[PATCH v2 2/2] arm64: Initialize TLB memory if CMO_BY_VA_ONLY

Ying-Chun Liu (PaulLiu) paul.liu at linaro.org
Wed Feb 8 21:54:28 CET 2023

From: Pierre-Clément Tosi <ptosi at google.com>

Memory used to hold the page tables is allocated from the top of RAM
with no prior initialization and could therefore hold invalid data. As
invalidate_dcache_all() will be called before the MMU has been
initialized and as that function relies indirectly on the page tables
when using CMO_BY_VA_ONLY, these must be in a valid state from their

Signed-off-by: Pierre-Clément Tosi <ptosi at google.com>
[ Paul: pick from the Android tree. Fix checkpatch warnings, and rebased
  to the upstream. ]
Signed-off-by: Ying-Chun Liu (PaulLiu) <paul.liu at linaro.org>
Cc: Tom Rini <trini at konsulko.com>
Link: https://android.googlesource.com/platform/external/u-boot/+/e3ceef4230b772186c6853cace4a676a407e6ab7
v2: Fix the Signed-off-by list.
 arch/arm/lib/cache.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm/lib/cache.c b/arch/arm/lib/cache.c
index 1a589c7e2a..7a16015867 100644
--- a/arch/arm/lib/cache.c
+++ b/arch/arm/lib/cache.c
@@ -159,6 +159,15 @@ __weak int arm_reserve_mmu(void)
 	gd->arch.tlb_allocated = gd->arch.tlb_addr;
+		/*
+		 * As invalidate_dcache_all() will be called before
+		 * mmu_setup(), we should make sure that the PTs are
+		 * already in a valid state.
+		 */
+		memset((void *)gd->arch.tlb_addr, 0, gd->arch.tlb_size);
+	}
 	return 0;

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