */ |
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| ((b1 & 0x0000100000000000) >> 23) /* ic -> bit 21 */ |
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| ((b0 >> 46) << 22) | ((b1 & 0x7fffff) << 40) /* imm41 -> bit 22 */ |
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| ((b1 & 0x0800000000000000) << 4)); /* i -> bit 63 */ |
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} |
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#endif /* !USE_BRL */ |
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void |
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module_arch_freeing_init (struct module *mod) |
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{ |
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if (mod->arch.init_unw_table) { |
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unw_remove_unwind_table(mod->arch.init_unw_table); |
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mod->arch.init_unw_table = NULL; |
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} |
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} |
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/* Have we already seen one of these relocations? */ |
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/* FIXME: we could look in other sections, too --RR */ |
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static int |
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duplicate_reloc (const Elf64_Rela *rela, unsigned int num) |
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{ |
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unsigned int i; |
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for (i = 0; i < num; i++) { |
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if (rela[i].r_info == rela[num].r_info && rela[i].r_addend == rela[num].r_addend) |
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return 1; |
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} |
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return 0; |
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} |
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/* Count how many GOT entries we may need */ |
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static unsigned int |
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count_gots (const Elf64_Rela *rela, unsigned int num) |
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{ |
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unsigned int i, ret = 0; |
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/* Sure, this is order(n^2), but it's usually short, and not |
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time critical */ |
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for (i = 0; i < num; i++) { |
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switch (ELF64_R_TYPE(rela[i].r_info)) { |
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case R_IA64_LTOFF22: |
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case R_IA64_LTOFF22X: |
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case R_IA64_LTOFF64I: |
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case R_IA64_LTOFF_FPTR22: |
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case R_IA64_LTOFF_FPTR64I: |
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case R_IA64_LTOFF_FPTR32MSB: |
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case R_IA64_LTOFF_FPTR32LSB: |
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case R_IA64_LTOFF_FPTR64MSB: |
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case R_IA64_LTOFF_FPTR64LSB: |
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if (!duplicate_reloc(rela, i)) |
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ret++; |
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break; |
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} |
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} |
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return ret; |
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} |
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/* Count how many PLT entries we may need */ |
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static unsigned int |
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count_plts (const Elf64_Rela *rela, unsigned int num) |
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{ |
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unsigned int i, ret = 0; |
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/* Sure, this is order(n^2), but it's usually short, and not |
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time critical */ |
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for (i = 0; i < num; i++) { |
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switch (ELF64_R_TYPE(rela[i].r_info)) { |
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case R_IA64_PCREL21B: |
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case R_IA64_PLTOFF22: |
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case R_IA64_PLTOFF64I: |
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case R_IA64_PLTOFF64MSB: |
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case R_IA64_PLTOFF64LSB: |
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case R_IA64_IPLTMSB: |
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case R_IA64_IPLTLSB: |
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if (!duplicate_reloc(rela, i)) |
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ret++; |
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break; |
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} |
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} |
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return ret; |
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} |
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/* We need to create an function-descriptors for any internal function |
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which is referenced. */ |
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static unsigned int |
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count_fdescs (const Elf64_Rela *rela, unsigned int num) |
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{ |
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unsigned int i, ret = 0; |
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/* Sure, this is order(n^2), but it's usually short, and not time critical. */ |
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for (i = 0; i < num; i++) { |
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switch (ELF64_R_TYPE(rela[i].r_info)) { |
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case R_IA64_FPTR64I: |
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case R_IA64_FPTR32LSB: |
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case R_IA64_FPTR32MSB: |
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case R_IA64_FPTR64LSB: |
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case R_IA64_FPTR64MSB: |
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case R_IA64_LTOFF_FPTR22: |
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case R_IA64_LTOFF_FPTR32LSB: |
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case R_IA64_LTOFF_FPTR32MSB: |
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case R_IA64_LTOFF_FPTR64I: |
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case R_IA64_LTOFF_FPTR64LSB: |
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case R_IA64_LTOFF_FPTR64MSB: |
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case R_IA64_IPLTMSB: |
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case R_IA64_IPLTLSB: |
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/* |
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* Jumps to static functions sometimes go straight to their |
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* offset. Of course, that may not be possible if the jump is |
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* from init -> core or vice. versa, so we need to generate an |
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* FDESC (and PLT etc) for that. |
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*/ |
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case R_IA64_PCREL21B: |
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if (!duplicate_reloc(rela, i)) |
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ret++; |
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break; |
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} |
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} |
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return ret; |
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} |
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int |
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module_frob_arch_sections (Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, char *secstrings, |
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struct module *mod) |
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{ |
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unsigned long core_plts = 0, init_plts = 0, gots = 0, fdescs = 0; |
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Elf64_Shdr *s, *sechdrs_end = sechdrs + ehdr->e_shnum; |
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|
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/* |
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* To store the PLTs and function-descriptors, we expand the .text section for |
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* core module-code and the .init.text section for initialization code. |
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*/ |
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for (s = sechdrs; s < sechdrs_end; ++s) |
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if (strcmp(".core.plt", secstrings + s->sh_name) == 0) |
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mod->arch.core_plt = s; |
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else if (strcmp(".init.plt", secstrings + s->sh_name) == 0) |
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mod->arch.init_plt = s; |
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else if (strcmp(".got", secstrings + s->sh_name) == 0) |
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mod->arch.got = s; |
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else if (strcmp(".opd", secstrings + s->sh_name) == 0) |
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mod->arch.opd = s; |
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else if (strcmp(".IA_64.unwind", secstrings + s->sh_name) == 0) |
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mod->arch.unwind = s; |
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if (!mod->arch.core_plt || !mod->arch.init_plt || !mod->arch.got || !mod->arch.opd) { |
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printk(KERN_ERR "%s: sections missing\n", mod->name); |
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return -ENOEXEC; |
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} |
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/* GOT and PLTs can occur in any relocated section... */ |
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for (s = sechdrs + 1; s < sechdrs_end; ++s) { |
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const Elf64_Rela *rels = (void *)ehdr + s->sh_offset; |
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unsigned long numrels = s->sh_size/sizeof(Elf64_Rela); |
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|
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if (s->sh_type != SHT_RELA) |
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continue; |
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gots += count_gots(rels, numrels); |
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fdescs += count_fdescs(rels, numrels); |
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if (strstr(secstrings + s->sh_name, ".init")) |
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init_plts += count_plts(rels, numrels); |
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else |
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core_plts += count_plts(rels, numrels); |
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} |
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mod->arch.core_plt->sh_type = SHT_NOBITS; |
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mod->arch.core_plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC; |
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mod->arch.core_plt->sh_addralign = 16; |
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mod->arch.core_plt->sh_size = core_plts * sizeof(struct plt_entry); |
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mod->arch.init_plt->sh_type = SHT_NOBITS; |
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mod->arch.init_plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC; |
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mod->arch.init_plt->sh_addralign = 16; |
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mod->arch.init_plt->sh_size = init_plts * sizeof(struct plt_entry); |
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mod->arch.got->sh_type = SHT_NOBITS; |
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mod->arch.got->sh_flags = ARCH_SHF_SMALL | SHF_ALLOC; |
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mod->arch.got->sh_addralign = 8; |
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mod->arch.got->sh_size = gots * sizeof(struct got_entry); |
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mod->arch.opd->sh_type = SHT_NOBITS; |
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mod->arch.opd->sh_flags = SHF_ALLOC; |
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mod->arch.opd->sh_addralign = 8; |
|
mod->arch.opd->sh_size = fdescs * sizeof(struct fdesc); |
|
DEBUGP("%s: core.plt=%lx, init.plt=%lx, got=%lx, fdesc=%lx\n", |
|
__func__, mod->arch.core_plt->sh_size, mod->arch.init_plt->sh_size, |
|
mod->arch.got->sh_size, mod->arch.opd->sh_size); |
|
return 0; |
|
} |
|
|
|
static inline int |
|
in_init (const struct module *mod, uint64_t addr) |
|
{ |
|
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->core_layout.base < mod->core_layout.size; |
|
} |
|
|
|
static inline int |
|
is_internal (const struct module *mod, uint64_t value) |
|
{ |
|
return in_init(mod, value) || in_core(mod, value); |
|
} |
|
|
|
/* |
|
* Get gp-relative offset for the linkage-table entry of VALUE. |
|
*/ |
|
static uint64_t |
|
get_ltoff (struct module *mod, uint64_t value, int *okp) |
|
{ |
|
struct got_entry *got, *e; |
|
|
|
if (!*okp) |
|
return 0; |
|
|
|
got = (void *) mod->arch.got->sh_addr; |
|
for (e = got; e < got + mod->arch.next_got_entry; ++e) |
|
if (e->val == value) |
|
goto found; |
|
|
|
/* Not enough GOT entries? */ |
|
BUG_ON(e >= (struct got_entry *) (mod->arch.got->sh_addr + mod->arch.got->sh_size)); |
|
|
|
e->val = value; |
|
++mod->arch.next_got_entry; |
|
found: |
|
return (uint64_t) e - mod->arch.gp; |
|
} |
|
|
|
static inline int |
|
gp_addressable (struct module *mod, uint64_t value) |
|
{ |
|
return value - mod->arch.gp + MAX_LTOFF/2 < MAX_LTOFF; |
|
} |
|
|
|
/* Get PC-relative PLT entry for this value. Returns 0 on failure. */ |
|
static uint64_t |
|
get_plt (struct module *mod, const struct insn *insn, uint64_t value, int *okp) |
|
{ |
|
struct plt_entry *plt, *plt_end; |
|
uint64_t target_ip, target_gp; |
|
|
|
if (!*okp) |
|
return 0; |
|
|
|
if (in_init(mod, (uint64_t) insn)) { |
|
plt = (void *) mod->arch.init_plt->sh_addr; |
|
plt_end = (void *) plt + mod->arch.init_plt->sh_size; |
|
} else { |
|
plt = (void *) mod->arch.core_plt->sh_addr; |
|
plt_end = (void *) plt + mod->arch.core_plt->sh_size; |
|
} |
|
|
|
/* "value" is a pointer to a function-descriptor; fetch the target ip/gp from it: */ |
|
target_ip = ((uint64_t *) value)[0]; |
|
target_gp = ((uint64_t *) value)[1]; |
|
|
|
/* Look for existing PLT entry. */ |
|
while (plt->bundle[0][0]) { |
|
if (plt_target(plt) == target_ip) |
|
goto found; |
|
if (++plt >= plt_end) |
|
BUG(); |
|
} |
|
*plt = ia64_plt_template; |
|
if (!patch_plt(mod, plt, target_ip, target_gp)) { |
|
*okp = 0; |
|
return 0; |
|
} |
|
#if ARCH_MODULE_DEBUG |
|
if (plt_target(plt) != target_ip) { |
|
printk("%s: mistargeted PLT: wanted %lx, got %lx\n", |
|
__func__, target_ip, plt_target(plt)); |
|
*okp = 0; |
|
return 0; |
|
} |
|
#endif |
|
found: |
|
return (uint64_t) plt; |
|
} |
|
|
|
/* Get function descriptor for VALUE. */ |
|
static uint64_t |
|
get_fdesc (struct module *mod, uint64_t value, int *okp) |
|
{ |
|
struct fdesc *fdesc = (void *) mod->arch.opd->sh_addr; |
|
|
|
if (!*okp) |
|
return 0; |
|
|
|
if (!value) { |
|
printk(KERN_ERR "%s: fdesc for zero requested!\n", mod->name); |
|
return 0; |
|
} |
|
|
|
if (!is_internal(mod, value)) |
|
/* |
|
* If it's not a module-local entry-point, "value" already points to a |
|
* function-descriptor. |
|
*/ |
|
return value; |
|
|
|
/* Look for existing function descriptor. */ |
|
while (fdesc->ip) { |
|
if (fdesc->ip == value) |
|
return (uint64_t)fdesc; |
|
if ((uint64_t) ++fdesc >= mod->arch.opd->sh_addr + mod->arch.opd->sh_size) |
|
BUG(); |
|
} |
|
|
|
/* Create new one */ |
|
fdesc->ip = value; |
|
fdesc->gp = mod->arch.gp; |
|
return (uint64_t) fdesc; |
|
} |
|
|
|
static inline int |
|
do_reloc (struct module *mod, uint8_t r_type, Elf64_Sym *sym, uint64_t addend, |
|
Elf64_Shdr *sec, void *location) |
|
{ |
|
enum reloc_target_format format = (r_type >> FORMAT_SHIFT) & FORMAT_MASK; |
|
enum reloc_value_formula formula = (r_type >> VALUE_SHIFT) & VALUE_MASK; |
|
uint64_t val; |
|
int ok = 1; |
|
|
|
val = sym->st_value + addend; |
|
|
|
switch (formula) { |
|
case RV_SEGREL: /* segment base is arbitrarily chosen to be 0 for kernel modules */ |
|
case RV_DIRECT: |
|
break; |
|
|
|
case RV_GPREL: val -= mod->arch.gp; break; |
|
case RV_LTREL: val = get_ltoff(mod, val, &ok); break; |
|
case RV_PLTREL: val = get_plt(mod, location, val, &ok); break; |
|
case RV_FPTR: val = get_fdesc(mod, val, &ok); break; |
|
case RV_SECREL: val -= sec->sh_addr; break; |
|
case RV_LTREL_FPTR: val = get_ltoff(mod, get_fdesc(mod, val, &ok), &ok); break; |
|
|
|
case RV_PCREL: |
|
switch (r_type) { |
|
case R_IA64_PCREL21B: |
|
if ((in_init(mod, val) && in_core(mod, (uint64_t)location)) || |
|
(in_core(mod, val) && in_init(mod, (uint64_t)location))) { |
|
/* |
|
* Init section may have been allocated far away from core, |
|
* if the branch won't reach, then allocate a plt for it. |
|
*/ |
|
uint64_t delta = ((int64_t)val - (int64_t)location) / 16; |
|
if (delta + (1 << 20) >= (1 << 21)) { |
|
val = get_fdesc(mod, val, &ok); |
|
val = get_plt(mod, location, val, &ok); |
|
} |
|
} else if (!is_internal(mod, val)) |
|
val = get_plt(mod, location, val, &ok); |
|
fallthrough; |
|
default: |
|
val -= bundle(location); |
|
break; |
|
|
|
case R_IA64_PCREL32MSB: |
|
case R_IA64_PCREL32LSB: |
|
case R_IA64_PCREL64MSB: |
|
case R_IA64_PCREL64LSB: |
|
val -= (uint64_t) location; |
|
break; |
|
|
|
} |
|
switch (r_type) { |
|
case R_IA64_PCREL60B: format = RF_INSN60; break; |
|
case R_IA64_PCREL21B: format = RF_INSN21B; break; |
|
case R_IA64_PCREL21M: format = RF_INSN21M; break; |
|
case R_IA64_PCREL21F: format = RF_INSN21F; break; |
|
default: break; |
|
} |
|
break; |
|
|
|
case RV_BDREL: |
|
val -= (uint64_t) (in_init(mod, val) ? mod->init_layout.base : mod->core_layout.base); |
|
break; |
|
|
|
case RV_LTV: |
|
/* can link-time value relocs happen here? */ |
|
BUG(); |
|
break; |
|
|
|
case RV_PCREL2: |
|
if (r_type == R_IA64_PCREL21BI) { |
|
if (!is_internal(mod, val)) { |
|
printk(KERN_ERR "%s: %s reloc against " |
|
"non-local symbol (%lx)\n", __func__, |
|
reloc_name[r_type], (unsigned long)val); |
|
return -ENOEXEC; |
|
} |
|
format = RF_INSN21B; |
|
} |
|
val -= bundle(location); |
|
break; |
|
|
|
case RV_SPECIAL: |
|
switch (r_type) { |
|
case R_IA64_IPLTMSB: |
|
case R_IA64_IPLTLSB: |
|
val = get_fdesc(mod, get_plt(mod, location, val, &ok), &ok); |
|
format = RF_64LSB; |
|
if (r_type == R_IA64_IPLTMSB) |
|
format = RF_64MSB; |
|
break; |
|
|
|
case R_IA64_SUB: |
|
val = addend - sym->st_value; |
|
format = RF_INSN64; |
|
break; |
|
|
|
case R_IA64_LTOFF22X: |
|
if (gp_addressable(mod, val)) |
|
val -= mod->arch.gp; |
|
else |
|
val = get_ltoff(mod, val, &ok); |
|
format = RF_INSN22; |
|
break; |
|
|
|
case R_IA64_LDXMOV: |
|
if (gp_addressable(mod, val)) { |
|
/* turn "ld8" into "mov": */ |
|
DEBUGP("%s: patching ld8 at %p to mov\n", __func__, location); |
|
ia64_patch((u64) location, 0x1fff80fe000UL, 0x10000000000UL); |
|
} |
|
return 0; |
|
|
|
default: |
|
if (reloc_name[r_type]) |
|
printk(KERN_ERR "%s: special reloc %s not supported", |
|
mod->name, reloc_name[r_type]); |
|
else |
|
printk(KERN_ERR "%s: unknown special reloc %x\n", |
|
mod->name, r_type); |
|
return -ENOEXEC; |
|
} |
|
break; |
|
|
|
case RV_TPREL: |
|
case RV_LTREL_TPREL: |
|
case RV_DTPMOD: |
|
case RV_LTREL_DTPMOD: |
|
case RV_DTPREL: |
|
case RV_LTREL_DTPREL: |
|
printk(KERN_ERR "%s: %s reloc not supported\n", |
|
mod->name, reloc_name[r_type] ? reloc_name[r_type] : "?"); |
|
return -ENOEXEC; |
|
|
|
default: |
|
printk(KERN_ERR "%s: unknown reloc %x\n", mod->name, r_type); |
|
return -ENOEXEC; |
|
} |
|
|
|
if (!ok) |
|
return -ENOEXEC; |
|
|
|
DEBUGP("%s: [%p]<-%016lx = %s(%lx)\n", __func__, location, val, |
|
reloc_name[r_type] ? reloc_name[r_type] : "?", sym->st_value + addend); |
|
|
|
switch (format) { |
|
case RF_INSN21B: ok = apply_imm21b(mod, location, (int64_t) val / 16); break; |
|
case RF_INSN22: ok = apply_imm22(mod, location, val); break; |
|
case RF_INSN64: ok = apply_imm64(mod, location, val); break; |
|
case RF_INSN60: ok = apply_imm60(mod, location, (int64_t) val / 16); break; |
|
case RF_32LSB: put_unaligned(val, (uint32_t *) location); break; |
|
case RF_64LSB: put_unaligned(val, (uint64_t *) location); break; |
|
case RF_32MSB: /* ia64 Linux is little-endian... */ |
|
case RF_64MSB: /* ia64 Linux is little-endian... */ |
|
case RF_INSN14: /* must be within-module, i.e., resolved by "ld -r" */ |
|
case RF_INSN21M: /* must be within-module, i.e., resolved by "ld -r" */ |
|
case RF_INSN21F: /* must be within-module, i.e., resolved by "ld -r" */ |
|
printk(KERN_ERR "%s: format %u needed by %s reloc is not supported\n", |
|
mod->name, format, reloc_name[r_type] ? reloc_name[r_type] : "?"); |
|
return -ENOEXEC; |
|
|
|
default: |
|
printk(KERN_ERR "%s: relocation %s resulted in unknown format %u\n", |
|
mod->name, reloc_name[r_type] ? reloc_name[r_type] : "?", format); |
|
return -ENOEXEC; |
|
} |
|
return ok ? 0 : -ENOEXEC; |
|
} |
|
|
|
int |
|
apply_relocate_add (Elf64_Shdr *sechdrs, const char *strtab, unsigned int symindex, |
|
unsigned int relsec, struct module *mod) |
|
{ |
|
unsigned int i, n = sechdrs[relsec].sh_size / sizeof(Elf64_Rela); |
|
Elf64_Rela *rela = (void *) sechdrs[relsec].sh_addr; |
|
Elf64_Shdr *target_sec; |
|
int ret; |
|
|
|
DEBUGP("%s: applying section %u (%u relocs) to %u\n", __func__, |
|
relsec, n, sechdrs[relsec].sh_info); |
|
|
|
target_sec = sechdrs + sechdrs[relsec].sh_info; |
|
|
|
if (target_sec->sh_entsize == ~0UL) |
|
/* |
|
* If target section wasn't allocated, we don't need to relocate it. |
|
* Happens, e.g., for debug sections. |
|
*/ |
|
return 0; |
|
|
|
if (!mod->arch.gp) { |
|
/* |
|
* XXX Should have an arch-hook for running this after final section |
|
* addresses have been selected... |
|
*/ |
|
uint64_t gp; |
|
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_layout.size - MAX_LTOFF / 2; |
|
else |
|
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); |
|
} |
|
|
|
for (i = 0; i < n; i++) { |
|
ret = do_reloc(mod, ELF64_R_TYPE(rela[i].r_info), |
|
((Elf64_Sym *) sechdrs[symindex].sh_addr |
|
+ ELF64_R_SYM(rela[i].r_info)), |
|
rela[i].r_addend, target_sec, |
|
(void *) target_sec->sh_addr + rela[i].r_offset); |
|
if (ret < 0) |
|
return ret; |
|
} |
|
return 0; |
|
} |
|
|
|
/* |
|
* Modules contain a single unwind table which covers both the core and the init text |
|
* sections but since the two are not contiguous, we need to split this table up such that |
|
* we can register (and unregister) each "segment" separately. Fortunately, this sounds |
|
* more complicated than it really is. |
|
*/ |
|
static void |
|
register_unwind_table (struct module *mod) |
|
{ |
|
struct unw_table_entry *start = (void *) mod->arch.unwind->sh_addr; |
|
struct unw_table_entry *end = start + mod->arch.unwind->sh_size / sizeof (*start); |
|
struct unw_table_entry tmp, *e1, *e2, *core, *init; |
|
unsigned long num_init = 0, num_core = 0; |
|
|
|
/* First, count how many init and core unwind-table entries there are. */ |
|
for (e1 = start; e1 < end; ++e1) |
|
if (in_init(mod, e1->start_offset)) |
|
++num_init; |
|
else |
|
++num_core; |
|
/* |
|
* Second, sort the table such that all unwind-table entries for the init and core |
|
* text sections are nicely separated. We do this with a stupid bubble sort |
|
* (unwind tables don't get ridiculously huge). |
|
*/ |
|
for (e1 = start; e1 < end; ++e1) { |
|
for (e2 = e1 + 1; e2 < end; ++e2) { |
|
if (e2->start_offset < e1->start_offset) { |
|
tmp = *e1; |
|
*e1 = *e2; |
|
*e2 = tmp; |
|
} |
|
} |
|
} |
|
/* |
|
* Third, locate the init and core segments in the unwind table: |
|
*/ |
|
if (in_init(mod, start->start_offset)) { |
|
init = start; |
|
core = start + num_init; |
|
} else { |
|
core = start; |
|
init = start + num_core; |
|
} |
|
|
|
DEBUGP("%s: name=%s, gp=%lx, num_init=%lu, num_core=%lu\n", __func__, |
|
mod->name, mod->arch.gp, num_init, num_core); |
|
|
|
/* |
|
* Fourth, register both tables (if not empty). |
|
*/ |
|
if (num_core > 0) { |
|
mod->arch.core_unw_table = unw_add_unwind_table(mod->name, 0, mod->arch.gp, |
|
core, core + num_core); |
|
DEBUGP("%s: core: handle=%p [%p-%p)\n", __func__, |
|
mod->arch.core_unw_table, core, core + num_core); |
|
} |
|
if (num_init > 0) { |
|
mod->arch.init_unw_table = unw_add_unwind_table(mod->name, 0, mod->arch.gp, |
|
init, init + num_init); |
|
DEBUGP("%s: init: handle=%p [%p-%p)\n", __func__, |
|
mod->arch.init_unw_table, init, init + num_init); |
|
} |
|
} |
|
|
|
int |
|
module_finalize (const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *mod) |
|
{ |
|
struct mod_arch_specific *mas = &mod->arch; |
|
|
|
DEBUGP("%s: init: entry=%p\n", __func__, mod->init); |
|
if (mas->unwind) |
|
register_unwind_table(mod); |
|
|
|
/* |
|
* ".opd" was already relocated to the final destination. Store |
|
* it's address for use in symbolizer. |
|
*/ |
|
mas->opd_addr = (void *)mas->opd->sh_addr; |
|
mas->opd_size = mas->opd->sh_size; |
|
|
|
/* |
|
* Module relocation was already done at this point. Section |
|
* headers are about to be deleted. Wipe out load-time context. |
|
*/ |
|
mas->core_plt = NULL; |
|
mas->init_plt = NULL; |
|
mas->got = NULL; |
|
mas->opd = NULL; |
|
mas->unwind = NULL; |
|
mas->gp = 0; |
|
mas->next_got_entry = 0; |
|
|
|
return 0; |
|
} |
|
|
|
void |
|
module_arch_cleanup (struct module *mod) |
|
{ |
|
if (mod->arch.init_unw_table) { |
|
unw_remove_unwind_table(mod->arch.init_unw_table); |
|
mod->arch.init_unw_table = NULL; |
|
} |
|
if (mod->arch.core_unw_table) { |
|
unw_remove_unwind_table(mod->arch.core_unw_table); |
|
mod->arch.core_unw_table = NULL; |
|
} |
|
} |
|
|
|
void *dereference_module_function_descriptor(struct module *mod, void *ptr) |
|
{ |
|
struct mod_arch_specific *mas = &mod->arch; |
|
|
|
if (ptr < mas->opd_addr || ptr >= mas->opd_addr + mas->opd_size) |
|
return ptr; |
|
|
|
return dereference_function_descriptor(ptr); |
|
}
|
|
|