diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/sbi/sbi_hart.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h index 8b0e8968..1b783436 100644 --- a/include/sbi/sbi_hart.h +++ b/include/sbi/sbi_hart.h @@ -45,6 +45,21 @@ enum sbi_hart_extensions { SBI_HART_EXT_MAX, }; +/* + * Smepmp enforces access boundaries between M-mode and + * S/U-mode. When it is enabled, the PMPs are programmed + * such that M-mode doesn't have access to S/U-mode memory. + * + * To give M-mode R/W access to the shared memory between M and + * S/U-mode, first entry is reserved. It is disabled at boot. + * When shared memory access is required, the physical address + * should be programmed into the first PMP entry with R/W + * permissions to the M-mode. Once the work is done, it should be + * unmapped. sbi_hart_map_saddr/sbi_hart_unmap_saddr function + * pair should be used to map/unmap the shared memory. + */ +#define SBI_SMEPMP_RESV_ENTRY 0 + struct sbi_hart_features { bool detected; int priv_version; |