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charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260505-kpkeys-v7-14-20c0bdd97197@arm.com> References: <20260505-kpkeys-v7-0-20c0bdd97197@arm.com> In-Reply-To: <20260505-kpkeys-v7-0-20c0bdd97197@arm.com> To: linux-hardening@vger.kernel.org Cc: Kevin Brodsky , Andrew Morton , Andy Lutomirski , Catalin Marinas , Dave Hansen , "David Hildenbrand (Arm)" , Ira Weiny , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linus Walleij , Marc Zyngier , Mark Brown , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , Quentin Perret , Rick Edgecombe , Ryan Roberts , Will Deacon , Yang Shi , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org, Lorenzo Stoakes , Thomas Gleixner , Vlastimil Babka X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1777997220; l=3365; i=kevin.brodsky@arm.com; s=20260427; h=from:subject:message-id; bh=PHibZSTZ+M49JBQ4ek0CSdAJ2no6ww2ow8catbJRkbA=; b=tgzTvZYCgZKHtLvh8bIbz88J3Sv+Gfhv63Gz+41QPPK0ecs+LDqfcfVQJszRcWPf09gQS/R2H Qy0ZIBKMqBXAfXZvmpbDux3ogpELrzjrv18rcm/SClO23PGIj/3dmFA X-Developer-Key: i=kevin.brodsky@arm.com; a=ed25519; pk=N2QG+eJKrvkNovwhhwJhnJ4+ScVfsGCHldmqLfcMTFs= X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260505_170811_376078_49C883B9 X-CRM114-Status: GOOD ( 14.53 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When the kpkeys_hardened_pgtables feature is enabled, make sure that vmemmap page tables are protected by using: * The standard pagetable_alloc() if the buddy allocator is available, as it already allocates protected memory. * The memblock-based kpkeys allocator for early allocations. These allocators are not NUMA-aware, so the page tables may be allocated on any node. This could potentially incur some overhead on large NUMA systems. Signed-off-by: Kevin Brodsky --- This is a minimal patch to protect vmemmmap page tables. More work may be needed here: * Restoring NUMA awareness * General refactoring of how these page tables are allocated: since we are not using the standard per-level functions (e.g. pmd_alloc()), we are not calling pagetable_*_ctor() or ptdesc_set_kernel(). [Maybe that doesn't matter because these page tables can only be freed via vmemmap_free()?] --- mm/sparse-vmemmap.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c index 6eadb9d116e4..0c0d3b1e356c 100644 --- a/mm/sparse-vmemmap.c +++ b/mm/sparse-vmemmap.c @@ -184,13 +184,28 @@ pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node, return pte; } -static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node) +static void * __meminit vmemmap_alloc_pgtable(int node) { - void *p = vmemmap_alloc_block(size, node); + void *p; + + if (slab_is_available()) { + struct ptdesc *ptdesc = pagetable_alloc(GFP_PGTABLE_KERNEL, 0); + + return ptdesc ? ptdesc_address(ptdesc) : NULL; + } + + if (kpkeys_hardened_pgtables_early_enabled()) { + phys_addr_t phys = kpkeys_physmem_pgtable_alloc(); + + p = phys ? phys_to_virt(phys) : NULL; + } else { + p = __earlyonly_bootmem_alloc(node, PAGE_SIZE, PAGE_SIZE, + __pa(MAX_DMA_ADDRESS)); + } if (!p) return NULL; - memset(p, 0, size); + memset(p, 0, PAGE_SIZE); return p; } @@ -199,7 +214,7 @@ pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) { pmd_t *pmd = pmd_offset(pud, addr); if (pmd_none(*pmd)) { - void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); + void *p = vmemmap_alloc_pgtable(node); if (!p) return NULL; kernel_pte_init(p); @@ -212,7 +227,7 @@ pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node) { pud_t *pud = pud_offset(p4d, addr); if (pud_none(*pud)) { - void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); + void *p = vmemmap_alloc_pgtable(node); if (!p) return NULL; pmd_init(p); @@ -225,7 +240,7 @@ p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node) { p4d_t *p4d = p4d_offset(pgd, addr); if (p4d_none(*p4d)) { - void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); + void *p = vmemmap_alloc_pgtable(node); if (!p) return NULL; pud_init(p); @@ -238,7 +253,7 @@ pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) { pgd_t *pgd = pgd_offset_k(addr); if (pgd_none(*pgd)) { - void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); + void *p = vmemmap_alloc_pgtable(node); if (!p) return NULL; pgd_populate_kernel(addr, pgd, p); -- 2.51.2