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lib: sbi: add Ssdbltrp ISA extension support

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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 an error is returned to the top
trap handler which will panic.

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
This commit is contained in:
Clément Léger
2024-10-18 10:40:04 +02:00
committed by Anup Patel
parent 80656bdb1d
commit 9c78593269
7 changed files with 46 additions and 1 deletions
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1
lib/sbi/objects.mk
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@@ -67,6 +67,7 @@ libsbi-objs-y += sbi_console.o
libsbi-objs-y += sbi_domain_context.o
libsbi-objs-y += sbi_domain_data.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

30
lib/sbi/sbi_double_trap.c Normal file
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@@ -0,0 +1,30 @@
/*
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2024 Rivos Inc.
*
* Authors:
* Clément Léger <clement.leger@rivosinc.com>
*/
#include <sbi/sbi_console.h>
#include <sbi/sbi_ecall_interface.h>
#include <sbi/sbi_error.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);
if (sbi_mstatus_prev_mode(regs->mstatus) != PRV_S)
return SBI_ERR_INVALID_PARAM;
/* Exception was taken in VS-mode, redirect it to S-mode */
if (prev_virt)
return sbi_trap_redirect(regs, trap);
return SBI_ENOTSUPP;
}

4
lib/sbi/sbi_hart.c
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@@ -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;
@@ -684,6 +687,7 @@ const struct sbi_hart_ext_data sbi_hart_ext[] = {
__SBI_HART_EXT_DATA(smnpm, SBI_HART_EXT_SMNPM),
__SBI_HART_EXT_DATA(zicfilp, SBI_HART_EXT_ZICFILP),
__SBI_HART_EXT_DATA(zicfiss, SBI_HART_EXT_ZICFISS),
__SBI_HART_EXT_DATA(ssdbltrp, SBI_HART_EXT_SSDBLTRP),
};
_Static_assert(SBI_HART_EXT_MAX == array_size(sbi_hart_ext),

4
lib/sbi/sbi_trap.c
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@@ -350,6 +350,10 @@ 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";