[RFC PATCH v2 2/4] lib: sbi: add support for Supervisor Software Events extension
Clément Léger
cleger at rivosinc.com
Wed Jan 17 05:29:18 PST 2024
Hi Himanshu and thanks for the review,
On 13/01/2024 04:59, Himanshu Chauhan wrote:
> Hi Clement,
>
> Thanks for the patch! My comments inline.
>
>> On 09-Jan-2024, at 4:14 PM, Clément Léger <cleger at rivosinc.com> wrote:
>>
>> This extension [1] allows to deliver events from SBI to supervisor via a
>> software mecanism. This extensions defines events (either local or
>> global) which are signaled by the SBI on specific signal sources (IRQ,
>> traps, etc) and are injected to be executed in supervisor mode.
>>
>> [1] https://lists.riscv.org/g/tech-prs/message/744
>>
>> Signed-off-by: Clément Léger <cleger at rivosinc.com>
>> ---
>> include/sbi/sbi_ecall_interface.h | 48 +-
>> include/sbi/sbi_error.h | 4 +-
>> include/sbi/sbi_sse.h | 93 +++
>> lib/sbi/Kconfig | 4 +
>> lib/sbi/objects.mk | 4 +
>> lib/sbi/sbi_ecall_sse.c | 58 ++
>> lib/sbi/sbi_init.c | 13 +
>> lib/sbi/sbi_ipi.c | 2 +-
>> lib/sbi/sbi_sse.c | 1078 +++++++++++++++++++++++++++++
>> 9 files changed, 1301 insertions(+), 3 deletions(-)
>> create mode 100644 include/sbi/sbi_sse.h
>> create mode 100644 lib/sbi/sbi_ecall_sse.c
>> create mode 100644 lib/sbi/sbi_sse.c
>>
>> diff --git a/include/sbi/sbi_ecall_interface.h b/include/sbi/sbi_ecall_interface.h
>> index d8c646d..a5f3edf 100644
>> --- a/include/sbi/sbi_ecall_interface.h
>> +++ b/include/sbi/sbi_ecall_interface.h
>> @@ -32,6 +32,7 @@
>> #define SBI_EXT_DBCN 0x4442434E
>> #define SBI_EXT_SUSP 0x53555350
>> #define SBI_EXT_CPPC 0x43505043
>> +#define SBI_EXT_SSE 0x535345
>>
>> /* SBI function IDs for BASE extension*/
>> #define SBI_EXT_BASE_GET_SPEC_VERSION 0x0
>> @@ -293,6 +294,48 @@ enum sbi_cppc_reg_id {
>> SBI_CPPC_NON_ACPI_LAST = SBI_CPPC_TRANSITION_LATENCY,
>> };
>>
>> +/* SBI Function IDs for SSE extension */
>> +#define SBI_EXT_SSE_READ_ATTR 0x00000000
>> +#define SBI_EXT_SSE_WRITE_ATTR 0x00000001
>> +#define SBI_EXT_SSE_REGISTER 0x00000002
>> +#define SBI_EXT_SSE_UNREGISTER 0x00000003
>> +#define SBI_EXT_SSE_ENABLE 0x00000004
>> +#define SBI_EXT_SSE_DISABLE 0x00000005
>> +#define SBI_EXT_SSE_COMPLETE 0x00000006
>> +#define SBI_EXT_SSE_INJECT 0x00000007
>> +
>> +/* SBI SSE Event Attributes. */
>> +#define SBI_SSE_ATTR_STATUS 0x00000000
>> +#define SBI_SSE_ATTR_PRIO 0x00000001
>> +#define SBI_SSE_ATTR_CONFIG 0x00000002
>> +#define SBI_SSE_ATTR_PREFERRED_HART 0x00000003
>> +#define SBI_SSE_ATTR_ENTRY_PC 0x00000004
>> +#define SBI_SSE_ATTR_ENTRY_A0 0x00000005
>> +#define SBI_SSE_ATTR_ENTRY_A6 0x00000006
>> +#define SBI_SSE_ATTR_ENTRY_A7 0x00000007
>> +#define SBI_SSE_ATTR_INTERRUPTED_MODE 0x00000008
>> +#define SBI_SSE_ATTR_INTERRUPTED_PC 0x00000009
>> +#define SBI_SSE_ATTR_INTERRUPTED_A0 0x0000000A
>> +#define SBI_SSE_ATTR_INTERRUPTED_A6 0x0000000B
>> +#define SBI_SSE_ATTR_INTERRUPTED_A7 0x0000000C
>> +
>> +#define SBI_SSE_ATTR_STATUS_STATE_OFFSET 0
>> +#define SBI_SSE_ATTR_STATUS_STATE_MASK 0x3
>> +#define SBI_SSE_ATTR_STATUS_PENDING_OFFSET 2
>> +#define SBI_SSE_ATTR_STATUS_INJECT_OFFSET 3
>> +
>> +#define SBI_SSE_ATTR_CONFIG_ONESHOT (1 << 0)
>> +
>> +/* SBI SSE Event IDs. */
>> +#define SBI_SSE_EVENT_LOCAL_RAS 0x00000000
>> +#define SBI_SSE_EVENT_GLOBAL_RAS 0x00008000
>
> Can we add a define for start of platform specific local events (0x4000)?
>
>> +#define SBI_SSE_EVENT_LOCAL_PMU 0x00010000
>> +#define SBI_SSE_EVENT_LOCAL_SOFTWARE 0xffff0000
>> +#define SBI_SSE_EVENT_GLOBAL_SOFTWARE 0xffff8000
>> +
>
> IMHO, we should add all the ranges defined in spec, used or not.
Since there are multiple ranges reserved for the same kind of events, it
will need a numbering of some sort, is something like this ok for you:
#define SBI_SSE_EVENT_LOCAL_RAS 0x00000000
#define SBI_SSE_EVENT_LOCAL_PLAT_0_START 0x00004000
#define SBI_SSE_EVENT_LOCAL_PLAT_0_END 0x00007fff
#define SBI_SSE_EVENT_GLOBAL_RAS 0x00008000
#define SBI_SSE_EVENT_GLOBAL_PLAT_0_START 0x00004000
#define SBI_SSE_EVENT_GLOBAL_PLAT_0_END 0x00007fff
#define SBI_SSE_EVENT_LOCAL_PMU 0x00010000
#define SBI_SSE_EVENT_LOCAL_PLAT_1_START 0x00014000
#define SBI_SSE_EVENT_LOCAL_PLAT_1_END 0x00017fff
#define SBI_SSE_EVENT_GLOBAL_PLAT_1_START 0x0001c000
#define SBI_SSE_EVENT_GLOBAL_PLAT_1_END 0x0001ffff
#define SBI_SSE_EVENT_LOCAL_PLAT_2_START 0x00024000
#define SBI_SSE_EVENT_LOCAL_PLAT_2_END 0x00027fff
#define SBI_SSE_EVENT_GLOBAL_PLAT_2_START 0x0002c000
#define SBI_SSE_EVENT_GLOBAL_PLAT_2_END 0x0002ffff
#define SBI_SSE_EVENT_LOCAL_SOFTWARE 0xffff0000
#define SBI_SSE_EVENT_LOCAL_PLAT_3_START 0xffff4000
#define SBI_SSE_EVENT_LOCAL_PLAT_3_END 0xffff7fff
#define SBI_SSE_EVENT_GLOBAL_SOFTWARE 0xffff8000
#define SBI_SSE_EVENT_GLOBAL_PLAT_3_START 0xffffc000
#define SBI_SSE_EVENT_GLOBAL_PLAT_3_END 0xffffffff
>
>> +#define SBI_SSE_EVENT_GLOBAL (1 << 15)
>> +#define SBI_SSE_EVENT_PLATFORM (1 << 14)
>> +
>> /* SBI base specification related macros */
>> #define SBI_SPEC_VERSION_MAJOR_OFFSET 24
>> #define SBI_SPEC_VERSION_MAJOR_MASK 0x7f
>> @@ -313,8 +356,11 @@ enum sbi_cppc_reg_id {
>> #define SBI_ERR_ALREADY_STARTED -7
>> #define SBI_ERR_ALREADY_STOPPED -8
>> #define SBI_ERR_NO_SHMEM -9
>> +#define SBI_ERR_INVALID_STATE -10
>> +#define SBI_ERR_BAD_RANGE -11
>> +#define SBI_ERR_BUSY -12
>>
>> -#define SBI_LAST_ERR SBI_ERR_NO_SHMEM
>> +#define SBI_LAST_ERR SBI_ERR_BUSY
>>
>> /* clang-format on */
>>
>> diff --git a/include/sbi/sbi_error.h b/include/sbi/sbi_error.h
>> index a77e3f8..5efb3b9 100644
>> --- a/include/sbi/sbi_error.h
>> +++ b/include/sbi/sbi_error.h
>> @@ -24,6 +24,9 @@
>> #define SBI_EALREADY_STARTED SBI_ERR_ALREADY_STARTED
>> #define SBI_EALREADY_STOPPED SBI_ERR_ALREADY_STOPPED
>> #define SBI_ENO_SHMEM SBI_ERR_NO_SHMEM
>> +#define SBI_EINVALID_STATE SBI_ERR_INVALID_STATE
>> +#define SBI_EBAD_RANGE SBI_ERR_BAD_RANGE
>> +#define SBI_EBUSY SBI_ERR_BUSY
>>
>> #define SBI_ENODEV -1000
>> #define SBI_ENOSYS -1001
>> @@ -34,7 +37,6 @@
>> #define SBI_ENOMEM -1006
>> #define SBI_EUNKNOWN -1007
>> #define SBI_ENOENT -1008
>> -
>> /* clang-format on */
>>
>> #endif
>> diff --git a/include/sbi/sbi_sse.h b/include/sbi/sbi_sse.h
>> new file mode 100644
>> index 0000000..ed1b138
>> --- /dev/null
>> +++ b/include/sbi/sbi_sse.h
>> @@ -0,0 +1,93 @@
>> +/*
>> + * SPDX-License-Identifier: BSD-2-Clause
>> + *
>> + * Copyright (c) 2023 Rivos Systems.
>> + */
>> +
>> +#ifndef __SBI_SSE_H__
>> +#define __SBI_SSE_H__
>> +
>> +#include <sbi/sbi_types.h>
>> +#include <sbi/sbi_list.h>
>> +#include <sbi/riscv_locks.h>
>> +
>> +struct sbi_scratch;
>> +
>> +#define EXC_MODE_PP_SHIFT 0
>> +#define EXC_MODE_PP BIT(EXC_MODE_PP_SHIFT)
>> +#define EXC_MODE_PV_SHIFT 1
>> +#define EXC_MODE_PV BIT(EXC_MODE_PV_SHIFT)
>> +#define EXC_MODE_SSTATUS_SPIE_SHIFT 2
>> +#define EXC_MODE_SSTATUS_SPIE BIT(EXC_MODE_SSTATUS_SPIE_SHIFT)
>> +
>> +
>> +struct sbi_sse_cb_ops {
>> + /**
>> + * Called when hart_id is changed on the event.
>> + */
>> + void (*set_hartid_cb)(uint32_t event_id, unsigned long hart_id);
>> +
>> + /**
>> + * Called when the SBI_EXT_SSE_COMPLETE is invoked on the event.
>> + */
>> + void (*complete_cb)(uint32_t event_id);
>> +
>> + /**
>> + * Called when the SBI_EXT_SSE_REGISTER is invoked on the event.
>> + */
>> + void (*register_cb)(uint32_t event_id);
>> +
>> + /**
>> + * Called when the SBI_EXT_SSE_UNREGISTER is invoked on the event.
>> + */
>> + void (*unregister_cb)(uint32_t event_id);
>> +
>> + /**
>> + * Called when the SBI_EXT_SSE_ENABLE is invoked on the event.
>> + */
>> + void (*enable_cb)(uint32_t event_id);
>> +
>> + /**
>> + * Called when the SBI_EXT_SSE_DISABLE is invoked on the event.
>> + */
>> + void (*disable_cb)(uint32_t event_id);
>> +};
>> +
>> +/* Set the callback operations for an event
>> + * @param event_id Event identifier (SBI_SSE_EVENT_*)
>> + * @param cb_ops Callback operations
>> + * @return 0 on success, error otherwise
>> + */
>> +int sbi_sse_set_cb_ops(uint32_t event_id, const struct sbi_sse_cb_ops *cb_ops);
>> +
>> +/* Inject an event to the current hard
>> + * @param event_id Event identifier (SBI_SSE_EVENT_*)
>> + * @param regs Registers that were used on SBI entry
>> + * @return 0 on success, error otherwise
>> + */
>> +int sbi_sse_inject_event(uint32_t event_id, struct sbi_trap_regs *regs);
>> +
>> +int sbi_sse_init(struct sbi_scratch *scratch, bool cold_boot);
>> +void sbi_sse_exit(struct sbi_scratch *scratch);
>> +
>> +/* Interface called from sbi_ecall_sse.c */
>> +int sbi_sse_register(uint32_t event_id, unsigned long handler_entry_pc,
>> + unsigned long handler_entry_a0,
>> + unsigned long handler_entry_a6,
>> + unsigned long handler_entry_a7);
>
> Wouldn’t it be better to only use defined length data types like uint32_t, uint64_t everywhere? Instead of mixing them up?
>
>> +int sbi_sse_unregister(uint32_t event_id);
>> +int sbi_sse_enable(uint32_t event_id);
>> +int sbi_sse_disable(uint32_t event_id);
>> +int sbi_sse_complete(uint32_t event_id, struct sbi_trap_regs *regs,
>> + struct sbi_ecall_return *out);
>> +int sbi_sse_inject_from_ecall(uint32_t event_id, unsigned long hart_id,
>> + struct sbi_trap_regs *regs,
>> + struct sbi_ecall_return *out);
>> +int sbi_sse_read_attrs(uint32_t event_id, uint32_t base_attr_id,
>> + uint32_t attr_count, unsigned long output_phys_lo,
>> + unsigned long output_phys_hi);
>> +int sbi_sse_write_attrs(uint32_t event_id, uint32_t base_attr_id,
>> + uint32_t attr_count, unsigned long input_phys_lo,
>> + unsigned long input_phys_hi);
>> +
>> +#endif
>> diff --git a/lib/sbi/Kconfig b/lib/sbi/Kconfig
>> index 477775e..1b713e9 100644
>> --- a/lib/sbi/Kconfig
>> +++ b/lib/sbi/Kconfig
>> @@ -46,4 +46,8 @@ config SBI_ECALL_VENDOR
>> bool "Platform-defined vendor extensions"
>> default y
>>
>> +config SBI_ECALL_SSE
>> + bool "SSE extension"
>> + default y
>> +
>> endmenu
>> diff --git a/lib/sbi/objects.mk b/lib/sbi/objects.mk
>> index c699187..011c824 100644
>> --- a/lib/sbi/objects.mk
>> +++ b/lib/sbi/objects.mk
>> @@ -52,6 +52,9 @@ libsbi-objs-$(CONFIG_SBI_ECALL_LEGACY) += sbi_ecall_legacy.o
>> carray-sbi_ecall_exts-$(CONFIG_SBI_ECALL_VENDOR) += ecall_vendor
>> libsbi-objs-$(CONFIG_SBI_ECALL_VENDOR) += sbi_ecall_vendor.o
>>
>> +carray-sbi_ecall_exts-$(CONFIG_SBI_ECALL_SSE) += ecall_sse
>> +libsbi-objs-$(CONFIG_SBI_ECALL_SSE) += sbi_ecall_sse.o
>> +
>> libsbi-objs-y += sbi_bitmap.o
>> libsbi-objs-y += sbi_bitops.o
>> libsbi-objs-y += sbi_console.o
>> @@ -71,6 +74,7 @@ libsbi-objs-y += sbi_misaligned_ldst.o
>> libsbi-objs-y += sbi_platform.o
>> libsbi-objs-y += sbi_pmu.o
>> libsbi-objs-y += sbi_scratch.o
>> +libsbi-objs-y += sbi_sse.o
>> libsbi-objs-y += sbi_string.o
>> libsbi-objs-y += sbi_system.o
>> libsbi-objs-y += sbi_timer.o
>> diff --git a/lib/sbi/sbi_ecall_sse.c b/lib/sbi/sbi_ecall_sse.c
>> new file mode 100644
>> index 0000000..15c1a65
>> --- /dev/null
>> +++ b/lib/sbi/sbi_ecall_sse.c
>> @@ -0,0 +1,58 @@
>> +#include <sbi/sbi_error.h>
>> +#include <sbi/sbi_ecall.h>
>> +#include <sbi/sbi_trap.h>
>> +#include <sbi/sbi_sse.h>
>> +
>> +static int sbi_ecall_sse_handler(unsigned long extid, unsigned long funcid,
>> + struct sbi_trap_regs *regs,
>> + struct sbi_ecall_return *out)
>> +{
>> + int ret;
>> +
>> + switch (funcid) {
>> + case SBI_EXT_SSE_READ_ATTR:
>> + ret = sbi_sse_read_attrs(regs->a0, regs->a1, regs->a2, regs->a3,
>> + regs->a4);
>> + break;
>> + case SBI_EXT_SSE_WRITE_ATTR:
>> + ret = sbi_sse_write_attrs(regs->a0, regs->a1, regs->a2,
>> + regs->a3, regs->a4);
>> + break;
>> + case SBI_EXT_SSE_REGISTER:
>> + ret = sbi_sse_register(regs->a0, regs->a1, regs->a2, regs->a3,
>> + regs->a2);
>> + break;
>> + case SBI_EXT_SSE_UNREGISTER:
>> + ret = sbi_sse_unregister(regs->a0);
>> + break;
>> + case SBI_EXT_SSE_ENABLE:
>> + ret = sbi_sse_enable(regs->a0);
>> + break;
>> + case SBI_EXT_SSE_DISABLE:
>> + ret = sbi_sse_disable(regs->a0);
>> + break;
>> + case SBI_EXT_SSE_COMPLETE:
>> + ret = sbi_sse_complete(regs->a0, regs, out);
>> + break;
>> + case SBI_EXT_SSE_INJECT:
>> + ret = sbi_sse_inject_from_ecall(regs->a0, regs->a1, regs, out);
>> + break;
>> + default:
>> + ret = SBI_ENOTSUPP;
>> + }
>> + return ret;
>> +}
>> +
>> +struct sbi_ecall_extension ecall_sse;
>> +
>> +static int sbi_ecall_sse_register_extensions(void)
>> +{
>> + return sbi_ecall_register_extension(&ecall_sse);
>> +}
>> +
>> +struct sbi_ecall_extension ecall_sse = {
>> + .extid_start = SBI_EXT_SSE,
>> + .extid_end = SBI_EXT_SSE,
>> + .register_extensions = sbi_ecall_sse_register_extensions,
>> + .handle = sbi_ecall_sse_handler,
>> +};
>> diff --git a/lib/sbi/sbi_init.c b/lib/sbi/sbi_init.c
>> index 6a98e13..f9e6bb9 100644
>> --- a/lib/sbi/sbi_init.c
>> +++ b/lib/sbi/sbi_init.c
>> @@ -23,6 +23,7 @@
>> #include <sbi/sbi_irqchip.h>
>> #include <sbi/sbi_platform.h>
>> #include <sbi/sbi_pmu.h>
>> +#include <sbi/sbi_sse.h>
>> #include <sbi/sbi_system.h>
>> #include <sbi/sbi_string.h>
>> #include <sbi/sbi_timer.h>
>> @@ -315,6 +316,12 @@ static void __noreturn init_coldboot(struct sbi_scratch *scratch, u32 hartid)
>> if (rc)
>> sbi_hart_hang();
>>
>> + rc = sbi_sse_init(scratch, true);
>> + if (rc) {
>> + sbi_printf("%s: sse init failed (error %d)\n", __func__, rc);
>> + sbi_hart_hang();
>> + }
>> +
>> rc = sbi_pmu_init(scratch, true);
>> if (rc) {
>> sbi_printf("%s: pmu init failed (error %d)\n",
>> @@ -435,6 +442,10 @@ static void __noreturn init_warm_startup(struct sbi_scratch *scratch,
>> if (rc)
>> sbi_hart_hang();
>>
>> + rc = sbi_sse_init(scratch, false);
>> + if (rc)
>> + sbi_hart_hang();
>> +
>> rc = sbi_pmu_init(scratch, false);
>> if (rc)
>> sbi_hart_hang();
>> @@ -639,6 +650,8 @@ void __noreturn sbi_exit(struct sbi_scratch *scratch)
>>
>> sbi_platform_early_exit(plat);
>>
>> + sbi_sse_exit(scratch);
>> +
>> sbi_pmu_exit(scratch);
>>
>> sbi_timer_exit(scratch);
>> diff --git a/lib/sbi/sbi_ipi.c b/lib/sbi/sbi_ipi.c
>> index 269d48a..9967016 100644
>> --- a/lib/sbi/sbi_ipi.c
>> +++ b/lib/sbi/sbi_ipi.c
>> @@ -66,7 +66,7 @@ static int sbi_ipi_send(struct sbi_scratch *scratch, u32 remote_hartindex,
>> * SBI_IPI_UPDATE_BREAK for self-IPIs. For other events, check
>> * for self-IPI and execute the callback directly here.
>> */
>> - ipi_ops->process(scratch);
>> + ipi_ops->process(scratch, NULL);
>> return 0;
>> }
>>
>> diff --git a/lib/sbi/sbi_sse.c b/lib/sbi/sbi_sse.c
>> new file mode 100644
>> index 0000000..7dc7881
>> --- /dev/null
>> +++ b/lib/sbi/sbi_sse.c
>> @@ -0,0 +1,1078 @@
>> +/*
>> + * SPDX-License-Identifier: BSD-2-Clause
>> + *
>> + * Copyright (c) 2023 Rivos Systems Inc.
>> + *
>> + */
>> +
>> +#include <sbi/riscv_asm.h>
>> +#include <sbi/riscv_barrier.h>
>> +#include <sbi/riscv_encoding.h>
>> +#include <sbi/riscv_locks.h>
>> +#include <sbi/sbi_domain.h>
>> +#include <sbi/sbi_ecall.h>
>> +#include <sbi/sbi_ecall_interface.h>
>> +#include <sbi/sbi_error.h>
>> +#include <sbi/sbi_fifo.h>
>> +#include <sbi/sbi_hart.h>
>> +#include <sbi/sbi_heap.h>
>> +#include <sbi/sbi_hsm.h>
>> +#include <sbi/sbi_ipi.h>
>> +#include <sbi/sbi_list.h>
>> +#include <sbi/sbi_platform.h>
>> +#include <sbi/sbi_pmu.h>
>> +#include <sbi/sbi_sse.h>
>> +#include <sbi/sbi_scratch.h>
>> +#include <sbi/sbi_string.h>
>> +#include <sbi/sbi_trap.h>
>> +
>> +#include <sbi/sbi_console.h>
>> +
>> +#define sse_get_hart_state_ptr(__scratch) \
>> + sbi_scratch_read_type((__scratch), void *, shs_ptr_off)
>> +
>> +#define sse_thishart_state_ptr() \
>> + sse_get_hart_state_ptr(sbi_scratch_thishart_ptr())
>> +
>> +#define sse_set_hart_state_ptr(__scratch, __sse_state) \
>> + sbi_scratch_write_type((__scratch), void *, shs_ptr_off, (__sse_state))
>> +
>> +/*
>> + * Rather than using memcpy to copy the context (which does it byte-per-byte),
>> + * copy each field which generates ld/lw.
>> + */
>> +#define sse_regs_copy(dst, src) \
>> + (dst)->a0 = (src)->a0; \
>> + (dst)->a6 = (src)->a6; \
>> + (dst)->a7 = (src)->a7
>> +
>> +#define EVENT_IS_GLOBAL(__event_id) ((__event_id) & SBI_SSE_EVENT_GLOBAL)
>> +
>> +static const uint32_t supported_events[] =
>> +{
>> + SBI_SSE_EVENT_LOCAL_RAS,
>> + SBI_SSE_EVENT_GLOBAL_RAS,
>> + SBI_SSE_EVENT_LOCAL_PMU,
>> + SBI_SSE_EVENT_LOCAL_SOFTWARE,
>> + SBI_SSE_EVENT_GLOBAL_SOFTWARE,
>> +};
>> +
>> +#define EVENT_COUNT array_size(supported_events)
>> +
>> +#define sse_event_invoke_cb(_event, _cb, ...) \
>> +{ \
>> + if (_event->cb_ops && _event->cb_ops->_cb) \
>> + _event->cb_ops->_cb(_event->event_id, ##__VA_ARGS__); \
>> +}
>> +
>> +#define SSE_EVENT_STATE(__e) __e->attrs.status.state
>> +#define SSE_EVENT_PENDING(__e) __e->attrs.status.pending
>> +#define SSE_EVENT_CAN_INJECT(__e) __e->attrs.status.inject
>> +#define SSE_EVENT_HARTID(__e) __e->attrs.hartid
>> +#define SSE_EVENT_PRIO(__e) __e->attrs.prio
>> +#define SSE_EVENT_CONFIG(__e) __e->attrs.config
>> +#define SSE_EVENT_ENTRY(__e) __e->attrs.entry
>> +#define SSE_EVENT_INTERRUPTED(__e) __e->attrs.interrupted
>> +
>> +struct sse_entry_state {
>> + /** Entry program counter */
>> + unsigned long pc;
>> + /** a0 register state */
>> + unsigned long a0;
>> + /** a6 register state */
>> + unsigned long a6;
>> + /** a7 register state */
>> + unsigned long a7;
>> +};
>> +
>> +struct sse_interrupted_state {
>> + /** Exception mode */
>> + unsigned long exc_mode;
>> + /** Interrupted program counter */
>> + unsigned long pc;
>> + /** a0 register state */
>> + unsigned long a0;
>> + /** a6 register state */
>> + unsigned long a6;
>> + /** a7 register state */
>> + unsigned long a7;
>> +};
>> +
>> +enum sbi_sse_state {
>> + SSE_STATE_UNUSED = 0,
>> + SSE_STATE_REGISTERED = 1,
>> + SSE_STATE_ENABLED = 2,
>> + SSE_STATE_RUNNING = 3,
>> +};
>> +
>> +struct sse_ipi_inject_data {
>> + uint32_t event_id;
>> +};
>> +
>> +struct sbi_sse_event_status {
>> + unsigned long state:2;
>> + unsigned long pending:1;
>> + unsigned long inject:1;
>> +} __packed;
>
> Can we have do away with bit fields? Like everywhere else use positions and masks?
> Why packed? We are making sure sse_event_attrs is aligned to unsigned long so that
> We can copy with loops. Probably make it a long with reserved entry? Unless you had
> Something else in mind.
Using bitfield was purely for the ease of use. I could of course use a
long with some shift masks if you prefer that over bitfields.
>
>> +
>> +struct sbi_sse_event_attrs {
>> + struct sbi_sse_event_status status;
>> + unsigned long prio;
>> + unsigned long config;
>> + unsigned long hartid;
>> + struct sse_entry_state entry;
>> + struct sse_interrupted_state interrupted;
>> +};
>> +
>> +/* Make sure all attributes are packed for direct memcpy in ATTR_READ */
>> +#define assert_field_offset(field, attr_offset) \
>> + _Static_assert( \
>> + ((offsetof(struct sbi_sse_event_attrs, field)) / sizeof(unsigned long)) == attr_offset, \
>> + "field "#field " from struct sbi_sse_event_attrs invalid offset, expected "#attr_offset \
>> + )
>> +
>> +assert_field_offset(status, SBI_SSE_ATTR_STATUS);
>> +assert_field_offset(prio, SBI_SSE_ATTR_PRIO);
>> +assert_field_offset(config, SBI_SSE_ATTR_CONFIG);
>> +assert_field_offset(hartid, SBI_SSE_ATTR_PREFERRED_HART);
>> +assert_field_offset(entry.pc, SBI_SSE_ATTR_ENTRY_PC);
>> +assert_field_offset(entry.a0, SBI_SSE_ATTR_ENTRY_A0);
>> +assert_field_offset(entry.a6, SBI_SSE_ATTR_ENTRY_A6);
>> +assert_field_offset(entry.a7, SBI_SSE_ATTR_ENTRY_A7);
>> +assert_field_offset(interrupted.exc_mode, SBI_SSE_ATTR_INTERRUPTED_MODE);
>> +assert_field_offset(interrupted.pc, SBI_SSE_ATTR_INTERRUPTED_PC);
>> +assert_field_offset(interrupted.a0, SBI_SSE_ATTR_INTERRUPTED_A0);
>> +assert_field_offset(interrupted.a6, SBI_SSE_ATTR_INTERRUPTED_A6);
>> +assert_field_offset(interrupted.a7, SBI_SSE_ATTR_INTERRUPTED_A7);
>> +
>> +struct sbi_sse_event {
>> + struct sbi_sse_event_attrs attrs;
>> + uint32_t event_id;
>> + const struct sbi_sse_cb_ops *cb_ops;
>> + struct sbi_dlist node;
>> + /* Only global events are using the lock, local ones don't need it */
>> + spinlock_t lock;
>> +};
>> +
>> +struct sse_hart_state {
>> + struct sbi_dlist event_list;
>> + spinlock_t list_lock;
>> + struct sbi_sse_event *local_events;
>> +};
>> +
>> +static unsigned int local_event_count;
>> +static unsigned int global_event_count;
>> +static struct sbi_sse_event *global_events;
>> +
>> +static unsigned long sse_inject_fifo_off;
>> +static unsigned long sse_inject_fifo_mem_off;
>> +/* Offset of pointer to SSE HART state in scratch space */
>> +static unsigned long shs_ptr_off;
>> +
>> +static u32 sse_ipi_inject_event = SBI_IPI_EVENT_MAX;
>> +
>> +static int sse_ipi_inject_send(unsigned long hartid, uint32_t event_id);
>> +
>> +static bool sse_event_is_global(struct sbi_sse_event *e)
>> +{
>> + return EVENT_IS_GLOBAL(e->event_id);
>> +}
>> +
>> +static void sse_global_event_lock(struct sbi_sse_event *e)
>> +{
>> + if (sse_event_is_global(e))
>> + spin_lock(&e->lock);
>> +}
>> +
>> +static void sse_global_event_unlock(struct sbi_sse_event *e)
>> +{
>> + if (sse_event_is_global(e))
>> + spin_unlock(&e->lock);
>> +}
>> +
>> +static void sse_event_set_state(struct sbi_sse_event *e,
>> + enum sbi_sse_state new_state)
>> +{
>> + enum sbi_sse_state prev_state = SSE_EVENT_STATE(e);
>> +
>> + if ((new_state - prev_state == 1) || (prev_state - new_state == 1)) {
>> + SSE_EVENT_STATE(e) = new_state;
>> + return;
>> + }
>> +
>> + sbi_panic("Invalid SSE state transition: %d -> %d\n", prev_state,
>> + new_state);
>
> Panic in a running system is not a good idea, IMHO. Thinking out loud, what if we let the state as is and return error (handled by caller and decide).
> In worst case, the event can be disabled but definitely not panic.
Yeah makes sense, Even if this is mostly debugging code, it could help
catch some nasty bug without crashing the system. I'll try to convert
that to return a value.
>
>> +}
>> +
>> +static struct sbi_sse_event *sse_event_get(uint32_t event)
>> +{
>> + unsigned int i;
>> + struct sbi_sse_event *events, *e;
>> + unsigned int count;
>> + struct sse_hart_state *shs;
>> +
>> + if (EVENT_IS_GLOBAL(event)) {
>> + count = global_event_count;
>> + events = global_events;
>> + } else {
>> + count = local_event_count;
>> + shs = sse_thishart_state_ptr();
>> + events = shs->local_events;
>> + }
>> +
>> + for (i = 0; i < count; i++) {
>> + e = &events[i];
>> + if (e->event_id == event)
>> + return e;
>> + }
>> +
>> + return NULL;
>> +}
>> +
>> +static struct sse_hart_state *sse_event_get_hart_state(struct sbi_sse_event *e)
>> +{
>> + struct sbi_scratch *s = sbi_hartid_to_scratch(SSE_EVENT_HARTID(e));
>> +
>> + return sse_get_hart_state_ptr(s);
>> +}
>> +
>> +static void sse_event_remove_from_list(struct sbi_sse_event *e)
>> +{
>> + struct sse_hart_state *state = sse_event_get_hart_state(e);
>> +
>> + spin_lock(&state->list_lock);
>> + sbi_list_del(&e->node);
>> + spin_unlock(&state->list_lock);
>> +}
>> +
>> +static void sse_event_add_to_list(struct sbi_sse_event *e)
>> +{
>> + struct sse_hart_state *state = sse_event_get_hart_state(e);
>> + struct sbi_sse_event *tmp;
>> +
>> + spin_lock(&state->list_lock);
>> + sbi_list_for_each_entry(tmp, &state->event_list, node) {
>> + if (SSE_EVENT_PRIO(e) < SSE_EVENT_PRIO(tmp))
>> + break;
>> + if (SSE_EVENT_PRIO(e) == SSE_EVENT_PRIO(tmp) &&
>> + e->event_id < tmp->event_id)
>> + break;
>> + }
>> + sbi_list_add_tail(&e->node, &tmp->node);
>> +
>> + spin_unlock(&state->list_lock);
>> +}
>> +
>> +static int sse_event_disable(struct sbi_sse_event *e)
>> +{
>> + if (SSE_EVENT_STATE(e) != SSE_STATE_ENABLED)
>> + return SBI_EINVALID_STATE;
>> +
>> + sse_event_invoke_cb(e, disable_cb);
>> +
>> + sse_event_remove_from_list(e);
>> + sse_event_set_state(e, SSE_STATE_REGISTERED);
>> +
>> + return SBI_OK;
>> +}
>> +
>> +static int sse_event_set_hart_id_check(struct sbi_sse_event *e,
>> + unsigned long new_hartid)
>> +{
>> + int hstate;
>> + unsigned int hartid = (uint32_t) new_hartid;
>> + struct sbi_domain * hd = sbi_domain_thishart_ptr();
>> +
>> + if (!sse_event_is_global(e))
>> + return SBI_EDENIED;
>
> Why denied? Why not invalid param?
Oops, probably a left over of some previous version.
>
>> +
>> + if (SSE_EVENT_STATE(e) >= SSE_STATE_ENABLED)
>> + return SBI_EBUSY;
>
> In the spec, whenever the state doesn’t match the required state, we say we return INVALID_STATE.
> Can we do that? This is the only place where EBUSY is used. It might be good to have EBUSY but then it’s out of the scope of this patch set.
Agreed, this was specified in a previous spec version also. I'll change
that.
>
>> +
>> + if (!sbi_domain_is_assigned_hart(hd, new_hartid))
>> + return SBI_EINVAL;
>> +
>> + hstate = sbi_hsm_hart_get_state(hd, hartid);
>> + if (hstate != SBI_HSM_STATE_STARTED)
>> + return SBI_EINVAL;
>> +
>> + return SBI_OK;
>> +}
>> +
>> +static int sse_event_set_attr_check(struct sbi_sse_event *e, uint32_t attr_id,
>> + unsigned long val)
>> +{
>> + int ret = SBI_OK;
>> +
>> + switch (attr_id) {
>> + case SBI_SSE_ATTR_CONFIG:
>> + if (val & ~SBI_SSE_ATTR_CONFIG_ONESHOT)
>> + ret = SBI_ERR_INVALID_PARAM;
>> + break;
>> + case SBI_SSE_ATTR_PRIO:
>> + if (SSE_EVENT_STATE(e) >= SSE_STATE_ENABLED)
>> + ret = SBI_EINVALID_STATE;
>> + break;
>> + case SBI_SSE_ATTR_PREFERRED_HART:
>> + ret = sse_event_set_hart_id_check(e, val);
>> + break;
>> + default:
>> + ret = SBI_EBAD_RANGE;
>> + break;
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static void sse_event_set_attr(struct sbi_sse_event *e, uint32_t attr_id,
>> + unsigned long val)
>> +{
>> + switch (attr_id) {
>> + case SBI_SSE_ATTR_CONFIG:
>> + SSE_EVENT_CONFIG(e) = val;
>> + break;
>> + case SBI_SSE_ATTR_PRIO:
>> + SSE_EVENT_PRIO(e) = (uint32_t)val;
>
> Another reason to used defined length data types. I think we can do away with typecasts like this.
>
>> + break;
>> + case SBI_SSE_ATTR_PREFERRED_HART:
>> + SSE_EVENT_HARTID(e) = val;
>> + sse_event_invoke_cb(e, set_hartid_cb, val);
>> + break;
>> + }
>> +}
>> +
>> +static int sse_event_register(struct sbi_sse_event *e,
>> + unsigned long handler_entry_pc,
>> + unsigned long handler_entry_a0,
>> + unsigned long handler_entry_a6,
>> + unsigned long handler_entry_a7)
>> +{
>> + if (sse_event_is_global(e) && SSE_EVENT_HARTID(e) != current_hartid())
>> + return SBI_EINVAL;
>> +
>> + if (SSE_EVENT_STATE(e) != SSE_STATE_UNUSED)
>> + return SBI_EINVALID_STATE;
>> +
>> + SSE_EVENT_ENTRY(e).a0 = handler_entry_a0;
>> + SSE_EVENT_ENTRY(e).a6 = handler_entry_a6;
>> + SSE_EVENT_ENTRY(e).a7 = handler_entry_a7;
>> + SSE_EVENT_ENTRY(e).pc = handler_entry_pc;
>> +
>> + sse_event_set_state(e, SSE_STATE_REGISTERED);
>
> Better return an error from set state (my previous comment). Handle it here based on what transition is expected.
> Here we just have crossed fingers that system won’t panic.
>
>> +
>> + sse_event_invoke_cb(e, register_cb);
>> +
>> + return 0;
>> +}
>> +
>> +static int sse_event_unregister(struct sbi_sse_event *e)
>> +{
>> + if (SSE_EVENT_STATE(e) != SSE_STATE_REGISTERED)
>> + return SBI_EINVALID_STATE;
>> +
>> + sse_event_invoke_cb(e, unregister_cb);
>> +
>> + sse_event_set_state(e, SSE_STATE_UNUSED);
>> +
>> + return 0;
>> +}
>> +
>> +static void sse_event_inject(struct sbi_sse_event *e,
>> + struct sbi_sse_event *prev_e,
>> + struct sbi_trap_regs *regs)
>> +{
>> + ulong prev_smode, prev_virt;
>> + struct sse_interrupted_state *i_ctx = &SSE_EVENT_INTERRUPTED(e);
>> + struct sse_interrupted_state *prev_i_ctx;
>> + struct sse_entry_state *e_ctx = &SSE_EVENT_ENTRY(e);
>> +
>> + sse_event_set_state(e, SSE_STATE_RUNNING);
>> + SSE_EVENT_PENDING(e) = false;
>> +
>> + if (prev_e) {
>> + /* back-to-back injection after another event, copy previous
>> + * event context for correct restoration
>> + */
>> + prev_i_ctx = &SSE_EVENT_INTERRUPTED(prev_e);
>> +
>> + sse_regs_copy(i_ctx, prev_i_ctx);
>> + i_ctx->exc_mode = prev_i_ctx->exc_mode;
>> + i_ctx->pc = prev_i_ctx->pc;
>> + } else {
>> + sse_regs_copy(i_ctx, regs);
>> +
>> + prev_smode = (regs->mstatus & MSTATUS_MPP) >> MSTATUS_MPP_SHIFT;
>> + #if __riscv_xlen == 32
>> + prev_virt = (regs->mstatusH & MSTATUSH_MPV) ? 1 : 0;
>> + #else
>> + prev_virt = (regs->mstatus & MSTATUS_MPV) ? 1 : 0;
>> + #endif
>> +
>> + i_ctx->exc_mode = prev_smode << EXC_MODE_PP_SHIFT;
>> + i_ctx->exc_mode |= prev_virt << EXC_MODE_PV_SHIFT;
>> + if (regs->mstatus & MSTATUS_SPIE)
>> + i_ctx->exc_mode |= EXC_MODE_SSTATUS_SPIE;
>> + i_ctx->pc = regs->mepc;
>> +
>> + /* We only want to set SPIE for the first event injected after
>> + * entering M-Mode. For the event injected right after another
>> + * event (after calling sse_event_complete(), we will keep the
>> + * saved SPIE).
>> + */
>> + regs->mstatus &= ~MSTATUS_SPIE;
>> + if (regs->mstatus & MSTATUS_SIE)
>> + regs->mstatus |= MSTATUS_SPIE;
>> + }
>> +
>> + sse_regs_copy(regs, e_ctx);
>> + regs->mepc = e_ctx->pc;
>> +
>> + regs->mstatus &= ~MSTATUS_MPP;
>> + regs->mstatus |= (PRV_S << MSTATUS_MPP_SHIFT);
>> +
>> + #if __riscv_xlen == 32
>> + regs->mstatusH &= ~MSTATUSH_MPV;
>> + #else
>> + regs->mstatus &= ~MSTATUS_MPV;
>> + #endif
>> +
>> + regs->mstatus &= ~MSTATUS_SIE;
>> +}
>> +
>> +static void sse_event_resume(struct sbi_sse_event *e, struct sbi_trap_regs *regs)
>> +{
>> + struct sse_interrupted_state *i_ctx = &SSE_EVENT_INTERRUPTED(e);
>> +
>> + sse_regs_copy(regs, i_ctx);
>> +
>> + /* Restore previous virtualization state */
>> +#if __riscv_xlen == 32
>> + regs->mstatusH &= ~MSTATUSH_MPV;
>> + if (i_ctx->exc_mode & EXC_MODE_PV)
>> + regs->mstatusH |= MSTATUSH_MPV;
>> +#else
>> + regs->mstatus &= ~MSTATUS_MPV;
>> + if (i_ctx->exc_mode & EXC_MODE_PV)
>> + regs->mstatus |= MSTATUS_MPV;
>> +#endif
>> +
>
> Probably have #error for undefined __riscv_xlen.
Acked
Thanks,
Clément
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