1 files changed, 132 insertions, 0 deletions

diff --git a/arch/mips/vdso/genvdso.h b/arch/mips/vdso/genvdso.h
new file mode 100644
index 000000000..9bfb87403
--- /dev/null
+++ b/arch/mips/vdso/genvdso.h
@@ -0,0 +1,132 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ */
+
+static inline bool FUNC(patch_vdso)(const char *path, void *vdso)
+{
+        const ELF(Ehdr) *ehdr = vdso;
+        void *shdrs;
+        ELF(Shdr) *shdr;
+        char *shstrtab, *name;
+        uint16_t sh_count, sh_entsize, i;
+
+        shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff);
+        sh_count = swap_uint16(ehdr->e_shnum);
+        sh_entsize = swap_uint16(ehdr->e_shentsize);
+
+        shdr = shdrs + (sh_entsize * swap_uint16(ehdr->e_shstrndx));
+        shstrtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
+
+        for (i = 0; i < sh_count; i++) {
+                shdr = shdrs + (i * sh_entsize);
+                name = shstrtab + swap_uint32(shdr->sh_name);
+
+                /*
+                 * Ensure there are no relocation sections - ld.so does not
+                 * relocate the VDSO so if there are relocations things will
+                 * break.
+                 */
+                switch (swap_uint32(shdr->sh_type)) {
+                case SHT_REL:
+                case SHT_RELA:
+                        fprintf(stderr,
+                                "%s: '%s' contains relocation sections\n",
+                                program_name, path);
+                        return false;
+                }
+
+                /* Check for existing sections. */
+                if (strcmp(name, ".MIPS.abiflags") == 0) {
+                        fprintf(stderr,
+                                "%s: '%s' already contains a '.MIPS.abiflags' section\n",
+                                program_name, path);
+                        return false;
+                }
+
+                if (strcmp(name, ".mips_abiflags") == 0) {
+                        strcpy(name, ".MIPS.abiflags");
+                        shdr->sh_type = swap_uint32(SHT_MIPS_ABIFLAGS);
+                        shdr->sh_entsize = shdr->sh_size;
+                }
+        }
+
+        return true;
+}
+
+static inline bool FUNC(get_symbols)(const char *path, void *vdso)
+{
+        const ELF(Ehdr) *ehdr = vdso;
+        void *shdrs, *symtab;
+        ELF(Shdr) *shdr;
+        const ELF(Sym) *sym;
+        char *strtab, *name;
+        uint16_t sh_count, sh_entsize, st_count, st_entsize, i, j;
+        uint64_t offset;
+        uint32_t flags;
+
+        shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff);
+        sh_count = swap_uint16(ehdr->e_shnum);
+        sh_entsize = swap_uint16(ehdr->e_shentsize);
+
+        for (i = 0; i < sh_count; i++) {
+                shdr = shdrs + (i * sh_entsize);
+
+                if (swap_uint32(shdr->sh_type) == SHT_SYMTAB)
+                        break;
+        }
+
+        if (i == sh_count) {
+                fprintf(stderr, "%s: '%s' has no symbol table\n", program_name,
+                        path);
+                return false;
+        }
+
+        /* Get flags */
+        flags = swap_uint32(ehdr->e_flags);
+        if (elf_class == ELFCLASS64)
+                elf_abi = ABI_N64;
+        else if (flags & EF_MIPS_ABI2)
+                elf_abi = ABI_N32;
+        else
+                elf_abi = ABI_O32;
+
+        /* Get symbol table. */
+        symtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
+        st_entsize = FUNC(swap_uint)(shdr->sh_entsize);
+        st_count = FUNC(swap_uint)(shdr->sh_size) / st_entsize;
+
+        /* Get string table. */
+        shdr = shdrs + (swap_uint32(shdr->sh_link) * sh_entsize);
+        strtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
+
+        /* Write offsets for symbols needed by the kernel. */
+        for (i = 0; vdso_symbols[i].name; i++) {
+                if (!(vdso_symbols[i].abis & elf_abi))
+                        continue;
+
+                for (j = 0; j < st_count; j++) {
+                        sym = symtab + (j * st_entsize);
+                        name = strtab + swap_uint32(sym->st_name);
+
+                        if (!strcmp(name, vdso_symbols[i].name)) {
+                                offset = FUNC(swap_uint)(sym->st_value);
+
+                                fprintf(out_file,
+                                        "\t.%s = 0x%" PRIx64 ",\n",
+                                        vdso_symbols[i].offset_name, offset);
+                                break;
+                        }
+                }
+
+                if (j == st_count) {
+                        fprintf(stderr,
+                                "%s: '%s' is missing required symbol '%s'\n",
+                                program_name, path, vdso_symbols[i].name);
+                        return false;
+                }
+        }
+
+        return true;
+}