[RFC PATCH 2/4] lib: riscv: add Ssdbltrp support
Clément Léger
cleger at rivosinc.com
Mon Jun 17 02:29:47 PDT 2024
On 10/06/2024 13:06, Anup Patel wrote:
> On Thu, Apr 18, 2024 at 7:25 PM Clément Léger <cleger at rivosinc.com> 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 | 3 +++
>> include/sbi/sbi_ecall_interface.h | 1 +
>> 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 477fa3a..8628e5a 100644
>> --- a/include/sbi/riscv_encoding.h
>> +++ b/include/sbi/riscv_encoding.h
>> @@ -32,6 +32,7 @@
>> #define MSTATUS_TVM _UL(0x00100000)
>> #define MSTATUS_TW _UL(0x00200000)
>> #define MSTATUS_TSR _UL(0x00400000)
>> +#define MSTATUS_SDT _UL(0x01000000)
>> #define MSTATUS32_SD _UL(0x80000000)
>> #if __riscv_xlen == 64
>> #define MSTATUS_UXL _ULL(0x0000000300000000)
>> @@ -213,6 +214,7 @@
>> #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 +765,7 @@
>> #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 0a3b77e..fd1f93d 100644
>> --- a/include/sbi/sbi_ecall_interface.h
>> +++ b/include/sbi/sbi_ecall_interface.h
>> @@ -382,6 +382,7 @@ enum sbi_sse_state {
>>
>> /* SBI SSE Event IDs. */
>> #define SBI_SSE_EVENT_LOCAL_RAS 0x00000000
>> +#define SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP 0x00000001
>
> Please send a patch for SBI spec first.
>
>> #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
>> diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
>> index 10dd90c..a89e6f0 100644
>> --- a/include/sbi/sbi_hart.h
>> +++ b/include/sbi/sbi_hart.h
>> @@ -65,7 +65,8 @@ enum sbi_hart_extensions {
>> SBI_HART_EXT_SSCCFG,
>> /** 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 211abad..88bcf10 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..15311ee
>> --- /dev/null
>> +++ b/lib/sbi/sbi_double_trap.c
>> @@ -0,0 +1,26 @@
>> +/*
>> + * SPDX-License-Identifier: BSD-2-Clause
>> + *
>> + * Copyright (c) 2019 Western Digital Corporation or its affiliates.
>> + *
>> + * Authors:
>> + * Anup Patel <anup.patel at wdc.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);
>> +}
>
> No need for a separate file, we can have this function directly in
> sbi_trap.c as a static function.
Acked. This was actually a PoC for double trap support but I'll fix that
when the spec will be released.
>
>> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
>> index 6908d22..8e4b730 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;
>> @@ -677,6 +680,7 @@ const struct sbi_hart_ext_data sbi_hart_ext[] = {
>> __SBI_HART_EXT_DATA(sscsrind, SBI_HART_EXT_SSCSRIND),
>> __SBI_HART_EXT_DATA(ssccfg, SBI_HART_EXT_SSCCFG),
>> __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 f0729f9..daaeb60 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";
>> --
>> 2.43.0
>>
>>
>> --
>> opensbi mailing list
>> opensbi at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/opensbi
>
> Regards,
> Anup
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