[PATCH 2/5] lib: sbi: add Ssdbltrp ISA extension support
Clément Léger
cleger at rivosinc.com
Thu Sep 12 23:34:46 PDT 2024
On 13/09/2024 01:22, Samuel Holland wrote:
> On 2024-09-12 7:10 AM, Clément Léger wrote:
>> Add Ssdbltrp trap handler support for S-mode double trap handling. If
>> the trap is received while in VS-mode, then the trap is redirected to
>> S-mode. If caught while in HS-mode, then a double trap SSE event is
>> delivered.
>>
>> Signed-off-by: Clément Léger <cleger at rivosinc.com>
>> ---
>> include/sbi/riscv_encoding.h | 2 ++
>> include/sbi/sbi_ecall_interface.h | 2 ++
>> include/sbi/sbi_hart.h | 3 ++-
>> include/sbi/sbi_trap_ldst.h | 2 ++
>> lib/sbi/objects.mk | 1 +
>> lib/sbi/sbi_double_trap.c | 26 ++++++++++++++++++++++++++
>> lib/sbi/sbi_hart.c | 4 ++++
>> lib/sbi/sbi_sse.c | 1 +
>> lib/sbi/sbi_trap.c | 4 ++++
>> 9 files changed, 44 insertions(+), 1 deletion(-)
>> create mode 100644 lib/sbi/sbi_double_trap.c
>>
>> diff --git a/include/sbi/riscv_encoding.h b/include/sbi/riscv_encoding.h
>> index 2e4391f..4728c63 100644
>> --- a/include/sbi/riscv_encoding.h
>> +++ b/include/sbi/riscv_encoding.h
>> @@ -213,6 +213,7 @@
>> #define ENVCFG_PBMTE (_ULL(1) << 62)
>> #define ENVCFG_ADUE (_ULL(1) << 61)
>> #define ENVCFG_CDE (_ULL(1) << 60)
>> +#define ENVCFG_DTE (_ULL(1) << 59)
>> #define ENVCFG_CBZE (_UL(1) << 7)
>> #define ENVCFG_CBCFE (_UL(1) << 6)
>> #define ENVCFG_CBIE_SHIFT 4
>> @@ -763,6 +764,7 @@
>> #define CAUSE_FETCH_PAGE_FAULT 0xc
>> #define CAUSE_LOAD_PAGE_FAULT 0xd
>> #define CAUSE_STORE_PAGE_FAULT 0xf
>> +#define CAUSE_DOUBLE_TRAP 0x10
>> #define CAUSE_FETCH_GUEST_PAGE_FAULT 0x14
>> #define CAUSE_LOAD_GUEST_PAGE_FAULT 0x15
>> #define CAUSE_VIRTUAL_INST_FAULT 0x16
>> diff --git a/include/sbi/sbi_ecall_interface.h b/include/sbi/sbi_ecall_interface.h
>> index e9a8167..d8077a7 100644
>> --- a/include/sbi/sbi_ecall_interface.h
>> +++ b/include/sbi/sbi_ecall_interface.h
>> @@ -379,7 +379,9 @@ enum sbi_sse_state {
>>
>> /* SBI SSE Event IDs. */
>> #define SBI_SSE_EVENT_LOCAL_RAS 0x00000000
>> +#define SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP 0x00000001
>> #define SBI_SSE_EVENT_LOCAL_PLAT_0_START 0x00004000
>> +#define SBI_SSE_EVENT_LOCAL_PLAT_0_START 0x00004000
>
> This duplicate definition looks like it was added accidentally. With this line
> removed:
Missed that indeed. Saw aswell that I added SSE event definition in the
same commit. I'll probably split that commit and add the SSE event
definition + usage in the double trap handler in a separate commit.
Thanks,
Clément
>
> Reviewed-by: Samuel Holland <samuel.holland at sifive.com>
>
>> #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
>> diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
>> index 81ec061..8aef2a1 100644
>> --- a/include/sbi/sbi_hart.h
>> +++ b/include/sbi/sbi_hart.h
>> @@ -67,7 +67,8 @@ enum sbi_hart_extensions {
>> SBI_HART_EXT_SVADE,
>> /** Hart has Svadu extension */
>> SBI_HART_EXT_SVADU,
>> -
>> + /** Hart has Ssdbltrp extension */
>> + SBI_HART_EXT_SSDBLTRP,
>> /** Maximum index of Hart extension */
>> SBI_HART_EXT_MAX,
>> };
>> diff --git a/include/sbi/sbi_trap_ldst.h b/include/sbi/sbi_trap_ldst.h
>> index 8aee316..4c5cc37 100644
>> --- a/include/sbi/sbi_trap_ldst.h
>> +++ b/include/sbi/sbi_trap_ldst.h
>> @@ -28,4 +28,6 @@ int sbi_load_access_handler(struct sbi_trap_context *tcntx);
>>
>> int sbi_store_access_handler(struct sbi_trap_context *tcntx);
>>
>> +int sbi_double_trap_handler(struct sbi_trap_context *tcntx);
>> +
>> #endif
>> diff --git a/lib/sbi/objects.mk b/lib/sbi/objects.mk
>> index 535aa70..7be943f 100644
>> --- a/lib/sbi/objects.mk
>> +++ b/lib/sbi/objects.mk
>> @@ -66,6 +66,7 @@ libsbi-objs-y += sbi_bitops.o
>> libsbi-objs-y += sbi_console.o
>> libsbi-objs-y += sbi_domain_context.o
>> libsbi-objs-y += sbi_domain.o
>> +libsbi-objs-y += sbi_double_trap.o
>> libsbi-objs-y += sbi_emulate_csr.o
>> libsbi-objs-y += sbi_fifo.o
>> libsbi-objs-y += sbi_fwft.o
>> diff --git a/lib/sbi/sbi_double_trap.c b/lib/sbi/sbi_double_trap.c
>> new file mode 100644
>> index 0000000..af3c991
>> --- /dev/null
>> +++ b/lib/sbi/sbi_double_trap.c
>> @@ -0,0 +1,26 @@
>> +/*
>> + * SPDX-License-Identifier: BSD-2-Clause
>> + *
>> + * Copyright (c) 2024 Rivos Inc.
>> + *
>> + * Authors:
>> + * Clément Léger <clement.leger at rivosinc.com>
>> + */
>> +
>> +#include <sbi/sbi_console.h>
>> +#include <sbi/sbi_ecall_interface.h>
>> +#include <sbi/sbi_sse.h>
>> +#include <sbi/sbi_trap.h>
>> +
>> +int sbi_double_trap_handler(struct sbi_trap_context *tcntx)
>> +{
>> + struct sbi_trap_regs *regs = &tcntx->regs;
>> + const struct sbi_trap_info *trap = &tcntx->trap;
>> + bool prev_virt = sbi_regs_from_virt(regs);
>> +
>> + /* Exception was taken in VS-mode, redirect it to S-mode */
>> + if (prev_virt)
>> + return sbi_trap_redirect(regs, trap);
>> +
>> + return sbi_sse_inject_event(SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP);
>> +}
>> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
>> index cc364fa..d6b9a0a 100644
>> --- a/lib/sbi/sbi_hart.c
>> +++ b/lib/sbi/sbi_hart.c
>> @@ -117,6 +117,9 @@ static void mstatus_init(struct sbi_scratch *scratch)
>> menvcfg_val |= ((uint64_t)csr_read(CSR_MENVCFGH)) << 32;
>> #endif
>>
>> + /* Disable double trap by default */
>> + menvcfg_val &= ~ENVCFG_DTE;
>> +
>> #define __set_menvcfg_ext(__ext, __bits) \
>> if (sbi_hart_has_extension(scratch, __ext)) \
>> menvcfg_val |= __bits;
>> @@ -680,6 +683,7 @@ const struct sbi_hart_ext_data sbi_hart_ext[] = {
>> __SBI_HART_EXT_DATA(ssccfg, SBI_HART_EXT_SSCCFG),
>> __SBI_HART_EXT_DATA(svade, SBI_HART_EXT_SVADE),
>> __SBI_HART_EXT_DATA(svadu, SBI_HART_EXT_SVADU),
>> + __SBI_HART_EXT_DATA(ssdbltrp, SBI_HART_EXT_SSDBLTRP),
>> };
>>
>> _Static_assert(SBI_HART_EXT_MAX == array_size(sbi_hart_ext),
>> diff --git a/lib/sbi/sbi_sse.c b/lib/sbi/sbi_sse.c
>> index 52172fc..b5f076a 100644
>> --- a/lib/sbi/sbi_sse.c
>> +++ b/lib/sbi/sbi_sse.c
>> @@ -41,6 +41,7 @@
>>
>> static const uint32_t supported_events[] = {
>> SBI_SSE_EVENT_LOCAL_RAS,
>> + SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP,
>> SBI_SSE_EVENT_GLOBAL_RAS,
>> SBI_SSE_EVENT_LOCAL_PMU,
>> SBI_SSE_EVENT_LOCAL_SOFTWARE,
>> diff --git a/lib/sbi/sbi_trap.c b/lib/sbi/sbi_trap.c
>> index 8bd2183..188f2a5 100644
>> --- a/lib/sbi/sbi_trap.c
>> +++ b/lib/sbi/sbi_trap.c
>> @@ -330,6 +330,10 @@ struct sbi_trap_context *sbi_trap_handler(struct sbi_trap_context *tcntx)
>> rc = sbi_store_access_handler(tcntx);
>> msg = "store fault handler failed";
>> break;
>> + case CAUSE_DOUBLE_TRAP:
>> + rc = sbi_double_trap_handler(tcntx);
>> + msg = "double trap handler failed";
>> + break;
>> default:
>> /* If the trap came from S or U mode, redirect it there */
>> msg = "trap redirect failed";
>
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