diff options
Diffstat (limited to 'arch/s390/kernel/alternative.c')
-rw-r--r-- | arch/s390/kernel/alternative.c | 61 |
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); } } |