arm64: Implement generic stage transitions for non-Tegra SoCs

The existing arm64 architecture code has been developed for the Tegra132
and Tegra210 SoCs, which only start their ARM64 cores in ramstage. It
interweaves the stage entry point with code that initializes a CPU (and
should not be run again if that CPU already ran a previous stage). It
also still contains some vestiges of SMP/secmon support (such as setting
up stacks in the BSS instead of using the stage-peristent one from
memlayout).

This patch splits those functions apart and makes the code layout
similar to how things work on ARM32. The default stage_entry() symbol is
a no-op wrapper that just calls main() for the current stage, for the
normal case where a stage ran on the same core as the last one. It can
be overridden by SoC code to support special cases like Tegra.

The CPU initialization code is split out into armv8/cpu.S (similar to
what arm_init_caches() does for ARM32) and called by the default
bootblock entry code. SoCs where a CPU starts up in a later stage can
call the same code from a stage_entry() override instead.

The Tegra132 and Tegra210 code is not touched by this patch to make it
easier to review and validate. A follow-up patch will bring those SoCs
in line with the model.

BRANCH=None
BUG=None
TEST=Booted Oak with a single mmu_init()/mmu_enable(). Built Ryu and
Smaug.

Change-Id: I28302a6ace47e8ab7a736e089f64922cef1a2f93
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/12077
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
This commit is contained in:
Julius Werner 2015-10-12 16:45:21 -07:00
parent 29016ea3b4
commit 66a476ad5f
14 changed files with 102 additions and 138 deletions

View File

@ -437,8 +437,8 @@ config HEAP_SIZE
config STACK_SIZE
hex
default 0x0 if (ARCH_RAMSTAGE_ARM || ARCH_RAMSTAGE_MIPS || ARCH_RAMSTAGE_RISCV)
default 0x1000
default 0x1000 if ARCH_X86
default 0x0
config MAX_CPUS
int

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@ -33,16 +33,6 @@ ifeq ($(CONFIG_ARCH_ROMSTAGE_ARM64),y)
CBFSTOOL_PRE1_OPTS = -m arm64 -s $(CONFIG_CBFS_SIZE)
endif
ifeq ($(CONFIG_ARCH_ARM64),y)
stages_c = $(src)/arch/arm64/stages.c
stages_o = $(obj)/arch/arm64/stages.o
$(stages_o): $(stages_c) $(obj)/config.h
@printf " CC $(subst $(obj)/,,$(@))\n"
$(CC_arm) -I. $(CPPFLAGS_arm) -c -o $@ $< -marm
endif
################################################################################
# bootblock
################################################################################
@ -55,9 +45,7 @@ $(obj)/arch/arm64/id.bootblock.o: $(obj)/build.h
bootblock-y += boot.c
bootblock-y += c_entry.c
bootblock-y += stage_entry.S
bootblock-y += cpu-stubs.c
bootblock-y += stages.c
bootblock-y += eabi_compat.c
bootblock-y += transition.c transition_asm.S
@ -89,7 +77,6 @@ verstage-y += eabi_compat.c
verstage-y += ../../lib/memset.c
verstage-y += ../../lib/memcpy.c
verstage-y += ../../lib/memmove.c
verstage-y += stages.c
endif # CONFIG_ARCH_VERSTAGE_ARM64
@ -101,9 +88,7 @@ ifeq ($(CONFIG_ARCH_ROMSTAGE_ARM64),y)
romstage-y += boot.c
romstage-y += c_entry.c
romstage-y += stage_entry.S
romstage-y += cpu-stubs.c
romstage-y += stages.c
romstage-y += div0.c
romstage-y += eabi_compat.c
romstage-y += memset.S
@ -129,7 +114,6 @@ endif # CONFIG_ARCH_ROMSTAGE_ARM64
ifeq ($(CONFIG_ARCH_RAMSTAGE_ARM64),y)
ramstage-y += c_entry.c
ramstage-y += stages.c
ramstage-y += div0.c
ramstage-y += eabi_compat.c
ramstage-y += boot.c
@ -137,11 +121,15 @@ ramstage-y += tables.c
ramstage-y += memset.S
ramstage-y += memcpy.S
ramstage-y += memmove.S
ramstage-y += stage_entry.S
ramstage-y += cpu-stubs.c
ramstage-$(CONFIG_ARM64_USE_ARM_TRUSTED_FIRMWARE) += arm_tf.c
ramstage-y += transition.c transition_asm.S
# TODO: Replace this with a simpler ramstage entry point in soc/nvidia/tegra*
ifeq ($(CONFIG_SOC_NVIDIA_TEGRA132)$(CONFIG_SOC_NVIDIA_TEGRA210),y)
ramstage-y += stage_entry.S
endif
rmodules_arm64-y += memset.S
rmodules_arm64-y += memcpy.S
rmodules_arm64-y += memmove.S

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@ -26,6 +26,9 @@ armv8_asm_flags = $(armv8_flags)
################################################################################
ifeq ($(CONFIG_ARCH_BOOTBLOCK_ARMV8_64),y)
ifneq ($(CONFIG_BOOTBLOCK_CUSTOM),y)
bootblock-y += bootblock.S
endif
bootblock-y += cache.c
bootblock-y += cache_helpers.S
bootblock-y += cpu.S

View File

@ -1,7 +1,7 @@
/*
* Early initialization code for aarch64 (a.k.a. armv8)
*
* Copyright 2013 Google Inc.
* Copyright 2015 Google Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
@ -14,21 +14,23 @@
* GNU General Public License for more details.
*/
.section ".id", "a", %progbits
#include <arch/asm.h>
.globl __id_start
__id_start:
ver:
.asciz COREBOOT_VERSION
vendor:
.asciz CONFIG_MAINBOARD_VENDOR
part:
.asciz CONFIG_MAINBOARD_PART_NUMBER
.long __id_end - ver /* Reverse offset to the vendor id */
.long __id_end - vendor /* Reverse offset to the vendor id */
.long __id_end - part /* Reverse offset to the part number */
.long CONFIG_ROM_SIZE /* Size of this romimage */
.globl __id_end
ENTRY(_start)
/* Initialize PSTATE, SCTLR and caches to clean state. */
bl arm64_init_cpu
__id_end:
.previous
/* Initialize stack with sentinel value to later check overflow. */
ldr x0, =_stack
ldr x1, =_estack
ldr x2, =0xdeadbeefdeadbeef
stack_init_loop:
stp x2, x2, [x0], #16
cmp x0, x1
bne stack_init_loop
/* Leave a line of beef dead for easier visibility in stack dumps. */
sub sp, x0, #16
bl main
ENDPROC(_start)

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@ -19,27 +19,40 @@
/*
* Bring an ARMv8 processor we just gained control of (e.g. from IROM) into a
* known state regarding caches/SCTLR. Completely cleans and invalidates
* known state regarding caches/SCTLR/PSTATE. Completely cleans and invalidates
* icache/dcache, disables MMU and dcache (if active), and enables unaligned
* accesses, icache and branch prediction (if inactive). Clobbers x4 and x5.
* accesses, icache and branch prediction (if inactive). Clobbers R22 and R23.
*/
ENTRY(arm_init_caches)
/* w4: SCTLR, return address: x8 (stay valid for the whole function) */
mov x8, x30
/* XXX: Assume that we always start running at EL3 */
mrs x4, sctlr_el3
ENTRY(arm64_init_cpu)
/* Initialize PSTATE (unmask all exceptions, select SP_EL0). */
msr SPSel, #0
msr DAIFClr, #0xf
/* FIXME: How to enable branch prediction on ARMv8? */
/* TODO: This is where we'd put non-boot CPUs into WFI if needed. */
/* x22: SCTLR, return address: x23 (callee-saved by subroutine) */
mov x23, x30
/* TODO: Assert that we always start running at EL3 */
mrs x22, sctlr_el3
/* Activate ICache (12) already for speed during cache flush below. */
orr x22, x22, #(1 << 12)
msr sctlr_el3, x22
isb
/* Flush and invalidate dcache */
mov x0, #DCCISW
bl flush_dcache_all
/* Deactivate MMU (0), Alignment Check (1) and DCache (2) */
and x4, x4, # ~(1 << 0) & ~(1 << 1) & ~(1 << 2)
/* Activate ICache (12) already for speed */
orr x4, x4, #(1 << 12)
msr sctlr_el3, x4
and x22, x22, # ~(1 << 0) & ~(1 << 1) & ~(1 << 2)
/* Activate Stack Alignment (3) because why not */
orr x22, x22, #(1 << 3)
/* Set to little-endian (25) */
and x22, x22, # ~(1 << 25)
/* Deactivate write-xor-execute enforcement (19) */
and x22, x22, # ~(1 << 19)
msr sctlr_el3, x22
/* Invalidate icache and TLB for good measure */
ic iallu
@ -47,26 +60,5 @@ ENTRY(arm_init_caches)
dsb sy
isb
ret x8
ENDPROC(arm_init_caches)
/* Based on u-boot transition.S */
ENTRY(switch_el3_to_el2)
mov x0, #0x5b1 /* Non-secure EL0/EL1 | HVC | 64bit EL2 */
msr scr_el3, x0
msr cptr_el3, xzr /* Disable coprocessor traps to EL3 */
mov x0, #0x33ff
msr cptr_el2, x0 /* Disable coprocessor traps to EL2 */
/* Return to the EL2_SP2 mode from EL3 */
mov x0, sp
msr sp_el2, x0 /* Migrate SP */
mrs x0, vbar_el3
msr vbar_el2, x0 /* Migrate VBAR */
mrs x0, sctlr_el3
msr sctlr_el2, x0 /* Migrate SCTLR */
mov x0, #0x3c9
msr spsr_el3, x0 /* EL2_SP2 | D | A | I | F */
msr elr_el3, x30
eret
ENDPROC(switch_el3_to_el2)
ret x23
ENDPROC(arm64_init_cpu)

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@ -36,6 +36,8 @@
#include <console/console.h>
#include <arch/lib_helpers.h>
uint8_t exception_stack[0x200] __attribute__((aligned(16)));
static const char *exception_names[NUM_EXC_VIDS] = {
[EXC_VID_CUR_SP_EL0_SYNC] = "_sync_sp_el0",
[EXC_VID_CUR_SP_EL0_IRQ] = "_irq_sp_el0",
@ -193,19 +195,17 @@ static uint64_t test_exception(void)
return 0;
}
void exception_hwinit(void)
{
exc_set_vbar();
}
void exception_init(void)
{
/* Load the exception table. */
exception_hwinit();
/* Load the exception table and initialize SP_EL3. */
exception_init_asm(exception_stack + ARRAY_SIZE(exception_stack));
printk(BIOS_DEBUG, "ARM64: Exception handlers installed.\n");
/* Only spend time testing on debug builds that are trying to detect more errors. */
if (IS_ENABLED(CONFIG_FATAL_ASSERTS)) {
printk(BIOS_DEBUG, "ARM64: Testing exception\n");
test_exception();
printk(BIOS_DEBUG, "ARM64: Done test exception\n");
}
}

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@ -71,3 +71,11 @@ void arch_prog_run(struct prog *prog)
doit(prog_entry_arg(prog));
}
#if !IS_ENABLED(CONFIG_SOC_NVIDIA_TEGRA132)
/* Generic stage entry point. Can be overridden by board/SoC if needed. */
__attribute__((weak)) void stage_entry(void)
{
main();
}
#endif

View File

@ -24,11 +24,7 @@ PHDRS
to_load PT_LOAD;
}
#if ENV_BOOTBLOCK
TARGET(binary)
#endif
#if ENV_RMODULE
#if ENV_BOOTBLOCK || ENV_RMODULE
ENTRY(_start)
#else
ENTRY(stage_entry)

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@ -22,13 +22,13 @@
REGION(ttb, addr, size, 4K) \
_ = ASSERT(size % 4K == 0, "TTB size must be divisible by 4K!");
/* ARM64 stacks need 16-byte alignment. The ramstage will set up its own stacks
* in BSS, so this is only used for the SRAM stages. */
#ifdef __PRE_RAM__
/* ARM64 stacks need 16-byte alignment. */
#if !(IS_ENABLED(CONFIG_SOC_NVIDIA_TEGRA132) || \
IS_ENABLED(CONFIG_SOC_NVIDIA_TEGRA210))
#define STACK(addr, size) \
REGION(stack, addr, size, 16) \
_ = ASSERT(size >= 2K, "stack should be >= 2K, see toolchain.inc");
#else
#else /* Hack around old Tegra stage_entry.S implementation. TODO: remove */
#define STACK(addr, size) REGION(preram_stack, addr, size, 16)
#endif

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@ -33,9 +33,11 @@
#include <arch/transition.h>
/* Initialize the exception handling on the current CPU. */
void exception_hwinit(void);
void exception_init(void);
/* Initialize VBAR and SP_EL3. */
void exception_init_asm(void *exception_stack_end);
/*
* Order matters for handling return values. The larger the value the higher
* the precedence.

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@ -1,44 +0,0 @@
/*
* This file is part of the coreboot project.
*
* Copyright 2014 Google Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
/*
* This file contains entry/exit functions for each stage during coreboot
* execution (bootblock entry and ramstage exit will depend on external
* loading).
*
* Entry points must be placed at the location the previous stage jumps
* to (the lowest address in the stage image). This is done by giving
* stage_entry() its own section in .text and placing it first in the
* linker script.
*/
#include <arch/stages.h>
#include <arch/cache.h>
/* we had marked 'doit' as 'noreturn'.
* There is no apparent harm in leaving it as something we can return from, and in the one
* case where we call a payload, the payload is allowed to return.
* Hence, leave it as something we can return from.
*/
void stage_exit(void *addr)
{
void (*doit)(void) = addr;
/*
* Most stages load code so we need to sync caches here. Should maybe
* go into cbfs_load_stage() instead...
*/
cache_sync_instructions();
doit();
}

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@ -155,11 +155,18 @@ ENTRY(exc_exit)
eret
ENDPROC(exc_exit)
/* exc_set_vbar: Initialize the exception entry address in vbar */
ENTRY(exc_set_vbar)
/*
* exception_init_asm: Initialize VBAR and point SP_EL3 to exception stack.
* x0 = end of exception stack
*/
ENTRY(exception_init_asm)
msr SPSel, #SPSR_USE_H
mov sp, x0
msr SPSel, #SPSR_USE_L
adr x0, exc_vectors
write_current vbar, x0, x1
dsb sy
isb
ret
ENDPROC(exc_set_vbar)
ENDPROC(exception_init_asm)

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@ -17,6 +17,11 @@ config SOC_NVIDIA_TEGRA132
if SOC_NVIDIA_TEGRA132
# TODO: Remove after replacing arch/arm64/stage_entry.S
config STACK_SIZE
hex
default 0x1000
config MAINBOARD_DO_DSI_INIT
bool "Use dsi graphics interface"
depends on MAINBOARD_DO_NATIVE_VGA_INIT

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@ -22,6 +22,11 @@ if SOC_NVIDIA_TEGRA210
config CHROMEOS
select CHROMEOS_RAMOOPS_NON_ACPI
# TODO: Remove after replacing arch/arm64/stage_entry.S
config STACK_SIZE
hex
default 0x1000
config MAINBOARD_DO_DSI_INIT
bool "Use dsi graphics interface"
depends on MAINBOARD_DO_NATIVE_VGA_INIT