[PATCH 20/27] ARM: mmu32: Fix pmd_flags_to_pte() for ARMv4/5/6

Sascha Hauer s.hauer at pengutronix.de
Fri May 12 04:10:01 PDT 2023


pmd_flags_to_pte() assumed ARMv7 page table format. This has the effect
that random bit values end up in the access permission bits. This works
because the domain is configured as manager in the DACR and thus the
access permissions are ignored by the MMU.
Nevertheless fix this and take the cpu architecture into account when
translating the bits. Don't bother to translate the access permission
bits though, just hardcode them as PTE_SMALL_AP_UNO_SRW.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 arch/arm/cpu/mmu_32.c | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/arch/arm/cpu/mmu_32.c b/arch/arm/cpu/mmu_32.c
index 63e1acdcfa..3939f60758 100644
--- a/arch/arm/cpu/mmu_32.c
+++ b/arch/arm/cpu/mmu_32.c
@@ -173,17 +173,22 @@ static u32 pmd_flags_to_pte(u32 pmd)
 		pte |= PTE_BUFFERABLE;
 	if (pmd & PMD_SECT_CACHEABLE)
 		pte |= PTE_CACHEABLE;
-	if (pmd & PMD_SECT_nG)
-		pte |= PTE_EXT_NG;
-	if (pmd & PMD_SECT_XN)
-		pte |= PTE_EXT_XN;
-
-	/* TEX[2:0] */
-	pte |= PTE_EXT_TEX((pmd >> 12) & 7);
-	/* AP[1:0] */
-	pte |= ((pmd >> 10) & 0x3) << 4;
-	/* AP[2] */
-	pte |= ((pmd >> 15) & 0x1) << 9;
+
+	if (cpu_architecture() >= CPU_ARCH_ARMv7) {
+		if (pmd & PMD_SECT_nG)
+			pte |= PTE_EXT_NG;
+		if (pmd & PMD_SECT_XN)
+			pte |= PTE_EXT_XN;
+
+		/* TEX[2:0] */
+		pte |= PTE_EXT_TEX((pmd >> 12) & 7);
+		/* AP[1:0] */
+		pte |= ((pmd >> 10) & 0x3) << 4;
+		/* AP[2] */
+		pte |= ((pmd >> 15) & 0x1) << 9;
+	} else {
+		pte |= PTE_SMALL_AP_UNO_SRW;
+	}
 
 	return pte;
 }
-- 
2.39.2




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