[PATCH 22/26] [HIJACKPROT] mm: Pass the 4-bit protection key in via PROT_ bits to syscalls

[Dave Hansen]

If a system call takes a PROT_{NONE,EXEC,WRITE,...} argument,
this adds support to it to take a protection key.

	mmap()
	mrprotect()
	drivers/char/agp/frontend.c's ioctl(AGPIOC_RESERVE)

This does not include direct support for shmat() since it uses
a different set of permission bits.  You can use mprotect()
after the attach to assign an attched SHM segment a protection
key.

---

 b/arch/x86/include/uapi/asm/mman.h       |    6 ++++++
 b/include/uapi/asm-generic/mman-common.h |    4 ++++
 2 files changed, 10 insertions(+)

diff -puN arch/x86/include/uapi/asm/mman.h~pkeys-80-user-abi-bits arch/x86/include/uapi/asm/mman.h
--- a/arch/x86/include/uapi/asm/mman.h~pkeys-80-user-abi-bits	2015-09-16 09:45:54.123412488 -0700
+++ b/arch/x86/include/uapi/asm/mman.h	2015-09-16 09:45:54.129412761 -0700
@@ -20,6 +20,12 @@
 		((vm_flags) & VM_PKEY_BIT1 ? _PAGE_PKEY_BIT1 : 0) |	\
 		((vm_flags) & VM_PKEY_BIT2 ? _PAGE_PKEY_BIT2 : 0) |	\
 		((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))
 #endif
 
 #include <asm-generic/mman.h>
diff -puN include/uapi/asm-generic/mman-common.h~pkeys-80-user-abi-bits include/uapi/asm-generic/mman-common.h
--- a/include/uapi/asm-generic/mman-common.h~pkeys-80-user-abi-bits	2015-09-16 09:45:54.125412579 -0700
+++ b/include/uapi/asm-generic/mman-common.h	2015-09-16 09:45:54.128412715 -0700
@@ -10,6 +10,10 @@
 #define PROT_WRITE	0x2		/* page can be written */
 #define PROT_EXEC	0x4		/* page can be executed */
 #define PROT_SEM	0x8		/* page may be used for atomic ops */
+#define PROT_PKEY0	0x10		/* protection key value (bit 0) */
+#define PROT_PKEY1	0x20		/* protection key value (bit 1) */
+#define PROT_PKEY2	0x40		/* protection key value (bit 2) */
+#define PROT_PKEY3	0x80		/* protection key value (bit 3) */
 #define PROT_NONE	0x0		/* page can not be accessed */
 #define PROT_GROWSDOWN	0x01000000	/* mprotect flag: extend change to start of growsdown vma */
 #define PROT_GROWSUP	0x02000000	/* mprotect flag: extend change to end of growsup vma */
_
--
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