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-rw-r--r--arch/powerpc/xmon/spr_access.S47
1 files changed, 47 insertions, 0 deletions
diff --git a/arch/powerpc/xmon/spr_access.S b/arch/powerpc/xmon/spr_access.S
new file mode 100644
index 0000000000..c308ddf268
--- /dev/null
+++ b/arch/powerpc/xmon/spr_access.S
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <asm/ppc_asm.h>
+#include <asm/asm-compat.h>
+
+/* unsigned long xmon_mfspr(sprn, default_value) */
+_GLOBAL(xmon_mfspr)
+ LOAD_REG_ADDR(r5, .Lmfspr_table)
+ b xmon_mxspr
+
+/* void xmon_mtspr(sprn, new_value) */
+_GLOBAL(xmon_mtspr)
+ LOAD_REG_ADDR(r5, .Lmtspr_table)
+ b xmon_mxspr
+
+/*
+ * r3 = sprn
+ * r4 = default or new value
+ * r5 = table base
+ */
+xmon_mxspr:
+ /*
+ * To index into the table of mxsprs we need:
+ * i = (sprn & 0x3ff) * 8
+ * or using rwlinm:
+ * i = (sprn << 3) & (0x3ff << 3)
+ */
+ rlwinm r3, r3, 3, 0x3ff << 3
+ add r5, r5, r3
+ mtctr r5
+ mr r3, r4 /* put default_value in r3 for mfspr */
+ bctr
+
+.Lmfspr_table:
+ spr = 0
+ .rept 1024
+ mfspr r3, spr
+ blr
+ spr = spr + 1
+ .endr
+
+.Lmtspr_table:
+ spr = 0
+ .rept 1024
+ mtspr spr, r4
+ blr
+ spr = spr + 1
+ .endr