riscv-trap-handling: Add preliminary trap handling for riscv

RISCV requires a trap handler at the machine stage to deal with
misaligned loads/stores, as well as to deal with calls that a linux
payload will make in its setup. Put required assembly for jumping
into and out of a trap here to be set up by the bootblock in a later
commit.

Change-Id: Ibf6b18e477aaa1c415a31dbeffa50a2470a7ab2e
Signed-off-by: Thaminda Edirisooriya <thaminda@google.com>
Reviewed-on: http://review.coreboot.org/11367
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Tested-by: build bot (Jenkins)

1 files changed, 57 insertions, 0 deletions

diff --git a/src/arch/riscv/include/bits.h b/src/arch/riscv/include/bits.h
new file mode 100644
index 0000000000..f69c7ec0da
--- /dev/null
+++ b/src/arch/riscv/include/bits.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2013, The Regents of the University of California (Regents).
+ * All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the Regents nor the
+ * names of its contributors may be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
+ * SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING
+ * OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS
+ * BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED
+ * HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE
+ * MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ */
+
+#ifndef _BITS_H
+#define _BITS_H
+
+#define CONST_POPCOUNT2(x) ((((x) >> 0) & 1) + (((x) >> 1) & 1))
+#define CONST_POPCOUNT4(x) (CONST_POPCOUNT2(x) + CONST_POPCOUNT2((x)>>2))
+#define CONST_POPCOUNT8(x) (CONST_POPCOUNT4(x) + CONST_POPCOUNT4((x)>>4))
+#define CONST_POPCOUNT16(x) (CONST_POPCOUNT8(x) + CONST_POPCOUNT8((x)>>8))
+#define CONST_POPCOUNT32(x) (CONST_POPCOUNT16(x) + CONST_POPCOUNT16((x)>>16))
+#define CONST_POPCOUNT64(x) (CONST_POPCOUNT32(x) + CONST_POPCOUNT32((x)>>32))
+#define CONST_POPCOUNT(x) CONST_POPCOUNT64(x)
+
+#define CONST_CTZ2(x) CONST_POPCOUNT2(((x) & -(x))-1)
+#define CONST_CTZ4(x) CONST_POPCOUNT4(((x) & -(x))-1)
+#define CONST_CTZ8(x) CONST_POPCOUNT8(((x) & -(x))-1)
+#define CONST_CTZ16(x) CONST_POPCOUNT16(((x) & -(x))-1)
+#define CONST_CTZ32(x) CONST_POPCOUNT32(((x) & -(x))-1)
+#define CONST_CTZ64(x) CONST_POPCOUNT64(((x) & -(x))-1)
+#define CONST_CTZ(x) CONST_CTZ64(x)
+
+#define STR(x) XSTR(x)
+#define XSTR(x) #x
+
+# define SLL32    sllw
+# define STORE    sd
+# define LOAD     ld
+# define LOG_REGBYTES 3
+
+#define REGBYTES (1 << LOG_REGBYTES)
+
+#endif