It was found that running libquantum on riscv-linux qemu produced an
incorrect result. After investigation, FP registers are not saved
during context switch due to incorrect mstatus.FS.
In current implementation tb->flags merges all non-disabled state to
dirty. This means the code in mark_fs_dirty in translate.c that
handles initial and clean states is unreachable.
This patch fixes it and is successfully tested with:
libquantum
Thanks to Richard for pointing out the actual bug.
Suggested-by: Richard Henderson <richard.hender...@linaro.org>
Signed-off-by: ShihPo Hung <shihpo.h...@sifive.com>
---
target/riscv/cpu.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index e59343e..f0ff57e 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -295,7 +295,7 @@ static inline void cpu_get_tb_cpu_state(CPURISCVState *env,
target_ulong *pc,
#else
*flags = cpu_mmu_index(env, 0);
if (riscv_cpu_fp_enabled(env)) {
- *flags |= TB_FLAGS_MSTATUS_FS;
+ *flags |= env->mstatus & MSTATUS_FS;
}
#endif
}
--
2.7.4
