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lib: sbi_domain: ensure consistent firmware PMP entries

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During domain context switches, all PMP entries are reconfigured
which can clear firmware access permissions, causing M-mode access
faults under SmePMP.

Sort domain regions to place firmware regions first, ensuring
consistent firmware PMP entries so they won't be revoked during
domain context switches.

Signed-off-by: Yu-Chien Peter Lin <peter.lin@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20251008084444.3525615-7-peter.lin@sifive.com
Signed-off-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Yu-Chien Peter Lin
2025-10-08 16:44:42 +08:00
committed by Anup Patel
parent b34caeef81
commit 631efeeb49
2 changed files with 16 additions and 0 deletions
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3
include/sbi/sbi_domain.h
View File

@@ -121,6 +121,9 @@ struct sbi_domain_memregion {
((__flags & SBI_DOMAIN_MEMREGION_SU_ACCESS_MASK) && \
!(__flags & SBI_DOMAIN_MEMREGION_M_ACCESS_MASK))
#define SBI_DOMAIN_MEMREGION_IS_FIRMWARE(__flags) \
((__flags & SBI_DOMAIN_MEMREGION_FW) ? true : false) \
/** Bit to control if permissions are enforced on all modes */
#define SBI_DOMAIN_MEMREGION_ENF_PERMISSIONS (1UL << 6)

13
lib/sbi/sbi_domain.c
View File

@@ -292,6 +292,19 @@ static bool is_region_compatible(const struct sbi_domain_memregion *regA,
static bool is_region_before(const struct sbi_domain_memregion *regA,
const struct sbi_domain_memregion *regB)
{
/*
* Enforce firmware region ordering for memory access
* under SmePMP.
* Place firmware regions first to ensure consistent
* PMP entries during domain context switches.
*/
if (SBI_DOMAIN_MEMREGION_IS_FIRMWARE(regA->flags) &&
!SBI_DOMAIN_MEMREGION_IS_FIRMWARE(regB->flags))
return true;
if (!SBI_DOMAIN_MEMREGION_IS_FIRMWARE(regA->flags) &&
SBI_DOMAIN_MEMREGION_IS_FIRMWARE(regB->flags))
return false;
if (regA->order < regB->order)
return true;