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[Qemu-devel] [PATCH v1 09/30] RISC-V: Implement atomic mip/sip CSR updat
From: |
Michael Clark |
Subject: |
[Qemu-devel] [PATCH v1 09/30] RISC-V: Implement atomic mip/sip CSR updates |
Date: |
Wed, 23 May 2018 12:14:56 +1200 |
Use the new CSR read/modify/write interface to implement
atomic updates to mip/sip.
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/csr.c | 56 +++++++++++++++++++++++++++---------------------------
1 file changed, 28 insertions(+), 28 deletions(-)
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index e08f3523d854..631a5ff9f7d8 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -493,25 +493,31 @@ static int write_mbadaddr(CPURISCVState *env, int csrno,
target_ulong val)
return 0;
}
-static int read_mip(CPURISCVState *env, int csrno, target_ulong *val)
-{
- *val = atomic_read(&env->mip);
- return 0;
-}
-
-static int write_mip(CPURISCVState *env, int csrno, target_ulong val)
+static int rmw_mip(CPURISCVState *env, int csrno, target_ulong *ret_value,
+ target_ulong new_value, target_ulong write_mask)
{
RISCVCPU *cpu = riscv_env_get_cpu(env);
+ target_ulong mask = write_mask & delegable_ints;
+ uint32_t old_mip;
+
+ /* We can't allow the supervisor to control SEIP as this would allow the
+ * supervisor to clear a pending external interrupt which will result in
+ * lost a interrupt in the case a PLIC is attached. The SEIP bit must be
+ * hardware controlled when a PLIC is attached. This should be an option
+ * for CPUs with software-delegated Supervisor External Interrupts. */
+ mask &= ~MIP_SEIP;
+
+ if (mask) {
+ qemu_mutex_lock_iothread();
+ old_mip = riscv_cpu_update_mip(cpu, mask, (new_value & mask));
+ qemu_mutex_unlock_iothread();
+ } else {
+ old_mip = atomic_read(&env->mip);
+ }
- /*
- * csrs, csrc on mip.SEIP is not decomposable into separate read and
- * write steps, so a different implementation is needed
- */
-
- qemu_mutex_lock_iothread();
- riscv_cpu_update_mip(cpu, MIP_SSIP | MIP_STIP,
- (val & (MIP_SSIP | MIP_STIP)));
- qemu_mutex_unlock_iothread();
+ if (ret_value) {
+ *ret_value = old_mip;
+ }
return 0;
}
@@ -631,17 +637,11 @@ static int write_sbadaddr(CPURISCVState *env, int csrno,
target_ulong val)
return 0;
}
-static int read_sip(CPURISCVState *env, int csrno, target_ulong *val)
-{
- *val = atomic_read(&env->mip) & env->mideleg;
- return 0;
-}
-
-static int write_sip(CPURISCVState *env, int csrno, target_ulong val)
+static int rmw_sip(CPURISCVState *env, int csrno, target_ulong *ret_value,
+ target_ulong new_value, target_ulong write_mask)
{
- target_ulong newval = (atomic_read(&env->mip) & ~env->mideleg)
- | (val & env->mideleg);
- return write_mip(env, CSR_MIP, newval);
+ return rmw_mip(env, CSR_MSTATUS, ret_value, new_value,
+ write_mask & env->mideleg);
}
/* Supervisor Protection and Translation */
@@ -823,7 +823,7 @@ static const riscv_csr_operations csr_ops[0xfff] = {
[CSR_MEPC] = { read_mepc, write_mepc },
[CSR_MCAUSE] = { read_mcause, write_mcause },
[CSR_MBADADDR] = { read_mbadaddr, write_mbadaddr },
- [CSR_MIP] = { read_mip, write_mip },
+ [CSR_MIP] = { NULL, NULL, rmw_mip },
/* Supervisor Trap Setup */
[CSR_SSTATUS] = { read_sstatus, write_sstatus },
@@ -836,7 +836,7 @@ static const riscv_csr_operations csr_ops[0xfff] = {
[CSR_SEPC] = { read_sepc, write_sepc },
[CSR_SCAUSE] = { read_scause, write_scause },
[CSR_SBADADDR] = { read_sbadaddr, write_sbadaddr },
- [CSR_SIP] = { read_sip, write_sip },
+ [CSR_SIP] = { NULL, NULL, rmw_sip },
/* Supervisor Protection and Translation */
[CSR_SATP] = { read_satp, write_satp },
--
2.7.0
- Re: [Qemu-devel] [PATCH v1 03/30] RISC-V: Use atomic_cmpxchg to update PLIC bitmaps, (continued)
- [Qemu-devel] [PATCH v1 04/30] RISC-V: Simplify riscv_cpu_local_irqs_pending, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 05/30] RISC-V: Allow setting and clearing multiple irqs, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 06/30] RISC-V: Move non-ops from op_helper to cpu_helper, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 07/30] RISC-V: Update CSR and interrupt definitions, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 09/30] RISC-V: Implement atomic mip/sip CSR updates,
Michael Clark <=
- [Qemu-devel] [PATCH v1 10/30] RISC-V: Implement existential predicates for CSRs, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 08/30] RISC-V: Implement modular CSR helper interface, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 11/30] RISC-V: Split out mstatus_fs from tb_flags, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 12/30] RISC-V: Mark mstatus.fs dirty, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 13/30] RISC-V: Implement mstatus.TSR/TW/TVM, Michael Clark, 2018/05/22