diff --git a/arch/s390/include/asm/alternative-asm.h b/arch/s390/include/asm/alternative-asm.h index bb3837d7387ce0..7db046596b93e8 100644 --- a/arch/s390/include/asm/alternative-asm.h +++ b/arch/s390/include/asm/alternative-asm.h @@ -4,19 +4,6 @@ #ifdef __ASSEMBLY__ -/* - * Check the length of an instruction sequence. The length may not be larger - * than 254 bytes and it has to be divisible by 2. - */ -.macro alt_len_check start,end - .if ( \end - \start ) > 254 - .error "cpu alternatives does not support instructions blocks > 254 bytes\n" - .endif - .if ( \end - \start ) % 2 - .error "cpu alternatives instructions length is odd\n" - .endif -.endm - /* * Issue one struct alt_instr descriptor entry (need to put it into * the section .altinstructions, see below). This entry contains @@ -28,66 +15,29 @@ .long \alt_start - . .word \feature .byte \orig_end - \orig_start - .byte \alt_end - \alt_start -.endm - -/* - * Fill up @bytes with nops. The macro emits 6-byte nop instructions - * for the bulk of the area, possibly followed by a 4-byte and/or - * a 2-byte nop if the size of the area is not divisible by 6. - */ -.macro alt_pad_fill bytes - .rept ( \bytes ) / 6 - brcl 0,0 - .endr - .rept ( \bytes ) % 6 / 4 - nop - .endr - .rept ( \bytes ) % 6 % 4 / 2 - nopr - .endr -.endm - -/* - * Fill up @bytes with nops. If the number of bytes is larger - * than 6, emit a jg instruction to branch over all nops, then - * fill an area of size (@bytes - 6) with nop instructions. - */ -.macro alt_pad bytes - .if ( \bytes > 0 ) - .if ( \bytes > 6 ) - jg . + \bytes - alt_pad_fill \bytes - 6 - .else - alt_pad_fill \bytes - .endif - .endif + .org . - ( \orig_end - \orig_start ) + ( \alt_end - \alt_start ) + .org . - ( \alt_end - \alt_start ) + ( \orig_end - \orig_start ) .endm /* * Define an alternative between two instructions. If @feature is * present, early code in apply_alternatives() replaces @oldinstr with - * @newinstr. ".skip" directive takes care of proper instruction padding - * in case @newinstr is longer than @oldinstr. + * @newinstr. */ .macro ALTERNATIVE oldinstr, newinstr, feature .pushsection .altinstr_replacement,"ax" 770: \newinstr 771: .popsection 772: \oldinstr -773: alt_len_check 770b, 771b - alt_len_check 772b, 773b - alt_pad ( ( 771b - 770b ) - ( 773b - 772b ) ) -774: .pushsection .altinstructions,"a" - alt_entry 772b, 774b, 770b, 771b, \feature +773: .pushsection .altinstructions,"a" + alt_entry 772b, 773b, 770b, 771b, \feature .popsection .endm /* * Define an alternative between two instructions. If @feature is * present, early code in apply_alternatives() replaces @oldinstr with - * @newinstr. ".skip" directive takes care of proper instruction padding - * in case @newinstr is longer than @oldinstr. + * @newinstr. */ .macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2 .pushsection .altinstr_replacement,"ax" @@ -95,17 +45,9 @@ 771: \newinstr2 772: .popsection 773: \oldinstr -774: alt_len_check 770b, 771b - alt_len_check 771b, 772b - alt_len_check 773b, 774b - .if ( 771b - 770b > 772b - 771b ) - alt_pad ( ( 771b - 770b ) - ( 774b - 773b ) ) - .else - alt_pad ( ( 772b - 771b ) - ( 774b - 773b ) ) - .endif -775: .pushsection .altinstructions,"a" - alt_entry 773b, 775b, 770b, 771b,\feature1 - alt_entry 773b, 775b, 771b, 772b,\feature2 +774: .pushsection .altinstructions,"a" + alt_entry 773b, 774b, 770b, 771b,\feature1 + alt_entry 773b, 774b, 771b, 772b,\feature2 .popsection .endm diff --git a/arch/s390/include/asm/alternative.h b/arch/s390/include/asm/alternative.h index 3f2856ed680831..904dd049f95476 100644 --- a/arch/s390/include/asm/alternative.h +++ b/arch/s390/include/asm/alternative.h @@ -13,32 +13,25 @@ struct alt_instr { s32 repl_offset; /* offset to replacement instruction */ u16 facility; /* facility bit set for replacement */ u8 instrlen; /* length of original instruction */ - u8 replacementlen; /* length of new instruction */ } __packed; void apply_alternative_instructions(void); void apply_alternatives(struct alt_instr *start, struct alt_instr *end); /* - * |661: |662: |6620 |663: - * +-----------+---------------------+ - * | oldinstr | oldinstr_padding | - * | +----------+----------+ - * | | | | - * | | >6 bytes |6/4/2 nops| - * | |6 bytes jg-----------> - * +-----------+---------------------+ - * ^^ static padding ^^ + * +---------------------------------+ + * |661: |662: + * | oldinstr | + * +---------------------------------+ * * .altinstr_replacement section - * +---------------------+-----------+ + * +---------------------------------+ * |6641: |6651: * | alternative instr 1 | - * +-----------+---------+- - - - - -+ - * |6642: |6652: | - * | alternative instr 2 | padding - * +---------------------+- - - - - -+ - * ^ runtime ^ + * +---------------------------------+ + * |6642: |6652: + * | alternative instr 2 | + * +---------------------------------+ * * .altinstructions section * +---------------------------------+ @@ -47,77 +40,31 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end); * +---------------------------------+ */ -#define b_altinstr(num) "664"#num -#define e_altinstr(num) "665"#num - -#define e_oldinstr_pad_end "663" +#define b_altinstr(num) "664"#num +#define e_altinstr(num) "665"#num #define oldinstr_len "662b-661b" -#define oldinstr_total_len e_oldinstr_pad_end"b-661b" #define altinstr_len(num) e_altinstr(num)"b-"b_altinstr(num)"b" -#define oldinstr_pad_len(num) \ - "-(((" altinstr_len(num) ")-(" oldinstr_len ")) > 0) * " \ - "((" altinstr_len(num) ")-(" oldinstr_len "))" - -#define INSTR_LEN_SANITY_CHECK(len) \ - ".if " len " > 254\n" \ - "\t.error \"cpu alternatives does not support instructions " \ - "blocks > 254 bytes\"\n" \ - ".endif\n" \ - ".if (" len ") %% 2\n" \ - "\t.error \"cpu alternatives instructions length is odd\"\n" \ - ".endif\n" - -#define OLDINSTR_PADDING(oldinstr, num) \ - ".if " oldinstr_pad_len(num) " > 6\n" \ - "\tjg " e_oldinstr_pad_end "f\n" \ - "6620:\n" \ - "\t.rept (" oldinstr_pad_len(num) " - (6620b-662b)) / 2\n" \ - "\tnopr\n" \ - ".else\n" \ - "\t.rept " oldinstr_pad_len(num) " / 6\n" \ - "\t.brcl 0,0\n" \ - "\t.endr\n" \ - "\t.rept " oldinstr_pad_len(num) " %% 6 / 4\n" \ - "\tnop\n" \ - "\t.endr\n" \ - "\t.rept " oldinstr_pad_len(num) " %% 6 %% 4 / 2\n" \ - "\tnopr\n" \ - ".endr\n" \ - ".endif\n" - -#define OLDINSTR(oldinstr, num) \ - "661:\n\t" oldinstr "\n662:\n" \ - OLDINSTR_PADDING(oldinstr, num) \ - e_oldinstr_pad_end ":\n" \ - INSTR_LEN_SANITY_CHECK(oldinstr_len) - -#define OLDINSTR_2(oldinstr, num1, num2) \ - "661:\n\t" oldinstr "\n662:\n" \ - ".if " altinstr_len(num1) " < " altinstr_len(num2) "\n" \ - OLDINSTR_PADDING(oldinstr, num2) \ - ".else\n" \ - OLDINSTR_PADDING(oldinstr, num1) \ - ".endif\n" \ - e_oldinstr_pad_end ":\n" \ - INSTR_LEN_SANITY_CHECK(oldinstr_len) + +#define OLDINSTR(oldinstr) \ + "661:\n\t" oldinstr "\n662:\n" #define ALTINSTR_ENTRY(facility, num) \ "\t.long 661b - .\n" /* old instruction */ \ "\t.long " b_altinstr(num)"b - .\n" /* alt instruction */ \ "\t.word " __stringify(facility) "\n" /* facility bit */ \ - "\t.byte " oldinstr_total_len "\n" /* source len */ \ - "\t.byte " altinstr_len(num) "\n" /* alt instruction len */ + "\t.byte " oldinstr_len "\n" /* instruction len */ \ + "\t.org . - (" oldinstr_len ") + (" altinstr_len(num) ")\n" \ + "\t.org . - (" altinstr_len(num) ") + (" oldinstr_len ")\n" #define ALTINSTR_REPLACEMENT(altinstr, num) /* replacement */ \ - b_altinstr(num)":\n\t" altinstr "\n" e_altinstr(num) ":\n" \ - INSTR_LEN_SANITY_CHECK(altinstr_len(num)) + b_altinstr(num)":\n\t" altinstr "\n" e_altinstr(num) ":\n" /* alternative assembly primitive: */ #define ALTERNATIVE(oldinstr, altinstr, facility) \ ".pushsection .altinstr_replacement, \"ax\"\n" \ ALTINSTR_REPLACEMENT(altinstr, 1) \ ".popsection\n" \ - OLDINSTR(oldinstr, 1) \ + OLDINSTR(oldinstr) \ ".pushsection .altinstructions,\"a\"\n" \ ALTINSTR_ENTRY(facility, 1) \ ".popsection\n" @@ -127,7 +74,7 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end); ALTINSTR_REPLACEMENT(altinstr1, 1) \ ALTINSTR_REPLACEMENT(altinstr2, 2) \ ".popsection\n" \ - OLDINSTR_2(oldinstr, 1, 2) \ + OLDINSTR(oldinstr) \ ".pushsection .altinstructions,\"a\"\n" \ ALTINSTR_ENTRY(facility1, 1) \ ALTINSTR_ENTRY(facility2, 2) \ diff --git a/arch/s390/kernel/alternative.c b/arch/s390/kernel/alternative.c index cce0ddee2d02d2..e7bca29f9c3485 100644 --- a/arch/s390/kernel/alternative.c +++ b/arch/s390/kernel/alternative.c @@ -7,8 +7,6 @@ #include #include -#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); } }