^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * Copyright (C) 2014-2017 Linaro Ltd. <ard.biesheuvel@linaro.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) #include <linux/elf.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) #include <linux/ftrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/sort.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/moduleloader.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <asm/cache.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <asm/opcodes.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #ifdef CONFIG_THUMB2_KERNEL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #define PLT_ENT_LDR __opcode_to_mem_thumb32(0xf8dff000 | \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) (PLT_ENT_STRIDE - 4))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) #define PLT_ENT_LDR __opcode_to_mem_arm(0xe59ff000 | \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) (PLT_ENT_STRIDE - 8))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) static const u32 fixed_plts[] = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) #ifdef CONFIG_DYNAMIC_FTRACE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) FTRACE_ADDR,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) MCOUNT_ADDR,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) static bool in_init(const struct module *mod, unsigned long loc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) return loc - (u32)mod->init_layout.base < mod->init_layout.size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) static void prealloc_fixed(struct mod_plt_sec *pltsec, struct plt_entries *plt)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) if (!ARRAY_SIZE(fixed_plts) || pltsec->plt_count)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) pltsec->plt_count = ARRAY_SIZE(fixed_plts);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) for (i = 0; i < ARRAY_SIZE(plt->ldr); ++i)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) plt->ldr[i] = PLT_ENT_LDR;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) BUILD_BUG_ON(sizeof(fixed_plts) > sizeof(plt->lit));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) memcpy(plt->lit, fixed_plts, sizeof(fixed_plts));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) u32 get_module_plt(struct module *mod, unsigned long loc, Elf32_Addr val)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) struct mod_plt_sec *pltsec = !in_init(mod, loc) ? &mod->arch.core :
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) &mod->arch.init;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) struct plt_entries *plt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) int idx;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) /* cache the address, ELF header is available only during module load */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) if (!pltsec->plt_ent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) pltsec->plt_ent = (struct plt_entries *)pltsec->plt->sh_addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) plt = pltsec->plt_ent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) prealloc_fixed(pltsec, plt);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) for (idx = 0; idx < ARRAY_SIZE(fixed_plts); ++idx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) if (plt->lit[idx] == val)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) return (u32)&plt->ldr[idx];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) idx = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) * Look for an existing entry pointing to 'val'. Given that the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) * relocations are sorted, this will be the last entry we allocated.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) * (if one exists).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) if (pltsec->plt_count > 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) plt += (pltsec->plt_count - 1) / PLT_ENT_COUNT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) idx = (pltsec->plt_count - 1) % PLT_ENT_COUNT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) if (plt->lit[idx] == val)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) return (u32)&plt->ldr[idx];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) idx = (idx + 1) % PLT_ENT_COUNT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) if (!idx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) plt++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) pltsec->plt_count++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) BUG_ON(pltsec->plt_count * PLT_ENT_SIZE > pltsec->plt->sh_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) if (!idx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) /* Populate a new set of entries */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) *plt = (struct plt_entries){
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) { [0 ... PLT_ENT_COUNT - 1] = PLT_ENT_LDR, },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) { val, }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) plt->lit[idx] = val;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) return (u32)&plt->ldr[idx];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) #define cmp_3way(a,b) ((a) < (b) ? -1 : (a) > (b))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) static int cmp_rel(const void *a, const void *b)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) const Elf32_Rel *x = a, *y = b;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) /* sort by type and symbol index */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) i = cmp_3way(ELF32_R_TYPE(x->r_info), ELF32_R_TYPE(y->r_info));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) if (i == 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) i = cmp_3way(ELF32_R_SYM(x->r_info), ELF32_R_SYM(y->r_info));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) return i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) static bool is_zero_addend_relocation(Elf32_Addr base, const Elf32_Rel *rel)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) u32 *tval = (u32 *)(base + rel->r_offset);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) * Do a bitwise compare on the raw addend rather than fully decoding
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) * the offset and doing an arithmetic comparison.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) * Note that a zero-addend jump/call relocation is encoded taking the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) * PC bias into account, i.e., -8 for ARM and -4 for Thumb2.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) switch (ELF32_R_TYPE(rel->r_info)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) u16 upper, lower;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) case R_ARM_THM_CALL:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) case R_ARM_THM_JUMP24:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) upper = __mem_to_opcode_thumb16(((u16 *)tval)[0]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) lower = __mem_to_opcode_thumb16(((u16 *)tval)[1]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) return (upper & 0x7ff) == 0x7ff && (lower & 0x2fff) == 0x2ffe;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) case R_ARM_CALL:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) case R_ARM_PC24:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) case R_ARM_JUMP24:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) return (__mem_to_opcode_arm(*tval) & 0xffffff) == 0xfffffe;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) BUG();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) static bool duplicate_rel(Elf32_Addr base, const Elf32_Rel *rel, int num)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) const Elf32_Rel *prev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) * Entries are sorted by type and symbol index. That means that,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) * if a duplicate entry exists, it must be in the preceding
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) * slot.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) if (!num)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) prev = rel + num - 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) return cmp_rel(rel + num, prev) == 0 &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) is_zero_addend_relocation(base, prev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) /* Count how many PLT entries we may need */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) static unsigned int count_plts(const Elf32_Sym *syms, Elf32_Addr base,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) const Elf32_Rel *rel, int num, Elf32_Word dstidx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) unsigned int ret = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) const Elf32_Sym *s;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) for (i = 0; i < num; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) switch (ELF32_R_TYPE(rel[i].r_info)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) case R_ARM_CALL:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) case R_ARM_PC24:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) case R_ARM_JUMP24:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) case R_ARM_THM_CALL:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) case R_ARM_THM_JUMP24:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) * We only have to consider branch targets that resolve
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) * to symbols that are defined in a different section.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) * This is not simply a heuristic, it is a fundamental
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) * limitation, since there is no guaranteed way to emit
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) * PLT entries sufficiently close to the branch if the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) * section size exceeds the range of a branch
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) * instruction. So ignore relocations against defined
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) * symbols if they live in the same section as the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) * relocation target.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) s = syms + ELF32_R_SYM(rel[i].r_info);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) if (s->st_shndx == dstidx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) * Jump relocations with non-zero addends against
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) * undefined symbols are supported by the ELF spec, but
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) * do not occur in practice (e.g., 'jump n bytes past
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) * the entry point of undefined function symbol f').
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) * So we need to support them, but there is no need to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) * take them into consideration when trying to optimize
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) * this code. So let's only check for duplicates when
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) * the addend is zero. (Note that calls into the core
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) * module via init PLT entries could involve section
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) * relative symbol references with non-zero addends, for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) * which we may end up emitting duplicates, but the init
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) * PLT is released along with the rest of the .init
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) * region as soon as module loading completes.)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) if (!is_zero_addend_relocation(base, rel + i) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) !duplicate_rel(base, rel, i))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) ret++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) char *secstrings, struct module *mod)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) unsigned long core_plts = ARRAY_SIZE(fixed_plts);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) unsigned long init_plts = ARRAY_SIZE(fixed_plts);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) Elf32_Shdr *s, *sechdrs_end = sechdrs + ehdr->e_shnum;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) Elf32_Sym *syms = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) * To store the PLTs, we expand the .text section for core module code
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) * and for initialization code.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) for (s = sechdrs; s < sechdrs_end; ++s) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) if (strcmp(".plt", secstrings + s->sh_name) == 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) mod->arch.core.plt = s;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) else if (strcmp(".init.plt", secstrings + s->sh_name) == 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) mod->arch.init.plt = s;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) else if (s->sh_type == SHT_SYMTAB)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) syms = (Elf32_Sym *)s->sh_addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) if (!mod->arch.core.plt || !mod->arch.init.plt) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) pr_err("%s: module PLT section(s) missing\n", mod->name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) return -ENOEXEC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) if (!syms) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) pr_err("%s: module symtab section missing\n", mod->name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) return -ENOEXEC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) for (s = sechdrs + 1; s < sechdrs_end; ++s) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) Elf32_Rel *rels = (void *)ehdr + s->sh_offset;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) int numrels = s->sh_size / sizeof(Elf32_Rel);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) Elf32_Shdr *dstsec = sechdrs + s->sh_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) if (s->sh_type != SHT_REL)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) /* ignore relocations that operate on non-exec sections */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) if (!(dstsec->sh_flags & SHF_EXECINSTR))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) /* sort by type and symbol index */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) sort(rels, numrels, sizeof(Elf32_Rel), cmp_rel, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) if (strncmp(secstrings + dstsec->sh_name, ".init", 5) != 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) core_plts += count_plts(syms, dstsec->sh_addr, rels,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) numrels, s->sh_info);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) init_plts += count_plts(syms, dstsec->sh_addr, rels,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) numrels, s->sh_info);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) mod->arch.core.plt->sh_type = SHT_NOBITS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) mod->arch.core.plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) mod->arch.core.plt->sh_addralign = L1_CACHE_BYTES;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) mod->arch.core.plt->sh_size = round_up(core_plts * PLT_ENT_SIZE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) sizeof(struct plt_entries));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) mod->arch.core.plt_count = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) mod->arch.core.plt_ent = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) mod->arch.init.plt->sh_type = SHT_NOBITS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) mod->arch.init.plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) mod->arch.init.plt->sh_addralign = L1_CACHE_BYTES;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) mod->arch.init.plt->sh_size = round_up(init_plts * PLT_ENT_SIZE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) sizeof(struct plt_entries));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) mod->arch.init.plt_count = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) mod->arch.init.plt_ent = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) pr_debug("%s: plt=%x, init.plt=%x\n", __func__,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) mod->arch.core.plt->sh_size, mod->arch.init.plt->sh_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) }
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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