[PATCH 3/8] lib: sbi_domain: print unsupported SmePMP permissions

Yu-Chien Peter Lin
2025-08-14T15:37:17Z

The reg->flag is encoded with 6 bits to specify RWX
permissions for M-mode and S-/U-mode. However, only 16
of the possible encodings are valid on SmePMP.

Previously, specifying an unsupported encoding could fail
silently. Add a warning log when an unsupported permission
encoding is detected, improving visibility for debugging.

Signed-off-by: Yu-Chien Peter Lin <peter.lin@sifive.com>
---
lib/sbi/sbi_domain.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/lib/sbi/sbi_domain.c b/lib/sbi/sbi_domain.c
index e8adf66f..d6566b12 100644
--- a/lib/sbi/sbi_domain.c
+++ b/lib/sbi/sbi_domain.c
@@ -125,6 +125,7 @@ void sbi_domain_memregion_init(unsigned long addr,
unsigned int sbi_domain_get_smepmp_flags(struct sbi_domain_memregion *reg)
{
unsigned int pmp_flags = 0;
+ unsigned long rstart, rend;

if ((reg->flags & SBI_DOMAIN_MEMREGION_ACCESS_MASK) == 0) {
/*
@@ -186,6 +187,13 @@ unsigned int sbi_domain_get_smepmp_flags(struct sbi_domain_memregion *reg)
pmp_flags |= PMP_W;
if (reg->flags & SBI_DOMAIN_MEMREGION_SU_EXECUTABLE)
pmp_flags |= PMP_X;
+ } else {
+ rstart = reg->base;
+ rend = (reg->order < __riscv_xlen) ?
+ rstart + ((1UL << reg->order) - 1) : -1UL;
+ sbi_printf("%s: Unsupported Smepmp permissions "
+ "on region 0x%" PRILX "-0x%" PRILX "\n",
+ __func__, rstart, rend);
}

return pmp_flags;