sparc32: add support for run-time patching of leon/sun single instructions

This will be used to handle that MMUREGS has different ASI for SUN and LEON.
This is the infrastructure only - users will come later.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Daniel Hellstrom <daniel@gaisler.com>
Cc: Konrad Eisele <konrad@gaisler.com>

arch/sparc/include/asm/asmmacro.h

@@ -20,4 +20,26 @@
 /* All traps low-level code here must end with this macro. */
 #define RESTORE_ALL b ret_trap_entry; clr %l6;
 
+/* Support for run-time patching of single instructions.
+ * This is used to handle the differences in the ASI for
+ * MMUREGS for LEON and SUN.
+ *
+ * Sample:
+ * LEON_PI(lda [%g0] ASI_LEON_MMUREGS, %o0
+ * SUN_PI_(lda [%g0] ASI_M_MMUREGS, %o0
+ * PI == Patch Instruction
+ *
+ * For LEON we will use the first variant,
+ * and for all other we will use the SUN variant.
+ * The order is important.
+ */
+#define LEON_PI(...)				\
+662:	__VA_ARGS__
+
+#define SUN_PI_(...)				\
+	.section .leon_1insn_patch, "ax";	\
+	.word 662b;				\
+	__VA_ARGS__;				\
+	.previous
+
 #endif /* !(_SPARC_ASMMACRO_H) */

arch/sparc/include/asm/sections.h

@@ -7,4 +7,7 @@
 /* sparc entry point */
 extern char _start[];
 
+extern char __leon_1insn_patch[];
+extern char __leon_1insn_patch_end[];
+
 #endif