summaryrefslogtreecommitdiff
path: root/arch/s390/include/asm/alternative.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/s390/include/asm/alternative.h')
-rw-r--r--arch/s390/include/asm/alternative.h252
1 files changed, 170 insertions, 82 deletions
diff --git a/arch/s390/include/asm/alternative.h b/arch/s390/include/asm/alternative.h
index 1c8a38f762a3..c7bf60a541e9 100644
--- a/arch/s390/include/asm/alternative.h
+++ b/arch/s390/include/asm/alternative.h
@@ -2,6 +2,55 @@
#ifndef _ASM_S390_ALTERNATIVE_H
#define _ASM_S390_ALTERNATIVE_H
+/*
+ * Each alternative comes with a 32 bit feature field:
+ * union {
+ * u32 feature;
+ * struct {
+ * u32 ctx : 4;
+ * u32 type : 8;
+ * u32 data : 20;
+ * };
+ * }
+ *
+ * @ctx is a bitfield, where only one bit must be set. Each bit defines
+ * in which context an alternative is supposed to be applied to the
+ * kernel image:
+ *
+ * - from the decompressor before the kernel itself is executed
+ * - from early kernel code from within the kernel
+ *
+ * @type is a number which defines the type and with that the type
+ * specific alternative patching.
+ *
+ * @data is additional type specific information which defines if an
+ * alternative should be applied.
+ */
+
+#define ALT_CTX_EARLY 1
+#define ALT_CTX_LATE 2
+#define ALT_CTX_ALL (ALT_CTX_EARLY | ALT_CTX_LATE)
+
+#define ALT_TYPE_FACILITY 0
+#define ALT_TYPE_FEATURE 1
+#define ALT_TYPE_SPEC 2
+
+#define ALT_DATA_SHIFT 0
+#define ALT_TYPE_SHIFT 20
+#define ALT_CTX_SHIFT 28
+
+#define ALT_FACILITY(facility) (ALT_CTX_EARLY << ALT_CTX_SHIFT | \
+ ALT_TYPE_FACILITY << ALT_TYPE_SHIFT | \
+ (facility) << ALT_DATA_SHIFT)
+
+#define ALT_FEATURE(feature) (ALT_CTX_EARLY << ALT_CTX_SHIFT | \
+ ALT_TYPE_FEATURE << ALT_TYPE_SHIFT | \
+ (feature) << ALT_DATA_SHIFT)
+
+#define ALT_SPEC(facility) (ALT_CTX_LATE << ALT_CTX_SHIFT | \
+ ALT_TYPE_SPEC << ALT_TYPE_SHIFT | \
+ (facility) << ALT_DATA_SHIFT)
+
#ifndef __ASSEMBLY__
#include <linux/types.h>
@@ -11,34 +60,45 @@
struct alt_instr {
s32 instr_offset; /* original instruction */
s32 repl_offset; /* offset to replacement instruction */
- u16 facility; /* facility bit set for replacement */
+ union {
+ u32 feature; /* feature required for replacement */
+ struct {
+ u32 ctx : 4; /* context */
+ u32 type : 8; /* type of alternative */
+ u32 data : 20; /* patching information */
+ };
+ };
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);
+extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
+
+void __apply_alternatives(struct alt_instr *start, struct alt_instr *end, unsigned int ctx);
+
+static inline void apply_alternative_instructions(void)
+{
+ __apply_alternatives(__alt_instructions, __alt_instructions_end, ALT_CTX_LATE);
+}
+
+static inline void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
+{
+ __apply_alternatives(start, end, ALT_CTX_ALL);
+}
/*
- * |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
* +---------------------------------+
@@ -47,83 +107,45 @@ 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.fill (" oldinstr_pad_len(num) " - (6620b-662b)) / 2, 2, 0x0700\n" \
- ".else\n" \
- "\t.fill " oldinstr_pad_len(num) " / 6, 6, 0xc0040000\n" \
- "\t.fill " oldinstr_pad_len(num) " %% 6 / 4, 4, 0x47000000\n" \
- "\t.fill " oldinstr_pad_len(num) " %% 6 %% 4 / 2, 2, 0x0700\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 ALTINSTR_ENTRY(facility, num) \
+
+#define OLDINSTR(oldinstr) \
+ "661:\n\t" oldinstr "\n662:\n"
+
+#define ALTINSTR_ENTRY(feature, 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.long " __stringify(feature) "\n" /* feature */ \
+ "\t.byte " oldinstr_len "\n" /* instruction len */ \
+ "\t.org . - (" oldinstr_len ") & 1\n" \
+ "\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) \
+#define ALTERNATIVE(oldinstr, altinstr, feature) \
".pushsection .altinstr_replacement, \"ax\"\n" \
ALTINSTR_REPLACEMENT(altinstr, 1) \
".popsection\n" \
- OLDINSTR(oldinstr, 1) \
+ OLDINSTR(oldinstr) \
".pushsection .altinstructions,\"a\"\n" \
- ALTINSTR_ENTRY(facility, 1) \
+ ALTINSTR_ENTRY(feature, 1) \
".popsection\n"
-#define ALTERNATIVE_2(oldinstr, altinstr1, facility1, altinstr2, facility2)\
+#define ALTERNATIVE_2(oldinstr, altinstr1, feature1, altinstr2, feature2)\
".pushsection .altinstr_replacement, \"ax\"\n" \
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) \
+ ALTINSTR_ENTRY(feature1, 1) \
+ ALTINSTR_ENTRY(feature2, 2) \
".popsection\n"
/*
@@ -138,12 +160,78 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
* For non barrier like inlines please define new variants
* without volatile and memory clobber.
*/
-#define alternative(oldinstr, altinstr, facility) \
- asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, facility) : : : "memory")
+#define alternative(oldinstr, altinstr, feature) \
+ asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, feature) : : : "memory")
+
+#define alternative_2(oldinstr, altinstr1, feature1, altinstr2, feature2) \
+ asm_inline volatile(ALTERNATIVE_2(oldinstr, altinstr1, feature1, \
+ altinstr2, feature2) ::: "memory")
+
+/* Alternative inline assembly with input. */
+#define alternative_input(oldinstr, newinstr, feature, input...) \
+ asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
+ : : input)
+
+/* Like alternative_input, but with a single output argument */
+#define alternative_io(oldinstr, altinstr, feature, output, input...) \
+ asm_inline volatile(ALTERNATIVE(oldinstr, altinstr, feature) \
+ : output : input)
+
+/* Use this macro if more than one output parameter is needed. */
+#define ASM_OUTPUT2(a...) a
+
+/* Use this macro if clobbers are needed without inputs. */
+#define ASM_NO_INPUT_CLOBBER(clobber...) : clobber
-#define alternative_2(oldinstr, altinstr1, facility1, altinstr2, facility2) \
- asm_inline volatile(ALTERNATIVE_2(oldinstr, altinstr1, facility1, \
- altinstr2, facility2) ::: "memory")
+#else /* __ASSEMBLY__ */
+
+/*
+ * Issue one struct alt_instr descriptor entry (need to put it into
+ * the section .altinstructions, see below). This entry contains
+ * enough information for the alternatives patching code to patch an
+ * instruction. See apply_alternatives().
+ */
+.macro alt_entry orig_start, orig_end, alt_start, alt_end, feature
+ .long \orig_start - .
+ .long \alt_start - .
+ .long \feature
+ .byte \orig_end - \orig_start
+ .org . - ( \orig_end - \orig_start ) & 1
+ .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.
+ */
+.macro ALTERNATIVE oldinstr, newinstr, feature
+ .pushsection .altinstr_replacement,"ax"
+770: \newinstr
+771: .popsection
+772: \oldinstr
+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.
+ */
+.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
+ .pushsection .altinstr_replacement,"ax"
+770: \newinstr1
+771: \newinstr2
+772: .popsection
+773: \oldinstr
+774: .pushsection .altinstructions,"a"
+ alt_entry 773b, 774b, 770b, 771b,\feature1
+ alt_entry 773b, 774b, 771b, 772b,\feature2
+ .popsection
+.endm
#endif /* __ASSEMBLY__ */
generated by cgit (git 2.34.1) at 2025-07-25 20:07:10 +0000