45 lines
1.5 KiB
Diff
45 lines
1.5 KiB
Diff
From: ShihPo Hung <shihpo.hung@sifive.com>
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Date: Tue, 14 Jan 2020 22:17:31 -0800
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Subject: [PATCH] target/riscv: Fix tb->flags FS status
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It was found that running libquantum on riscv-linux qemu produced an
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incorrect result. After investigation, FP registers are not saved
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during context switch due to incorrect mstatus.FS.
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In current implementation tb->flags merges all non-disabled state to
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dirty. This means the code in mark_fs_dirty in translate.c that
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handles initial and clean states is unreachable.
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This patch fixes it and is successfully tested with:
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libquantum
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Thanks to Richard for pointing out the actual bug.
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v3: remove the redundant condition
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v2: root cause FS problem
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Suggested-by: Richard Henderson <richard.henderson@linaro.org>
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Signed-off-by: ShihPo Hung <shihpo.hung@sifive.com>
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Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
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Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
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---
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target/riscv/cpu.h | 5 +----
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1 file changed, 1 insertion(+), 4 deletions(-)
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diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
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index e59343e13c..de0a8d893a 100644
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--- a/target/riscv/cpu.h
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+++ b/target/riscv/cpu.h
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@@ -293,10 +293,7 @@ static inline void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc,
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#ifdef CONFIG_USER_ONLY
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*flags = TB_FLAGS_MSTATUS_FS;
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#else
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- *flags = cpu_mmu_index(env, 0);
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- if (riscv_cpu_fp_enabled(env)) {
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- *flags |= TB_FLAGS_MSTATUS_FS;
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- }
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+ *flags = cpu_mmu_index(env, 0) | (env->mstatus & MSTATUS_FS);
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#endif
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}
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