linux_dsm_epyc7002/arch/powerpc/include/asm/module.h
Michael Ellerman 73aca179d7 powerpc/modules: Fix crashes by adding CONFIG_RELOCATABLE to vermagic
If you build the kernel with CONFIG_RELOCATABLE=n, then install the
modules, rebuild the kernel with CONFIG_RELOCATABLE=y and leave the
old modules installed, we crash something like:

  Unable to handle kernel paging request for data at address 0xd000000018d66cef
  Faulting instruction address: 0xc0000000021ddd08
  Oops: Kernel access of bad area, sig: 11 [#1]
  Modules linked in: x_tables autofs4
  CPU: 2 PID: 1 Comm: systemd Not tainted 4.16.0-rc6-gcc_ubuntu_le-g99fec39 #1
  ...
  NIP check_version.isra.22+0x118/0x170
  Call Trace:
    __ksymtab_xt_unregister_table+0x58/0xfffffffffffffcb8 [x_tables] (unreliable)
    resolve_symbol+0xb4/0x150
    load_module+0x10e8/0x29a0
    SyS_finit_module+0x110/0x140
    system_call+0x58/0x6c

This happens because since commit 71810db27c ("modversions: treat
symbol CRCs as 32 bit quantities"), a relocatable kernel encodes and
handles symbol CRCs differently from a non-relocatable kernel.

Although it's possible we could try and detect this situation and
handle it, it's much more robust to simply make the state of
CONFIG_RELOCATABLE part of the module vermagic.

Fixes: 71810db27c ("modversions: treat symbol CRCs as 32 bit quantities")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-04-09 13:21:02 +10:00

112 lines
2.8 KiB
C

#ifndef _ASM_POWERPC_MODULE_H
#define _ASM_POWERPC_MODULE_H
#ifdef __KERNEL__
/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/list.h>
#include <asm/bug.h>
#include <asm-generic/module.h>
#ifdef CC_USING_MPROFILE_KERNEL
#define MODULE_ARCH_VERMAGIC_FTRACE "mprofile-kernel "
#else
#define MODULE_ARCH_VERMAGIC_FTRACE ""
#endif
#ifdef CONFIG_RELOCATABLE
#define MODULE_ARCH_VERMAGIC_RELOCATABLE "relocatable "
#else
#define MODULE_ARCH_VERMAGIC_RELOCATABLE ""
#endif
#define MODULE_ARCH_VERMAGIC MODULE_ARCH_VERMAGIC_FTRACE MODULE_ARCH_VERMAGIC_RELOCATABLE
#ifndef __powerpc64__
/*
* Thanks to Paul M for explaining this.
*
* PPC can only do rel jumps += 32MB, and often the kernel and other
* modules are further away than this. So, we jump to a table of
* trampolines attached to the module (the Procedure Linkage Table)
* whenever that happens.
*/
struct ppc_plt_entry {
/* 16 byte jump instruction sequence (4 instructions) */
unsigned int jump[4];
};
#endif /* __powerpc64__ */
struct mod_arch_specific {
#ifdef __powerpc64__
unsigned int stubs_section; /* Index of stubs section in module */
unsigned int toc_section; /* What section is the TOC? */
bool toc_fixed; /* Have we fixed up .TOC.? */
#ifdef CONFIG_DYNAMIC_FTRACE
unsigned long toc;
unsigned long tramp;
#endif
/* For module function descriptor dereference */
unsigned long start_opd;
unsigned long end_opd;
#else /* powerpc64 */
/* Indices of PLT sections within module. */
unsigned int core_plt_section;
unsigned int init_plt_section;
#ifdef CONFIG_DYNAMIC_FTRACE
unsigned long tramp;
#endif
#endif /* powerpc64 */
/* List of BUG addresses, source line numbers and filenames */
struct list_head bug_list;
struct bug_entry *bug_table;
unsigned int num_bugs;
};
/*
* Select ELF headers.
* Make empty section for module_frob_arch_sections to expand.
*/
#ifdef __powerpc64__
# ifdef MODULE
asm(".section .stubs,\"ax\",@nobits; .align 3; .previous");
# endif
#else
# ifdef MODULE
asm(".section .plt,\"ax\",@nobits; .align 3; .previous");
asm(".section .init.plt,\"ax\",@nobits; .align 3; .previous");
# endif /* MODULE */
#endif
#ifdef CONFIG_DYNAMIC_FTRACE
# ifdef MODULE
asm(".section .ftrace.tramp,\"ax\",@nobits; .align 3; .previous");
# endif /* MODULE */
#endif
int module_trampoline_target(struct module *mod, unsigned long trampoline,
unsigned long *target);
#ifdef CONFIG_DYNAMIC_FTRACE
int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs);
#else
static inline int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs)
{
return 0;
}
#endif
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_MODULE_H */