mirror of
https://github.com/smaeul/u-boot.git
synced 2025-11-04 14:00:19 +00:00
cd82f19985
A U-Boot image could be loaded and executed at a different location than it was linked at. For example, Aspeed takes a stable release version of U-Boot image as the golden one for recovery purposes. When the primary storage such as flash is corrupted, the golden image would be loaded to any SRAM/DRAM address on demands through ethernet/UART/etc and run for rescue. To deal with this condition, the PIE is needed as there is only one signed, golden image, which could be however executed at different places. This patch adds the PIE support for ARMv7 platform. Signed-off-by: Chia-Wei Wang <chiawei_wang@aspeedtech.com>
194 lines
5.5 KiB
ArmAsm
194 lines
5.5 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0+ */
|
|
/*
|
|
* crt0 - C-runtime startup Code for ARM U-Boot
|
|
*
|
|
* Copyright (c) 2012 Albert ARIBAUD <albert.u.boot@aribaud.net>
|
|
*/
|
|
|
|
#include <config.h>
|
|
#include <asm-offsets.h>
|
|
#include <linux/linkage.h>
|
|
#include <asm/assembler.h>
|
|
|
|
/*
|
|
* This file handles the target-independent stages of the U-Boot
|
|
* start-up where a C runtime environment is needed. Its entry point
|
|
* is _main and is branched into from the target's start.S file.
|
|
*
|
|
* _main execution sequence is:
|
|
*
|
|
* 1. Set up initial environment for calling board_init_f().
|
|
* This environment only provides a stack and a place to store
|
|
* the GD ('global data') structure, both located in some readily
|
|
* available RAM (SRAM, locked cache...). In this context, VARIABLE
|
|
* global data, initialized or not (BSS), are UNAVAILABLE; only
|
|
* CONSTANT initialized data are available. GD should be zeroed
|
|
* before board_init_f() is called.
|
|
*
|
|
* 2. Call board_init_f(). This function prepares the hardware for
|
|
* execution from system RAM (DRAM, DDR...) As system RAM may not
|
|
* be available yet, , board_init_f() must use the current GD to
|
|
* store any data which must be passed on to later stages. These
|
|
* data include the relocation destination, the future stack, and
|
|
* the future GD location.
|
|
*
|
|
* 3. Set up intermediate environment where the stack and GD are the
|
|
* ones allocated by board_init_f() in system RAM, but BSS and
|
|
* initialized non-const data are still not available.
|
|
*
|
|
* 4a.For U-Boot proper (not SPL), call relocate_code(). This function
|
|
* relocates U-Boot from its current location into the relocation
|
|
* destination computed by board_init_f().
|
|
*
|
|
* 4b.For SPL, board_init_f() just returns (to crt0). There is no
|
|
* code relocation in SPL.
|
|
*
|
|
* 5. Set up final environment for calling board_init_r(). This
|
|
* environment has BSS (initialized to 0), initialized non-const
|
|
* data (initialized to their intended value), and stack in system
|
|
* RAM (for SPL moving the stack and GD into RAM is optional - see
|
|
* CONFIG_SPL_STACK_R). GD has retained values set by board_init_f().
|
|
*
|
|
* 6. For U-Boot proper (not SPL), some CPUs have some work left to do
|
|
* at this point regarding memory, so call c_runtime_cpu_setup.
|
|
*
|
|
* 7. Branch to board_init_r().
|
|
*
|
|
* For more information see 'Board Initialisation Flow in README.
|
|
*/
|
|
|
|
/*
|
|
* Macro for clearing BSS during SPL execution. Usually called during the
|
|
* relocation process for most boards before entering board_init_r(), but
|
|
* can also be done early before entering board_init_f() on plaforms that
|
|
* can afford it due to sufficient memory being available early.
|
|
*/
|
|
|
|
.macro CLEAR_BSS
|
|
ldr r0, =__bss_start /* this is auto-relocated! */
|
|
|
|
#ifdef CONFIG_USE_ARCH_MEMSET
|
|
ldr r3, =__bss_end /* this is auto-relocated! */
|
|
mov r1, #0x00000000 /* prepare zero to clear BSS */
|
|
|
|
subs r2, r3, r0 /* r2 = memset len */
|
|
bl memset
|
|
#else
|
|
ldr r1, =__bss_end /* this is auto-relocated! */
|
|
mov r2, #0x00000000 /* prepare zero to clear BSS */
|
|
|
|
clbss_l:cmp r0, r1 /* while not at end of BSS */
|
|
strlo r2, [r0] /* clear 32-bit BSS word */
|
|
addlo r0, r0, #4 /* move to next */
|
|
blo clbss_l
|
|
#endif
|
|
.endm
|
|
|
|
/*
|
|
* entry point of crt0 sequence
|
|
*/
|
|
|
|
ENTRY(_main)
|
|
|
|
/*
|
|
* Set up initial C runtime environment and call board_init_f(0).
|
|
*/
|
|
|
|
#if defined(CONFIG_TPL_BUILD) && defined(CONFIG_TPL_NEEDS_SEPARATE_STACK)
|
|
ldr r0, =(CONFIG_TPL_STACK)
|
|
#elif defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK)
|
|
ldr r0, =(CONFIG_SPL_STACK)
|
|
#else
|
|
ldr r0, =(CONFIG_SYS_INIT_SP_ADDR)
|
|
#endif
|
|
bic r0, r0, #7 /* 8-byte alignment for ABI compliance */
|
|
mov sp, r0
|
|
bl board_init_f_alloc_reserve
|
|
mov sp, r0
|
|
/* set up gd here, outside any C code */
|
|
mov r9, r0
|
|
bl board_init_f_init_reserve
|
|
|
|
#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_EARLY_BSS)
|
|
CLEAR_BSS
|
|
#endif
|
|
|
|
mov r0, #0
|
|
bl board_init_f
|
|
|
|
#if ! defined(CONFIG_SPL_BUILD)
|
|
|
|
/*
|
|
* Set up intermediate environment (new sp and gd) and call
|
|
* relocate_code(addr_moni). Trick here is that we'll return
|
|
* 'here' but relocated.
|
|
*/
|
|
|
|
ldr r0, [r9, #GD_START_ADDR_SP] /* sp = gd->start_addr_sp */
|
|
bic r0, r0, #7 /* 8-byte alignment for ABI compliance */
|
|
mov sp, r0
|
|
ldr r9, [r9, #GD_NEW_GD] /* r9 <- gd->new_gd */
|
|
|
|
adr lr, here
|
|
#if defined(CONFIG_POSITION_INDEPENDENT)
|
|
adr r0, _main
|
|
ldr r1, _start_ofs
|
|
add r0, r1
|
|
ldr r1, =CONFIG_SYS_TEXT_BASE
|
|
sub r1, r0
|
|
add lr, r1
|
|
#endif
|
|
ldr r0, [r9, #GD_RELOC_OFF] /* r0 = gd->reloc_off */
|
|
add lr, lr, r0
|
|
#if defined(CONFIG_CPU_V7M)
|
|
orr lr, #1 /* As required by Thumb-only */
|
|
#endif
|
|
ldr r0, [r9, #GD_RELOCADDR] /* r0 = gd->relocaddr */
|
|
b relocate_code
|
|
here:
|
|
/*
|
|
* now relocate vectors
|
|
*/
|
|
|
|
bl relocate_vectors
|
|
|
|
/* Set up final (full) environment */
|
|
|
|
bl c_runtime_cpu_setup /* we still call old routine here */
|
|
#endif
|
|
#if !defined(CONFIG_SPL_BUILD) || CONFIG_IS_ENABLED(FRAMEWORK)
|
|
|
|
#if !defined(CONFIG_SPL_BUILD) || !defined(CONFIG_SPL_EARLY_BSS)
|
|
CLEAR_BSS
|
|
#endif
|
|
|
|
# ifdef CONFIG_SPL_BUILD
|
|
/* Use a DRAM stack for the rest of SPL, if requested */
|
|
bl spl_relocate_stack_gd
|
|
cmp r0, #0
|
|
movne sp, r0
|
|
movne r9, r0
|
|
# endif
|
|
|
|
#if ! defined(CONFIG_SPL_BUILD)
|
|
bl coloured_LED_init
|
|
bl red_led_on
|
|
#endif
|
|
/* call board_init_r(gd_t *id, ulong dest_addr) */
|
|
mov r0, r9 /* gd_t */
|
|
ldr r1, [r9, #GD_RELOCADDR] /* dest_addr */
|
|
/* call board_init_r */
|
|
#if CONFIG_IS_ENABLED(SYS_THUMB_BUILD)
|
|
ldr lr, =board_init_r /* this is auto-relocated! */
|
|
bx lr
|
|
#else
|
|
ldr pc, =board_init_r /* this is auto-relocated! */
|
|
#endif
|
|
/* we should not return here. */
|
|
#endif
|
|
|
|
ENDPROC(_main)
|
|
|
|
_start_ofs:
|
|
.word _start - _main
|