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-rw-r--r--arch/riscv/include/asm/alternative-macros.h205
1 files changed, 205 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/alternative-macros.h b/arch/riscv/include/asm/alternative-macros.h
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index 000000000..ec2f3f1b8
--- /dev/null
+++ b/arch/riscv/include/asm/alternative-macros.h
@@ -0,0 +1,205 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_ALTERNATIVE_MACROS_H
+#define __ASM_ALTERNATIVE_MACROS_H
+
+#ifdef CONFIG_RISCV_ALTERNATIVE
+
+#ifdef __ASSEMBLY__
+
+.macro ALT_ENTRY oldptr newptr vendor_id errata_id new_len
+ RISCV_PTR \oldptr
+ RISCV_PTR \newptr
+ REG_ASM \vendor_id
+ REG_ASM \new_len
+ .word \errata_id
+.endm
+
+.macro ALT_NEW_CONTENT vendor_id, errata_id, enable = 1, new_c : vararg
+ .if \enable
+ .pushsection .alternative, "a"
+ ALT_ENTRY 886b, 888f, \vendor_id, \errata_id, 889f - 888f
+ .popsection
+ .subsection 1
+888 :
+ .option push
+ .option norvc
+ .option norelax
+ \new_c
+ .option pop
+889 :
+ .org . - (889b - 888b) + (887b - 886b)
+ .org . - (887b - 886b) + (889b - 888b)
+ .previous
+ .endif
+.endm
+
+.macro __ALTERNATIVE_CFG old_c, new_c, vendor_id, errata_id, enable
+886 :
+ .option push
+ .option norvc
+ .option norelax
+ \old_c
+ .option pop
+887 :
+ ALT_NEW_CONTENT \vendor_id, \errata_id, \enable, \new_c
+.endm
+
+#define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, CONFIG_k) \
+ __ALTERNATIVE_CFG old_c, new_c, vendor_id, errata_id, IS_ENABLED(CONFIG_k)
+
+.macro __ALTERNATIVE_CFG_2 old_c, new_c_1, vendor_id_1, errata_id_1, enable_1, \
+ new_c_2, vendor_id_2, errata_id_2, enable_2
+886 :
+ .option push
+ .option norvc
+ .option norelax
+ \old_c
+ .option pop
+887 :
+ ALT_NEW_CONTENT \vendor_id_1, \errata_id_1, \enable_1, \new_c_1
+ ALT_NEW_CONTENT \vendor_id_2, \errata_id_2, \enable_2, \new_c_2
+.endm
+
+#define _ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, \
+ CONFIG_k_1, \
+ new_c_2, vendor_id_2, errata_id_2, \
+ CONFIG_k_2) \
+ __ALTERNATIVE_CFG_2 old_c, new_c_1, vendor_id_1, errata_id_1, \
+ IS_ENABLED(CONFIG_k_1), \
+ new_c_2, vendor_id_2, errata_id_2, \
+ IS_ENABLED(CONFIG_k_2)
+
+#else /* !__ASSEMBLY__ */
+
+#include <asm/asm.h>
+#include <linux/stringify.h>
+
+#define ALT_ENTRY(oldptr, newptr, vendor_id, errata_id, newlen) \
+ RISCV_PTR " " oldptr "\n" \
+ RISCV_PTR " " newptr "\n" \
+ REG_ASM " " vendor_id "\n" \
+ REG_ASM " " newlen "\n" \
+ ".word " errata_id "\n"
+
+#define ALT_NEW_CONTENT(vendor_id, errata_id, enable, new_c) \
+ ".if " __stringify(enable) " == 1\n" \
+ ".pushsection .alternative, \"a\"\n" \
+ ALT_ENTRY("886b", "888f", __stringify(vendor_id), __stringify(errata_id), "889f - 888f") \
+ ".popsection\n" \
+ ".subsection 1\n" \
+ "888 :\n" \
+ ".option push\n" \
+ ".option norvc\n" \
+ ".option norelax\n" \
+ new_c "\n" \
+ ".option pop\n" \
+ "889 :\n" \
+ ".org . - (887b - 886b) + (889b - 888b)\n" \
+ ".org . - (889b - 888b) + (887b - 886b)\n" \
+ ".previous\n" \
+ ".endif\n"
+
+#define __ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, enable) \
+ "886 :\n" \
+ ".option push\n" \
+ ".option norvc\n" \
+ ".option norelax\n" \
+ old_c "\n" \
+ ".option pop\n" \
+ "887 :\n" \
+ ALT_NEW_CONTENT(vendor_id, errata_id, enable, new_c)
+
+#define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, CONFIG_k) \
+ __ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, IS_ENABLED(CONFIG_k))
+
+#define __ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, \
+ enable_1, \
+ new_c_2, vendor_id_2, errata_id_2, \
+ enable_2) \
+ "886 :\n" \
+ ".option push\n" \
+ ".option norvc\n" \
+ ".option norelax\n" \
+ old_c "\n" \
+ ".option pop\n" \
+ "887 :\n" \
+ ALT_NEW_CONTENT(vendor_id_1, errata_id_1, enable_1, new_c_1) \
+ ALT_NEW_CONTENT(vendor_id_2, errata_id_2, enable_2, new_c_2)
+
+#define _ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, \
+ CONFIG_k_1, \
+ new_c_2, vendor_id_2, errata_id_2, \
+ CONFIG_k_2) \
+ __ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, \
+ IS_ENABLED(CONFIG_k_1), \
+ new_c_2, vendor_id_2, errata_id_2, \
+ IS_ENABLED(CONFIG_k_2))
+
+#endif /* __ASSEMBLY__ */
+
+#else /* CONFIG_RISCV_ALTERNATIVE */
+#ifdef __ASSEMBLY__
+
+.macro __ALTERNATIVE_CFG old_c
+ \old_c
+.endm
+
+#define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, CONFIG_k) \
+ __ALTERNATIVE_CFG old_c
+
+#define _ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, \
+ CONFIG_k_1, \
+ new_c_2, vendor_id_2, errata_id_2, \
+ CONFIG_k_2) \
+ __ALTERNATIVE_CFG old_c
+
+#else /* !__ASSEMBLY__ */
+
+#define __ALTERNATIVE_CFG(old_c) \
+ old_c "\n"
+
+#define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, CONFIG_k) \
+ __ALTERNATIVE_CFG(old_c)
+
+#define _ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, \
+ CONFIG_k_1, \
+ new_c_2, vendor_id_2, errata_id_2, \
+ CONFIG_k_2) \
+ __ALTERNATIVE_CFG(old_c)
+
+#endif /* __ASSEMBLY__ */
+#endif /* CONFIG_RISCV_ALTERNATIVE */
+
+/*
+ * Usage:
+ * ALTERNATIVE(old_content, new_content, vendor_id, errata_id, CONFIG_k)
+ * in the assembly code. Otherwise,
+ * asm(ALTERNATIVE(old_content, new_content, vendor_id, errata_id, CONFIG_k));
+ *
+ * old_content: The old content which is probably replaced with new content.
+ * new_content: The new content.
+ * vendor_id: The CPU vendor ID.
+ * errata_id: The errata ID.
+ * CONFIG_k: The Kconfig of this errata. When Kconfig is disabled, the old
+ * content will alwyas be executed.
+ */
+#define ALTERNATIVE(old_content, new_content, vendor_id, errata_id, CONFIG_k) \
+ _ALTERNATIVE_CFG(old_content, new_content, vendor_id, errata_id, CONFIG_k)
+
+/*
+ * A vendor wants to replace an old_content, but another vendor has used
+ * ALTERNATIVE() to patch its customized content at the same location. In
+ * this case, this vendor can create a new macro ALTERNATIVE_2() based
+ * on the following sample code and then replace ALTERNATIVE() with
+ * ALTERNATIVE_2() to append its customized content.
+ */
+#define ALTERNATIVE_2(old_content, new_content_1, vendor_id_1, \
+ errata_id_1, CONFIG_k_1, \
+ new_content_2, vendor_id_2, \
+ errata_id_2, CONFIG_k_2) \
+ _ALTERNATIVE_CFG_2(old_content, new_content_1, vendor_id_1, \
+ errata_id_1, CONFIG_k_1, \
+ new_content_2, vendor_id_2, \
+ errata_id_2, CONFIG_k_2)
+
+#endif
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