um: support some of ARCH_HAS_SET_MEMORY

For now, only support set_memory_ro()/rw() which we need for
the stack protection in the next patch.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 1c57599b82fa78f183d55fc0801b3a8cec774b70..70ee19cc6ec689e48d7fe2f2bab312e1dbbb2e95 100644 (file)
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -15,6 +15,7 @@ config UML
        select HAVE_DEBUG_KMEMLEAK
        select HAVE_DEBUG_BUGVERBOSE
        select NO_DMA
+       select ARCH_HAS_SET_MEMORY
        select GENERIC_IRQ_SHOW
        select GENERIC_CPU_DEVICES
        select GENERIC_CLOCKEVENTS

diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h
index def376194dce63a3c7b80f8986033e59d3a81be8..39376bb63abf58596e30dcdd35971d66c4aaf707 100644 (file)
--- a/arch/um/include/asm/pgtable.h
+++ b/arch/um/include/asm/pgtable.h
@@ -55,12 +55,15 @@ extern unsigned long end_iomem;
 #define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
 #define __PAGE_KERNEL_EXEC                                              \
         (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
+#define __PAGE_KERNEL_RO                                               \
+        (_PAGE_PRESENT | _PAGE_DIRTY | _PAGE_ACCESSED)
 #define PAGE_NONE      __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
 #define PAGE_SHARED    __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED)
 #define PAGE_COPY      __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
 #define PAGE_READONLY  __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
 #define PAGE_KERNEL    __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
 #define PAGE_KERNEL_EXEC       __pgprot(__PAGE_KERNEL_EXEC)
+#define PAGE_KERNEL_RO         __pgprot(__PAGE_KERNEL_RO)
 
 /*
  * The i386 can't do page protection for execute, and considers that the same

diff --git a/arch/um/include/asm/set_memory.h b/arch/um/include/asm/set_memory.h
new file mode 100644 (file)
index 0000000..24266c6
--- /dev/null
+++ b/arch/um/include/asm/set_memory.h
@@ -0,0 +1 @@
+#include <asm-generic/set_memory.h>

diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c
index 61776790cd678110f4a2a8af3953778598362b18..437d1f1cc5ecd862890d8d0405d49f668bd75e29 100644 (file)
--- a/arch/um/kernel/tlb.c
+++ b/arch/um/kernel/tlb.c
@@ -608,3 +608,57 @@ void force_flush_all(void)
                vma = vma->vm_next;
        }
 }
+
+struct page_change_data {
+       unsigned int set_mask, clear_mask;
+};
+
+static int change_page_range(pte_t *ptep, unsigned long addr, void *data)
+{
+       struct page_change_data *cdata = data;
+       pte_t pte = READ_ONCE(*ptep);
+
+       pte_clear_bits(pte, cdata->clear_mask);
+       pte_set_bits(pte, cdata->set_mask);
+
+       set_pte(ptep, pte);
+       return 0;
+}
+
+static int change_memory(unsigned long start, unsigned long pages,
+                        unsigned int set_mask, unsigned int clear_mask)
+{
+       unsigned long size = pages * PAGE_SIZE;
+       struct page_change_data data;
+       int ret;
+
+       data.set_mask = set_mask;
+       data.clear_mask = clear_mask;
+
+       ret = apply_to_page_range(&init_mm, start, size, change_page_range,
+                                 &data);
+
+       flush_tlb_kernel_range(start, start + size);
+
+       return ret;
+}
+
+int set_memory_ro(unsigned long addr, int numpages)
+{
+       return change_memory(addr, numpages, 0, _PAGE_RW);
+}
+
+int set_memory_rw(unsigned long addr, int numpages)
+{
+       return change_memory(addr, numpages, _PAGE_RW, 0);
+}
+
+int set_memory_nx(unsigned long addr, int numpages)
+{
+       return -EOPNOTSUPP;
+}
+
+int set_memory_x(unsigned long addr, int numpages)
+{
+       return -EOPNOTSUPP;
+}