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https://github.com/edk2-porting/linux-next.git
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5336377d62
With all the recent module loading cleanups, we've minimized the code
that sits under module_mutex, fixing various deadlocks and making it
possible to do most of the module loading in parallel.
However, that whole conversion totally missed the rather obscure code
that adds a new module to the list for BUG() handling. That code was
doubly obscure because (a) the code itself lives in lib/bugs.c (for
dubious reasons) and (b) it gets called from the architecture-specific
"module_finalize()" rather than from generic code.
Calling it from arch-specific code makes no sense what-so-ever to begin
with, and is now actively wrong since that code isn't protected by the
module loading lock any more.
So this commit moves the "module_bug_{finalize,cleanup}()" calls away
from the arch-specific code, and into the generic code - and in the
process protects it with the module_mutex so that the list operations
are now safe.
Future fixups:
- move the module list handling code into kernel/module.c where it
belongs.
- get rid of 'module_bug_list' and just use the regular list of modules
(called 'modules' - imagine that) that we already create and maintain
for other reasons.
Reported-and-tested-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Adrian Bunk <bunk@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
121 lines
2.8 KiB
C
121 lines
2.8 KiB
C
#include <linux/moduleloader.h>
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#include <linux/elf.h>
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#include <linux/vmalloc.h>
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#include <linux/fs.h>
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#include <linux/string.h>
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#include <linux/kernel.h>
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#if 0
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#define DEBUGP printk
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#else
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#define DEBUGP(fmt...)
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#endif
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void *module_alloc(unsigned long size)
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{
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if (size == 0)
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return NULL;
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return vmalloc(size);
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}
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/* Free memory returned from module_alloc */
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void module_free(struct module *mod, void *module_region)
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{
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vfree(module_region);
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}
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/* We don't need anything special. */
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int module_frob_arch_sections(Elf_Ehdr *hdr,
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Elf_Shdr *sechdrs,
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char *secstrings,
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struct module *mod)
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{
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return 0;
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}
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int apply_relocate(Elf32_Shdr *sechdrs,
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const char *strtab,
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unsigned int symindex,
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unsigned int relsec,
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struct module *me)
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{
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printk(KERN_ERR "module %s: RELOCATION unsupported\n",
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me->name);
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return -ENOEXEC;
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}
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int apply_relocate_add(Elf32_Shdr *sechdrs,
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const char *strtab,
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unsigned int symindex,
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unsigned int relsec,
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struct module *me)
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{
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unsigned int i;
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Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
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DEBUGP("Applying relocate section %u to %u\n", relsec,
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sechdrs[relsec].sh_info);
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for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
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/* This is where to make the change */
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uint32_t *loc = (uint32_t *)(sechdrs[sechdrs[relsec].sh_info].sh_addr
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+ rela[i].r_offset);
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/* This is the symbol it is referring to. Note that all
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undefined symbols have been resolved. */
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Elf32_Sym *sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
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+ ELF32_R_SYM(rela[i].r_info);
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uint32_t v = sym->st_value + rela[i].r_addend;
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switch (ELF32_R_TYPE(rela[i].r_info)) {
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case R_H8_DIR24R8:
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loc = (uint32_t *)((uint32_t)loc - 1);
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*loc = (*loc & 0xff000000) | ((*loc & 0xffffff) + v);
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break;
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case R_H8_DIR24A8:
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if (ELF32_R_SYM(rela[i].r_info))
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*loc += v;
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break;
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case R_H8_DIR32:
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case R_H8_DIR32A16:
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*loc += v;
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break;
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case R_H8_PCREL16:
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v -= (unsigned long)loc + 2;
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if ((Elf32_Sword)v > 0x7fff ||
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(Elf32_Sword)v < -(Elf32_Sword)0x8000)
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goto overflow;
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else
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*(unsigned short *)loc = v;
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break;
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case R_H8_PCREL8:
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v -= (unsigned long)loc + 1;
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if ((Elf32_Sword)v > 0x7f ||
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(Elf32_Sword)v < -(Elf32_Sword)0x80)
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goto overflow;
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else
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*(unsigned char *)loc = v;
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break;
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default:
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printk(KERN_ERR "module %s: Unknown relocation: %u\n",
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me->name, ELF32_R_TYPE(rela[i].r_info));
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return -ENOEXEC;
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}
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}
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return 0;
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overflow:
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printk(KERN_ERR "module %s: relocation offset overflow: %08x\n",
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me->name, rela[i].r_offset);
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return -ENOEXEC;
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}
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int module_finalize(const Elf_Ehdr *hdr,
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const Elf_Shdr *sechdrs,
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struct module *me)
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{
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return 0;
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}
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void module_arch_cleanup(struct module *mod)
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{
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}
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