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-rw-r--r--arch/x86/include/asm/alternative-asm.h43
-rw-r--r--arch/x86/include/asm/alternative.h65
-rw-r--r--arch/x86/include/asm/cpufeature.h22
-rw-r--r--arch/x86/include/asm/smap.h4
4 files changed, 100 insertions, 34 deletions
diff --git a/arch/x86/include/asm/alternative-asm.h b/arch/x86/include/asm/alternative-asm.h
index 372231c22a47..524bddce0b76 100644
--- a/arch/x86/include/asm/alternative-asm.h
+++ b/arch/x86/include/asm/alternative-asm.h
@@ -18,12 +18,53 @@
.endm
#endif
-.macro altinstruction_entry orig alt feature orig_len alt_len
+.macro altinstruction_entry orig alt feature orig_len alt_len pad_len
.long \orig - .
.long \alt - .
.word \feature
.byte \orig_len
.byte \alt_len
+ .byte \pad_len
+.endm
+
+.macro ALTERNATIVE oldinstr, newinstr, feature
+140:
+ \oldinstr
+141:
+ .skip -(((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)),0x90
+142:
+
+ .pushsection .altinstructions,"a"
+ altinstruction_entry 140b,143f,\feature,142b-140b,144f-143f,142b-141b
+ .popsection
+
+ .pushsection .altinstr_replacement,"ax"
+143:
+ \newinstr
+144:
+ .popsection
+.endm
+
+.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
+140:
+ \oldinstr
+141:
+ .skip -(((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)),0x90
+ .skip -(((145f-144f)-(144f-143f)-(141b-140b)) > 0) * ((145f-144f)-(144f-143f)-(141b-140b)),0x90
+142:
+
+ .pushsection .altinstructions,"a"
+ altinstruction_entry 140b,143f,\feature1,142b-140b,144f-143f,142b-141b
+ altinstruction_entry 140b,144f,\feature2,142b-140b,145f-144f,142b-141b
+ .popsection
+
+ .pushsection .altinstr_replacement,"ax"
+143:
+ \newinstr1
+144:
+ \newinstr2
+145:
+ .popsection
.endm
#endif /* __ASSEMBLY__ */
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 473bdbee378a..5aef6a97d80e 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -48,8 +48,9 @@ struct alt_instr {
s32 repl_offset; /* offset to replacement instruction */
u16 cpuid; /* cpuid bit set for replacement */
u8 instrlen; /* length of original instruction */
- u8 replacementlen; /* length of new instruction, <= instrlen */
-};
+ u8 replacementlen; /* length of new instruction */
+ u8 padlen; /* length of build-time padding */
+} __packed;
extern void alternative_instructions(void);
extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
@@ -76,50 +77,61 @@ static inline int alternatives_text_reserved(void *start, void *end)
}
#endif /* CONFIG_SMP */
-#define OLDINSTR(oldinstr) "661:\n\t" oldinstr "\n662:\n"
+#define b_replacement(num) "664"#num
+#define e_replacement(num) "665"#num
-#define b_replacement(number) "663"#number
-#define e_replacement(number) "664"#number
+#define alt_end_marker "663"
+#define alt_slen "662b-661b"
+#define alt_pad_len alt_end_marker"b-662b"
+#define alt_total_slen alt_end_marker"b-661b"
+#define alt_rlen(num) e_replacement(num)"f-"b_replacement(num)"f"
-#define alt_slen "662b-661b"
-#define alt_rlen(number) e_replacement(number)"f-"b_replacement(number)"f"
+#define __OLDINSTR(oldinstr, num) \
+ "661:\n\t" oldinstr "\n662:\n" \
+ ".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * " \
+ "((" alt_rlen(num) ")-(" alt_slen ")),0x90\n"
-#define ALTINSTR_ENTRY(feature, number) \
+#define OLDINSTR(oldinstr, num) \
+ __OLDINSTR(oldinstr, num) \
+ alt_end_marker ":\n"
+
+/*
+ * Pad the second replacement alternative with additional NOPs if it is
+ * additionally longer than the first replacement alternative.
+ */
+#define OLDINSTR_2(oldinstr, num1, num2) \
+ __OLDINSTR(oldinstr, num1) \
+ ".skip -(((" alt_rlen(num2) ")-(" alt_rlen(num1) ")-(662b-661b)) > 0) * " \
+ "((" alt_rlen(num2) ")-(" alt_rlen(num1) ")-(662b-661b)),0x90\n" \
+ alt_end_marker ":\n"
+
+#define ALTINSTR_ENTRY(feature, num) \
" .long 661b - .\n" /* label */ \
- " .long " b_replacement(number)"f - .\n" /* new instruction */ \
+ " .long " b_replacement(num)"f - .\n" /* new instruction */ \
" .word " __stringify(feature) "\n" /* feature bit */ \
- " .byte " alt_slen "\n" /* source len */ \
- " .byte " alt_rlen(number) "\n" /* replacement len */
+ " .byte " alt_total_slen "\n" /* source len */ \
+ " .byte " alt_rlen(num) "\n" /* replacement len */ \
+ " .byte " alt_pad_len "\n" /* pad len */
-#define DISCARD_ENTRY(number) /* rlen <= slen */ \
- " .byte 0xff + (" alt_rlen(number) ") - (" alt_slen ")\n"
-
-#define ALTINSTR_REPLACEMENT(newinstr, feature, number) /* replacement */ \
- b_replacement(number)":\n\t" newinstr "\n" e_replacement(number) ":\n\t"
+#define ALTINSTR_REPLACEMENT(newinstr, feature, num) /* replacement */ \
+ b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n\t"
/* alternative assembly primitive: */
#define ALTERNATIVE(oldinstr, newinstr, feature) \
- OLDINSTR(oldinstr) \
+ OLDINSTR(oldinstr, 1) \
".pushsection .altinstructions,\"a\"\n" \
ALTINSTR_ENTRY(feature, 1) \
".popsection\n" \
- ".pushsection .discard,\"aw\",@progbits\n" \
- DISCARD_ENTRY(1) \
- ".popsection\n" \
".pushsection .altinstr_replacement, \"ax\"\n" \
ALTINSTR_REPLACEMENT(newinstr, feature, 1) \
".popsection"
#define ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2)\
- OLDINSTR(oldinstr) \
+ OLDINSTR_2(oldinstr, 1, 2) \
".pushsection .altinstructions,\"a\"\n" \
ALTINSTR_ENTRY(feature1, 1) \
ALTINSTR_ENTRY(feature2, 2) \
".popsection\n" \
- ".pushsection .discard,\"aw\",@progbits\n" \
- DISCARD_ENTRY(1) \
- DISCARD_ENTRY(2) \
- ".popsection\n" \
".pushsection .altinstr_replacement, \"ax\"\n" \
ALTINSTR_REPLACEMENT(newinstr1, feature1, 1) \
ALTINSTR_REPLACEMENT(newinstr2, feature2, 2) \
@@ -146,6 +158,9 @@ static inline int alternatives_text_reserved(void *start, void *end)
#define alternative(oldinstr, newinstr, feature) \
asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) : : : "memory")
+#define alternative_2(oldinstr, newinstr1, feature1, newinstr2, feature2) \
+ asm volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2) ::: "memory")
+
/*
* Alternative inline assembly with input.
*
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 90a54851aedc..9b1df43dadbb 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -418,6 +418,7 @@ static __always_inline __pure bool __static_cpu_has(u16 bit)
" .word %P0\n" /* 1: do replace */
" .byte 2b - 1b\n" /* source len */
" .byte 0\n" /* replacement len */
+ " .byte 0\n" /* pad len */
".previous\n"
/* skipping size check since replacement size = 0 */
: : "i" (X86_FEATURE_ALWAYS) : : t_warn);
@@ -432,6 +433,7 @@ static __always_inline __pure bool __static_cpu_has(u16 bit)
" .word %P0\n" /* feature bit */
" .byte 2b - 1b\n" /* source len */
" .byte 0\n" /* replacement len */
+ " .byte 0\n" /* pad len */
".previous\n"
/* skipping size check since replacement size = 0 */
: : "i" (bit) : : t_no);
@@ -457,6 +459,7 @@ static __always_inline __pure bool __static_cpu_has(u16 bit)
" .word %P1\n" /* feature bit */
" .byte 2b - 1b\n" /* source len */
" .byte 4f - 3f\n" /* replacement len */
+ " .byte 0\n" /* pad len */
".previous\n"
".section .discard,\"aw\",@progbits\n"
" .byte 0xff + (4f-3f) - (2b-1b)\n" /* size check */
@@ -491,23 +494,28 @@ static __always_inline __pure bool _static_cpu_has_safe(u16 bit)
*/
asm_volatile_goto("1: .byte 0xe9\n .long %l[t_dynamic] - 2f\n"
"2:\n"
+ ".skip -(((5f-4f) - (2b-1b)) > 0) * "
+ "((5f-4f) - (2b-1b)),0x90\n"
+ "3:\n"
".section .altinstructions,\"a\"\n"
" .long 1b - .\n" /* src offset */
- " .long 3f - .\n" /* repl offset */
+ " .long 4f - .\n" /* repl offset */
" .word %P1\n" /* always replace */
- " .byte 2b - 1b\n" /* src len */
- " .byte 4f - 3f\n" /* repl len */
+ " .byte 3b - 1b\n" /* src len */
+ " .byte 5f - 4f\n" /* repl len */
+ " .byte 3b - 2b\n" /* pad len */
".previous\n"
".section .altinstr_replacement,\"ax\"\n"
- "3: .byte 0xe9\n .long %l[t_no] - 2b\n"
- "4:\n"
+ "4: .byte 0xe9\n .long %l[t_no] - 2b\n"
+ "5:\n"
".previous\n"
".section .altinstructions,\"a\"\n"
" .long 1b - .\n" /* src offset */
" .long 0\n" /* no replacement */
" .word %P0\n" /* feature bit */
- " .byte 2b - 1b\n" /* src len */
+ " .byte 3b - 1b\n" /* src len */
" .byte 0\n" /* repl len */
+ " .byte 0\n" /* pad len */
".previous\n"
: : "i" (bit), "i" (X86_FEATURE_ALWAYS)
: : t_dynamic, t_no);
@@ -527,6 +535,7 @@ static __always_inline __pure bool _static_cpu_has_safe(u16 bit)
" .word %P2\n" /* always replace */
" .byte 2b - 1b\n" /* source len */
" .byte 4f - 3f\n" /* replacement len */
+ " .byte 0\n" /* pad len */
".previous\n"
".section .discard,\"aw\",@progbits\n"
" .byte 0xff + (4f-3f) - (2b-1b)\n" /* size check */
@@ -541,6 +550,7 @@ static __always_inline __pure bool _static_cpu_has_safe(u16 bit)
" .word %P1\n" /* feature bit */
" .byte 4b - 3b\n" /* src len */
" .byte 6f - 5f\n" /* repl len */
+ " .byte 0\n" /* pad len */
".previous\n"
".section .discard,\"aw\",@progbits\n"
" .byte 0xff + (6f-5f) - (4b-3b)\n" /* size check */
diff --git a/arch/x86/include/asm/smap.h b/arch/x86/include/asm/smap.h
index 8d3120f4e270..c56cb4f37be9 100644
--- a/arch/x86/include/asm/smap.h
+++ b/arch/x86/include/asm/smap.h
@@ -33,7 +33,7 @@
662: __ASM_CLAC ; \
.popsection ; \
.pushsection .altinstructions, "a" ; \
- altinstruction_entry 661b, 662b, X86_FEATURE_SMAP, 3, 3 ; \
+ altinstruction_entry 661b, 662b, X86_FEATURE_SMAP, 3, 3, 0 ; \
.popsection
#define ASM_STAC \
@@ -42,7 +42,7 @@
662: __ASM_STAC ; \
.popsection ; \
.pushsection .altinstructions, "a" ; \
- altinstruction_entry 661b, 662b, X86_FEATURE_SMAP, 3, 3 ; \
+ altinstruction_entry 661b, 662b, X86_FEATURE_SMAP, 3, 3, 0 ; \
.popsection
#else /* CONFIG_X86_SMAP */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-11 00:27:54 +0000