These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / arch / arm64 / include / asm / alternative.h

diff --git a/kernel/arch/arm64/include/asm/alternative.h b/kernel/arch/arm64/include/asm/alternative.h
index d261f01..d56ec07 100644 (file)
--- a/kernel/arch/arm64/include/asm/alternative.h
+++ b/kernel/arch/arm64/include/asm/alternative.h
@@ -1,6 +1,10 @@
 #ifndef __ASM_ALTERNATIVE_H
 #define __ASM_ALTERNATIVE_H
 
+#ifndef __ASSEMBLY__
+
+#include <linux/init.h>
+#include <linux/kconfig.h>
 #include <linux/types.h>
 #include <linux/stddef.h>
 #include <linux/stringify.h>
@@ -13,7 +17,7 @@ struct alt_instr {
        u8  alt_len;            /* size of new instruction(s), <= orig_len */
 };
 
-void apply_alternatives_all(void);
+void __init apply_alternatives_all(void);
 void apply_alternatives(void *start, size_t length);
 void free_alternatives_memory(void);
 
@@ -24,8 +28,22 @@ void free_alternatives_memory(void);
        " .byte 662b-661b\n"                            /* source len      */ \
        " .byte 664f-663f\n"                            /* replacement len */
 
-/* alternative assembly primitive: */
-#define ALTERNATIVE(oldinstr, newinstr, feature)                       \
+/*
+ * alternative assembly primitive:
+ *
+ * If any of these .org directive fail, it means that insn1 and insn2
+ * don't have the same length. This used to be written as
+ *
+ * .if ((664b-663b) != (662b-661b))
+ *     .error "Alternatives instruction length mismatch"
+ * .endif
+ *
+ * but most assemblers die if insn1 or insn2 have a .inst. This should
+ * be fixed in a binutils release posterior to 2.25.51.0.2 (anything
+ * containing commit 4e4d08cf7399b606 or c1baaddf8861).
+ */
+#define __ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg_enabled)    \
+       ".if "__stringify(cfg_enabled)" == 1\n"                         \
        "661:\n\t"                                                      \
        oldinstr "\n"                                                   \
        "662:\n"                                                        \
@@ -37,8 +55,98 @@ void free_alternatives_memory(void);
        newinstr "\n"                                                   \
        "664:\n\t"                                                      \
        ".popsection\n\t"                                               \
-       ".if ((664b-663b) != (662b-661b))\n\t"                          \
-       "       .error \"Alternatives instruction length mismatch\"\n\t"\
+       ".org   . - (664b-663b) + (662b-661b)\n\t"                      \
+       ".org   . - (662b-661b) + (664b-663b)\n"                        \
        ".endif\n"
 
+#define _ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg, ...)        \
+       __ALTERNATIVE_CFG(oldinstr, newinstr, feature, IS_ENABLED(cfg))
+
+#else
+
+.macro altinstruction_entry orig_offset alt_offset feature orig_len alt_len
+       .word \orig_offset - .
+       .word \alt_offset - .
+       .hword \feature
+       .byte \orig_len
+       .byte \alt_len
+.endm
+
+.macro alternative_insn insn1, insn2, cap, enable = 1
+       .if \enable
+661:   \insn1
+662:   .pushsection .altinstructions, "a"
+       altinstruction_entry 661b, 663f, \cap, 662b-661b, 664f-663f
+       .popsection
+       .pushsection .altinstr_replacement, "ax"
+663:   \insn2
+664:   .popsection
+       .org    . - (664b-663b) + (662b-661b)
+       .org    . - (662b-661b) + (664b-663b)
+       .endif
+.endm
+
+/*
+ * Begin an alternative code sequence.
+ *
+ * The code that follows this macro will be assembled and linked as
+ * normal. There are no restrictions on this code.
+ */
+.macro alternative_if_not cap, enable = 1
+       .if \enable
+       .pushsection .altinstructions, "a"
+       altinstruction_entry 661f, 663f, \cap, 662f-661f, 664f-663f
+       .popsection
+661:
+       .endif
+.endm
+
+/*
+ * Provide the alternative code sequence.
+ *
+ * The code that follows this macro is assembled into a special
+ * section to be used for dynamic patching. Code that follows this
+ * macro must:
+ *
+ * 1. Be exactly the same length (in bytes) as the default code
+ *    sequence.
+ *
+ * 2. Not contain a branch target that is used outside of the
+ *    alternative sequence it is defined in (branches into an
+ *    alternative sequence are not fixed up).
+ */
+.macro alternative_else, enable = 1
+       .if \enable
+662:   .pushsection .altinstr_replacement, "ax"
+663:
+       .endif
+.endm
+
+/*
+ * Complete an alternative code sequence.
+ */
+.macro alternative_endif, enable = 1
+       .if \enable
+664:   .popsection
+       .org    . - (664b-663b) + (662b-661b)
+       .org    . - (662b-661b) + (664b-663b)
+       .endif
+.endm
+
+#define _ALTERNATIVE_CFG(insn1, insn2, cap, cfg, ...)  \
+       alternative_insn insn1, insn2, cap, IS_ENABLED(cfg)
+
+
+#endif  /*  __ASSEMBLY__  */
+
+/*
+ * Usage: asm(ALTERNATIVE(oldinstr, newinstr, feature));
+ *
+ * Usage: asm(ALTERNATIVE(oldinstr, newinstr, feature, CONFIG_FOO));
+ * N.B. If CONFIG_FOO is specified, but not selected, the whole block
+ *      will be omitted, including oldinstr.
+ */
+#define ALTERNATIVE(oldinstr, newinstr, ...)   \
+       _ALTERNATIVE_CFG(oldinstr, newinstr, __VA_ARGS__, 1)
+
 #endif /* __ASM_ALTERNATIVE_H */