riscv: tools: Prelink u-boot

Add prelink-riscv to arrange .rela.dyn and .rela.got
in compile time. So that u-boot can be directly
executed without fixup.

Signed-off-by: Chih-Mao Chen <cmchen@andestech.com>
Signed-off-by: Rick Chen <rick@andestech.com>
Signed-off-by: Rick Chen <rickchen36@gmail.com>
Signed-off-by: Greentime Hu <green.hu@gmail.com>

Makefile

@@ -1264,6 +1264,10 @@ ifeq ($(CONFIG_KALLSYMS),y)
 	$(call cmd,u-boot__) common/system_map.o
 endif
 
+ifeq ($(CONFIG_RISCV),y)
+	@tools/prelink-riscv $@ 0
+endif
+
 quiet_cmd_sym ?= SYM     $@
       cmd_sym ?= $(OBJDUMP) -t $< > $@
 u-boot.sym: u-boot FORCE

tools/Makefile

@@ -185,6 +185,7 @@ hostprogs-$(CONFIG_KIRKWOOD) += kwboot
 hostprogs-$(CONFIG_ARCH_MVEBU) += kwboot
 hostprogs-y += proftool
 hostprogs-$(CONFIG_STATIC_RELA) += relocate-rela
+hostprogs-$(CONFIG_RISCV) += prelink-riscv
 
 hostprogs-y += fdtgrep
 fdtgrep-objs += $(LIBFDT_OBJS) fdtgrep.o

tools/prelink-riscv.c

@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2017 Andes Technology
+ * Chih-Mao Chen <cmchen@andestech.com>
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ *
+ * Statically process runtime relocations on RISC-V ELF images
+ * so that it can be directly executed when loaded at LMA
+ * without fixup. Both RV32 and RV64 are supported.
+ */
+
+#if __BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__
+#error "Only little-endian host is supported"
+#endif
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <elf.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#ifndef EM_RISCV
+#define EM_RISCV 243
+#endif
+
+#ifndef R_RISCV_32
+#define R_RISCV_32 1
+#endif
+
+#ifndef R_RISCV_64
+#define R_RISCV_64 2
+#endif
+
+#ifndef R_RISCV_RELATIVE
+#define R_RISCV_RELATIVE 3
+#endif
+
+const char *argv0;
+
+#define die(fmt, ...) \
+	do { \
+		fprintf(stderr, "%s: " fmt "\n", argv0, ## __VA_ARGS__); \
+		exit(EXIT_FAILURE); \
+	} while (0)
+
+#define PRELINK_INC_BITS 32
+#include "prelink-riscv.inc"
+#undef PRELINK_INC_BITS
+
+#define PRELINK_INC_BITS 64
+#include "prelink-riscv.inc"
+#undef PRELINK_INC_BITS
+
+int main(int argc, const char *const *argv)
+{
+	argv0 = argv[0];
+
+	if (argc < 2) {
+		fprintf(stderr, "Usage: %s <u-boot>\n", argv0);
+		exit(EXIT_FAILURE);
+	}
+
+	int fd = open(argv[1], O_RDWR, 0);
+
+	if (fd < 0)
+		die("Cannot open %s: %s", argv[1], strerror(errno));
+
+	struct stat st;
+
+	if (fstat(fd, &st) < 0)
+		die("Cannot stat %s: %s", argv[1], strerror(errno));
+
+	void *data =
+		mmap(0, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+
+	if (data == MAP_FAILED)
+		die("Cannot mmap %s: %s", argv[1], strerror(errno));
+
+	close(fd);
+
+	unsigned char *e_ident = (unsigned char *)data;
+
+	if (memcmp(e_ident, ELFMAG, SELFMAG) != 0)
+		die("Invalid ELF file %s", argv[1]);
+
+	bool is64 = e_ident[EI_CLASS] == ELFCLASS64;
+
+	if (is64)
+		prelink64(data);
+	else
+		prelink32(data);
+
+	return 0;
+}

tools/prelink-riscv.inc

@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2017 Andes Technology
+ * Chih-Mao Chen <cmchen@andestech.com>
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ *
+ * Statically process runtime relocations on RISC-V ELF images
+ * so that it can be directly executed when loaded at LMA
+ * without fixup. Both RV32 and RV64 are supported.
+ */
+
+#define CONCAT_IMPL(x, y) x##y
+#define CONCAT(x, y) CONCAT_IMPL(x, y)
+#define CONCAT3(x, y, z) CONCAT(CONCAT(x, y), z)
+
+#define prelink_nn      CONCAT(prelink, PRELINK_INC_BITS)
+#define uintnn_t        CONCAT3(uint, PRELINK_INC_BITS, _t)
+#define get_offset_nn   CONCAT(get_offset_, PRELINK_INC_BITS)
+#define Elf_Ehdr        CONCAT3(Elf, PRELINK_INC_BITS, _Ehdr)
+#define Elf_Phdr        CONCAT3(Elf, PRELINK_INC_BITS, _Phdr)
+#define Elf_Rela        CONCAT3(Elf, PRELINK_INC_BITS, _Rela)
+#define Elf_Sym         CONCAT3(Elf, PRELINK_INC_BITS, _Sym)
+#define Elf_Dyn         CONCAT3(Elf, PRELINK_INC_BITS, _Dyn)
+#define Elf_Addr        CONCAT3(Elf, PRELINK_INC_BITS, _Addr)
+#define ELF_R_TYPE      CONCAT3(ELF, PRELINK_INC_BITS, _R_TYPE)
+#define ELF_R_SYM       CONCAT3(ELF, PRELINK_INC_BITS, _R_SYM)
+
+static void* get_offset_nn (void* data, Elf_Phdr* phdrs, size_t phnum, Elf_Addr addr)
+{
+	Elf_Phdr *p;
+
+	for (p = phdrs; p < phdrs + phnum; ++p)
+		if (p->p_vaddr <= addr && p->p_vaddr + p->p_memsz > addr)
+			return data + p->p_offset + (addr - p->p_vaddr);
+
+	return NULL;
+}
+
+static void prelink_nn(void *data)
+{
+	Elf_Ehdr *ehdr = data;
+	Elf_Phdr *p;
+	Elf_Dyn *dyn;
+	Elf_Rela *r;
+
+	if (ehdr->e_machine != EM_RISCV)
+		die("Machine type is not RISC-V");
+
+	Elf_Phdr *phdrs = data + ehdr->e_phoff;
+
+	Elf_Dyn *dyns = NULL;
+	for (p = phdrs; p < phdrs + ehdr->e_phnum; ++p) {
+		if (p->p_type == PT_DYNAMIC) {
+			dyns = data + p->p_offset;
+			break;
+		}
+	}
+
+	if (dyns == NULL)
+		die("No dynamic section found");
+
+	Elf_Rela *rela_dyn = NULL;
+	size_t rela_count = 0;
+	Elf_Sym *dynsym = NULL;
+	for (dyn = dyns;; ++dyn) {
+		if (dyn->d_tag == DT_NULL)
+			break;
+		else if (dyn->d_tag == DT_RELA)
+			rela_dyn = get_offset_nn(data, phdrs, ehdr->e_phnum, + dyn->d_un.d_ptr);
+		else if (dyn->d_tag == DT_RELASZ)
+			rela_count = dyn->d_un.d_val / sizeof(Elf_Rela);
+		else if (dyn->d_tag == DT_SYMTAB)
+			dynsym = get_offset_nn(data, phdrs, ehdr->e_phnum, + dyn->d_un.d_ptr);
+
+	}
+
+	if (rela_dyn == NULL)
+		die("No .rela.dyn found");
+
+	if (dynsym == NULL)
+		die("No .dynsym found");
+
+	for (r = rela_dyn; r < rela_dyn + rela_count; ++r) {
+		void* buf = get_offset_nn(data, phdrs, ehdr->e_phnum, r->r_offset);
+
+		if (buf == NULL)
+			continue;
+
+		if (ELF_R_TYPE(r->r_info) == R_RISCV_RELATIVE)
+			*((uintnn_t*) buf) = r->r_addend;
+		else if (ELF_R_TYPE(r->r_info) == R_RISCV_32)
+			*((uint32_t*) buf) = dynsym[ELF_R_SYM(r->r_info)].st_value;
+		else if (ELF_R_TYPE(r->r_info) == R_RISCV_64)
+			*((uint64_t*) buf) = dynsym[ELF_R_SYM(r->r_info)].st_value;
+	}
+}
+
+#undef prelink_nn
+#undef uintnn_t
+#undef get_offset_nn
+#undef Elf_Ehdr
+#undef Elf_Phdr
+#undef Elf_Rela
+#undef Elf_Sym
+#undef Elf_Dyn
+#undef Elf_Addr
+#undef ELF_R_TYPE
+#undef ELF_R_SYM
+
+#undef CONCAT_IMPL
+#undef CONCAT
+#undef CONCAT3