This is a quick hack that puts very x86-specific bits in to
mprotect.c. I will fix this up properly if we decide to go
forward with the PROT_* scheme for the user ABI for setting up
protection keys.
---
b/arch/x86/include/uapi/asm/mman.h | 9 +++++----
b/mm/mprotect.c | 13 ++++++++++++-
2 files changed, 17 insertions(+), 5 deletions(-)
diff -puN arch/x86/include/uapi/asm/mman.h~pkeys-82-mprotect-flag-copy arch/x86/include/uapi/asm/mman.h
--- a/arch/x86/include/uapi/asm/mman.h~pkeys-82-mprotect-flag-copy 2015-09-16 09:45:54.977451221 -0700
+++ b/arch/x86/include/uapi/asm/mman.h 2015-09-16 09:45:54.982451448 -0700
@@ -24,10 +24,11 @@
((vm_flags) & VM_PKEY_BIT3 ? _PAGE_PKEY_BIT3 : 0))
#define arch_calc_vm_prot_bits(prot) ( \
- ((prot) & PROT_PKEY0 ? VM_PKEY_BIT0 : 0) | \
- ((prot) & PROT_PKEY1 ? VM_PKEY_BIT1 : 0) | \
- ((prot) & PROT_PKEY2 ? VM_PKEY_BIT2 : 0) | \
- ((prot) & PROT_PKEY3 ? VM_PKEY_BIT3 : 0))
+ (!boot_cpu_has(X86_FEATURE_OSPKE) ? 0 : \
+ ((prot) & PROT_PKEY0 ? VM_PKEY_BIT0 : 0) | \
+ ((prot) & PROT_PKEY1 ? VM_PKEY_BIT1 : 0) | \
+ ((prot) & PROT_PKEY2 ? VM_PKEY_BIT2 : 0) | \
+ ((prot) & PROT_PKEY3 ? VM_PKEY_BIT3 : 0)))
#ifndef arch_validate_prot
/*
diff -puN mm/mprotect.c~pkeys-82-mprotect-flag-copy mm/mprotect.c
--- a/mm/mprotect.c~pkeys-82-mprotect-flag-copy 2015-09-16 09:45:54.978451266 -0700
+++ b/mm/mprotect.c 2015-09-16 09:45:54.982451448 -0700
@@ -344,6 +344,15 @@ fail:
return error;
}
+static unsigned long vm_flags_unaffected_by_mprotect(unsigned long vm_flags)
+{
+ unsigned long mask_off = VM_READ | VM_WRITE | VM_EXEC;
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+ mask_off |= VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | VM_PKEY_BIT3;
+#endif
+ return vm_flags & ~mask_off;
+}
+
SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
unsigned long, prot)
{
@@ -407,8 +416,10 @@ SYSCALL_DEFINE3(mprotect, unsigned long,
/* Here we know that vma->vm_start <= nstart < vma->vm_end. */
+ /* Set the vm_flags from the PROT_* bits passed to mprotect */
newflags = vm_flags;
- newflags |= (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
+ /* Copy over all other VMA flags unaffected by mprotect */
+ newflags |= vm_flags_unaffected_by_mprotect(vma->vm_flags);
/* newflags >> 4 shift VM_MAY% in place of VM_% */
if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) {
_
--
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