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[Qemu-devel] [PATCH v1 19/30] RISC-V: Allow interrupt controllers to cla
From: |
Michael Clark |
Subject: |
[Qemu-devel] [PATCH v1 19/30] RISC-V: Allow interrupt controllers to claim interrupts |
Date: |
Wed, 23 May 2018 12:15:06 +1200 |
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 logic was previously hard-coded so SEIP was always masked even
if no PLIC was attached. This patch adds riscv_cpu_claim_interrupts
so that the PLIC can register control of SEIP. In the case of models
without a PLIC (spike), the SEIP bit remains software controlled.
This interface allows for hardware control of supervisor timer and
software interrupts by other interrupt controller models.
Cc: Palmer Dabbelt <address@hidden>
Cc: Sagar Karandikar <address@hidden>
Cc: Bastian Koppelmann <address@hidden>
Cc: Alistair Francis <address@hidden>
Signed-off-by: Michael Clark <address@hidden>
---
hw/riscv/sifive_plic.c | 13 +++++++++++++
target/riscv/cpu.h | 2 ++
target/riscv/cpu_helper.c | 11 +++++++++++
target/riscv/csr.c | 12 ++++--------
4 files changed, 30 insertions(+), 8 deletions(-)
diff --git a/hw/riscv/sifive_plic.c b/hw/riscv/sifive_plic.c
index dc6f4924e282..28e28d932f7c 100644
--- a/hw/riscv/sifive_plic.c
+++ b/hw/riscv/sifive_plic.c
@@ -23,6 +23,7 @@
#include "qemu/error-report.h"
#include "hw/sysbus.h"
#include "target/riscv/cpu.h"
+#include "sysemu/sysemu.h"
#include "hw/riscv/sifive_plic.h"
#define RISCV_DEBUG_PLIC 0
@@ -447,6 +448,18 @@ static void sifive_plic_realize(DeviceState *dev, Error
**errp)
for (i = 0; i <= plic->num_sources; i++) {
plic->irqs[i] = qemu_allocate_irq(sifive_plic_irq_request, plic, i);
}
+
+ /* 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. */
+ for (i = 0; i < smp_cpus; i++) {
+ RISCVCPU *cpu = RISCV_CPU(qemu_get_cpu(i));
+ if (riscv_cpu_claim_interrupts(cpu, MIP_SEIP) < 0) {
+ error_report("sifive_plic_realize: SEIP already claimed");
+ exit(1);
+ }
+ }
}
static void sifive_plic_class_init(ObjectClass *klass, void *data)
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index d6bb3136db18..ae0e3f6a544d 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -138,6 +138,7 @@ struct CPURISCVState {
* mip is 32-bits to allow atomic_read on 32-bit hosts.
*/
uint32_t mip;
+ uint32_t miclaim;
target_ulong mie;
target_ulong mideleg;
@@ -262,6 +263,7 @@ void riscv_cpu_list(FILE *f, fprintf_function cpu_fprintf);
#define cpu_mmu_index riscv_cpu_mmu_index
#ifndef CONFIG_USER_ONLY
+int riscv_cpu_claim_interrupts(RISCVCPU *cpu, uint32_t interrupts);
uint32_t riscv_cpu_update_mip(RISCVCPU *cpu, uint32_t mask, uint32_t value);
#define BOOL_TO_MASK(x) (-!!(x)) /* helper for riscv_cpu_update_mip value */
#endif
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index b4bbf7a9fa0a..7c9f6c46c75a 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -72,6 +72,17 @@ bool riscv_cpu_exec_interrupt(CPUState *cs, int
interrupt_request)
#if !defined(CONFIG_USER_ONLY)
+int riscv_cpu_claim_interrupts(RISCVCPU *cpu, uint32_t interrupts)
+{
+ CPURISCVState *env = &cpu->env;
+ if (env->miclaim & interrupts) {
+ return -1;
+ } else {
+ env->miclaim |= interrupts;
+ return 0;
+ }
+}
+
/* iothread_mutex must be held */
uint32_t riscv_cpu_update_mip(RISCVCPU *cpu, uint32_t mask, uint32_t value)
{
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 45e33d876034..9bbe81a110a5 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -502,15 +502,11 @@ 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;
+ /* Allow software control of delegable interrupts not claimed by hardware
*/
+ target_ulong mask = write_mask & delegable_ints & ~env->miclaim;
+
+ uint32_t old_mip;
if (mask) {
qemu_mutex_lock_iothread();
--
2.7.0
- [Qemu-devel] [PATCH v1 15/30] RISC-V: Add hartid and \n to interrupt logging, (continued)
- [Qemu-devel] [PATCH v1 15/30] RISC-V: Add hartid and \n to interrupt logging, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 16/30] RISC-V: Use riscv prefix consistently on cpu helpers, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 17/30] RISC-V: Replace __builtin_popcount with ctpop8 in PLIC, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 18/30] RISC-V: Add missing free for plic_hart_config, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 19/30] RISC-V: Allow interrupt controllers to claim interrupts,
Michael Clark <=
- [Qemu-devel] [PATCH v1 20/30] RISC-V: Add misa to DisasContext, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 21/30] RISC-V: Add misa.MAFD checks to translate, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 22/30] RISC-V: Add misa runtime write support, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 23/30] RISC-V: Fix CLINT timecmp low 32-bit writes, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 24/30] RISC-V: Fix PLIC pending bitfield reads, Michael Clark, 2018/05/22
- [Qemu-devel] [PATCH v1 25/30] RISC-V: Enable second UART on sifive_e and sifive_u, Michael Clark, 2018/05/22