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authorJohannes Berg <johannes.berg@intel.com>2020-12-05 23:50:17 +0300
committerRichard Weinberger <richard@nod.at>2020-12-14 00:38:06 +0300
commit963285b0b47a1b8e1dfa5481717855a7057ccec6 (patch)
tree5cc496b11441604641ded80b7fc1b8551993f7c5 /arch/um
parent58b09f68697066dfde948153c82dd5d85e10f127 (diff)
downloadlinux-963285b0b47a1b8e1dfa5481717855a7057ccec6.tar.xz
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>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/Kconfig1
-rw-r--r--arch/um/include/asm/pgtable.h3
-rw-r--r--arch/um/include/asm/set_memory.h1
-rw-r--r--arch/um/kernel/tlb.c54
4 files changed, 59 insertions, 0 deletions
diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 1c57599b82fa..70ee19cc6ec6 100644
--- 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 def376194dce..39376bb63abf 100644
--- 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
index 000000000000..24266c63720d
--- /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 61776790cd67..437d1f1cc5ec 100644
--- 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;
+}