Files
OpenCellular/src/include/program_loading.h
Julius Werner 99f4683adf Introduce bootblock self-decompression
Masked ROMs are the silent killers of boot speed on devices without
memory-mapped SPI flash. They often contain awfully slow SPI drivers
(presumably bit-banged) that take hundreds of milliseconds to load our
bootblock, and every extra kilobyte of bootblock size has a hugely
disproportionate impact on boot speed. The coreboot timestamps can never
show that component, but it impacts our users all the same.

This patch tries to alleviate that issue a bit by allowing us to
compress the bootblock with LZ4, which can cut its size down to nearly
half. Of course, masked ROMs usually don't come with decompression
algorithms built in, so we need to introduce a little decompression stub
that can decompress the rest of the bootblock. This is done by creating
a new "decompressor" stage which runs before the bootblock, but includes
the compressed bootblock code in its data section. It needs to be as
small as possible to get a real benefit from this approach, which means
no device drivers, no console output, no exception handling, etc.
Besides the decompression algorithm itself we only include the timer
driver so that we can measure the boot speed impact of decompression. On
ARM and ARM64 systems, we also need to give SoC code a chance to
initialize the MMU, since running decompression without MMU is
prohibitively slow on these architectures.

This feature is implemented for ARM and ARM64 architectures for now,
although most of it is architecture-independent and it should be
relatively simple to port to other platforms where a masked ROM loads
the bootblock into SRAM. It is also supposed to be a clean starting
point from which later optimizations can hopefully cut down the
decompression stub size (currently ~4K on RK3399) a bit more.

NOTE: Bootblock compression is not for everyone. Possible side effects
include trying to run LZ4 on CPUs that come out of reset extremely
underclocked or enabling this too early in SoC bring-up and getting
frustrated trying to find issues in an undebuggable environment. Ask
your SoC vendor if bootblock compression is right for you.

Change-Id: I0dc1cad9ae7508892e477739e743cd1afb5945e8
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/26340
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2018-05-22 02:44:14 +00:00

210 lines
5.8 KiB
C

/*
* This file is part of the coreboot project.
*
* Copyright 2015 Google Inc.
* Copyright (C) 2014 Imagination Technologies
*
* 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.
*/
#ifndef PROGRAM_LOADING_H
#define PROGRAM_LOADING_H
#include <commonlib/region.h>
#include <stdint.h>
#include <stddef.h>
enum {
/* Last segment of program. Can be used to take different actions for
* cache maintenance of a program load. */
SEG_FINAL = 1 << 0,
};
enum prog_type {
PROG_UNKNOWN,
PROG_BOOTBLOCK,
PROG_VERSTAGE,
PROG_ROMSTAGE,
PROG_RAMSTAGE,
PROG_REFCODE,
PROG_PAYLOAD,
PROG_BL31,
PROG_BL32,
};
/*
* prog_segment_loaded() is called for each segment of a program loaded. The
* SEG_FINAL flag will be set on the last segment loaded. The following two
* functions, platform_segment_loaded() and arch_segment_loaded(), are called
* in that order within prog_segment_loaded(). In short, rely on
* prog_segment_loaded() to perform the proper dispatch sequence.
*/
void prog_segment_loaded(uintptr_t start, size_t size, int flags);
void platform_segment_loaded(uintptr_t start, size_t size, int flags);
void arch_segment_loaded(uintptr_t start, size_t size, int flags);
/* Return true if arch supports bounce buffer. */
int arch_supports_bounce_buffer(void);
/* Representation of a program. */
struct prog {
/* The region_device is the source of program content to load. After
* loading program it represents the memory region of the stages and
* payload. For architectures that use a bounce buffer
* then it would represent the bounce buffer. */
enum prog_type type;
uint32_t cbfs_type;
const char *name;
struct region_device rdev;
/* Entry to program with optional argument. It's up to the architecture
* to decide if argument is passed. */
void (*entry)(void *);
void *arg;
};
#define PROG_INIT(type_, name_) \
{ \
.type = (type_), \
.name = (name_), \
}
static inline const char *prog_name(const struct prog *prog)
{
return prog->name;
}
static inline enum prog_type prog_type(const struct prog *prog)
{
return prog->type;
}
static inline uint32_t prog_cbfs_type(const struct prog *prog)
{
return prog->cbfs_type;
}
static inline struct region_device *prog_rdev(struct prog *prog)
{
return &prog->rdev;
}
/* Only valid for loaded programs. */
static inline size_t prog_size(const struct prog *prog)
{
return region_device_sz(&prog->rdev);
}
/* Only valid for loaded programs. */
static inline void *prog_start(const struct prog *prog)
{
return rdev_mmap_full(&prog->rdev);
}
static inline void *prog_entry(const struct prog *prog)
{
return prog->entry;
}
static inline void *prog_entry_arg(const struct prog *prog)
{
return prog->arg;
}
/* region_device representing the 32-bit flat address space. */
extern const struct mem_region_device addrspace_32bit;
static inline void prog_memory_init(struct prog *prog, uintptr_t ptr,
size_t size)
{
rdev_chain(&prog->rdev, &addrspace_32bit.rdev, ptr, size);
}
static inline void prog_set_area(struct prog *prog, void *start, size_t size)
{
prog_memory_init(prog, (uintptr_t)start, size);
}
static inline void prog_set_entry(struct prog *prog, void *e, void *arg)
{
prog->entry = e;
prog->arg = arg;
}
/* Locate the identified program to run. Return 0 on success. < 0 on error. */
int prog_locate(struct prog *prog);
/* Run the program described by prog. */
void prog_run(struct prog *prog);
/* Per architecture implementation running a program. */
void arch_prog_run(struct prog *prog);
/* Platform (SoC/chipset) specific overrides for running a program. This is
* called prior to calling the arch_prog_run. Thus, if there is anything
* special that needs to be done by the platform similar to the architecture
* code it needs to that as well. */
void platform_prog_run(struct prog *prog);
struct prog_loader_ops {
const char *name;
/* Determine if the loader is the active one. If so returns 1 else 0
* or < 0 on error. */
int (*is_loader_active)(struct prog *prog);
/* Returns < 0 on error or 0 on success. This function locates
* the rdev representing the file data associated with the passed in
* prog. */
int (*locate)(struct prog *prog);
};
/************************
* ROMSTAGE LOADING *
************************/
/* Run romstage from bootblock. */
void run_romstage(void);
/************************
* RAMSTAGE LOADING *
************************/
/* Run ramstage from romstage. */
void run_ramstage(void);
/* Determine where stack for ramstage loader is located. */
enum { ROMSTAGE_STACK_CBMEM, ROMSTAGE_STACK_LOW_MEM };
uintptr_t romstage_ram_stack_base(size_t size, int src);
uintptr_t romstage_ram_stack_top(void);
uintptr_t romstage_ram_stack_bottom(void);
/* Backup OS memory to CBMEM_ID_RESUME on ACPI S3 resume path,
* if ramstage overwrites low memory. */
void backup_ramstage_section(uintptr_t base, size_t size);
/***********************
* PAYLOAD LOADING *
***********************/
/* Load payload into memory in preparation to run. */
void payload_load(void);
/* Run the loaded payload. */
void payload_run(void);
/* Mirror the payload to be loaded. */
void mirror_payload(struct prog *payload);
/*
* Set check_regions to true to check that the payload targets usable memory.
* With this flag set, if it does not, the load will fail and this function
* will return NULL.
*
* Defined in src/lib/selfboot.c
*/
void *selfload(struct prog *payload, bool check_regions);
#endif /* PROGRAM_LOADING_H */