Commit e10863ff authored by Heiko Carstens's avatar Heiko Carstens Committed by Jason A. Donenfeld
Browse files

s390/vdso: Allow alternatives in vdso code 



Implement the infrastructure required to allow alternatives in vdso code.

Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
parent a919390e

arch/s390/kernel/vdso.c

+19 −0
Original line number Diff line number Diff line
@@ -12,12 +12,14 @@ 
#include <linux/errno.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/mm.h>

#include <linux/slab.h>

#include <linux/smp.h>

#include <linux/time_namespace.h>

#include <linux/random.h>

#include <vdso/datapage.h>

#include <asm/alternative.h>

#include <asm/vdso.h>



extern char vdso64_start[], vdso64_end[];
@@ -250,8 +252,25 @@ static struct page ** __init vdso_setup_pages(void *start, void *end) 
	return pagelist;

}



static void vdso_apply_alternatives(void)

{

	const struct elf64_shdr *alt, *shdr;

	struct alt_instr *start, *end;

	const struct elf64_hdr *hdr;



	hdr = (struct elf64_hdr *)vdso64_start;

	shdr = (void *)hdr + hdr->e_shoff;

	alt = find_section(hdr, shdr, ".altinstructions");

	if (!alt)

		return;

	start = (void *)hdr + alt->sh_offset;

	end = (void *)hdr + alt->sh_offset + alt->sh_size;

	apply_alternatives(start, end);

}



static int __init vdso_init(void)

{

	vdso_apply_alternatives();

	vdso64_mapping.pages = vdso_setup_pages(vdso64_start, vdso64_end);

	if (IS_ENABLED(CONFIG_COMPAT))

		vdso32_mapping.pages = vdso_setup_pages(vdso32_start, vdso32_end);

arch/s390/kernel/vdso64/vdso64.lds.S

+4 −0
Original line number Diff line number Diff line
@@ -42,6 +42,10 @@ SECTIONS 
	.rodata		: { *(.rodata .rodata.* .gnu.linkonce.r.*) }

	.rodata1	: { *(.rodata1) }



	. = ALIGN(8);

	.altinstructions	: { *(.altinstructions) }

	.altinstr_replacement	: { *(.altinstr_replacement) }



	.dynamic	: { *(.dynamic) }		:text	:dynamic



	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr