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AFNElJ+H1wr6rSYy1xYRKZC3xAnvEQLKCuSuCD6NjA7+XCbgzjKotYhhv2igv702XEPIaCEiazRH8hqv3w==@kvack.org X-Gm-Message-State: AOJu0Yx7+XQ7M6cquEGdy5RVm0L6LJ0lEMV6xeM+C4oQ40z1dTKSIMmF CKIaZDiAtS59PBp2QaiW8ttTavww9WVQNVcCGIbZy/7cPKUcQ1xrIUtUdPF9CnDlNm5LQLL7Ug= = X-Received: from wrna16.prod.google.com ([2002:adf:e5d0:0:b0:43f:df99:cb43]) (user=ardb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6000:b05:b0:45e:e3ea:1101 with SMTP id ffacd0b85a97d-45ef6b3a9d3mr250438f8f.17.1780066942102; Fri, 29 May 2026 08:02:22 -0700 (PDT) Date: Fri, 29 May 2026 17:01:55 +0200 In-Reply-To: <20260529150150.1670604-17-ardb+git@google.com> Mime-Version: 1.0 References: <20260529150150.1670604-17-ardb+git@google.com> X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=1360; i=ardb@kernel.org; h=from:subject; bh=zgVblspip5ZINNAWS3J63kCjniwJXU0OYP5r0DXGxEI=; b=owGbwMvMwCVmkMcZplerG8N4Wi2JIUtyVfJJkczPYfGm/hd8+FL02y7q1vnc3l5lLz2B/bWeR ZyU8q+OUhYGMS4GWTFFFoHZf9/tPD1RqtZ5lizMHFYmkCEMXJwCMJGrFxn+e55rMk6KmS+o8qjx TFPydss+tp/hHKtbs3vkHc/PO8RoyvA/WrE+UfB50QXpS/Hr3nSqW/oxK2XsCGS8dSmZxXNHTQs /AA== X-Mailer: git-send-email 2.54.0.823.g6e5bcc1fc9-goog Message-ID: <20260529150150.1670604-21-ardb+git@google.com> Subject: [PATCH v7 04/15] arm64: mm: Preserve existing table mappings when mapping DRAM From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com, Ard Biesheuvel , Ryan Roberts , Anshuman Khandual , Kevin Brodsky , Liz Prucka , Seth Jenkins , Kees Cook , Mike Rapoport , David Hildenbrand , Andrew Morton , Jann Horn , linux-mm@kvack.org, linux-hardening@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-sh@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Queue-Id: E6CCD140008 X-Rspamd-Server: rspam03 X-Stat-Signature: sm1xhgyncqdk65hso76oetfunssaa4xz X-HE-Tag: 1780066943-503782 X-HE-Meta: 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 +B9yF0ZK 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Ard Biesheuvel Instead of blindly overwriting an existing table entry when mapping DRAM regions, take care not to replace a pre-existing table entry with a block entry. This permits the logic of mapping the kernel's linear alias to be simplified in a subsequent patch. Reviewed-by: Ryan Roberts Signed-off-by: Ard Biesheuvel --- arch/arm64/mm/mmu.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index b2ba5b35c35f..5c827fa3cd38 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -256,7 +256,8 @@ static int init_pmd(pmd_t *pmdp, unsigned long addr, unsigned long end, /* try section mapping first */ if (((addr | next | phys) & ~PMD_MASK) == 0 && - (flags & NO_BLOCK_MAPPINGS) == 0) { + (flags & NO_BLOCK_MAPPINGS) == 0 && + !pmd_table(old_pmd)) { WARN_ON(!pmd_set_huge(pmdp, phys, prot)); /* @@ -379,7 +380,8 @@ static int alloc_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end, */ if (pud_sect_supported() && ((addr | next | phys) & ~PUD_MASK) == 0 && - (flags & NO_BLOCK_MAPPINGS) == 0) { + (flags & NO_BLOCK_MAPPINGS) == 0 && + !pud_table(old_pud)) { WARN_ON(!pud_set_huge(pudp, phys, prot)); /* -- 2.54.0.823.g6e5bcc1fc9-goog