diff options
| author | Johannes Berg <johannes.berg@intel.com> | 2020-12-05 23:50:17 +0300 |
|---|---|---|
| committer | Richard Weinberger <richard@nod.at> | 2020-12-14 00:38:06 +0300 |
| commit | 963285b0b47a1b8e1dfa5481717855a7057ccec6 (patch) | |
| tree | 5cc496b11441604641ded80b7fc1b8551993f7c5 /arch/um | |
| parent | 58b09f68697066dfde948153c82dd5d85e10f127 (diff) | |
| download | linux-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/Kconfig | 1 | ||||
| -rw-r--r-- | arch/um/include/asm/pgtable.h | 3 | ||||
| -rw-r--r-- | arch/um/include/asm/set_memory.h | 1 | ||||
| -rw-r--r-- | arch/um/kernel/tlb.c | 54 |
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; +} |