OpenE2K
/
qemu-e2k
13
4
Fork 0
Code Issues 4 Pull Requests Projects 2 Releases Activity

RISC-V: Make mtvec/stvec ignore vectored traps 

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 <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>
This commit is contained in:
Michael Clark 2018-03-06 10:17:11 +13:00
parent 6fce529c4b
commit 1d1ee55274
No known key found for this signature in database
GPG Key ID: 6BF1D7B357EF3E4F
1 changed files with 8 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
target/riscv/op_helper.c
View File

@ -287,11 +287,12 @@ 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) {
/* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */
if ((val_to_write & 3) == 0) {
env->stvec = val_to_write >> 2 << 2;
} else {
qemu_log_mask(LOG_UNIMP, "CSR_STVEC: vectored traps not supported");
goto do_illegal;
}
env->stvec = val_to_write >> 2 << 2;
break;
case CSR_SCOUNTEREN:
if (env->priv_ver >= PRIV_VERSION_1_10_0) {
@ -313,11 +314,12 @@ 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) {
/* bits [1:0] indicate mode; 0 = direct, 1 = vectored, 2 >= reserved */
if ((val_to_write & 3) == 0) {
env->mtvec = val_to_write >> 2 << 2;
} else {
qemu_log_mask(LOG_UNIMP, "CSR_MTVEC: vectored traps not supported");
goto do_illegal;
}
env->mtvec = val_to_write >> 2 << 2;
break;
case CSR_MCOUNTEREN:
if (env->priv_ver >= PRIV_VERSION_1_10_0) {