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Diffstat (limited to 'arch/x86/include/asm/alternative.h')
-rw-r--r--arch/x86/include/asm/alternative.h137
1 files changed, 102 insertions, 35 deletions
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 69b74a7b877..0a3f9c9f98d 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -5,6 +5,7 @@
#include <linux/stddef.h>
#include <linux/stringify.h>
#include <asm/asm.h>
+#include <asm/ptrace.h>
/*
* Alternative inline assembly for SMP.
@@ -28,30 +29,26 @@
*/
#ifdef CONFIG_SMP
-#define LOCK_PREFIX \
- ".section .smp_locks,\"a\"\n" \
- _ASM_ALIGN "\n" \
- _ASM_PTR "661f\n" /* address */ \
- ".previous\n" \
- "661:\n\tlock; "
+#define LOCK_PREFIX_HERE \
+ ".pushsection .smp_locks,\"a\"\n" \
+ ".balign 4\n" \
+ ".long 671f - .\n" /* offset */ \
+ ".popsection\n" \
+ "671:"
+
+#define LOCK_PREFIX LOCK_PREFIX_HERE "\n\tlock; "
#else /* ! CONFIG_SMP */
+#define LOCK_PREFIX_HERE ""
#define LOCK_PREFIX ""
#endif
-/* This must be included *after* the definition of LOCK_PREFIX */
-#include <asm/cpufeature.h>
-
struct alt_instr {
- u8 *instr; /* original instruction */
- u8 *replacement;
- u8 cpuid; /* cpuid bit set for replacement */
+ s32 instr_offset; /* original instruction */
+ 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 pad1;
-#ifdef CONFIG_X86_64
- u32 pad2;
-#endif
};
extern void alternative_instructions(void);
@@ -64,31 +61,75 @@ extern void alternatives_smp_module_add(struct module *mod, char *name,
void *locks, void *locks_end,
void *text, void *text_end);
extern void alternatives_smp_module_del(struct module *mod);
-extern void alternatives_smp_switch(int smp);
+extern void alternatives_enable_smp(void);
+extern int alternatives_text_reserved(void *start, void *end);
+extern bool skip_smp_alternatives;
#else
static inline void alternatives_smp_module_add(struct module *mod, char *name,
void *locks, void *locks_end,
void *text, void *text_end) {}
static inline void alternatives_smp_module_del(struct module *mod) {}
-static inline void alternatives_smp_switch(int smp) {}
+static inline void alternatives_enable_smp(void) {}
+static inline int alternatives_text_reserved(void *start, void *end)
+{
+ return 0;
+}
#endif /* CONFIG_SMP */
+#define OLDINSTR(oldinstr) "661:\n\t" oldinstr "\n662:\n"
+
+#define b_replacement(number) "663"#number
+#define e_replacement(number) "664"#number
+
+#define alt_slen "662b-661b"
+#define alt_rlen(number) e_replacement(number)"f-"b_replacement(number)"f"
+
+#define ALTINSTR_ENTRY(feature, number) \
+ " .long 661b - .\n" /* label */ \
+ " .long " b_replacement(number)"f - .\n" /* new instruction */ \
+ " .word " __stringify(feature) "\n" /* feature bit */ \
+ " .byte " alt_slen "\n" /* source len */ \
+ " .byte " alt_rlen(number) "\n" /* replacement 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"
+
/* alternative assembly primitive: */
#define ALTERNATIVE(oldinstr, newinstr, feature) \
- \
- "661:\n\t" oldinstr "\n662:\n" \
- ".section .altinstructions,\"a\"\n" \
- _ASM_ALIGN "\n" \
- _ASM_PTR "661b\n" /* label */ \
- _ASM_PTR "663f\n" /* new instruction */ \
- " .byte " __stringify(feature) "\n" /* feature bit */ \
- " .byte 662b-661b\n" /* sourcelen */ \
- " .byte 664f-663f\n" /* replacementlen */ \
- " .byte 0xff + (664f-663f) - (662b-661b)\n" /* rlen <= slen */ \
- ".previous\n" \
- ".section .altinstr_replacement, \"ax\"\n" \
- "663:\n\t" newinstr "\n664:\n" /* replacement */ \
- ".previous"
+ OLDINSTR(oldinstr) \
+ ".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) \
+ ".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) \
+ ".popsection"
+
+/*
+ * This must be included *after* the definition of ALTERNATIVE due to
+ * <asm/arch_hweight.h>
+ */
+#include <asm/cpufeature.h>
/*
* Alternative instructions for different CPU types or capabilities.
@@ -125,11 +166,35 @@ static inline void alternatives_smp_switch(int smp) {}
asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
: output : "i" (0), ## input)
+/* Like alternative_io, but for replacing a direct call with another one. */
+#define alternative_call(oldfunc, newfunc, feature, output, input...) \
+ asm volatile (ALTERNATIVE("call %P[old]", "call %P[new]", feature) \
+ : output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
+
+/*
+ * Like alternative_call, but there are two features and respective functions.
+ * If CPU has feature2, function2 is used.
+ * Otherwise, if CPU has feature1, function1 is used.
+ * Otherwise, old function is used.
+ */
+#define alternative_call_2(oldfunc, newfunc1, feature1, newfunc2, feature2, \
+ output, input...) \
+ asm volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", feature1,\
+ "call %P[new2]", feature2) \
+ : output : [old] "i" (oldfunc), [new1] "i" (newfunc1), \
+ [new2] "i" (newfunc2), ## input)
+
/*
* use this macro(s) if you need more than one output parameter
* in alternative_io
*/
-#define ASM_OUTPUT2(a, b) a, b
+#define ASM_OUTPUT2(a...) a
+
+/*
+ * use this macro if you need clobbers but no inputs in
+ * alternative_{input,io,call}()
+ */
+#define ASM_NO_INPUT_CLOBBER(clbr...) "i" (0) : clbr
struct paravirt_patch_site;
#ifdef CONFIG_PARAVIRT
@@ -143,6 +208,8 @@ static inline void apply_paravirt(struct paravirt_patch_site *start,
#define __parainstructions_end NULL
#endif
+extern void *text_poke_early(void *addr, const void *opcode, size_t len);
+
/*
* Clear and restore the kernel write-protection flag on the local CPU.
* Allows the kernel to edit read-only pages.
@@ -154,11 +221,11 @@ static inline void apply_paravirt(struct paravirt_patch_site *start,
* no thread can be preempted in the instructions being modified (no iret to an
* invalid instruction possible) or if the instructions are changed from a
* consistent state to another consistent state atomically.
- * More care must be taken when modifying code in the SMP case because of
- * Intel's errata.
* On the local CPU you need to be protected again NMI or MCE handlers seeing an
* inconsistent instruction while you patch.
*/
extern void *text_poke(void *addr, const void *opcode, size_t len);
+extern int poke_int3_handler(struct pt_regs *regs);
+extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
#endif /* _ASM_X86_ALTERNATIVE_H */
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-09 07:02:14 +0000