Commit 2cb54ce9 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'modversions' (modversions fixes for powerpc from Ard) 

Merge kcrctab entry fixes from Ard Biesheuvel:
 "This is a followup to [0] 'modversions: redefine kcrctab entries as
  relative CRC pointers', but since relative CRC pointers do not work in
  modules, and are actually only needed by powerpc with
  CONFIG_RELOCATABLE=y, I have made it a Kconfig selectable feature
  instead.

  First it introduces the MODULE_REL_CRCS Kconfig symbol, and adds the
  kbuild handling of it, i.e., modpost, genksyms and kallsyms.

  Then it switches all architectures to 32-bit CRC entries in kcrctab,
  where all architectures except powerpc with CONFIG_RELOCATABLE=y use
  absolute ELF symbol references as before"

[0] http://marc.info/?l=linux-arch&m=148493613415294&w=2

* emailed patches from Ard Biesheuvel:
  module: unify absolute krctab definitions for 32-bit and 64-bit
  modversions: treat symbol CRCs as 32 bit quantities
  kbuild: modversions: add infrastructure for emitting relative CRCs
parents 29905b52 4b9eee96

arch/powerpc/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -484,6 +484,7 @@ config RELOCATABLE 
	bool "Build a relocatable kernel"

	depends on (PPC64 && !COMPILE_TEST) || (FLATMEM && (44x || FSL_BOOKE))

	select NONSTATIC_KERNEL

	select MODULE_REL_CRCS if MODVERSIONS

	help

	  This builds a kernel image that is capable of running at the

	  location the kernel is loaded at. For ppc32, there is no any

arch/powerpc/include/asm/module.h

+0 −4
Original line number Diff line number Diff line
@@ -90,9 +90,5 @@ static inline int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sec 
}

#endif



#if defined(CONFIG_MODVERSIONS) && defined(CONFIG_PPC64)

#define ARCH_RELOCATES_KCRCTAB

#define reloc_start PHYSICAL_START

#endif

#endif /* __KERNEL__ */

#endif	/* _ASM_POWERPC_MODULE_H */

arch/powerpc/kernel/module_64.c

+0 −8
Original line number Diff line number Diff line
@@ -286,14 +286,6 @@ static void dedotify_versions(struct modversion_info *vers, 
	for (end = (void *)vers + size; vers < end; vers++)

		if (vers->name[0] == '.') {

			memmove(vers->name, vers->name+1, strlen(vers->name));

#ifdef ARCH_RELOCATES_KCRCTAB

			/* The TOC symbol has no CRC computed. To avoid CRC

			 * check failing, we must force it to the expected

			 * value (see CRC check in module.c).

			 */

			if (!strcmp(vers->name, "TOC."))

				vers->crc = -(unsigned long)reloc_start;

#endif

		}

}

include/asm-generic/export.h

+6 −5
Original line number Diff line number Diff line
@@ -9,18 +9,15 @@ 
#ifndef KSYM_ALIGN

#define KSYM_ALIGN 8

#endif

#ifndef KCRC_ALIGN

#define KCRC_ALIGN 8

#endif

#else

#define __put .long

#ifndef KSYM_ALIGN

#define KSYM_ALIGN 4

#endif

#endif

#ifndef KCRC_ALIGN

#define KCRC_ALIGN 4

#endif

#endif



#ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX

#define KSYM(name) _##name
@@ -52,7 +49,11 @@ KSYM(__kstrtab_\name): 
	.section ___kcrctab\sec+\name,"a"

	.balign KCRC_ALIGN

KSYM(__kcrctab_\name):

	__put KSYM(__crc_\name)

#if defined(CONFIG_MODULE_REL_CRCS)

	.long KSYM(__crc_\name) - .

#else

	.long KSYM(__crc_\name)

#endif

	.weak KSYM(__crc_\name)

	.previous

#endif

include/linux/export.h

+12 −5
Original line number Diff line number Diff line
@@ -43,12 +43,19 @@ extern struct module __this_module; 
#ifdef CONFIG_MODVERSIONS

/* Mark the CRC weak since genksyms apparently decides not to

 * generate a checksums for some symbols */

#if defined(CONFIG_MODULE_REL_CRCS)

#define __CRC_SYMBOL(sym, sec)						\

	extern __visible void *__crc_##sym __attribute__((weak));	\

	static const unsigned long __kcrctab_##sym			\

	__used								\

	__attribute__((section("___kcrctab" sec "+" #sym), used))	\

	= (unsigned long) &__crc_##sym;

	asm("	.section \"___kcrctab" sec "+" #sym "\", \"a\"	\n"	\

	    "	.weak	" VMLINUX_SYMBOL_STR(__crc_##sym) "	\n"	\

	    "	.long	" VMLINUX_SYMBOL_STR(__crc_##sym) " - .	\n"	\

	    "	.previous					\n");

#else

#define __CRC_SYMBOL(sym, sec)						\

	asm("	.section \"___kcrctab" sec "+" #sym "\", \"a\"	\n"	\

	    "	.weak	" VMLINUX_SYMBOL_STR(__crc_##sym) "	\n"	\

	    "	.long	" VMLINUX_SYMBOL_STR(__crc_##sym) "	\n"	\

	    "	.previous					\n");

#endif

#else

#define __CRC_SYMBOL(sym, sec)

#endif

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