riscv: Add setjmp/longjmp code
To support efi_loader we need to have platform support for setjmp/longjmp.
Add it here.
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/riscv/lib/setjmp.S b/arch/riscv/lib/setjmp.S
new file mode 100644
index 0000000..103f359
--- /dev/null
+++ b/arch/riscv/lib/setjmp.S
@@ -0,0 +1,66 @@
+/*
+ * (C) 2018 Alexander Graf <agraf@suse.de>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <config.h>
+#include <linux/linkage.h>
+
+#ifdef CONFIG_CPU_RISCV_64
+#define STORE_IDX(reg, idx) sd reg, (idx*8)(a0)
+#define LOAD_IDX(reg, idx) ld reg, (idx*8)(a0)
+#else
+#define STORE_IDX(reg, idx) sw reg, (idx*4)(a0)
+#define LOAD_IDX(reg, idx) lw reg, (idx*4)(a0)
+#endif
+
+.pushsection .text.setjmp, "ax"
+ENTRY(setjmp)
+ /* Preserve all callee-saved registers and the SP */
+ STORE_IDX(s0, 0)
+ STORE_IDX(s1, 1)
+ STORE_IDX(s2, 2)
+ STORE_IDX(s3, 3)
+ STORE_IDX(s4, 4)
+ STORE_IDX(s5, 5)
+ STORE_IDX(s6, 6)
+ STORE_IDX(s7, 7)
+ STORE_IDX(s8, 8)
+ STORE_IDX(s9, 9)
+ STORE_IDX(s10, 10)
+ STORE_IDX(s11, 11)
+ STORE_IDX(ra, 12)
+ STORE_IDX(sp, 13)
+ li a0, 0
+ ret
+ENDPROC(setjmp)
+.popsection
+
+.pushsection .text.longjmp, "ax"
+ENTRY(longjmp)
+ LOAD_IDX(s0, 0)
+ LOAD_IDX(s1, 1)
+ LOAD_IDX(s2, 2)
+ LOAD_IDX(s3, 3)
+ LOAD_IDX(s4, 4)
+ LOAD_IDX(s5, 5)
+ LOAD_IDX(s6, 6)
+ LOAD_IDX(s7, 7)
+ LOAD_IDX(s8, 8)
+ LOAD_IDX(s9, 9)
+ LOAD_IDX(s10, 10)
+ LOAD_IDX(s11, 11)
+ LOAD_IDX(ra, 12)
+ LOAD_IDX(sp, 13)
+
+ /* Move the return value in place, but return 1 if passed 0. */
+ beq a1, zero, longjmp_1
+ mv a0, a1
+ ret
+
+ longjmp_1:
+ li a0, 1
+ ret
+ENDPROC(longjmp)
+.popsection