From: Oleksij Rempel <[email protected]> this patch i a port of following patch from u-boot with some additional integration changes and fixes of original code: | Subject: [PATCH] MIPS: Stop building position independent code | | U-Boot has up until now built with -fpic for the MIPS architecture, | producing position independent code which uses indirection through a | global offset table, making relocation fairly straightforward as it | simply involves patching up GOT entries. | | Using -fpic does however have some downsides. The biggest of these is | that generated code is bloated in various ways. For example, function | calls are indirected through the GOT & the t9 register: | | 8f998064 lw t9,-32668(gp) | 0320f809 jalr t9 | | Without -fpic the call is simply: | | 0f803f01 jal be00fc04 <puts> | | This is more compact & faster (due to the lack of the load & the | dependency the jump has on its result). It is also easier to read & | debug because the disassembly shows what function is being called, | rather than just an offset from gp which would then have to be looked up | in the ELF to discover the target function. | | Another disadvantage of -fpic is that each function begins with a | sequence to calculate the value of the gp register, for example: | | 3c1c0004 lui gp,0x4 | 279c3384 addiu gp,gp,13188 | 0399e021 addu gp,gp,t9 | | Without using -fpic this sequence no longer appears at the start of each | function, reducing code size considerably. | | This patch switches U-Boot from building with -fpic to building with | -fno-pic, in order to gain the benefits described above. The cost of | this is an extra step during the build process to extract relocation | data from the ELF & write it into a new .rel section in a compact | format, plus the added complexity of dealing with multiple types of | relocation rather than the single type that applied to the GOT. The | benefit is smaller, cleaner, more debuggable code. The relocate_code() | function is reimplemented in C to handle the new relocation scheme, | which also makes it easier to read & debug. | | Taking maltael_defconfig as an example the size of u-boot.bin built | using the Codescape MIPS 2016.05-06 toolchain (gcc 4.9.2, binutils | 2.24.90) shrinks from 254KiB to 224KiB. | | Signed-off-by: Paul Burton <[email protected]>
Signed-off-by: Oleksij Rempel <[email protected]> --- arch/mips/Kconfig | 18 ++ arch/mips/Makefile | 9 +- arch/mips/boot/main_entry-pbl.c | 4 +- arch/mips/boot/start.S | 4 +- arch/mips/include/asm/relocs.h | 23 ++ arch/mips/include/asm/sections.h | 14 + arch/mips/lib/Makefile | 2 + arch/mips/lib/barebox.lds.S | 27 +- arch/mips/lib/reloc.c | 182 +++++++++++++ arch/mips/lib/sections.c | 9 + scripts/Makefile | 1 + scripts/mips-relocs.c | 426 +++++++++++++++++++++++++++++++ 12 files changed, 712 insertions(+), 7 deletions(-) create mode 100644 arch/mips/include/asm/relocs.h create mode 100644 arch/mips/lib/reloc.c create mode 100644 arch/mips/lib/sections.c create mode 100644 scripts/mips-relocs.c diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index eab9452de9..49f238df58 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -32,6 +32,24 @@ config PHYS_ADDR_T_64BIT menu "Machine selection" +config MIPS_RELOCATION_TABLE_SIZE + hex "Relocation table size" + range 0x100 0x10000 + default "0x8000" + ---help--- + A table of relocation data will be appended to the Barebox binary + and parsed in relocate_code() to fix up all offsets in the relocated + Barebox. + + This option allows the amount of space reserved for the table to be + adjusted in a range from 256 up to 64k. The default is 32k and should + be ok in most cases. Reduce this value to shrink the size of U-Boot + binary. + + The build will fail and a valid size suggested if this is too small. + + If unsure, leave at the default value. + config BUILTIN_DTB bool "link a DTB into the barebox image" depends on OFTREE diff --git a/arch/mips/Makefile b/arch/mips/Makefile index 5fbd51ceee..7830f44be4 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -59,7 +59,7 @@ CPPFLAGS += -DTEXT_BASE=$(CONFIG_TEXT_BASE) ifndef CONFIG_MODULES # Add cleanup flags CPPFLAGS += -fdata-sections -ffunction-sections -LDFLAGS_barebox += -static --gc-sections +LDFLAGS_barebox += -static --gc-sections --emit-relocs endif ifdef CONFIG_IMAGE_COMPRESSION @@ -116,6 +116,13 @@ CFLAGS += $(cflags-y) lds-$(CONFIG_GENERIC_LINKER_SCRIPT) := arch/mips/lib/barebox.lds +cmd_barebox__ ?= $(LD) $(LDFLAGS) $(LDFLAGS_barebox) -o $@ \ + -T $(barebox-lds) \ + --start-group $(barebox-common) --end-group \ + $(filter-out $(barebox-lds) $(barebox-common) FORCE ,$^); \ + $(srctree)/scripts/mips-relocs $@ + + CLEAN_FILES += arch/mips/lib/barebox.lds barebox.map barebox.S pbl := arch/mips/pbl diff --git a/arch/mips/boot/main_entry-pbl.c b/arch/mips/boot/main_entry-pbl.c index 28eaa8791f..60be645148 100644 --- a/arch/mips/boot/main_entry-pbl.c +++ b/arch/mips/boot/main_entry-pbl.c @@ -38,7 +38,7 @@ void __section(.text_entry) pbl_main_entry(void *fdt, void *fdt_end, { u32 pg_start, pg_end, pg_len, fdt_len; void *fdt_new; - void (*barebox)(void *fdt, u32 fdt_len); + void (*barebox)(void *fdt, u32 fdt_len, u32 ram_size); puts_ll("pbl_main_entry()\n"); @@ -56,5 +56,5 @@ void __section(.text_entry) pbl_main_entry(void *fdt, void *fdt_end, memcpy(fdt_new, fdt, fdt_len); barebox = (void *)TEXT_BASE; - barebox(fdt_new, fdt_len); + barebox(fdt_new, fdt_len, ram_size); } diff --git a/arch/mips/boot/start.S b/arch/mips/boot/start.S index 6efe03e98d..c1cd2d9dd5 100644 --- a/arch/mips/boot/start.S +++ b/arch/mips/boot/start.S @@ -18,6 +18,7 @@ EXPORT(_start) /* save dtb pointer */ move s0, a0 move s1, a1 + move s2, a2 /* disable watchpoints */ mtc0 zero, CP0_WATCHLO @@ -32,7 +33,8 @@ EXPORT(_start) /* restore dtb pointer */ move a0, s0 move a1, s1 - la v0, main_entry + move a2, s2 + la v0, relocate_code jal v0 nop diff --git a/arch/mips/include/asm/relocs.h b/arch/mips/include/asm/relocs.h new file mode 100644 index 0000000000..0987c4bb13 --- /dev/null +++ b/arch/mips/include/asm/relocs.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * MIPS Relocations + * + * Copyright (c) 2017 Imagination Technologies Ltd. + */ + +#ifndef __ASM_MIPS_RELOCS_H__ +#define __ASM_MIPS_RELOCS_H__ + +#define R_MIPS_NONE 0 +#define R_MIPS_32 2 +#define R_MIPS_26 4 +#define R_MIPS_HI16 5 +#define R_MIPS_LO16 6 +#define R_MIPS_PC16 10 +#define R_MIPS_64 18 +#define R_MIPS_HIGHER 28 +#define R_MIPS_HIGHEST 29 +#define R_MIPS_PC21_S2 60 +#define R_MIPS_PC26_S2 61 + +#endif /* __ASM_MIPS_RELOCS_H__ */ diff --git a/arch/mips/include/asm/sections.h b/arch/mips/include/asm/sections.h index 2b8c516038..8e004eaf34 100644 --- a/arch/mips/include/asm/sections.h +++ b/arch/mips/include/asm/sections.h @@ -1 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ + +#ifndef __ASM_MIPS_SECTIONS_H +#define __ASM_MIPS_SECTIONS_H + #include <asm-generic/sections.h> + +/** + * __rel_start: Relocation data generated by the mips-relocs tool + * + * See arch/mips/lib/reloc.c for details on the format & use of this data. + */ +extern uint8_t __rel_start[]; + +#endif diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile index 7372e8dc27..4ba42e526e 100644 --- a/arch/mips/lib/Makefile +++ b/arch/mips/lib/Makefile @@ -4,6 +4,8 @@ obj-y += cpu-probe.o lwl-y += end.o obj-y += traps.o obj-y += genex.o +obj-y += reloc.o +obj-y += sections.o obj-y += shutdown.o obj-y += dma-default.o diff --git a/arch/mips/lib/barebox.lds.S b/arch/mips/lib/barebox.lds.S index 8ddf954517..58b0c5919d 100644 --- a/arch/mips/lib/barebox.lds.S +++ b/arch/mips/lib/barebox.lds.S @@ -13,6 +13,8 @@ SECTIONS . = TEXT_BASE; . = ALIGN(4); + + .image_start : { *(.__image_start) } .text : { _stext = .; @@ -79,9 +81,28 @@ SECTIONS .dtb : { BAREBOX_DTB() } _edata = .; + .image_end : { *(.__image_end) } + . = ALIGN(4); - __bss_start = .; - .bss : { *(.bss*) } - __bss_stop = .; + /* + * .rel must come last so that the mips-relocs tool can shrink + * the section size & the PT_LOAD program header filesz. + */ + .data.reloc : { + __rel_start = .; + BYTE(0x0) + . += (32 * 1024) - 1; + } + _end = .; + + .bss __rel_start (OVERLAY) : { + __bss_start = .; + *(.sbss.*) + *(.bss.*) + *(COMMON) + . = ALIGN(4); + __bss_stop = .; + } + } diff --git a/arch/mips/lib/reloc.c b/arch/mips/lib/reloc.c new file mode 100644 index 0000000000..9756d61666 --- /dev/null +++ b/arch/mips/lib/reloc.c @@ -0,0 +1,182 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * MIPS Relocation + * + * Copyright (c) 2017 Imagination Technologies Ltd. + * + * Relocation data, found in the .rel section, is generated by the mips-relocs + * tool & contains a record of all locations in the Barebox binary that need to + * be fixed up during relocation. + * + * The data is a sequence of unsigned integers, which are of somewhat arbitrary + * size. This is achieved by encoding integers as a sequence of bytes, each of + * which contains 7 bits of data with the most significant bit indicating + * whether any further bytes need to be read. The least significant bits of the + * integer are found in the first byte - ie. it somewhat resembles little + * endian. + * + * Each pair of two integers represents a relocation that must be applied. The + * first integer represents the type of relocation as a standard ELF relocation + * type (ie. R_MIPS_*). The second integer represents the offset at which to + * apply the relocation, relative to the previous relocation or for the first + * relocation the start of the relocated .text section. + * + * The end of the relocation data is indicated when type R_MIPS_NONE (0) is + * read, at which point no further integers should be read. That is, the + * terminating R_MIPS_NONE reloc includes no offset. + */ + +#include <common.h> + +#include <asm/bitops.h> +#include <asm/cache.h> +#include <asm/cacheops.h> +#include <asm/cpu.h> +#include <asm/cpu-info.h> +#include <asm/io.h> +#include <asm/mipsregs.h> +#include <asm/relocs.h> +#include <asm/sections.h> +#include <linux/sizes.h> +#include <asm-generic/memory_layout.h> + +#define MAX_BSS_SIZE SZ_1M + +void main_entry(void *fdt, u32 fdt_size); +void relocate_code(void *fdt, u32 fdt_size, u32 relocaddr); + +/** + * read_uint() - Read an unsigned integer from the buffer + * @buf: pointer to a pointer to the reloc buffer + * + * Read one whole unsigned integer from the relocation data pointed to by @buf, + * advancing @buf past the bytes encoding the integer. + * + * Returns: the integer read from @buf + */ +static unsigned long read_uint(uint8_t **buf) +{ + unsigned long val = 0; + unsigned int shift = 0; + uint8_t new; + + do { + new = *(*buf)++; + val |= (new & 0x7f) << shift; + shift += 7; + } while (new & 0x80); + + return val; +} + +/** + * apply_reloc() - Apply a single relocation + * @type: the type of reloc (R_MIPS_*) + * @addr: the address that the reloc should be applied to + * @off: the relocation offset, ie. number of bytes we're moving Barebox by + * + * Apply a single relocation of type @type at @addr. This function is + * intentionally simple, and does the bare minimum needed to fixup the + * relocated Barebox - in particular, it does not check for overflows. + */ +static void apply_reloc(unsigned int type, void *addr, long off) +{ + uint32_t u32; + + switch (type) { + case R_MIPS_26: + u32 = *(uint32_t *)addr; + u32 = (u32 & GENMASK(31, 26)) | + ((u32 + (off >> 2)) & GENMASK(25, 0)); + *(uint32_t *)addr = u32; + break; + + case R_MIPS_32: + *(uint32_t *)addr += off; + break; + + case R_MIPS_64: + *(uint64_t *)addr += off; + break; + + case R_MIPS_HI16: + *(uint32_t *)addr += off >> 16; + break; + + default: + panic("Unhandled reloc type %u\n", type); + } +} + +/** + * relocate_code() - Relocate Barebox, generally from flash to DDR + * @start_addr_sp: new stack pointer + * @new_gd: pointer to relocated global data + * @relocaddr: the address to relocate to + * + * Relocate Barebox from its current location (generally in flash) to a new one + * (generally in DDR). This function will copy the Barebox binary & apply + * relocations as necessary, then jump to board_init_r in the new build of + * Barebox. As such, this function does not return. + */ +void relocate_code(void *fdt, u32 fdt_size, u32 ram_size) +{ + unsigned long addr, length, bss_len; + u32 relocaddr, new_stack; + uint8_t *buf, *bss_start; + unsigned int type; + long off; + + length = barebox_image_size + MAX_BSS_SIZE; + relocaddr = ALIGN_DOWN(ram_size - barebox_image_size, SZ_64K); + relocaddr = KSEG0ADDR(relocaddr); + new_stack = relocaddr - MALLOC_SIZE - 16; + + /* + * Ensure that we're relocating by an offset which is a multiple of + * 64KiB, ie. doesn't change the least significant 16 bits of any + * addresses. This allows us to discard R_MIPS_LO16 relocs, saving + * space in the Barebox binary & complexity in handling them. + */ + off = relocaddr - (unsigned long)__image_start; + if (off & 0xffff) + panic("Mis-aligned relocation\n"); + + /* Copy Barebox to RAM */ + memcpy((void *)relocaddr, __image_start, length); + + /* Now apply relocations to the copy in RAM */ + buf = __rel_start; + addr = relocaddr; + while (true) { + type = read_uint(&buf); + if (type == R_MIPS_NONE) + break; + + addr += read_uint(&buf) << 2; + apply_reloc(type, (void *)addr, off); + } + + /* Ensure the icache is coherent */ + flush_cache_all(); + + /* Clear the .bss section */ + bss_start = (uint8_t *)((unsigned long)__bss_start + off); + bss_len = (unsigned long)&__bss_stop - (unsigned long)__bss_start; + memset(bss_start, 0, bss_len); + + __asm__ __volatile__ ( + "move $a0, %0\n" + " move $a1, %1\n" + " move $31, $0\n" + " move $sp, %2\n" + " jr %3\n" + : /* no outputs */ + : "r"(fdt), + "r"(fdt_size), + "r"(new_stack), + "r"((unsigned long)main_entry + off)); + + /* Since we jumped to the new Barebox above, we won't get here */ + unreachable(); +} diff --git a/arch/mips/lib/sections.c b/arch/mips/lib/sections.c new file mode 100644 index 0000000000..66d559f94a --- /dev/null +++ b/arch/mips/lib/sections.c @@ -0,0 +1,9 @@ +#include <common.h> +#include <asm/sections.h> +#include <linux/types.h> + +char _text[0] __attribute__((section("._text"))); +char __bss_start[0] __attribute__((section(".__bss_start"))); +char __bss_stop[0] __attribute__((section(".__bss_stop"))); +char __image_start[0] __attribute__((section(".__image_start"))); +char __image_end[0] __attribute__((section(".__image_end"))); diff --git a/scripts/Makefile b/scripts/Makefile index ff0a3c2a07..62d4ab20aa 100644 --- a/scripts/Makefile +++ b/scripts/Makefile @@ -12,6 +12,7 @@ hostprogs-y += bareboxcrc32 hostprogs-y += kernel-install hostprogs-$(CONFIG_IMD) += bareboximd hostprogs-$(CONFIG_KALLSYMS) += kallsyms +hostprogs-$(CONFIG_MIPS) += mips-relocs hostprogs-$(CONFIG_MVEBU_HOSTTOOLS) += kwbimage kwboot hostprogs-$(CONFIG_ARCH_NETX) += gen_netx_image hostprogs-$(CONFIG_ARCH_OMAP) += omap_signGP mk-omap-image diff --git a/scripts/mips-relocs.c b/scripts/mips-relocs.c new file mode 100644 index 0000000000..7916159581 --- /dev/null +++ b/scripts/mips-relocs.c @@ -0,0 +1,426 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * MIPS Relocation Data Generator + * + * Copyright (c) 2017 Imagination Technologies Ltd. + */ + +#include <assert.h> +#include <elf.h> +#include <errno.h> +#include <fcntl.h> +#include <limits.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <unistd.h> + +#include <../../arch/mips/include/asm/relocs.h> + +#define hdr_field(pfx, idx, field) ({ \ + uint64_t _val; \ + unsigned int _size; \ + \ + if (is_64) { \ + _val = pfx##hdr64[idx].field; \ + _size = sizeof(pfx##hdr64[0].field); \ + } else { \ + _val = pfx##hdr32[idx].field; \ + _size = sizeof(pfx##hdr32[0].field); \ + } \ + \ + switch (_size) { \ + case 1: \ + break; \ + case 2: \ + _val = is_be ? be16toh(_val) : le16toh(_val); \ + break; \ + case 4: \ + _val = is_be ? be32toh(_val) : le32toh(_val); \ + break; \ + case 8: \ + _val = is_be ? be64toh(_val) : le64toh(_val); \ + break; \ + } \ + \ + _val; \ +}) + +#define set_hdr_field(pfx, idx, field, val) ({ \ + uint64_t _val; \ + unsigned int _size; \ + \ + if (is_64) \ + _size = sizeof(pfx##hdr64[0].field); \ + else \ + _size = sizeof(pfx##hdr32[0].field); \ + \ + switch (_size) { \ + case 1: \ + _val = val; \ + break; \ + case 2: \ + _val = is_be ? htobe16(val) : htole16(val); \ + break; \ + case 4: \ + _val = is_be ? htobe32(val) : htole32(val); \ + break; \ + case 8: \ + _val = is_be ? htobe64(val) : htole64(val); \ + break; \ + default: \ + /* We should never reach here */ \ + _val = 0; \ + assert(0); \ + break; \ + } \ + \ + if (is_64) \ + pfx##hdr64[idx].field = _val; \ + else \ + pfx##hdr32[idx].field = _val; \ +}) + +#define ehdr_field(field) \ + hdr_field(e, 0, field) +#define phdr_field(idx, field) \ + hdr_field(p, idx, field) +#define shdr_field(idx, field) \ + hdr_field(s, idx, field) + +#define set_phdr_field(idx, field, val) \ + set_hdr_field(p, idx, field, val) +#define set_shdr_field(idx, field, val) \ + set_hdr_field(s, idx, field, val) + +#define shstr(idx) (&shstrtab[idx]) + +bool is_64, is_be; +uint64_t text_base; + +struct mips_reloc { + uint8_t type; + uint64_t offset; +} *relocs; +size_t relocs_sz, relocs_idx; + +static int add_reloc(unsigned int type, uint64_t off) +{ + struct mips_reloc *new; + size_t new_sz; + + switch (type) { + case R_MIPS_NONE: + case R_MIPS_LO16: + case R_MIPS_PC16: + case R_MIPS_HIGHER: + case R_MIPS_HIGHEST: + case R_MIPS_PC21_S2: + case R_MIPS_PC26_S2: + /* Skip these relocs */ + return 0; + + default: + break; + } + + if (relocs_idx == relocs_sz) { + new_sz = relocs_sz ? relocs_sz * 2 : 128; + new = realloc(relocs, new_sz * sizeof(*relocs)); + if (!new) { + fprintf(stderr, "Out of memory\n"); + return -ENOMEM; + } + + relocs = new; + relocs_sz = new_sz; + } + + relocs[relocs_idx++] = (struct mips_reloc){ + .type = type, + .offset = off, + }; + + return 0; +} + +static int parse_mips32_rel(const void *_rel) +{ + const Elf32_Rel *rel = _rel; + uint32_t off, type; + + off = is_be ? be32toh(rel->r_offset) : le32toh(rel->r_offset); + off -= text_base; + + type = is_be ? be32toh(rel->r_info) : le32toh(rel->r_info); + type = ELF32_R_TYPE(type); + + return add_reloc(type, off); +} + +static int parse_mips64_rela(const void *_rel) +{ + const Elf64_Rela *rel = _rel; + uint64_t off, type; + + off = is_be ? be64toh(rel->r_offset) : le64toh(rel->r_offset); + off -= text_base; + + type = rel->r_info >> (64 - 8); + + return add_reloc(type, off); +} + +static void output_uint(uint8_t **buf, uint64_t val) +{ + uint64_t tmp; + + do { + tmp = val & 0x7f; + val >>= 7; + tmp |= !!val << 7; + *(*buf)++ = tmp; + } while (val); +} + +static int compare_relocs(const void *a, const void *b) +{ + const struct mips_reloc *ra = a, *rb = b; + + return ra->offset - rb->offset; +} + +int main(int argc, char *argv[]) +{ + unsigned int i, j, i_rel_shdr, sh_type, sh_entsize, sh_entries; + size_t rel_size, rel_actual_size; + const char *shstrtab, *sh_name, *rel_pfx; + int (*parse_fn)(const void *rel); + uint8_t *buf_start, *buf; + const Elf32_Ehdr *ehdr32; + const Elf64_Ehdr *ehdr64; + uintptr_t sh_offset; + Elf32_Shdr *shdr32; + Elf64_Shdr *shdr64; + struct stat st; + int err, fd; + void *elf; + bool skip; + + fd = open(argv[1], O_RDWR); + if (fd == -1) { + fprintf(stderr, "Unable to open input file %s\n", argv[1]); + err = errno; + goto out_ret; + } + + err = fstat(fd, &st); + if (err) { + fprintf(stderr, "Unable to fstat() input file\n"); + goto out_close_fd; + } + + elf = mmap(NULL, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + if (elf == MAP_FAILED) { + fprintf(stderr, "Unable to mmap() input file\n"); + err = errno; + goto out_close_fd; + } + + ehdr32 = elf; + ehdr64 = elf; + + if (memcmp(&ehdr32->e_ident[EI_MAG0], ELFMAG, SELFMAG)) { + fprintf(stderr, "Input file is not an ELF\n"); + err = -EINVAL; + goto out_free_relocs; + } + + if (ehdr32->e_ident[EI_VERSION] != EV_CURRENT) { + fprintf(stderr, "Unrecognised ELF version\n"); + err = -EINVAL; + goto out_free_relocs; + } + + switch (ehdr32->e_ident[EI_CLASS]) { + case ELFCLASS32: + is_64 = false; + break; + case ELFCLASS64: + is_64 = true; + break; + default: + fprintf(stderr, "Unrecognised ELF class\n"); + err = -EINVAL; + goto out_free_relocs; + } + + switch (ehdr32->e_ident[EI_DATA]) { + case ELFDATA2LSB: + is_be = false; + break; + case ELFDATA2MSB: + is_be = true; + break; + default: + fprintf(stderr, "Unrecognised ELF data encoding\n"); + err = -EINVAL; + goto out_free_relocs; + } + + if (ehdr_field(e_type) != ET_EXEC) { + fprintf(stderr, "Input ELF is not an executable\n"); + printf("type 0x%lx\n", ehdr_field(e_type)); + err = -EINVAL; + goto out_free_relocs; + } + + if (ehdr_field(e_machine) != EM_MIPS) { + fprintf(stderr, "Input ELF does not target MIPS\n"); + err = -EINVAL; + goto out_free_relocs; + } + + shdr32 = elf + ehdr_field(e_shoff); + shdr64 = elf + ehdr_field(e_shoff); + shstrtab = elf + shdr_field(ehdr_field(e_shstrndx), sh_offset); + + i_rel_shdr = UINT_MAX; + for (i = 0; i < ehdr_field(e_shnum); i++) { + sh_name = shstr(shdr_field(i, sh_name)); + + if (!strcmp(sh_name, ".data.reloc")) { + i_rel_shdr = i; + continue; + } + + if (!strcmp(sh_name, ".text")) { + text_base = shdr_field(i, sh_addr); + continue; + } + } + if (i_rel_shdr == UINT_MAX) { + fprintf(stderr, "Unable to find .rel section\n"); + err = -EINVAL; + goto out_free_relocs; + } + if (!text_base) { + fprintf(stderr, "Unable to find .text base address\n"); + err = -EINVAL; + goto out_free_relocs; + } + + rel_pfx = is_64 ? ".rela." : ".rel."; + + for (i = 0; i < ehdr_field(e_shnum); i++) { + sh_type = shdr_field(i, sh_type); + if ((sh_type != SHT_REL) && (sh_type != SHT_RELA)) + continue; + + sh_name = shstr(shdr_field(i, sh_name)); + if (strncmp(sh_name, rel_pfx, strlen(rel_pfx))) { + if (strcmp(sh_name, ".rel") && strcmp(sh_name, ".rel.dyn")) + fprintf(stderr, "WARNING: Unexpected reloc section name '%s'\n", sh_name); + continue; + } + + /* + * Skip reloc sections which either don't correspond to another + * section in the ELF, or whose corresponding section isn't + * loaded as part of the U-Boot binary (ie. doesn't have the + * alloc flags set). + */ + skip = true; + for (j = 0; j < ehdr_field(e_shnum); j++) { + if (strcmp(&sh_name[strlen(rel_pfx) - 1], shstr(shdr_field(j, sh_name)))) + continue; + + skip = !(shdr_field(j, sh_flags) & SHF_ALLOC); + break; + } + if (skip) + continue; + + sh_offset = shdr_field(i, sh_offset); + sh_entsize = shdr_field(i, sh_entsize); + sh_entries = shdr_field(i, sh_size) / sh_entsize; + + if (sh_type == SHT_REL) { + if (is_64) { + fprintf(stderr, "REL-style reloc in MIPS64 ELF?\n"); + err = -EINVAL; + goto out_free_relocs; + } else { + parse_fn = parse_mips32_rel; + } + } else { + if (is_64) { + parse_fn = parse_mips64_rela; + } else { + fprintf(stderr, "RELA-style reloc in MIPS32 ELF?\n"); + err = -EINVAL; + goto out_free_relocs; + } + } + + for (j = 0; j < sh_entries; j++) { + err = parse_fn(elf + sh_offset + (j * sh_entsize)); + if (err) + goto out_free_relocs; + } + } + + if (!relocs) { + fprintf(stderr, "No relocs was found. Try to configure linker with --emit-relocs\n"); + err = -EINVAL; + goto out_free_relocs; + } + + /* Sort relocs in ascending order of offset */ + qsort(relocs, relocs_idx, sizeof(*relocs), compare_relocs); + + /* Make reloc offsets relative to their predecessor */ + for (i = relocs_idx - 1; i > 0; i--) { + relocs[i].offset -= relocs[i - 1].offset; + } + + /* Write the relocations to the .rel section */ + buf = buf_start = elf + shdr_field(i_rel_shdr, sh_offset); + for (i = 0; i < relocs_idx; i++) { + output_uint(&buf, relocs[i].type); + output_uint(&buf, relocs[i].offset >> 2); + } + + /* Write a terminating R_MIPS_NONE (0) */ + output_uint(&buf, R_MIPS_NONE); + + /* Ensure the relocs didn't overflow the .rel section */ + rel_size = shdr_field(i_rel_shdr, sh_size); + rel_actual_size = buf - buf_start; + if (rel_actual_size > rel_size) { + fprintf(stderr, "Relocations overflow available space of 0x%lx (required 0x%lx)!\n", + rel_size, rel_actual_size); + fprintf(stderr, "Please adjust CONFIG_MIPS_RELOCATION_TABLE_SIZE to at least 0x%lx\n", + (rel_actual_size + 0x100) & ~0xFF); + err = -ENOMEM; + goto out_free_relocs; + } + + /* Make sure data is written back to the file */ + err = msync(elf, st.st_size, MS_SYNC); + if (err) { + fprintf(stderr, "Failed to msync: %d\n", errno); + goto out_free_relocs; + } + +out_free_relocs: + free(relocs); + munmap(elf, st.st_size); +out_close_fd: + close(fd); +out_ret: + return err; +} -- 2.20.1 _______________________________________________ barebox mailing list [email protected] http://lists.infradead.org/mailman/listinfo/barebox
