merge elf loading and adc streaming
commit
989f4038c6
@ -0,0 +1,14 @@
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all:
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@arm-none-eabi-gcc -mcpu=cortex-m4 -mthumb -Os --specs=nosys.specs -nostartfiles -fPIE -c test.cpp
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@arm-none-eabi-ld -shared -n -N -z max-page-size=512 -Ttext-segment=0 \
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test.o -o test.so
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@arm-none-eabi-strip -s -S --strip-unneeded test.so
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@arm-none-eabi-objcopy --remove-section .dynsym \
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--remove-section .dynstr \
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--remove-section .dynamic \
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--remove-section .hash \
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--remove-section .ARM.exidx \
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--remove-section .ARM.attributes \
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--remove-section .comment \
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test.so
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#include <cstdint>
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using adcsample_t = uint16_t;
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__attribute__((section(".process_data")))
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void process_data(adcsample_t *samples, unsigned int size);
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////////////////////////////////////////////////////////////////////////////////
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void process_data(adcsample_t *samples, unsigned int size)
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{
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size--;
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for (unsigned int i = 0; i < size; i++)
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samples[i] = samples[i] * 80 / 100 + samples[i + 1] * 20 / 100;
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}
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@ -0,0 +1,93 @@
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#ifndef STMDSP_ELF_FORMAT_HPP_
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#define STMDSP_ELF_FORMAT_HPP_
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#include <cstdint>
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#define EI_NIDENT 16
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#define PT_NULL 0
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#define PT_LOAD 1
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#define PT_DYNAMIC 2
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#define PT_INTERP 3
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#define PT_NOTE 4
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#define PT_SHLIB 5
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#define PT_PHDR 6
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#define PT_RESERVED 0x70000000
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#define ELF32_ST_BIND(i) ((i) >> 4)
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#define ELF32_ST_TYPE(i) ((i) & 0xF)
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#define ELF32_ST_INFO(b, t) (((b) << 4) + ((t) & 0xF))
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#define ELF32_R_SYM(i) ((i) >> 8)
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#define ELF32_R_TYPE(i) ((i) & 0xFF)
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#define ELF32_R_INFO(s, t) (((s) << 8) + ((t) & 0xFF))
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typedef uint32_t Elf32_Addr;
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typedef uint16_t Elf32_Half;
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typedef uint32_t Elf32_Off;
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typedef uint32_t Elf32_Sword;
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typedef uint32_t Elf32_Word;
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typedef struct {
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unsigned char e_ident[EI_NIDENT];
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Elf32_Half e_type;
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Elf32_Half e_machine;
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Elf32_Word e_version;
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Elf32_Addr e_entry;
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Elf32_Off e_phoff;
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Elf32_Off e_shoff;
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Elf32_Word e_flags;
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Elf32_Half e_ehsize;
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Elf32_Half e_phentsize;
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Elf32_Half e_phnum;
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Elf32_Half e_shentsize;
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Elf32_Half e_shnum;
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Elf32_Half e_shstrndx;
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} __attribute__((packed)) Elf32_Ehdr;
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typedef struct {
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Elf32_Word sh_name;
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Elf32_Word sh_type;
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Elf32_Word sh_flags;
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Elf32_Addr sh_addr;
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Elf32_Off sh_offset;
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Elf32_Word sh_size;
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Elf32_Word sh_link;
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Elf32_Word sh_info;
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Elf32_Word sh_addralign;
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Elf32_Word sh_entsize;
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} __attribute__((packed)) Elf32_Shdr;
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typedef struct {
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Elf32_Word st_name;
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Elf32_Addr st_value;
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Elf32_Word st_size;
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unsigned char st_info;
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unsigned char st_other;
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Elf32_Half st_shndx;
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} __attribute__((packed)) Elf32_Sym;
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typedef struct {
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Elf32_Addr r_offset;
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Elf32_Word r_info;
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} __attribute__((packed)) Elf32_Rel;
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typedef struct {
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Elf32_Addr r_offset;
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Elf32_Word r_info;
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Elf32_Sword r_addend;
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} __attribute__((packed)) Elf32_Rela;
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typedef struct {
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Elf32_Word p_type;
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Elf32_Off p_offset;
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Elf32_Addr p_vaddr;
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Elf32_Addr p_paddr;
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Elf32_Word p_filesz;
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Elf32_Word p_memsz;
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Elf32_Word p_flags;
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Elf32_Word p_align;
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} __attribute__((packed)) Elf32_Phdr;
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#endif // STMDSP_ELF_FORMAT_HPP_
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@ -0,0 +1,77 @@
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#include "elf_load.hpp"
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#include "elf_format.hpp"
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#include <algorithm>
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#include <cstring>
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extern void *elf_load_offset;
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static const unsigned char elf_header[] = { '\177', 'E', 'L', 'F' };
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template<typename T>
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constexpr static auto ptr_from_offset(void *base, uint32_t offset)
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{
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return reinterpret_cast<T>(reinterpret_cast<uint8_t *>(base) + offset);
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}
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static Elf32_Shdr *find_section(Elf32_Ehdr *ehdr, const char *name);
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namespace elf {
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entry_t elf_load(void *elf_data)
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{
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auto ehdr = reinterpret_cast<Elf32_Ehdr *>(elf_data);
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if (std::equal(ehdr->e_ident, ehdr->e_ident + 4, elf_header))
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return nullptr;
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auto phdr = ptr_from_offset<Elf32_Phdr *>(elf_data, ehdr->e_phoff);
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for (Elf32_Half i = 0; i < ehdr->e_phnum; i++) {
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if (phdr->p_type == PT_LOAD) {
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std::memcpy(ptr_from_offset<void *>(elf_load_offset, phdr->p_vaddr),
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ptr_from_offset<void *>(elf_data, phdr->p_offset),
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phdr->p_filesz);
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//break;
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}
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}
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// Zero .bss section
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if (auto bss_section = find_section(ehdr, ".bss"); bss_section) {
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auto bss = ptr_from_offset<uint32_t *>(elf_load_offset, bss_section->sh_addr);
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std::fill(bss, bss + bss_section->sh_size / sizeof(uint32_t), 0);
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}
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// Fix global offset table (GOT) entries
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if (auto got_section = find_section(ehdr, ".got"); got_section) {
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auto got = ptr_from_offset<void **>(elf_load_offset, got_section->sh_addr);
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for (size_t i = 0; i < got_section->sh_size / sizeof(void *); i++)
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got[i] = ptr_from_offset<void *>(got[i], reinterpret_cast<uint32_t>(elf_load_offset));
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}
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//// Run any initial constructors
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//if (auto init_section = find_section(ehdr, ".init_array"); init_section) {
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// auto init_array = reinterpret_cast<void (**)()>(elf_load_offset + init_section->sh_addr);
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// std::for_each(init_array, init_array + init_section->sh_size / sizeof(void (*)()),
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// [elf_load_offset](auto func) { (func + elf_load_offset)(); });
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//}
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return ptr_from_offset<entry_t>(elf_load_offset, ehdr->e_entry);
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}
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} // namespace elf
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Elf32_Shdr *find_section(Elf32_Ehdr *ehdr, const char *name)
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{
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auto shdr = ptr_from_offset<Elf32_Shdr *>(ehdr, ehdr->e_shoff);
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auto shdr_str = ptr_from_offset<Elf32_Shdr *>(ehdr,
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ehdr->e_shoff + ehdr->e_shstrndx * ehdr->e_shentsize);
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for (Elf32_Half i = 0; i < ehdr->e_shnum; i++) {
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char *section = ptr_from_offset<char *>(ehdr, shdr_str->sh_offset) + shdr->sh_name;
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if (!strcmp(section, name))
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return shdr;
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shdr = ptr_from_offset<Elf32_Shdr *>(shdr, ehdr->e_shentsize);
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}
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return 0;
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}
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@ -0,0 +1,12 @@
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#ifndef ELF_LOAD_HPP_
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#define ELF_LOAD_HPP_
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namespace elf
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{
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using entry_t = void (*)();
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entry_t load(void *file_data);
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}
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#endif // ELF_LOAD_HPP_
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