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u-boot/arch/arm/cpu/armv8/start.S
Andre Przywara 1416e2d225 armv8: make SPL exception vectors optional 
Even though the exception vector table is a fundamental part of the ARM
architecture, U-Boot mostly does not make real use of it, except when
crash dumping. But having it in takes up quite some space, partly due to
the architectural alignment requirement of 2KB. Since we don't take special
care of that, the compiler adds a more or less random amount of padding
space, which increases the image size quite a bit, especially for the SPL.

On a typical Allwinner build this is around 1.5KB of padding, plus 1KB
for the vector table (mostly padding space again), then some extra code
to do the actual handling. This amounts to almost 10% of the maximum image
size, which is quite a lot for a pure debugging feature.

Add a Kconfig symbol to allow the exception vector table to be left out
of the build for the SPL.
For now this is "default y" for everyone, but specific defconfigs,
platforms or .config files can opt out here at will, to mitigate the code
size pressure we see for some SPLs.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
2018-08-03 19:53:54 -04:00

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/* SPDX-License-Identifier: GPL-2.0+ */
/*
* (C) Copyright 2013
* David Feng <fenghua@phytium.com.cn>
*/
#include <asm-offsets.h>
#include <config.h>
#include <linux/linkage.h>
#include <asm/macro.h>
#include <asm/armv8/mmu.h>
/*************************************************************************
*
* Startup Code (reset vector)
*
*************************************************************************/
.globl _start
_start:
#if defined(LINUX_KERNEL_IMAGE_HEADER)
#include <asm/boot0-linux-kernel-header.h>
#elif defined(CONFIG_ENABLE_ARM_SOC_BOOT0_HOOK)
/*
* Various SoCs need something special and SoC-specific up front in
* order to boot, allow them to set that in their boot0.h file and then
* use it here.
*/
#include <asm/arch/boot0.h>
#else
b reset
#endif
.align 3
.globl _TEXT_BASE
_TEXT_BASE:
.quad CONFIG_SYS_TEXT_BASE
/*
* These are defined in the linker script.
*/
.globl _end_ofs
_end_ofs:
.quad _end - _start
.globl _bss_start_ofs
_bss_start_ofs:
.quad __bss_start - _start
.globl _bss_end_ofs
_bss_end_ofs:
.quad __bss_end - _start
reset:
/* Allow the board to save important registers */
b save_boot_params
.globl save_boot_params_ret
save_boot_params_ret:
#if CONFIG_POSITION_INDEPENDENT
/*
* Fix .rela.dyn relocations. This allows U-Boot to be loaded to and
* executed at a different address than it was linked at.
*/
pie_fixup:
adr x0, _start /* x0 <- Runtime value of _start */
ldr x1, _TEXT_BASE /* x1 <- Linked value of _start */
sub x9, x0, x1 /* x9 <- Run-vs-link offset */
adr x2, __rel_dyn_start /* x2 <- Runtime &__rel_dyn_start */
adr x3, __rel_dyn_end /* x3 <- Runtime &__rel_dyn_end */
pie_fix_loop:
ldp x0, x1, [x2], #16 /* (x0, x1) <- (Link location, fixup) */
ldr x4, [x2], #8 /* x4 <- addend */
cmp w1, #1027 /* relative fixup? */
bne pie_skip_reloc
/* relative fix: store addend plus offset at dest location */
add x0, x0, x9
add x4, x4, x9
str x4, [x0]
pie_skip_reloc:
cmp x2, x3
b.lo pie_fix_loop
pie_fixup_done:
#endif
#ifdef CONFIG_SYS_RESET_SCTRL
bl reset_sctrl
#endif
#if defined(CONFIG_ARMV8__SPL_EXCEPTION_VECTORS) || !defined(CONFIG_SPL_BUILD)
.macro set_vbar, regname, reg
msr \regname, \reg
.endm
adr x0, vectors
#else
.macro set_vbar, regname, reg
.endm
#endif
/*
* Could be EL3/EL2/EL1, Initial State:
* Little Endian, MMU Disabled, i/dCache Disabled
*/
switch_el x1, 3f, 2f, 1f
3: set_vbar vbar_el3, x0
mrs x0, scr_el3
orr x0, x0, #0xf /* SCR_EL3.NS|IRQ|FIQ|EA */
msr scr_el3, x0
msr cptr_el3, xzr /* Enable FP/SIMD */
#ifdef COUNTER_FREQUENCY
ldr x0, =COUNTER_FREQUENCY
msr cntfrq_el0, x0 /* Initialize CNTFRQ */
#endif
b 0f
2: set_vbar vbar_el2, x0
mov x0, #0x33ff
msr cptr_el2, x0 /* Enable FP/SIMD */
b 0f
1: set_vbar vbar_el1, x0
mov x0, #3 << 20
msr cpacr_el1, x0 /* Enable FP/SIMD */
0:
/*
* Enable SMPEN bit for coherency.
* This register is not architectural but at the moment
* this bit should be set for A53/A57/A72.
*/
#ifdef CONFIG_ARMV8_SET_SMPEN
switch_el x1, 3f, 1f, 1f
3:
mrs x0, S3_1_c15_c2_1 /* cpuectlr_el1 */
orr x0, x0, #0x40
msr S3_1_c15_c2_1, x0
1:
#endif
/* Apply ARM core specific erratas */
bl apply_core_errata
/*
* Cache/BPB/TLB Invalidate
* i-cache is invalidated before enabled in icache_enable()
* tlb is invalidated before mmu is enabled in dcache_enable()
* d-cache is invalidated before enabled in dcache_enable()
*/
/* Processor specific initialization */
bl lowlevel_init
#if defined(CONFIG_ARMV8_SPIN_TABLE) && !defined(CONFIG_SPL_BUILD)
branch_if_master x0, x1, master_cpu
b spin_table_secondary_jump
/* never return */
#elif defined(CONFIG_ARMV8_MULTIENTRY)
branch_if_master x0, x1, master_cpu
/*
* Slave CPUs
*/
slave_cpu:
wfe
ldr x1, =CPU_RELEASE_ADDR
ldr x0, [x1]
cbz x0, slave_cpu
br x0 /* branch to the given address */
#endif /* CONFIG_ARMV8_MULTIENTRY */
master_cpu:
bl _main
#ifdef CONFIG_SYS_RESET_SCTRL
reset_sctrl:
switch_el x1, 3f, 2f, 1f
3:
mrs x0, sctlr_el3
b 0f
2:
mrs x0, sctlr_el2
b 0f
1:
mrs x0, sctlr_el1
0:
ldr x1, =0xfdfffffa
and x0, x0, x1
switch_el x1, 6f, 5f, 4f
6:
msr sctlr_el3, x0
b 7f
5:
msr sctlr_el2, x0
b 7f
4:
msr sctlr_el1, x0
7:
dsb sy
isb
b __asm_invalidate_tlb_all
ret
#endif
/*-----------------------------------------------------------------------*/
WEAK(apply_core_errata)
mov x29, lr /* Save LR */
/* For now, we support Cortex-A53, Cortex-A57 specific errata */
/* Check if we are running on a Cortex-A53 core */
branch_if_a53_core x0, apply_a53_core_errata
/* Check if we are running on a Cortex-A57 core */
branch_if_a57_core x0, apply_a57_core_errata
0:
mov lr, x29 /* Restore LR */
ret
apply_a53_core_errata:
#ifdef CONFIG_ARM_ERRATA_855873
mrs x0, midr_el1
tst x0, #(0xf << 20)
b.ne 0b
mrs x0, midr_el1
and x0, x0, #0xf
cmp x0, #3
b.lt 0b
mrs x0, S3_1_c15_c2_0 /* cpuactlr_el1 */
/* Enable data cache clean as data cache clean/invalidate */
orr x0, x0, #1 << 44
msr S3_1_c15_c2_0, x0 /* cpuactlr_el1 */
#endif
b 0b
apply_a57_core_errata:
#ifdef CONFIG_ARM_ERRATA_828024
mrs x0, S3_1_c15_c2_0 /* cpuactlr_el1 */
/* Disable non-allocate hint of w-b-n-a memory type */
orr x0, x0, #1 << 49
/* Disable write streaming no L1-allocate threshold */
orr x0, x0, #3 << 25
/* Disable write streaming no-allocate threshold */
orr x0, x0, #3 << 27
msr S3_1_c15_c2_0, x0 /* cpuactlr_el1 */
#endif
#ifdef CONFIG_ARM_ERRATA_826974
mrs x0, S3_1_c15_c2_0 /* cpuactlr_el1 */
/* Disable speculative load execution ahead of a DMB */
orr x0, x0, #1 << 59
msr S3_1_c15_c2_0, x0 /* cpuactlr_el1 */
#endif
#ifdef CONFIG_ARM_ERRATA_833471
mrs x0, S3_1_c15_c2_0 /* cpuactlr_el1 */
/* FPSCR write flush.
* Note that in some cases where a flush is unnecessary this
could impact performance. */
orr x0, x0, #1 << 38
msr S3_1_c15_c2_0, x0 /* cpuactlr_el1 */
#endif
#ifdef CONFIG_ARM_ERRATA_829520
mrs x0, S3_1_c15_c2_0 /* cpuactlr_el1 */
/* Disable Indirect Predictor bit will prevent this erratum
from occurring
* Note that in some cases where a flush is unnecessary this
could impact performance. */
orr x0, x0, #1 << 4
msr S3_1_c15_c2_0, x0 /* cpuactlr_el1 */
#endif
#ifdef CONFIG_ARM_ERRATA_833069
mrs x0, S3_1_c15_c2_0 /* cpuactlr_el1 */
/* Disable Enable Invalidates of BTB bit */
and x0, x0, #0xE
msr S3_1_c15_c2_0, x0 /* cpuactlr_el1 */
#endif
b 0b
ENDPROC(apply_core_errata)
/*-----------------------------------------------------------------------*/
WEAK(lowlevel_init)
mov x29, lr /* Save LR */
#if defined(CONFIG_GICV2) || defined(CONFIG_GICV3)
branch_if_slave x0, 1f
ldr x0, =GICD_BASE
bl gic_init_secure
1:
#if defined(CONFIG_GICV3)
ldr x0, =GICR_BASE
bl gic_init_secure_percpu
#elif defined(CONFIG_GICV2)
ldr x0, =GICD_BASE
ldr x1, =GICC_BASE
bl gic_init_secure_percpu
#endif
#endif
#ifdef CONFIG_ARMV8_MULTIENTRY
branch_if_master x0, x1, 2f
/*
* Slave should wait for master clearing spin table.
* This sync prevent salves observing incorrect
* value of spin table and jumping to wrong place.
*/
#if defined(CONFIG_GICV2) || defined(CONFIG_GICV3)
#ifdef CONFIG_GICV2
ldr x0, =GICC_BASE
#endif
bl gic_wait_for_interrupt
#endif
/*
* All slaves will enter EL2 and optionally EL1.
*/
adr x4, lowlevel_in_el2
ldr x5, =ES_TO_AARCH64
bl armv8_switch_to_el2
lowlevel_in_el2:
#ifdef CONFIG_ARMV8_SWITCH_TO_EL1
adr x4, lowlevel_in_el1
ldr x5, =ES_TO_AARCH64
bl armv8_switch_to_el1
lowlevel_in_el1:
#endif
#endif /* CONFIG_ARMV8_MULTIENTRY */
2:
mov lr, x29 /* Restore LR */
ret
ENDPROC(lowlevel_init)
WEAK(smp_kick_all_cpus)
/* Kick secondary cpus up by SGI 0 interrupt */
#if defined(CONFIG_GICV2) || defined(CONFIG_GICV3)
ldr x0, =GICD_BASE
b gic_kick_secondary_cpus
#endif
ret
ENDPROC(smp_kick_all_cpus)
/*-----------------------------------------------------------------------*/
ENTRY(c_runtime_cpu_setup)
#if defined(CONFIG_ARMV8__SPL_EXCEPTION_VECTORS) || !defined(CONFIG_SPL_BUILD)
/* Relocate vBAR */
adr x0, vectors
switch_el x1, 3f, 2f, 1f
3: msr vbar_el3, x0
b 0f
2: msr vbar_el2, x0
b 0f
1: msr vbar_el1, x0
0:
#endif
ret
ENDPROC(c_runtime_cpu_setup)
WEAK(save_boot_params)
b save_boot_params_ret /* back to my caller */
ENDPROC(save_boot_params)
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