RISC-V: Add kexec_file support

This patch adds support for kexec_file on RISC-V. I tested it on riscv64
QEMU with busybear-linux and single core along with the OpenSBI firmware
fw_jump.bin for generic platform.

On SMP system, it depends on CONFIG_{HOTPLUG_CPU, RISCV_SBI} to
resume/stop hart through OpenSBI firmware, it also needs a OpenSBI that
support the HSM extension.

Signed-off-by: Liao Chang <liaochang1@huawei.com>
Signed-off-by: Li Zhengyu <lizhengyu3@huawei.com>
Link: https://lore.kernel.org/r/20220408100914.150110-4-lizhengyu3@huawei.com
[Palmer: Make 64-bit only]
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Liao Chang 2022-04-08 18:09:11 +08:00 committed by Palmer Dabbelt
parent b7fb4d78a6
commit 6261586e0c
No known key found for this signature in database
GPG Key ID: EF4CA1502CCBAB41
5 changed files with 213 additions and 0 deletions

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@ -383,6 +383,20 @@ config KEXEC
The name comes from the similarity to the exec system call.
config KEXEC_FILE
bool "kexec file based systmem call"
select KEXEC_CORE
select KEXEC_ELF
select HAVE_IMA_KEXEC if IMA
depends on 64BIT
help
This is new version of kexec system call. This system call is
file based and takes file descriptors as system call argument
for kernel and initramfs as opposed to list of segments as
accepted by previous system call.
If you don't know what to do here, say Y.
config CRASH_DUMP
bool "Build kdump crash kernel"
help

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@ -53,4 +53,8 @@ typedef void (*riscv_kexec_method)(unsigned long first_ind_entry,
extern riscv_kexec_method riscv_kexec_norelocate;
#ifdef CONFIG_KEXEC_FILE
extern const struct kexec_file_ops elf_kexec_ops;
#endif
#endif

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@ -64,6 +64,7 @@ endif
obj-$(CONFIG_HOTPLUG_CPU) += cpu-hotplug.o
obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_KEXEC) += kexec_relocate.o crash_save_regs.o machine_kexec.o
obj-$(CONFIG_KEXEC_FILE) += elf_kexec.o machine_kexec_file.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o

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@ -0,0 +1,180 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* Load ELF vmlinux file for the kexec_file_load syscall.
*
* Copyright (C) 2021 Huawei Technologies Co, Ltd.
*
* Author: Liao Chang (liaochang1@huawei.com)
*
* Based on kexec-tools' kexec-elf-riscv.c, heavily modified
* for kernel.
*/
#define pr_fmt(fmt) "kexec_image: " fmt
#include <linux/elf.h>
#include <linux/kexec.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/libfdt.h>
#include <linux/types.h>
static int riscv_kexec_elf_load(struct kimage *image, struct elfhdr *ehdr,
struct kexec_elf_info *elf_info, unsigned long old_pbase,
unsigned long new_pbase)
{
int i;
int ret = 0;
size_t size;
struct kexec_buf kbuf;
const struct elf_phdr *phdr;
kbuf.image = image;
for (i = 0; i < ehdr->e_phnum; i++) {
phdr = &elf_info->proghdrs[i];
if (phdr->p_type != PT_LOAD)
continue;
size = phdr->p_filesz;
if (size > phdr->p_memsz)
size = phdr->p_memsz;
kbuf.buffer = (void *) elf_info->buffer + phdr->p_offset;
kbuf.bufsz = size;
kbuf.buf_align = phdr->p_align;
kbuf.mem = phdr->p_paddr - old_pbase + new_pbase;
kbuf.memsz = phdr->p_memsz;
kbuf.top_down = false;
ret = kexec_add_buffer(&kbuf);
if (ret)
break;
}
return ret;
}
/*
* Go through the available phsyical memory regions and find one that hold
* an image of the specified size.
*/
static int elf_find_pbase(struct kimage *image, unsigned long kernel_len,
struct elfhdr *ehdr, struct kexec_elf_info *elf_info,
unsigned long *old_pbase, unsigned long *new_pbase)
{
int i;
int ret;
struct kexec_buf kbuf;
const struct elf_phdr *phdr;
unsigned long lowest_paddr = ULONG_MAX;
unsigned long lowest_vaddr = ULONG_MAX;
for (i = 0; i < ehdr->e_phnum; i++) {
phdr = &elf_info->proghdrs[i];
if (phdr->p_type != PT_LOAD)
continue;
if (lowest_paddr > phdr->p_paddr)
lowest_paddr = phdr->p_paddr;
if (lowest_vaddr > phdr->p_vaddr)
lowest_vaddr = phdr->p_vaddr;
}
kbuf.image = image;
kbuf.buf_min = lowest_paddr;
kbuf.buf_max = ULONG_MAX;
kbuf.buf_align = PAGE_SIZE;
kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
kbuf.memsz = ALIGN(kernel_len, PAGE_SIZE);
kbuf.top_down = false;
ret = arch_kexec_locate_mem_hole(&kbuf);
if (!ret) {
*old_pbase = lowest_paddr;
*new_pbase = kbuf.mem;
image->start = ehdr->e_entry - lowest_vaddr + kbuf.mem;
}
return ret;
}
static void *elf_kexec_load(struct kimage *image, char *kernel_buf,
unsigned long kernel_len, char *initrd,
unsigned long initrd_len, char *cmdline,
unsigned long cmdline_len)
{
int ret;
unsigned long old_kernel_pbase = ULONG_MAX;
unsigned long new_kernel_pbase = 0UL;
unsigned long initrd_pbase = 0UL;
void *fdt;
struct elfhdr ehdr;
struct kexec_buf kbuf;
struct kexec_elf_info elf_info;
ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info);
if (ret)
return ERR_PTR(ret);
ret = elf_find_pbase(image, kernel_len, &ehdr, &elf_info,
&old_kernel_pbase, &new_kernel_pbase);
if (ret)
goto out;
pr_notice("The entry point of kernel at 0x%lx\n", image->start);
/* Add the kernel binary to the image */
ret = riscv_kexec_elf_load(image, &ehdr, &elf_info,
old_kernel_pbase, new_kernel_pbase);
if (ret)
goto out;
kbuf.image = image;
kbuf.buf_min = new_kernel_pbase + kernel_len;
kbuf.buf_max = ULONG_MAX;
/* Add the initrd to the image */
if (initrd != NULL) {
kbuf.buffer = initrd;
kbuf.bufsz = kbuf.memsz = initrd_len;
kbuf.buf_align = PAGE_SIZE;
kbuf.top_down = false;
kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
ret = kexec_add_buffer(&kbuf);
if (ret)
goto out;
initrd_pbase = kbuf.mem;
pr_notice("Loaded initrd at 0x%lx\n", initrd_pbase);
}
/* Add the DTB to the image */
fdt = of_kexec_alloc_and_setup_fdt(image, initrd_pbase,
initrd_len, cmdline, 0);
if (!fdt) {
pr_err("Error setting up the new device tree.\n");
ret = -EINVAL;
goto out;
}
fdt_pack(fdt);
kbuf.buffer = fdt;
kbuf.bufsz = kbuf.memsz = fdt_totalsize(fdt);
kbuf.buf_align = PAGE_SIZE;
kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
kbuf.top_down = true;
ret = kexec_add_buffer(&kbuf);
if (ret) {
pr_err("Error add DTB kbuf ret=%d\n", ret);
goto out_free_fdt;
}
pr_notice("Loaded device tree at 0x%lx\n", kbuf.mem);
goto out;
out_free_fdt:
kvfree(fdt);
out:
kexec_free_elf_info(&elf_info);
return ret ? ERR_PTR(ret) : NULL;
}
const struct kexec_file_ops elf_kexec_ops = {
.probe = kexec_elf_probe,
.load = elf_kexec_load,
};

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@ -0,0 +1,14 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* kexec_file for riscv, use vmlinux as the dump-capture kernel image.
*
* Copyright (C) 2021 Huawei Technologies Co, Ltd.
*
* Author: Liao Chang (liaochang1@huawei.com)
*/
#include <linux/kexec.h>
const struct kexec_file_ops * const kexec_file_loaders[] = {
&elf_kexec_ops,
NULL
};