diff options
| author | Michael Clark <mjc@sifive.com> | 2018-03-06 10:33:31 +1300 |
|---|---|---|
| committer | Michael Clark <mjc@sifive.com> | 2018-05-06 10:39:38 +1200 |
| commit | b8643bd6084be1787a6dc8768a7a1983921fc945 (patch) | |
| tree | 89d854a5e83b6aad4e7656604ccad89a29d169a5 /target/riscv/op_helper.c | |
| parent | 1d1ee55274860bfcc511d50d83c84394c2685ba8 (diff) | |
RISC-V: No traps on writes to misa,minstret,mcycle
These fields are marked WARL (Write Any Values, Reads
Legal Values) in the RISC-V Privileged Architecture
Specification so instead of raising exceptions,
illegal writes are silently dropped.
Cc: Sagar Karandikar <sagark@eecs.berkeley.edu>
Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Alistair Francis <Alistair.Francis@wdc.com>
Signed-off-by: Michael Clark <mjc@sifive.com>
Diffstat (limited to 'target/riscv/op_helper.c')
| -rw-r--r-- | target/riscv/op_helper.c | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c index af0c52a484..3abf52453c 100644 --- a/target/riscv/op_helper.c +++ b/target/riscv/op_helper.c @@ -213,17 +213,19 @@ void csr_write_helper(CPURISCVState *env, target_ulong val_to_write, break; } case CSR_MINSTRET: - qemu_log_mask(LOG_UNIMP, "CSR_MINSTRET: write not implemented"); - goto do_illegal; + /* minstret is WARL so unsupported writes are ignored */ + break; case CSR_MCYCLE: - qemu_log_mask(LOG_UNIMP, "CSR_MCYCLE: write not implemented"); - goto do_illegal; + /* mcycle is WARL so unsupported writes are ignored */ + break; +#if defined(TARGET_RISCV32) case CSR_MINSTRETH: - qemu_log_mask(LOG_UNIMP, "CSR_MINSTRETH: write not implemented"); - goto do_illegal; + /* minstreth is WARL so unsupported writes are ignored */ + break; case CSR_MCYCLEH: - qemu_log_mask(LOG_UNIMP, "CSR_MCYCLEH: write not implemented"); - goto do_illegal; + /* mcycleh is WARL so unsupported writes are ignored */ + break; +#endif case CSR_MUCOUNTEREN: if (env->priv_ver <= PRIV_VERSION_1_09_1) { env->scounteren = val_to_write; @@ -337,10 +339,9 @@ void csr_write_helper(CPURISCVState *env, target_ulong val_to_write, case CSR_MBADADDR: env->mbadaddr = val_to_write; break; - case CSR_MISA: { - qemu_log_mask(LOG_UNIMP, "CSR_MISA: misa writes not supported"); - goto do_illegal; - } + case CSR_MISA: + /* misa is WARL so unsupported writes are ignored */ + break; case CSR_PMPCFG0: case CSR_PMPCFG1: case CSR_PMPCFG2: |