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[Qemu-devel] [PATCH v8 16/35] RISC-V: Make mtvec/stvec ignore vectored t
From: |
Michael Clark |
Subject: |
[Qemu-devel] [PATCH v8 16/35] RISC-V: Make mtvec/stvec ignore vectored traps |
Date: |
Thu, 26 Apr 2018 11:45:19 +1200 |
Vectored traps for asynchrounous interrupts are optional.
The mtvec/stvec mode field is WARL and hence does not trap
if an illegal value is written. Illegal values are ignored.
Later we can add RISCV_FEATURE_VECTORED_TRAPS however
until then the correct behavior for WARL (Write Any, Read
Legal) fields is to drop writes to unsupported bits.
Cc: Sagar Karandikar <address@hidden>
Cc: Bastian Koppelmann <address@hidden>
Cc: Palmer Dabbelt <address@hidden>
Cc: Alistair Francis <address@hidden>
Signed-off-by: Michael Clark <address@hidden>
---
target/riscv/op_helper.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
index 101dac1..828f20c 100644
--- a/target/riscv/op_helper.c
+++ b/target/riscv/op_helper.c
@@ -276,11 +276,10 @@ void csr_write_helper(CPURISCVState *env, target_ulong
val_to_write,
env->sepc = val_to_write;
break;
case CSR_STVEC:
- if (val_to_write & 1) {
- qemu_log_mask(LOG_UNIMP, "CSR_STVEC: vectored traps not
supported");
- goto do_illegal;
+ /* we do not support vectored traps for asynchrounous interrupts */
+ if ((val_to_write & 3) == 0) {
+ env->stvec = val_to_write >> 2 << 2;
}
- env->stvec = val_to_write >> 2 << 2;
break;
case CSR_SCOUNTEREN:
env->scounteren = val_to_write;
@@ -298,11 +297,10 @@ void csr_write_helper(CPURISCVState *env, target_ulong
val_to_write,
env->mepc = val_to_write;
break;
case CSR_MTVEC:
- if (val_to_write & 1) {
- qemu_log_mask(LOG_UNIMP, "CSR_MTVEC: vectored traps not
supported");
- goto do_illegal;
+ /* we do not support vectored traps for asynchrounous interrupts */
+ if ((val_to_write & 3) == 0) {
+ env->mtvec = val_to_write >> 2 << 2;
}
- env->mtvec = val_to_write >> 2 << 2;
break;
case CSR_MCOUNTEREN:
env->mcounteren = val_to_write;
--
2.7.0
- Re: [Qemu-devel] [patches] [PATCH v8 10/35] RISC-V: Remove erroneous comment from translate.c, (continued)
- [Qemu-devel] [PATCH v8 12/35] RISC-V: Update address bits to support sv39 and sv48, Michael Clark, 2018/04/25
- [Qemu-devel] [PATCH v8 11/35] RISC-V: Mark ROM read-only after copying in code, Michael Clark, 2018/04/25
- [Qemu-devel] [PATCH v8 13/35] RISC-V: Improve page table walker spec compliance, Michael Clark, 2018/04/25
- [Qemu-devel] [PATCH v8 14/35] RISC-V: Update E order and I extension order, Michael Clark, 2018/04/25
- [Qemu-devel] [PATCH v8 15/35] RISC-V: Hardwire satp to 0 for no-mmu case, Michael Clark, 2018/04/25
- [Qemu-devel] [PATCH v8 16/35] RISC-V: Make mtvec/stvec ignore vectored traps,
Michael Clark <=
- [Qemu-devel] [PATCH v8 17/35] RISC-V: No traps on writes to misa, minstret, mcycle, Michael Clark, 2018/04/25
- [Qemu-devel] [PATCH v8 18/35] RISC-V: Clear mtval/stval on exceptions without info, Michael Clark, 2018/04/25
- [Qemu-devel] [PATCH v8 19/35] RISC-V: Allow S-mode mxr access when priv ISA >= v1.10, Michael Clark, 2018/04/25
- [Qemu-devel] [PATCH v8 20/35] RISC-V: Use [ms]counteren CSRs when priv ISA >= v1.10, Michael Clark, 2018/04/25
- [Qemu-devel] [PATCH v8 21/35] RISC-V: Add mcycle/minstret support for -icount auto, Michael Clark, 2018/04/25
- [Qemu-devel] [PATCH v8 22/35] RISC-V: Use atomic_cmpxchg to update PLIC bitmaps, Michael Clark, 2018/04/25