rseq/selftests: Add support for RISC-V

Add support for RISC-V in the rseq selftests, which covers both
64-bit and 32-bit ISA with little endian mode.

Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Tested-by: Eric Lin <eric.lin@sifive.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Author: VincentZWC

tools/testing/selftests/rseq/param_test.c

@@ -207,6 +207,29 @@ unsigned int yield_mod_cnt, nr_abort;
 	"addiu " INJECT_ASM_REG ", -1\n\t" \
 	"bnez " INJECT_ASM_REG ", 222b\n\t" \
 	"333:\n\t"
+#elif defined(__riscv)
+
+#define RSEQ_INJECT_INPUT \
+	, [loop_cnt_1]"m"(loop_cnt[1]) \
+	, [loop_cnt_2]"m"(loop_cnt[2]) \
+	, [loop_cnt_3]"m"(loop_cnt[3]) \
+	, [loop_cnt_4]"m"(loop_cnt[4]) \
+	, [loop_cnt_5]"m"(loop_cnt[5]) \
+	, [loop_cnt_6]"m"(loop_cnt[6])
+
+#define INJECT_ASM_REG	"t1"
+
+#define RSEQ_INJECT_CLOBBER \
+	, INJECT_ASM_REG
+
+#define RSEQ_INJECT_ASM(n)					\
+	"lw " INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t"		\
+	"beqz " INJECT_ASM_REG ", 333f\n\t"			\
+	"222:\n\t"						\
+	"addi  " INJECT_ASM_REG "," INJECT_ASM_REG ", -1\n\t"	\
+	"bnez " INJECT_ASM_REG ", 222b\n\t"			\
+	"333:\n\t"
+
 
 #else
 #error unsupported target