Revert "um: support some of ARCH_HAS_SET_MEMORY"

This reverts commit 963285b0b47a ("um: support some of
ARCH_HAS_SET_MEMORY"), as it turns out that it's not only not
working (due to um never using the protection bits in the
page tables) but also corrupts the page tables if used on a
non-vmalloc page, since um never allocates proper page tables
for the 'physmem' in the first place.

Fixing all this will take more effort, so for now revert it.

Reported-by: Benjamin Berg <benjamin@sipsolutions.net>
Fixes: 963285b0b47a ("um: support some of ARCH_HAS_SET_MEMORY")
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 34d302d..c3030db 100644 (file)
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -15,7 +15,6 @@ 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 HAVE_GCC_PLUGINS

diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h
index 39376bb..def3761 100644 (file)
--- a/arch/um/include/asm/pgtable.h
+++ b/arch/um/include/asm/pgtable.h
@@ -55,15 +55,12 @@ 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
deleted file mode 100644 (file)
index 24266c6..0000000
--- a/arch/um/include/asm/set_memory.h
+++ /dev/null
@@ -1 +0,0 @@
-#include <asm-generic/set_memory.h>

diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c
index 437d1f1..6177679 100644 (file)
--- a/arch/um/kernel/tlb.c
+++ b/arch/um/kernel/tlb.c
@@ -608,57 +608,3 @@ 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;
-}