diff options
Diffstat (limited to 'arch/mips')
| -rw-r--r-- | arch/mips/Makefile.postlink | 23 | ||||
| -rw-r--r-- | arch/mips/config.mk | 21 | ||||
| -rw-r--r-- | arch/mips/cpu/start.S | 130 | ||||
| -rw-r--r-- | arch/mips/cpu/u-boot.lds | 41 | ||||
| -rw-r--r-- | arch/mips/include/asm/relocs.h | 24 | ||||
| -rw-r--r-- | arch/mips/include/asm/sections.h | 7 | ||||
| -rw-r--r-- | arch/mips/lib/Makefile | 1 | ||||
| -rw-r--r-- | arch/mips/lib/reloc.c | 164 |
8 files changed, 233 insertions, 178 deletions
diff --git a/arch/mips/Makefile.postlink b/arch/mips/Makefile.postlink new file mode 100644 index 0000000..7da3acd --- /dev/null +++ b/arch/mips/Makefile.postlink @@ -0,0 +1,23 @@ +# +# Copyright (c) 2017 Imagination Technologies Ltd. +# +# SPDX-License-Identifier: GPL-2.0+ +# + +PHONY := __archpost +__archpost: + +-include include/config/auto.conf +include scripts/Kbuild.include + +CMD_RELOCS = tools/mips-relocs +quiet_cmd_relocs = RELOCS $@ + cmd_relocs = $(CMD_RELOCS) $@ + +u-boot: FORCE + @true + $(call if_changed,relocs) + +.PHONY: FORCE + +FORCE: diff --git a/arch/mips/config.mk b/arch/mips/config.mk index 2c72c15..cefdbe6 100644 --- a/arch/mips/config.mk +++ b/arch/mips/config.mk @@ -56,25 +56,14 @@ PLATFORM_ELFFLAGS += -B mips $(OBJCOPYFLAGS) # LDFLAGS_vmlinux += -G 0 -static -n -nostdlib # MODFLAGS += -mlong-calls # -# On the other hand, we want PIC in the U-Boot code to relocate it from ROM -# to RAM. $28 is always used as gp. -# -ifdef CONFIG_SPL_BUILD -PF_ABICALLS := -mno-abicalls -PF_PIC := -fno-pic -PF_PIE := -else -PF_ABICALLS := -mabicalls -PF_PIC := -fpic -PF_PIE := -pie -PF_OBJCOPY := -j .got -j .rel.dyn -j .padding -PF_OBJCOPY += -j .dtb.init.rodata +ifndef CONFIG_SPL_BUILD +OBJCOPYFLAGS += -j .got -j .rel -j .padding -j .dtb.init.rodata +LDFLAGS_FINAL += --emit-relocs endif -PLATFORM_CPPFLAGS += -G 0 $(PF_ABICALLS) $(PF_PIC) +PLATFORM_CPPFLAGS += -G 0 -mno-abicalls -fno-pic PLATFORM_CPPFLAGS += -msoft-float PLATFORM_LDFLAGS += -G 0 -static -n -nostdlib PLATFORM_RELFLAGS += -ffunction-sections -fdata-sections -LDFLAGS_FINAL += --gc-sections $(PF_PIE) +LDFLAGS_FINAL += --gc-sections OBJCOPYFLAGS += -j .text -j .rodata -j .data -j .u_boot_list -OBJCOPYFLAGS += $(PF_OBJCOPY) diff --git a/arch/mips/cpu/start.S b/arch/mips/cpu/start.S index d01ee9f..952c57a 100644 --- a/arch/mips/cpu/start.S +++ b/arch/mips/cpu/start.S @@ -221,18 +221,6 @@ wr_done: ehb #endif - /* - * Initialize $gp, force pointer sized alignment of bal instruction to - * forbid the compiler to put nop's between bal and _gp. This is - * required to keep _gp and ra aligned to 8 byte. - */ - .align PTRLOG - bal 1f - nop - PTR _gp -1: - PTR_L gp, 0(ra) - #ifdef CONFIG_MIPS_CM PTR_LA t9, mips_cm_map jalr t9 @@ -291,121 +279,3 @@ wr_done: move ra, zero END(_start) - -/* - * void relocate_code (addr_sp, gd, addr_moni) - * - * This "function" does not return, instead it continues in RAM - * after relocating the monitor code. - * - * a0 = addr_sp - * a1 = gd - * a2 = destination address - */ -ENTRY(relocate_code) - move sp, a0 # set new stack pointer - move fp, sp - - move s0, a1 # save gd in s0 - move s2, a2 # save destination address in s2 - - PTR_LI t0, CONFIG_SYS_MONITOR_BASE - PTR_SUB s1, s2, t0 # s1 <-- relocation offset - - PTR_LA t2, __image_copy_end - move t1, a2 - - /* - * t0 = source address - * t1 = target address - * t2 = source end address - */ -1: - PTR_L t3, 0(t0) - PTR_S t3, 0(t1) - PTR_ADDU t0, PTRSIZE - blt t0, t2, 1b - PTR_ADDU t1, PTRSIZE - - /* - * Now we want to update GOT. - * - * GOT[0] is reserved. GOT[1] is also reserved for the dynamic object - * generated by GNU ld. Skip these reserved entries from relocation. - */ - PTR_LA t3, num_got_entries - PTR_LA t8, _GLOBAL_OFFSET_TABLE_ - PTR_ADD t8, s1 # t8 now holds relocated _G_O_T_ - PTR_ADDIU t8, t8, 2 * PTRSIZE # skipping first two entries - PTR_LI t2, 2 -1: - PTR_L t1, 0(t8) - beqz t1, 2f - PTR_ADD t1, s1 - PTR_S t1, 0(t8) -2: - PTR_ADDIU t2, 1 - blt t2, t3, 1b - PTR_ADDIU t8, PTRSIZE - - /* Update dynamic relocations */ - PTR_LA t1, __rel_dyn_start - PTR_LA t2, __rel_dyn_end - - b 2f # skip first reserved entry - PTR_ADDIU t1, 2 * PTRSIZE - -1: - lw t8, -4(t1) # t8 <-- relocation info - - PTR_LI t3, MIPS_RELOC - bne t8, t3, 2f # skip non-MIPS_RELOC entries - nop - - PTR_L t3, -(2 * PTRSIZE)(t1) # t3 <-- location to fix up in FLASH - - PTR_L t8, 0(t3) # t8 <-- original pointer - PTR_ADD t8, s1 # t8 <-- adjusted pointer - - PTR_ADD t3, s1 # t3 <-- location to fix up in RAM - PTR_S t8, 0(t3) - -2: - blt t1, t2, 1b - PTR_ADDIU t1, 2 * PTRSIZE # each rel.dyn entry is 2*PTRSIZE bytes - - /* - * Flush caches to ensure our newly modified instructions are visible - * to the instruction cache. We're still running with the old GOT, so - * apply the reloc offset to the start address. - */ - PTR_LA a0, __text_start - PTR_LA a1, __text_end - PTR_SUB a1, a1, a0 - PTR_LA t9, flush_cache - jalr t9 - PTR_ADD a0, s1 - - PTR_ADD gp, s1 # adjust gp - - /* - * Clear BSS - * - * GOT is now relocated. Thus __bss_start and __bss_end can be - * accessed directly via $gp. - */ - PTR_LA t1, __bss_start # t1 <-- __bss_start - PTR_LA t2, __bss_end # t2 <-- __bss_end - -1: - PTR_S zero, 0(t1) - blt t1, t2, 1b - PTR_ADDIU t1, PTRSIZE - - move a0, s0 # a0 <-- gd - move a1, s2 - PTR_LA t9, board_init_r - jr t9 - move ra, zero - - END(relocate_code) diff --git a/arch/mips/cpu/u-boot.lds b/arch/mips/cpu/u-boot.lds index 0129c99..bd5536f 100644 --- a/arch/mips/cpu/u-boot.lds +++ b/arch/mips/cpu/u-boot.lds @@ -34,15 +34,6 @@ SECTIONS *(.data*) } - . = .; - _gp = ALIGN(16) + 0x7ff0; - - .got : { - *(.got) - } - - num_got_entries = SIZEOF(.got) >> PTR_COUNT_SHIFT; - . = ALIGN(4); .sdata : { *(.sdata*) @@ -57,33 +48,19 @@ SECTIONS __image_copy_end = .; __init_end = .; - .rel.dyn : { - __rel_dyn_start = .; - *(.rel.dyn) - __rel_dyn_end = .; - } - - .padding : { - /* - * Workaround for a binutils feature (or bug?). - * - * The GNU ld from binutils puts the dynamic relocation - * entries into the .rel.dyn section. Sometimes it - * allocates more dynamic relocation entries than it needs - * and the unused slots are set to R_MIPS_NONE entries. - * - * However the size of the .rel.dyn section in the ELF - * section header does not cover the unused entries, so - * objcopy removes those during stripping. - * - * Create a small section here to avoid that. - */ - LONG(0xFFFFFFFF) + /* + * .rel must come last so that the mips-relocs tool can shrink + * the section size & the PT_LOAD program header filesz. + */ + .rel : { + __rel_start = .; + BYTE(0x0) + . += (32 * 1024) - 1; } _end = .; - .bss __rel_dyn_start (OVERLAY) : { + .bss __rel_start (OVERLAY) : { __bss_start = .; *(.sbss.*) *(.bss.*) diff --git a/arch/mips/include/asm/relocs.h b/arch/mips/include/asm/relocs.h new file mode 100644 index 0000000..92e9d04 --- /dev/null +++ b/arch/mips/include/asm/relocs.h @@ -0,0 +1,24 @@ +/* + * MIPS Relocations + * + * Copyright (c) 2017 Imagination Technologies Ltd. + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#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 fc4640a..b9d2179 100644 --- a/arch/mips/include/asm/sections.h +++ b/arch/mips/include/asm/sections.h @@ -8,4 +8,11 @@ #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 659c6ad..ef557c6 100644 --- a/arch/mips/lib/Makefile +++ b/arch/mips/lib/Makefile @@ -8,6 +8,7 @@ obj-y += cache.o obj-y += cache_init.o obj-y += genex.o +obj-y += reloc.o obj-y += stack.o obj-y += traps.o diff --git a/arch/mips/lib/reloc.c b/arch/mips/lib/reloc.c new file mode 100644 index 0000000..d0c52c9 --- /dev/null +++ b/arch/mips/lib/reloc.c @@ -0,0 +1,164 @@ +/* + * MIPS Relocation + * + * Copyright (c) 2017 Imagination Technologies Ltd. + * + * SPDX-License-Identifier: GPL-2.0+ + * + * Relocation data, found in the .rel section, is generated by the mips-relocs + * tool & contains a record of all locations in the U-Boot 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/relocs.h> +#include <asm/sections.h> + +/** + * 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 U-Boot 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 U-Boot - 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 U-Boot, 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 U-Boot from its current location (generally in flash) to a new one + * (generally in DDR). This function will copy the U-Boot binary & apply + * relocations as necessary, then jump to board_init_r in the new build of + * U-Boot. As such, this function does not return. + */ +void relocate_code(ulong start_addr_sp, gd_t *new_gd, ulong relocaddr) +{ + unsigned long addr, length, bss_len; + uint8_t *buf, *bss_start; + unsigned int type; + long off; + + /* + * 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 U-Boot binary & complexity in handling them. + */ + off = relocaddr - (unsigned long)__text_start; + if (off & 0xffff) + panic("Mis-aligned relocation\n"); + + /* Copy U-Boot to RAM */ + length = __image_copy_end - __text_start; + memcpy((void *)relocaddr, __text_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(relocaddr, length); + + /* Clear the .bss section */ + bss_start = (uint8_t *)((unsigned long)__bss_start + off); + bss_len = (unsigned long)&__bss_end - (unsigned long)__bss_start; + memset(bss_start, 0, bss_len); + + /* Jump to the relocated U-Boot */ + asm volatile( + "move $29, %0\n" + " move $4, %1\n" + " move $5, %2\n" + " move $31, $0\n" + " jr %3" + : /* no outputs */ + : "r"(start_addr_sp), + "r"(new_gd), + "r"(relocaddr), + "r"((unsigned long)board_init_r + off)); + + /* Since we jumped to the new U-Boot above, we won't get here */ + unreachable(); +} |