// 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>
#include <linux/elf.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/libfdt.h>
#include <linux/types.h>
#include <linux/memblock.h>
#include <linux/vmalloc.h>
#include <asm/setup.h>
#include <asm/insn.h>

const struct kexec_file_ops * const kexec_file_loaders[] = {
        &elf_kexec_ops,
        &image_kexec_ops,
        NULL
};

int arch_kimage_file_post_load_cleanup(struct kimage *image)
{
        kvfree(image->arch.fdt);
        image->arch.fdt = NULL;

        vfree(image->elf_headers);
        image->elf_headers = NULL;
        image->elf_headers_sz = 0;

        return kexec_image_post_load_cleanup_default(image);
}

#ifdef CONFIG_CRASH_DUMP
static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
{
        unsigned int *nr_ranges = arg;

        (*nr_ranges)++;
        return 0;
}

static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
{
        struct crash_mem *cmem = arg;

        cmem->ranges[cmem->nr_ranges].start = res->start;
        cmem->ranges[cmem->nr_ranges].end = res->end;
        cmem->nr_ranges++;

        return 0;
}

static int prepare_elf_headers(void **addr, unsigned long *sz)
{
        struct crash_mem *cmem;
        unsigned int nr_ranges;
        int ret;

        nr_ranges = 1; /* For exclusion of crashkernel region */
        walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);

        cmem = kmalloc_flex(*cmem, ranges, nr_ranges);
        if (!cmem)
                return -ENOMEM;

        cmem->max_nr_ranges = nr_ranges;
        cmem->nr_ranges = 0;
        ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
        if (ret)
                goto out;

        /* Exclude crashkernel region */
        ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
        if (!ret)
                ret = crash_prepare_elf64_headers(cmem, true, addr, sz);

out:
        kfree(cmem);
        return ret;
}

static char *setup_kdump_cmdline(struct kimage *image, char *cmdline,
                                 unsigned long cmdline_len)
{
        int elfcorehdr_strlen;
        char *cmdline_ptr;

        cmdline_ptr = kzalloc(COMMAND_LINE_SIZE, GFP_KERNEL);
        if (!cmdline_ptr)
                return NULL;

        elfcorehdr_strlen = sprintf(cmdline_ptr, "elfcorehdr=0x%lx ",
                image->elf_load_addr);

        if (elfcorehdr_strlen + cmdline_len > COMMAND_LINE_SIZE) {
                pr_err("Appending elfcorehdr=<addr> exceeds cmdline size\n");
                kfree(cmdline_ptr);
                return NULL;
        }

        memcpy(cmdline_ptr + elfcorehdr_strlen, cmdline, cmdline_len);
        /* Ensure it's nul terminated */
        cmdline_ptr[COMMAND_LINE_SIZE - 1] = '\0';
        return cmdline_ptr;
}
#endif

#define RISCV_IMM_BITS 12
#define RISCV_IMM_REACH (1LL << RISCV_IMM_BITS)
#define RISCV_CONST_HIGH_PART(x) \
        (((x) + (RISCV_IMM_REACH >> 1)) & ~(RISCV_IMM_REACH - 1))
#define RISCV_CONST_LOW_PART(x) ((x) - RISCV_CONST_HIGH_PART(x))

#define ENCODE_ITYPE_IMM(x) \
        (RV_X(x, 0, 12) << 20)
#define ENCODE_BTYPE_IMM(x) \
        ((RV_X(x, 1, 4) << 8) | (RV_X(x, 5, 6) << 25) | \
        (RV_X(x, 11, 1) << 7) | (RV_X(x, 12, 1) << 31))
#define ENCODE_UTYPE_IMM(x) \
        (RV_X(x, 12, 20) << 12)
#define ENCODE_JTYPE_IMM(x) \
        ((RV_X(x, 1, 10) << 21) | (RV_X(x, 11, 1) << 20) | \
        (RV_X(x, 12, 8) << 12) | (RV_X(x, 20, 1) << 31))
#define ENCODE_CBTYPE_IMM(x) \
        ((RV_X(x, 1, 2) << 3) | (RV_X(x, 3, 2) << 10) | (RV_X(x, 5, 1) << 2) | \
        (RV_X(x, 6, 2) << 5) | (RV_X(x, 8, 1) << 12))
#define ENCODE_CJTYPE_IMM(x) \
        ((RV_X(x, 1, 3) << 3) | (RV_X(x, 4, 1) << 11) | (RV_X(x, 5, 1) << 2) | \
        (RV_X(x, 6, 1) << 7) | (RV_X(x, 7, 1) << 6) | (RV_X(x, 8, 2) << 9) | \
        (RV_X(x, 10, 1) << 8) | (RV_X(x, 11, 1) << 12))
#define ENCODE_UJTYPE_IMM(x) \
        (ENCODE_UTYPE_IMM(RISCV_CONST_HIGH_PART(x)) | \
        (ENCODE_ITYPE_IMM(RISCV_CONST_LOW_PART(x)) << 32))
#define ENCODE_UITYPE_IMM(x) \
        (ENCODE_UTYPE_IMM(x) | (ENCODE_ITYPE_IMM(x) << 32))

#define CLEAN_IMM(type, x) \
        ((~ENCODE_##type##_IMM((uint64_t)(-1))) & (x))

int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
                                     Elf_Shdr *section,
                                     const Elf_Shdr *relsec,
                                     const Elf_Shdr *symtab)
{
        const char *strtab, *name, *shstrtab;
        const Elf_Shdr *sechdrs;
        Elf64_Rela *relas;
        int i, r_type;

        /* String & section header string table */
        sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
        strtab = (char *)pi->ehdr + sechdrs[symtab->sh_link].sh_offset;
        shstrtab = (char *)pi->ehdr + sechdrs[pi->ehdr->e_shstrndx].sh_offset;

        relas = (void *)pi->ehdr + relsec->sh_offset;

        for (i = 0; i < relsec->sh_size / sizeof(*relas); i++) {
                const Elf_Sym *sym;     /* symbol to relocate */
                unsigned long addr;     /* final location after relocation */
                unsigned long val;      /* relocated symbol value */
                unsigned long sec_base; /* relocated symbol value */
                void *loc;              /* tmp location to modify */

                sym = (void *)pi->ehdr + symtab->sh_offset;
                sym += ELF64_R_SYM(relas[i].r_info);

                if (sym->st_name)
                        name = strtab + sym->st_name;
                else
                        name = shstrtab + sechdrs[sym->st_shndx].sh_name;

                loc = pi->purgatory_buf;
                loc += section->sh_offset;
                loc += relas[i].r_offset;

                if (sym->st_shndx == SHN_ABS)
                        sec_base = 0;
                else if (sym->st_shndx >= pi->ehdr->e_shnum) {
                        pr_err("Invalid section %d for symbol %s\n",
                               sym->st_shndx, name);
                        return -ENOEXEC;
                } else
                        sec_base = pi->sechdrs[sym->st_shndx].sh_addr;

                val = sym->st_value;
                val += sec_base;
                val += relas[i].r_addend;

                addr = section->sh_addr + relas[i].r_offset;

                r_type = ELF64_R_TYPE(relas[i].r_info);

                switch (r_type) {
                case R_RISCV_BRANCH:
                        *(u32 *)loc = CLEAN_IMM(BTYPE, *(u32 *)loc) |
                                 ENCODE_BTYPE_IMM(val - addr);
                        break;
                case R_RISCV_JAL:
                        *(u32 *)loc = CLEAN_IMM(JTYPE, *(u32 *)loc) |
                                 ENCODE_JTYPE_IMM(val - addr);
                        break;
                /*
                 * With no R_RISCV_PCREL_LO12_S, R_RISCV_PCREL_LO12_I
                 * sym is expected to be next to R_RISCV_PCREL_HI20
                 * in purgatory relsec. Handle it like R_RISCV_CALL
                 * sym, instead of searching the whole relsec.
                 */
                case R_RISCV_PCREL_HI20:
                case R_RISCV_CALL_PLT:
                case R_RISCV_CALL:
                        *(u64 *)loc = CLEAN_IMM(UITYPE, *(u64 *)loc) |
                                 ENCODE_UJTYPE_IMM(val - addr);
                        break;
                case R_RISCV_RVC_BRANCH:
                        *(u32 *)loc = CLEAN_IMM(CBTYPE, *(u32 *)loc) |
                                 ENCODE_CBTYPE_IMM(val - addr);
                        break;
                case R_RISCV_RVC_JUMP:
                        *(u32 *)loc = CLEAN_IMM(CJTYPE, *(u32 *)loc) |
                                 ENCODE_CJTYPE_IMM(val - addr);
                        break;
                case R_RISCV_ADD16:
                        *(u16 *)loc += val;
                        break;
                case R_RISCV_SUB16:
                        *(u16 *)loc -= val;
                        break;
                case R_RISCV_ADD32:
                        *(u32 *)loc += val;
                        break;
                case R_RISCV_SUB32:
                        *(u32 *)loc -= val;
                        break;
                /* It has been applied by R_RISCV_PCREL_HI20 sym */
                case R_RISCV_PCREL_LO12_I:
                case R_RISCV_ALIGN:
                case R_RISCV_RELAX:
                        break;
                case R_RISCV_64:
                        *(u64 *)loc = val;
                        break;
                default:
                        pr_err("Unknown rela relocation: %d\n", r_type);
                        return -ENOEXEC;
                }
        }
        return 0;
}


int load_extra_segments(struct kimage *image, unsigned long kernel_start,
                            unsigned long kernel_len, char *initrd,
                            unsigned long initrd_len, char *cmdline,
                            unsigned long cmdline_len)
{
        int ret;
        void *fdt;
        unsigned long initrd_pbase = 0UL;
        struct kexec_buf kbuf = {};
        char *modified_cmdline = NULL;

        kbuf.image = image;
        kbuf.buf_min = kernel_start + kernel_len;
        kbuf.buf_max = ULONG_MAX;

#ifdef CONFIG_CRASH_DUMP
        /* Add elfcorehdr */
        if (image->type == KEXEC_TYPE_CRASH) {
                void *headers;
                unsigned long headers_sz;
                ret = prepare_elf_headers(&headers, &headers_sz);
                if (ret) {
                        pr_err("Preparing elf core header failed\n");
                        goto out;
                }

                kbuf.buffer = headers;
                kbuf.bufsz = headers_sz;
                kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
                kbuf.memsz = headers_sz;
                kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
                kbuf.top_down = true;

                ret = kexec_add_buffer(&kbuf);
                if (ret) {
                        vfree(headers);
                        goto out;
                }
                image->elf_headers = headers;
                image->elf_load_addr = kbuf.mem;
                image->elf_headers_sz = headers_sz;

                kexec_dprintk("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
                              image->elf_load_addr, kbuf.bufsz, kbuf.memsz);

                /* Setup cmdline for kdump kernel case */
                modified_cmdline = setup_kdump_cmdline(image, cmdline,
                                                       cmdline_len);
                if (!modified_cmdline) {
                        pr_err("Setting up cmdline for kdump kernel failed\n");
                        ret = -EINVAL;
                        goto out;
                }
                cmdline = modified_cmdline;
        }
#endif

#ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY
        /* Add purgatory to the image */
        kbuf.top_down = true;
        kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
        ret = kexec_load_purgatory(image, &kbuf);
        if (ret) {
                pr_err("Error loading purgatory ret=%d\n", ret);
                goto out;
        }
        kexec_dprintk("Loaded purgatory at 0x%lx\n", kbuf.mem);

        ret = kexec_purgatory_get_set_symbol(image, "riscv_kernel_entry",
                                             &kernel_start,
                                             sizeof(kernel_start), 0);
        if (ret)
                pr_err("Error update purgatory ret=%d\n", ret);
#endif /* CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY */

        /* 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 = true;
                kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
                ret = kexec_add_buffer(&kbuf);
                if (ret)
                        goto out;
                initrd_pbase = kbuf.mem;
                kexec_dprintk("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;
        }
        /* Cache the fdt buffer address for memory cleanup */
        image->arch.fdt = fdt;
        kexec_dprintk("Loaded device tree at 0x%lx\n", kbuf.mem);
        goto out;

out_free_fdt:
        kvfree(fdt);
out:
        kfree(modified_cmdline);
        return ret;
}