coreboot-kgpe-d16/util/cbfstool/cbfs-payload-linux.c

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/*
* cbfs-payload-linux
*
* Copyright (C) 2013 Patrick Georgi <patrick@georgi-clan.de>
*
* 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.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "common.h"
#include "cbfs.h"
#include "linux.h"
/* trampoline */
extern unsigned char trampoline[];
extern unsigned int trampoline_len;
/*
* Current max number of segments include:
*
* 1. parameters
* 2. kernel
* 3. trampoline
* 4. optional cmdline
* 5. optional initrd
* 6. terminating entry segment
*/
#define MAX_NUM_SEGMENTS 6
struct bzpayload {
/* Input variables. */
int num_segments;
struct cbfs_payload_segment segs[MAX_NUM_SEGMENTS];
struct buffer parameters;
struct buffer kernel;
struct buffer trampoline;
struct buffer cmdline;
struct buffer initrd;
/* Output variables. */
enum comp_algo algo;
comp_func_ptr compress;
struct buffer output;
size_t offset;
struct cbfs_payload_segment *out_seg;
};
static int bzp_init(struct bzpayload *bzp, enum comp_algo algo)
{
memset(bzp, 0, sizeof(*bzp));
/*
* Need at least the terminating entry segment.
*/
bzp->num_segments = 1;
bzp->algo = algo;
bzp->compress = compression_function(algo);
if (bzp->compress == NULL) {
ERROR("Invalid compression algorithm specified.\n");
return -1;
}
return 0;
}
static int bzp_add_initrd(struct bzpayload *bzp, const char *fname)
{
if (fname == NULL)
return 0;
if (buffer_from_file(&bzp->initrd, fname)) {
ERROR("could not open initrd.\n");
return -1;
}
bzp->num_segments++;
return 0;
}
static void bzp_add_segment(struct bzpayload *bzp, struct buffer *b, void *data,
size_t size)
{
buffer_init(b, NULL, data, size);
bzp->num_segments++;
}
static int bzp_add_trampoline(struct bzpayload *bzp)
{
bzp_add_segment(bzp, &bzp->trampoline, trampoline,
trampoline_len);
return 0;
}
static int bzp_add_cmdline(struct bzpayload *bzp, char *cmdline)
{
if (cmdline == NULL)
return 0;
bzp_add_segment(bzp, &bzp->cmdline, cmdline, strlen(cmdline) + 1);
return 0;
}
static int bzp_add_params(struct bzpayload *bzp, struct linux_params *params)
{
bzp_add_segment(bzp, &bzp->parameters, params, sizeof(*params));
return 0;
}
static int bzp_add_kernel(struct bzpayload *bzp, const struct buffer *in,
size_t setup_size)
{
char *input = buffer_get(in);
size_t kern_sz = buffer_size(in) - setup_size;
bzp_add_segment(bzp, &bzp->kernel, &input[setup_size], kern_sz);
return 0;
}
static int bzp_init_output(struct bzpayload *bzp, const char *name)
{
size_t sz = 0;
sz += buffer_size(&bzp->parameters);
sz += buffer_size(&bzp->kernel);
sz += buffer_size(&bzp->trampoline);
sz += buffer_size(&bzp->cmdline);
sz += buffer_size(&bzp->initrd);
bzp->offset = bzp->num_segments * sizeof(struct cbfs_payload_segment);
sz += bzp->offset;
if (buffer_create(&bzp->output, sz, name) != 0)
return -1;
bzp->out_seg = &bzp->segs[0];
return 0;
}
static void bzp_output_segment(struct bzpayload *bzp, struct buffer *b,
uint32_t type, uint64_t load_addr)
{
struct buffer out;
struct cbfs_payload_segment *seg;
int len = 0;
/* Don't process empty buffers. */
if (b != NULL && buffer_size(b) == 0)
return;
seg = bzp->out_seg;
seg->type = type;
seg->load_addr = load_addr;
bzp->out_seg++;
/* No buffer associated with segment. */
if (b == NULL)
return;
/* Use a temp buffer for easier management. */
buffer_splice(&out, &bzp->output, bzp->offset, buffer_size(b));
seg->mem_len = buffer_size(b);
seg->offset = bzp->offset;
bzp->compress(buffer_get(b), buffer_size(b), buffer_get(&out), &len);
seg->compression = bzp->algo;
seg->len = len;
/* Update output offset. */
bzp->offset += len;
}
/* TODO:
* handle special arguments
* mem= argument - only affects loading decisions (kernel + initrd), not e820 -> build time
* vga= argument (FILO ignores this)
* add support for more parameters to trampoline:
* alt_mem_k, ext_mem_k (not strictly necessary since e820 takes precedence)
* framebuffer/console values
*
* larger work:
* is compress() safe to use in a size constrained buffer? ie. do(es) the
* compression algorithm(s) stop once the compression result reaches input
* size (ie. incompressible data)?
*/
int parse_bzImage_to_payload(const struct buffer *input,
struct buffer *output, const char *initrd_name,
char *cmdline, enum comp_algo algo)
{
struct bzpayload bzp;
unsigned int initrd_base = 64*1024*1024;
struct linux_header *hdr = (struct linux_header *)input->data;
unsigned int setup_size = 4 * 512;
if (bzp_init(&bzp, algo) != 0)
return -1;
if (bzp_add_trampoline(&bzp) != 0)
return -1;
if (bzp_add_initrd(&bzp, initrd_name) != 0)
return -1;
if (bzp_add_cmdline(&bzp, cmdline) != 0)
return -1;
if (hdr->setup_sects != 0) {
setup_size = (hdr->setup_sects + 1) * 512;
}
/* Setup parameter block. Imitate FILO. */
struct linux_params params;
params.mount_root_rdonly = hdr->root_flags;
params.orig_root_dev = hdr->root_dev;
/* Sensible video defaults. Might be overridden on runtime by coreboot tables. */
params.orig_video_mode = 3;
params.orig_video_cols = 80;
params.orig_video_lines = 25;
params.orig_video_isVGA = 1;
params.orig_video_points = 16;
params.loader_type = 0xff; /* Unregistered Linux loader */
if (cmdline != NULL) {
if (hdr->protocol_version < 0x202) {
params.cl_magic = CL_MAGIC_VALUE;
params.cl_offset = COMMAND_LINE_LOC - LINUX_PARAM_LOC;
} else {
params.cmd_line_ptr = COMMAND_LINE_LOC;
}
}
unsigned long kernel_base = 0x100000;
if ((hdr->protocol_version >= 0x200) && (!hdr->loadflags & 1)) {
kernel_base = 0x1000; /* zImage kernel */
}
/* kernel prefers an address, so listen */
if ((hdr->protocol_version >= 0x20a) && (!(hdr->pref_address >> 32))) {
kernel_base = hdr->pref_address;
}
if (hdr->protocol_version >= 0x205) {
params.relocatable_kernel = hdr->relocatable_kernel;
params.kernel_alignment = hdr->kernel_alignment;
if (hdr->relocatable_kernel != 0) {
/* 16 MB should be way outside coreboot's playground,
* so if possible (relocatable kernel) use that to
* avoid a trampoline copy. */
kernel_base = ALIGN(16*1024*1024, params.kernel_alignment);
}
}
/* We have a trampoline and use that, but it can simply use
* this information for its jump to real Linux. */
params.kernel_start = kernel_base;
if (bzp_add_kernel(&bzp, input, setup_size) != 0)
return -1;
if (buffer_size(&bzp.initrd) != 0) {
/* TODO: this is a bit of a hack. Linux recommends to store
* initrd near to end-of-mem, but that's hard to do on build
* time. It definitely fails to read the image if it's too
* close to the kernel, so give it some room.
*/
initrd_base = kernel_base + buffer_size(&bzp.kernel);
initrd_base = ALIGN(initrd_base, 16*1024*1024);
params.initrd_start = initrd_base;
params.initrd_size = buffer_size(&bzp.initrd);
}
if (bzp_add_params(&bzp, &params) != 0)
return -1;
if (bzp_init_output(&bzp, input->name) != 0)
return -1;
/* parameter block */
bzp_output_segment(&bzp, &bzp.parameters,
PAYLOAD_SEGMENT_DATA, LINUX_PARAM_LOC);
/* code block */
bzp_output_segment(&bzp, &bzp.kernel,
PAYLOAD_SEGMENT_CODE, kernel_base);
/* trampoline */
bzp_output_segment(&bzp, &bzp.trampoline,
cbfstool:linux_trampoline: config CS and DS segment descriptors The Linux trampoline code does not set up the segment descriptors for __BOOT_CS and __BOOT_DS as described in the Linux kernel documentation: ... a GDT must be loaded with the descriptors for selectors __BOOT_CS(0x10) and __BOOT_DS(0x18); both descriptors must be 4G flat segment; __BOOT_CS must have execute/read permission, and __BOOT_DS must have read/write permission; This is not a problem when launching a Linux payload from coreboot, as coreboot configures the segment descriptors at selectors 0x10 and 0x18. Coreboot configures these selectors in the ramstage to match what the Linux kernel expects (see coreboot/src/arch/x86/lib/c_start.S). When the cbfs payload is launched in other environments, SeaBIOS for example, the segment descriptors are configured differently and the cbfs Linux payload does not work. If the cbfs Linux payload is to be used in multiple environments should the trampoline needs to take care of the descriptors that Linux requires. This patch updates the Linux trampoline code to configure the 4G flat descriptors that Linux expects. The configuration is borrowed from the descriptor configs in coreboot/src/arch/x86/lib/c_start.S for selectors 0x10 and 0x18. The linux_trampoline code is slightly refractored by defining the trampoline entry address, 0x40000, as TRAMPOLINE_ENTRY_LOC. This definition is moved into a separate header file, linux_trampoline.h. This header file is now included by both the trampoline assembly language code and the trampoline loader C code. The trampoline assembly language code can now use TRAMPOLINE_ENTRY_LOC as scratch space for the sgdt CPU instruction. Testing Done: Verified the Linux payload is booted correctly in the following environments: 1. Coreboot -> Linux Payload 2. Coreboot -> SeaBIOS -> Linux Payload: (previously did not work) Change-Id: I888f74ff43073a6b7318f6713a8d4ecb804c0162 Signed-off-by: Curt Brune <curt@cumulusnetworks.com> Reviewed-on: http://review.coreboot.org/6796 Tested-by: build bot (Jenkins) Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net> Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2014-08-29 19:43:36 +02:00
PAYLOAD_SEGMENT_CODE, TRAMPOLINE_ENTRY_LOC);
/* cmdline */
bzp_output_segment(&bzp, &bzp.cmdline,
PAYLOAD_SEGMENT_DATA, COMMAND_LINE_LOC);
/* initrd */
bzp_output_segment(&bzp, &bzp.initrd,
PAYLOAD_SEGMENT_DATA, initrd_base);
/* Terminating entry segment. */
cbfstool:linux_trampoline: config CS and DS segment descriptors The Linux trampoline code does not set up the segment descriptors for __BOOT_CS and __BOOT_DS as described in the Linux kernel documentation: ... a GDT must be loaded with the descriptors for selectors __BOOT_CS(0x10) and __BOOT_DS(0x18); both descriptors must be 4G flat segment; __BOOT_CS must have execute/read permission, and __BOOT_DS must have read/write permission; This is not a problem when launching a Linux payload from coreboot, as coreboot configures the segment descriptors at selectors 0x10 and 0x18. Coreboot configures these selectors in the ramstage to match what the Linux kernel expects (see coreboot/src/arch/x86/lib/c_start.S). When the cbfs payload is launched in other environments, SeaBIOS for example, the segment descriptors are configured differently and the cbfs Linux payload does not work. If the cbfs Linux payload is to be used in multiple environments should the trampoline needs to take care of the descriptors that Linux requires. This patch updates the Linux trampoline code to configure the 4G flat descriptors that Linux expects. The configuration is borrowed from the descriptor configs in coreboot/src/arch/x86/lib/c_start.S for selectors 0x10 and 0x18. The linux_trampoline code is slightly refractored by defining the trampoline entry address, 0x40000, as TRAMPOLINE_ENTRY_LOC. This definition is moved into a separate header file, linux_trampoline.h. This header file is now included by both the trampoline assembly language code and the trampoline loader C code. The trampoline assembly language code can now use TRAMPOLINE_ENTRY_LOC as scratch space for the sgdt CPU instruction. Testing Done: Verified the Linux payload is booted correctly in the following environments: 1. Coreboot -> Linux Payload 2. Coreboot -> SeaBIOS -> Linux Payload: (previously did not work) Change-Id: I888f74ff43073a6b7318f6713a8d4ecb804c0162 Signed-off-by: Curt Brune <curt@cumulusnetworks.com> Reviewed-on: http://review.coreboot.org/6796 Tested-by: build bot (Jenkins) Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net> Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2014-08-29 19:43:36 +02:00
bzp_output_segment(&bzp, NULL, PAYLOAD_SEGMENT_ENTRY, TRAMPOLINE_ENTRY_LOC);
/* Set size of buffer taking into account potential compression. */
buffer_set_size(&bzp.output, bzp.offset);
/* Make passed-in output buffer be valid. */
buffer_clone(output, &bzp.output);
/* Serialize the segments with the correct encoding. */
xdr_segs(output, bzp.segs, bzp.num_segments);
return 0;
}