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-rw-r--r--arch/powerpc/mm/pageattr.c99
1 files changed, 99 insertions, 0 deletions
diff --git a/arch/powerpc/mm/pageattr.c b/arch/powerpc/mm/pageattr.c
new file mode 100644
index 000000000..6163e484b
--- /dev/null
+++ b/arch/powerpc/mm/pageattr.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * MMU-generic set_memory implementation for powerpc
+ *
+ * Copyright 2019-2021, IBM Corporation.
+ */
+
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/set_memory.h>
+
+#include <asm/mmu.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+
+static pte_basic_t pte_update_delta(pte_t *ptep, unsigned long addr,
+ unsigned long old, unsigned long new)
+{
+ return pte_update(&init_mm, addr, ptep, old & ~new, new & ~old, 0);
+}
+
+/*
+ * Updates the attributes of a page atomically.
+ *
+ * This sequence is safe against concurrent updates, and also allows updating the
+ * attributes of a page currently being executed or accessed.
+ */
+static int change_page_attr(pte_t *ptep, unsigned long addr, void *data)
+{
+ long action = (long)data;
+
+ addr &= PAGE_MASK;
+ /* modify the PTE bits as desired */
+ switch (action) {
+ case SET_MEMORY_RO:
+ /* Don't clear DIRTY bit */
+ pte_update_delta(ptep, addr, _PAGE_KERNEL_RW & ~_PAGE_DIRTY, _PAGE_KERNEL_RO);
+ break;
+ case SET_MEMORY_RW:
+ pte_update_delta(ptep, addr, _PAGE_KERNEL_RO, _PAGE_KERNEL_RW);
+ break;
+ case SET_MEMORY_NX:
+ pte_update_delta(ptep, addr, _PAGE_KERNEL_ROX, _PAGE_KERNEL_RO);
+ break;
+ case SET_MEMORY_X:
+ pte_update_delta(ptep, addr, _PAGE_KERNEL_RO, _PAGE_KERNEL_ROX);
+ break;
+ case SET_MEMORY_NP:
+ pte_update(&init_mm, addr, ptep, _PAGE_PRESENT, 0, 0);
+ break;
+ case SET_MEMORY_P:
+ pte_update(&init_mm, addr, ptep, 0, _PAGE_PRESENT, 0);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ break;
+ }
+
+ /* See ptesync comment in radix__set_pte_at() */
+ if (radix_enabled())
+ asm volatile("ptesync": : :"memory");
+
+ flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
+
+ return 0;
+}
+
+int change_memory_attr(unsigned long addr, int numpages, long action)
+{
+ unsigned long start = ALIGN_DOWN(addr, PAGE_SIZE);
+ unsigned long size = numpages * PAGE_SIZE;
+
+ if (!numpages)
+ return 0;
+
+ if (WARN_ON_ONCE(is_vmalloc_or_module_addr((void *)addr) &&
+ is_vm_area_hugepages((void *)addr)))
+ return -EINVAL;
+
+#ifdef CONFIG_PPC_BOOK3S_64
+ /*
+ * On hash, the linear mapping is not in the Linux page table so
+ * apply_to_existing_page_range() will have no effect. If in the future
+ * the set_memory_* functions are used on the linear map this will need
+ * to be updated.
+ */
+ if (!radix_enabled()) {
+ int region = get_region_id(addr);
+
+ if (WARN_ON_ONCE(region != VMALLOC_REGION_ID && region != IO_REGION_ID))
+ return -EINVAL;
+ }
+#endif
+
+ return apply_to_existing_page_range(&init_mm, start, size,
+ change_page_attr, (void *)action);
+}