首先：我不是专家，所以请原谅我试图解释自己的任何错误。
我正在尝试使用 Sparc- 为 SPARC 机器交叉编译外部 Linux 模块Linux-GCC-4.4.2。Linux 内核的版本是2.6.36.4-00037-g059aa91-dirty. 它已经用LEON处理器的一些文件进行了修补。向我提供了构建流程，它使用LinuxBuild、Buildroot和Busybox. 我正在尝试制作 32 位操作系统。
一切似乎都正常，但是在我编译模块并尝试将其安装到 SPARC 系统后，我收到此错误：
module hellok: Unknown relocation: 6
这个错误来自于~/linuxbuild-1.0.3/linux/linux-2.6-git/arch/sparc/kernel/module.c
为了完整起见，我将提供整个方法：
int apply_relocate_add(Elf_Shdr *sechdrs,
const char *strtab,
unsigned int symindex,
unsigned int relsec,
struct module *me)
{
unsigned int i;
Elf_Rela *rel = (void *)sechdrs[relsec].sh_addr;
Elf_Sym *sym;
u8 *location;
u32 *loc32;
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
Elf_Addr v;
/* This is where to make the change */
location = (u8 *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rel[i].r_offset;
loc32 = (u32 *) location;
#ifdef CONFIG_SPARC64
BUG_ON(((u64)location >> (u64)32) != (u64)0);
#endif /* CONFIG_SPARC64 */
/* This is the symbol it is referring to. Note that all
undefined symbols have been resolved. */
sym = (Elf_Sym *)sechdrs[symindex].sh_addr
+ ELF_R_SYM(rel[i].r_info);
v = sym->st_value + rel[i].r_addend;
switch (ELF_R_TYPE(rel[i].r_info) & 0xff) {
#ifdef CONFIG_SPARC64
case R_SPARC_64:
location[0] = v >> 56;
location[1] = v >> 48;
location[2] = v >> 40;
location[3] = v >> 32;
location[4] = v >> 24;
location[5] = v >> 16;
location[6] = v >> 8;
location[7] = v >> 0;
break;
case R_SPARC_DISP32:
v -= (Elf_Addr) location;
*loc32 = v;
break;
case R_SPARC_WDISP19:
v -= (Elf_Addr) location;
*loc32 = (*loc32 & ~0x7ffff) |
((v >> 2) & 0x7ffff);
break;
case R_SPARC_OLO10:
*loc32 = (*loc32 & ~0x1fff) |
(((v & 0x3ff) +
(ELF_R_TYPE(rel[i].r_info) >> 8))
& 0x1fff);
break;
#endif /* CONFIG_SPARC64 */
case R_SPARC_32:
case R_SPARC_UA32:
location[0] = v >> 24;
location[1] = v >> 16;
location[2] = v >> 8;
location[3] = v >> 0;
break;
case R_SPARC_WDISP30:
v -= (Elf_Addr) location;
*loc32 = (*loc32 & ~0x3fffffff) |
((v >> 2) & 0x3fffffff);
break;
case R_SPARC_WDISP22:
v -= (Elf_Addr) location;
*loc32 = (*loc32 & ~0x3fffff) |
((v >> 2) & 0x3fffff);
break;
case R_SPARC_LO10:
*loc32 = (*loc32 & ~0x3ff) | (v & 0x3ff);
break;
case R_SPARC_HI22:
*loc32 = (*loc32 & ~0x3fffff) |
((v >> 10) & 0x3fffff);
break;
default:
printk(KERN_ERR "module %s: Unknown relocation: %x\n",
me->name,
(int) (ELF_R_TYPE(rel[i].r_info) & 0xff));
return -ENOEXEC;
};
}
return 0;
}
因此，我了解默认情况是我所遇到的情况。ELF_R_TYPE(rel[i].r_info(SPARC Relocations) 类型在我的~/linuxbuild-1.0.3/dist/buildroot/build-br/staging/usr/include/elf.h文件中定义，其中一些类型如下：
/* SPARC relocs. */
#define R_SPARC_NONE 0 /* No reloc */
#define R_SPARC_8 1 /* Direct 8 bit */
#define R_SPARC_16 2 /* Direct 16 bit */
#define R_SPARC_32 3 /* Direct 32 bit */
#define R_SPARC_DISP8 4 /* PC relative 8 bit */
#define R_SPARC_DISP16 5 /* PC relative 16 bit */
#define R_SPARC_DISP32 6 /* PC relative 32 bit */
#define R_SPARC_WDISP30 7 /* PC relative 30 bit shifted */
#define R_SPARC_WDISP22 8 /* PC relative 22 bit shifted */
#define R_SPARC_HI22 9 /* High 22 bit */
#define R_SPARC_22 10 /* Direct 22 bit */
#define R_SPARC_13 11 /* Direct 13 bit */
#define R_SPARC_LO10 12 /* Truncated 10 bit */
#define R_SPARC_GOT10 13 /* Truncated 10 bit GOT entry */
#define R_SPARC_GOT13 14 /* 13 bit GOT entry */
#define R_SPARC_GOT22 15 /* 22 bit GOT entry shifted */
#define R_SPARC_PC10 16 /* PC relative 10 bit truncated */
#define R_SPARC_PC22 17 /* PC relative 22 bit shifted */
#define R_SPARC_WPLT30 18 /* 30 bit PC relative PLT address */
#define R_SPARC_COPY 19 /* Copy symbol at runtime */
#define R_SPARC_GLOB_DAT 20 /* Create GOT entry */
#define R_SPARC_JMP_SLOT 21 /* Create PLT entry */
#define R_SPARC_RELATIVE 22 /* Adjust by program base */
#define R_SPARC_UA32 23 /* Direct 32 bit unaligned */
/* Additional Sparc64 relocs. */
...
所以重定位 6 对应于R_SPARC_DISP32akaPC相对 32 位。这在module.ccase 语句中定义，但仅限于 64 位部分。我想我要么需要自己编写重定位，要么弄清楚我需要什么重定位标志并在编译期间更改标志。我真的不明白重定位代码中发生了什么，所以请帮我弄清楚我应该如何解决这个问题。我不认为我可以将操作系统构建为 64 位，因为它似乎会破坏系统，所以请帮助我找到替代解决方案。