Files
opensbi/platform/generic/sifive/sifive_dev_platform.c
Yu-Chien Peter Lin 9e14e03032 sifive_dev_platform: Set default MMIO region when SmePMP is enabled
Set a default MMIO region with a single SmePMP entry, which allows us
to save entries for M-mode only devices. The default entry has M-/S-mode
shared permission, so system-level resource protection, such as RISC-V
World extension and WorldGuard checker, will be introduced to protect
M-mode only region access from lower privilege modes.

Reviewed-by: Greentime Hu <greentime.hu@sifive.com>
Reviewed-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Yu-Chien Peter Lin <peter.lin@sifive.com>
Link: https://lore.kernel.org/r/20260224031733.3817148-3-peter.lin@sifive.com
Signed-off-by: Anup Patel <anup@brainfault.org>
2026-04-06 11:04:33 +05:30

74 lines
1.6 KiB
C

/*
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2026 SiFive Inc.
*/
#include <platform_override.h>
#include <sbi/sbi_hart.h>
#include <sbi/sbi_scratch.h>
/*
* Instead of allocating individual PMP entries for each M-mode
* MMIO driver, configure SMEPMP regions to grant R/W permission
* to peripheral and system ports for all privilege modes.
* Finer-grained access control is enforced by wgChecker rules.
*/
static int sifive_smepmp_setup(void)
{
struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
int rc;
if (!sbi_hart_has_extension(scratch, SBI_HART_EXT_SMEPMP))
return 0;
/* Peripheral port region: 0 to 2GiB */
rc = sbi_domain_root_add_memrange(0x0, 0x80000000, 0x80000000,
SBI_DOMAIN_MEMREGION_MMIO |
SBI_DOMAIN_MEMREGION_SHARED_SURW_MRW);
if (rc)
return rc;
#if __riscv_xlen > 32
/* System port region: 512GiB to 1TiB */
rc = sbi_domain_root_add_memrange(0x8000000000ULL, 0x8000000000ULL, 0x8000000000ULL,
SBI_DOMAIN_MEMREGION_MMIO |
SBI_DOMAIN_MEMREGION_SHARED_SURW_MRW);
if (rc)
return rc;
#endif
return 0;
}
static int sifive_early_init(bool cold_boot)
{
int rc;
if (cold_boot) {
rc = sifive_smepmp_setup();
if (rc)
return rc;
}
return generic_early_init(cold_boot);
}
static int sifive_platform_init(const void *fdt, int nodeoff,
const struct fdt_match *match)
{
generic_platform_ops.early_init = sifive_early_init;
return 0;
}
static const struct fdt_match sifive_dev_platform_match[] = {
{ .compatible = "sifive-dev" },
{ },
};
const struct fdt_driver sifive_dev_platform = {
.match_table = sifive_dev_platform_match,
.init = sifive_platform_init,
};