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s390/vdso: Allow alternatives in vdso code

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Implement the infrastructure required to allow alternatives in vdso code.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Heiko Carstens 2024-09-13 15:05:41 +02:00 committed by Jason A. Donenfeld
parent a919390e91
commit e10863fffe
2 changed files with 23 additions and 0 deletions
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19
arch/s390/kernel/vdso.c
View File

@ -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);

4
arch/s390/kernel/vdso64/vdso64.lds.S
View File

@ -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