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Diffstat (limited to 'arch/s390/kernel/alternative.c')
-rw-r--r--arch/s390/kernel/alternative.c61
1 files changed, 2 insertions, 59 deletions
diff --git a/arch/s390/kernel/alternative.c b/arch/s390/kernel/alternative.c
index cce0ddee2d02..e7bca29f9c34 100644
--- a/arch/s390/kernel/alternative.c
+++ b/arch/s390/kernel/alternative.c
@@ -7,8 +7,6 @@
#include <asm/facility.h>
#include <asm/nospec-branch.h>
-#define MAX_PATCH_LEN (255 - 1)
-
static int __initdata_or_module alt_instr_disabled;
static int __init disable_alternative_instructions(char *str)
@@ -19,85 +17,30 @@ static int __init disable_alternative_instructions(char *str)
early_param("noaltinstr", disable_alternative_instructions);
-struct brcl_insn {
- u16 opc;
- s32 disp;
-} __packed;
-
-static u16 __initdata_or_module nop16 = 0x0700;
-static u32 __initdata_or_module nop32 = 0x47000000;
-static struct brcl_insn __initdata_or_module nop48 = {
- 0xc004, 0
-};
-
-static const void *nops[] __initdata_or_module = {
- &nop16,
- &nop32,
- &nop48
-};
-
-static void __init_or_module add_jump_padding(void *insns, unsigned int len)
-{
- struct brcl_insn brcl = {
- 0xc0f4,
- len / 2
- };
-
- memcpy(insns, &brcl, sizeof(brcl));
- insns += sizeof(brcl);
- len -= sizeof(brcl);
-
- while (len > 0) {
- memcpy(insns, &nop16, 2);
- insns += 2;
- len -= 2;
- }
-}
-
-static void __init_or_module add_padding(void *insns, unsigned int len)
-{
- if (len > 6)
- add_jump_padding(insns, len);
- else if (len >= 2)
- memcpy(insns, nops[len / 2 - 1], len);
-}
-
static void __init_or_module __apply_alternatives(struct alt_instr *start,
struct alt_instr *end)
{
struct alt_instr *a;
u8 *instr, *replacement;
- u8 insnbuf[MAX_PATCH_LEN];
/*
* The scan order should be from start to end. A later scanned
* alternative code can overwrite previously scanned alternative code.
*/
for (a = start; a < end; a++) {
- int insnbuf_sz = 0;
-
instr = (u8 *)&a->instr_offset + a->instr_offset;
replacement = (u8 *)&a->repl_offset + a->repl_offset;
if (!__test_facility(a->facility, alt_stfle_fac_list))
continue;
- if (unlikely(a->instrlen % 2 || a->replacementlen % 2)) {
+ if (unlikely(a->instrlen % 2)) {
WARN_ONCE(1, "cpu alternatives instructions length is "
"odd, skipping patching\n");
continue;
}
- memcpy(insnbuf, replacement, a->replacementlen);
- insnbuf_sz = a->replacementlen;
-
- if (a->instrlen > a->replacementlen) {
- add_padding(insnbuf + a->replacementlen,
- a->instrlen - a->replacementlen);
- insnbuf_sz += a->instrlen - a->replacementlen;
- }
-
- s390_kernel_write(instr, insnbuf, insnbuf_sz);
+ s390_kernel_write(instr, replacement, a->instrlen);
}
}