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Commit 4a9cb360 authored by Russell King's avatar Russell King
Browse files

ARM: fixup SMP alternatives in modules 



With certain configurations, we inline the unlock functions in modules,
which results in SMP alternatives being created in modules.  We need to
fix those up when loading a module to prevent undefined instruction
faults.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 0193c00e

arch/arm/kernel/head.S

+26 −12
Original line number Diff line number Diff line
@@ -391,6 +391,7 @@ ENDPROC(__turn_mmu_on) 




#ifdef CONFIG_SMP_ON_UP

	__INIT

__fixup_smp:

	and	r3, r9, #0x000f0000	@ architecture version

	teq	r3, #0x000f0000		@ CPU ID supported?
@@ -415,18 +416,7 @@ __fixup_smp_on_up: 
	sub	r3, r0, r3

	add	r4, r4, r3

	add	r5, r5, r3

2:	cmp	r4, r5

	movhs	pc, lr

	ldmia	r4!, {r0, r6}

 ARM(	str	r6, [r0, r3]	)

 THUMB(	add	r0, r0, r3	)

#ifdef __ARMEB__

 THUMB(	mov	r6, r6, ror #16	)	@ Convert word order for big-endian.

#endif

 THUMB(	strh	r6, [r0], #2	)	@ For Thumb-2, store as two halfwords

 THUMB(	mov	r6, r6, lsr #16	)	@ to be robust against misaligned r3.

 THUMB(	strh	r6, [r0]	)

	b	2b

	b	__do_fixup_smp_on_up

ENDPROC(__fixup_smp)



	.align
@@ -440,7 +430,31 @@ smp_on_up: 
	ALT_SMP(.long	1)

	ALT_UP(.long	0)

	.popsection

#endif



	.text

__do_fixup_smp_on_up:

	cmp	r4, r5

	movhs	pc, lr

	ldmia	r4!, {r0, r6}

 ARM(	str	r6, [r0, r3]	)

 THUMB(	add	r0, r0, r3	)

#ifdef __ARMEB__

 THUMB(	mov	r6, r6, ror #16	)	@ Convert word order for big-endian.

#endif

 THUMB(	strh	r6, [r0], #2	)	@ For Thumb-2, store as two halfwords

 THUMB(	mov	r6, r6, lsr #16	)	@ to be robust against misaligned r3.

 THUMB(	strh	r6, [r0]	)

	b	__do_fixup_smp_on_up

ENDPROC(__do_fixup_smp_on_up)



ENTRY(fixup_smp)

	stmfd	sp!, {r4 - r6, lr}

	mov	r4, r0

	add	r5, r0, r1

	mov	r3, #0

	bl	__do_fixup_smp_on_up

	ldmfd	sp!, {r4 - r6, pc}

ENDPROC(fixup_smp)



#include "head-common.S"

arch/arm/kernel/module.c

+21 −1
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 


#include <asm/pgtable.h>

#include <asm/sections.h>

#include <asm/smp_plat.h>

#include <asm/unwind.h>



#ifdef CONFIG_XIP_KERNEL
@@ -268,12 +269,28 @@ struct mod_unwind_map { 
	const Elf_Shdr *txt_sec;

};



static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,

	const Elf_Shdr *sechdrs, const char *name)

{

	const Elf_Shdr *s, *se;

	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;



	for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)

		if (strcmp(name, secstrs + s->sh_name) == 0)

			return s;



	return NULL;

}



extern void fixup_smp(const void *, unsigned long);



int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,

		    struct module *mod)

{

	const Elf_Shdr * __maybe_unused s = NULL;

#ifdef CONFIG_ARM_UNWIND

	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;

	const Elf_Shdr *s, *sechdrs_end = sechdrs + hdr->e_shnum;

	const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;

	struct mod_unwind_map maps[ARM_SEC_MAX];

	int i;
@@ -315,6 +332,9 @@ int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, 
					         maps[i].txt_sec->sh_addr,

					         maps[i].txt_sec->sh_size);

#endif

	s = find_mod_section(hdr, sechdrs, ".alt.smp.init");

	if (s && !is_smp())

		fixup_smp((void *)s->sh_addr, s->sh_size);

	return 0;

}