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qemu/hw/riscv/boot.c
Alexandre Ghiti 119ea3576b hw: riscv: Allow large kernels to boot by moving the initrd further away in RAM 
Currently, the initrd is placed at 128MB, which overlaps with the kernel
when it is large (for example syzbot kernels are). From the kernel side,
there is no reason we could not push the initrd further away in memory
to accommodate large kernels, so move the initrd at 512MB when possible.

The ideal solution would have been to place the initrd based on the
kernel size but we actually can't since the bss size is not known when
the image is loaded by load_image_targphys_as() and the initrd would
then overlap with this section.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-ID: <20240206154042.514698-1-alexghiti@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
2024-03-08 15:41:31 +10:00

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/*
* QEMU RISC-V Boot Helper
*
* Copyright (c) 2017 SiFive, Inc.
* Copyright (c) 2019 Alistair Francis <alistair.francis@wdc.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2 or later, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu/datadir.h"
#include "qemu/units.h"
#include "qemu/error-report.h"
#include "exec/cpu-defs.h"
#include "hw/boards.h"
#include "hw/loader.h"
#include "hw/riscv/boot.h"
#include "hw/riscv/boot_opensbi.h"
#include "elf.h"
#include "sysemu/device_tree.h"
#include "sysemu/qtest.h"
#include "sysemu/kvm.h"
#include "sysemu/reset.h"
#include <libfdt.h>
bool riscv_is_32bit(RISCVHartArrayState *harts)
{
RISCVCPUClass *mcc = RISCV_CPU_GET_CLASS(&harts->harts[0]);
return mcc->misa_mxl_max == MXL_RV32;
}
/*
* Return the per-socket PLIC hart topology configuration string
* (caller must free with g_free())
*/
char *riscv_plic_hart_config_string(int hart_count)
{
g_autofree const char **vals = g_new(const char *, hart_count + 1);
int i;
for (i = 0; i < hart_count; i++) {
CPUState *cs = qemu_get_cpu(i);
CPURISCVState *env = &RISCV_CPU(cs)->env;
if (kvm_enabled()) {
vals[i] = "S";
} else if (riscv_has_ext(env, RVS)) {
vals[i] = "MS";
} else {
vals[i] = "M";
}
}
vals[i] = NULL;
/* g_strjoinv() obliges us to cast away const here */
return g_strjoinv(",", (char **)vals);
}
target_ulong riscv_calc_kernel_start_addr(RISCVHartArrayState *harts,
target_ulong firmware_end_addr) {
if (riscv_is_32bit(harts)) {
return QEMU_ALIGN_UP(firmware_end_addr, 4 * MiB);
} else {
return QEMU_ALIGN_UP(firmware_end_addr, 2 * MiB);
}
}
const char *riscv_default_firmware_name(RISCVHartArrayState *harts)
{
if (riscv_is_32bit(harts)) {
return RISCV32_BIOS_BIN;
}
return RISCV64_BIOS_BIN;
}
static char *riscv_find_bios(const char *bios_filename)
{
char *filename;
filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_filename);
if (filename == NULL) {
if (!qtest_enabled()) {
/*
* We only ship OpenSBI binary bios images in the QEMU source.
* For machines that use images other than the default bios,
* running QEMU test will complain hence let's suppress the error
* report for QEMU testing.
*/
error_report("Unable to find the RISC-V BIOS \"%s\"",
bios_filename);
exit(1);
}
}
return filename;
}
char *riscv_find_firmware(const char *firmware_filename,
const char *default_machine_firmware)
{
char *filename = NULL;
if ((!firmware_filename) || (!strcmp(firmware_filename, "default"))) {
/*
* The user didn't specify -bios, or has specified "-bios default".
* That means we are going to load the OpenSBI binary included in
* the QEMU source.
*/
filename = riscv_find_bios(default_machine_firmware);
} else if (strcmp(firmware_filename, "none")) {
filename = riscv_find_bios(firmware_filename);
}
return filename;
}
target_ulong riscv_find_and_load_firmware(MachineState *machine,
const char *default_machine_firmware,
hwaddr firmware_load_addr,
symbol_fn_t sym_cb)
{
char *firmware_filename;
target_ulong firmware_end_addr = firmware_load_addr;
firmware_filename = riscv_find_firmware(machine->firmware,
default_machine_firmware);
if (firmware_filename) {
/* If not "none" load the firmware */
firmware_end_addr = riscv_load_firmware(firmware_filename,
firmware_load_addr, sym_cb);
g_free(firmware_filename);
}
return firmware_end_addr;
}
target_ulong riscv_load_firmware(const char *firmware_filename,
hwaddr firmware_load_addr,
symbol_fn_t sym_cb)
{
uint64_t firmware_entry, firmware_end;
ssize_t firmware_size;
g_assert(firmware_filename != NULL);
if (load_elf_ram_sym(firmware_filename, NULL, NULL, NULL,
&firmware_entry, NULL, &firmware_end, NULL,
0, EM_RISCV, 1, 0, NULL, true, sym_cb) > 0) {
return firmware_end;
}
firmware_size = load_image_targphys_as(firmware_filename,
firmware_load_addr,
current_machine->ram_size, NULL);
if (firmware_size > 0) {
return firmware_load_addr + firmware_size;
}
error_report("could not load firmware '%s'", firmware_filename);
exit(1);
}
static void riscv_load_initrd(MachineState *machine, uint64_t kernel_entry)
{
const char *filename = machine->initrd_filename;
uint64_t mem_size = machine->ram_size;
void *fdt = machine->fdt;
hwaddr start, end;
ssize_t size;
g_assert(filename != NULL);
/*
* We want to put the initrd far enough into RAM that when the
* kernel is uncompressed it will not clobber the initrd. However
* on boards without much RAM we must ensure that we still leave
* enough room for a decent sized initrd, and on boards with large
* amounts of RAM, we put the initrd at 512MB to allow large kernels
* to boot.
* So for boards with less than 1GB of RAM we put the initrd
* halfway into RAM, and for boards with 1GB of RAM or more we put
* the initrd at 512MB.
*/
start = kernel_entry + MIN(mem_size / 2, 512 * MiB);
size = load_ramdisk(filename, start, mem_size - start);
if (size == -1) {
size = load_image_targphys(filename, start, mem_size - start);
if (size == -1) {
error_report("could not load ramdisk '%s'", filename);
exit(1);
}
}
/* Some RISC-V machines (e.g. opentitan) don't have a fdt. */
if (fdt) {
end = start + size;
qemu_fdt_setprop_cell(fdt, "/chosen", "linux,initrd-start", start);
qemu_fdt_setprop_cell(fdt, "/chosen", "linux,initrd-end", end);
}
}
target_ulong riscv_load_kernel(MachineState *machine,
RISCVHartArrayState *harts,
target_ulong kernel_start_addr,
bool load_initrd,
symbol_fn_t sym_cb)
{
const char *kernel_filename = machine->kernel_filename;
uint64_t kernel_load_base, kernel_entry;
void *fdt = machine->fdt;
g_assert(kernel_filename != NULL);
/*
* NB: Use low address not ELF entry point to ensure that the fw_dynamic
* behaviour when loading an ELF matches the fw_payload, fw_jump and BBL
* behaviour, as well as fw_dynamic with a raw binary, all of which jump to
* the (expected) load address load address. This allows kernels to have
* separate SBI and ELF entry points (used by FreeBSD, for example).
*/
if (load_elf_ram_sym(kernel_filename, NULL, NULL, NULL,
NULL, &kernel_load_base, NULL, NULL, 0,
EM_RISCV, 1, 0, NULL, true, sym_cb) > 0) {
kernel_entry = kernel_load_base;
goto out;
}
if (load_uimage_as(kernel_filename, &kernel_entry, NULL, NULL,
NULL, NULL, NULL) > 0) {
goto out;
}
if (load_image_targphys_as(kernel_filename, kernel_start_addr,
current_machine->ram_size, NULL) > 0) {
kernel_entry = kernel_start_addr;
goto out;
}
error_report("could not load kernel '%s'", kernel_filename);
exit(1);
out:
/*
* For 32 bit CPUs 'kernel_entry' can be sign-extended by
* load_elf_ram_sym().
*/
if (riscv_is_32bit(harts)) {
kernel_entry = extract64(kernel_entry, 0, 32);
}
if (load_initrd && machine->initrd_filename) {
riscv_load_initrd(machine, kernel_entry);
}
if (fdt && machine->kernel_cmdline && *machine->kernel_cmdline) {
qemu_fdt_setprop_string(fdt, "/chosen", "bootargs",
machine->kernel_cmdline);
}
return kernel_entry;
}
/*
* This function makes an assumption that the DRAM interval
* 'dram_base' + 'dram_size' is contiguous.
*
* Considering that 'dram_end' is the lowest value between
* the end of the DRAM block and MachineState->ram_size, the
* FDT location will vary according to 'dram_base':
*
* - if 'dram_base' is less that 3072 MiB, the FDT will be
* put at the lowest value between 3072 MiB and 'dram_end';
*
* - if 'dram_base' is higher than 3072 MiB, the FDT will be
* put at 'dram_end'.
*
* The FDT is fdt_packed() during the calculation.
*/
uint64_t riscv_compute_fdt_addr(hwaddr dram_base, hwaddr dram_size,
MachineState *ms)
{
int ret = fdt_pack(ms->fdt);
hwaddr dram_end, temp;
int fdtsize;
/* Should only fail if we've built a corrupted tree */
g_assert(ret == 0);
fdtsize = fdt_totalsize(ms->fdt);
if (fdtsize <= 0) {
error_report("invalid device-tree");
exit(1);
}
/*
* A dram_size == 0, usually from a MemMapEntry[].size element,
* means that the DRAM block goes all the way to ms->ram_size.
*/
dram_end = dram_base;
dram_end += dram_size ? MIN(ms->ram_size, dram_size) : ms->ram_size;
/*
* We should put fdt as far as possible to avoid kernel/initrd overwriting
* its content. But it should be addressable by 32 bit system as well.
* Thus, put it at an 2MB aligned address that less than fdt size from the
* end of dram or 3GB whichever is lesser.
*/
temp = (dram_base < 3072 * MiB) ? MIN(dram_end, 3072 * MiB) : dram_end;
return QEMU_ALIGN_DOWN(temp - fdtsize, 2 * MiB);
}
/*
* 'fdt_addr' is received as hwaddr because boards might put
* the FDT beyond 32-bit addressing boundary.
*/
void riscv_load_fdt(hwaddr fdt_addr, void *fdt)
{
uint32_t fdtsize = fdt_totalsize(fdt);
/* copy in the device tree */
qemu_fdt_dumpdtb(fdt, fdtsize);
rom_add_blob_fixed_as("fdt", fdt, fdtsize, fdt_addr,
&address_space_memory);
qemu_register_reset_nosnapshotload(qemu_fdt_randomize_seeds,
rom_ptr_for_as(&address_space_memory, fdt_addr, fdtsize));
}
void riscv_rom_copy_firmware_info(MachineState *machine, hwaddr rom_base,
hwaddr rom_size, uint32_t reset_vec_size,
uint64_t kernel_entry)
{
struct fw_dynamic_info dinfo;
size_t dinfo_len;
if (sizeof(dinfo.magic) == 4) {
dinfo.magic = cpu_to_le32(FW_DYNAMIC_INFO_MAGIC_VALUE);
dinfo.version = cpu_to_le32(FW_DYNAMIC_INFO_VERSION);
dinfo.next_mode = cpu_to_le32(FW_DYNAMIC_INFO_NEXT_MODE_S);
dinfo.next_addr = cpu_to_le32(kernel_entry);
} else {
dinfo.magic = cpu_to_le64(FW_DYNAMIC_INFO_MAGIC_VALUE);
dinfo.version = cpu_to_le64(FW_DYNAMIC_INFO_VERSION);
dinfo.next_mode = cpu_to_le64(FW_DYNAMIC_INFO_NEXT_MODE_S);
dinfo.next_addr = cpu_to_le64(kernel_entry);
}
dinfo.options = 0;
dinfo.boot_hart = 0;
dinfo_len = sizeof(dinfo);
/**
* copy the dynamic firmware info. This information is specific to
* OpenSBI but doesn't break any other firmware as long as they don't
* expect any certain value in "a2" register.
*/
if (dinfo_len > (rom_size - reset_vec_size)) {
error_report("not enough space to store dynamic firmware info");
exit(1);
}
rom_add_blob_fixed_as("mrom.finfo", &dinfo, dinfo_len,
rom_base + reset_vec_size,
&address_space_memory);
}
void riscv_setup_rom_reset_vec(MachineState *machine, RISCVHartArrayState *harts,
hwaddr start_addr,
hwaddr rom_base, hwaddr rom_size,
uint64_t kernel_entry,
uint64_t fdt_load_addr)
{
int i;
uint32_t start_addr_hi32 = 0x00000000;
uint32_t fdt_load_addr_hi32 = 0x00000000;
if (!riscv_is_32bit(harts)) {
start_addr_hi32 = start_addr >> 32;
fdt_load_addr_hi32 = fdt_load_addr >> 32;
}
/* reset vector */
uint32_t reset_vec[10] = {
0x00000297, /* 1: auipc t0, %pcrel_hi(fw_dyn) */
0x02828613, /* addi a2, t0, %pcrel_lo(1b) */
0xf1402573, /* csrr a0, mhartid */
0,
0,
0x00028067, /* jr t0 */
start_addr, /* start: .dword */
start_addr_hi32,
fdt_load_addr, /* fdt_laddr: .dword */
fdt_load_addr_hi32,
/* fw_dyn: */
};
if (riscv_is_32bit(harts)) {
reset_vec[3] = 0x0202a583; /* lw a1, 32(t0) */
reset_vec[4] = 0x0182a283; /* lw t0, 24(t0) */
} else {
reset_vec[3] = 0x0202b583; /* ld a1, 32(t0) */
reset_vec[4] = 0x0182b283; /* ld t0, 24(t0) */
}
if (!harts->harts[0].cfg.ext_zicsr) {
/*
* The Zicsr extension has been disabled, so let's ensure we don't
* run the CSR instruction. Let's fill the address with a non
* compressed nop.
*/
reset_vec[2] = 0x00000013; /* addi x0, x0, 0 */
}
/* copy in the reset vector in little_endian byte order */
for (i = 0; i < ARRAY_SIZE(reset_vec); i++) {
reset_vec[i] = cpu_to_le32(reset_vec[i]);
}
rom_add_blob_fixed_as("mrom.reset", reset_vec, sizeof(reset_vec),
rom_base, &address_space_memory);
riscv_rom_copy_firmware_info(machine, rom_base, rom_size, sizeof(reset_vec),
kernel_entry);
}
void riscv_setup_direct_kernel(hwaddr kernel_addr, hwaddr fdt_addr)
{
CPUState *cs;
for (cs = first_cpu; cs; cs = CPU_NEXT(cs)) {
RISCVCPU *riscv_cpu = RISCV_CPU(cs);
riscv_cpu->env.kernel_addr = kernel_addr;
riscv_cpu->env.fdt_addr = fdt_addr;
}
}
void riscv_setup_firmware_boot(MachineState *machine)
{
if (machine->kernel_filename) {
FWCfgState *fw_cfg;
fw_cfg = fw_cfg_find();
assert(fw_cfg);
/*
* Expose the kernel, the command line, and the initrd in fw_cfg.
* We don't process them here at all, it's all left to the
* firmware.
*/
load_image_to_fw_cfg(fw_cfg,
FW_CFG_KERNEL_SIZE, FW_CFG_KERNEL_DATA,
machine->kernel_filename,
true);
load_image_to_fw_cfg(fw_cfg,
FW_CFG_INITRD_SIZE, FW_CFG_INITRD_DATA,
machine->initrd_filename, false);
if (machine->kernel_cmdline) {
fw_cfg_add_i32(fw_cfg, FW_CFG_CMDLINE_SIZE,
strlen(machine->kernel_cmdline) + 1);
fw_cfg_add_string(fw_cfg, FW_CFG_CMDLINE_DATA,
machine->kernel_cmdline);
}
}
}
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