Messages in this thread | | | Date | Thu, 07 May 2015 12:19:23 -0700 | From | Dave Hansen <> | Subject | Re: [PATCH 07/12] mm: Pass the 4-bit protection key in via PROT_ bits to syscalls |
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On 05/07/2015 12:11 PM, One Thousand Gnomes wrote: >> diff -puN include/uapi/asm-generic/mman-common.h~pkeys-11-user-abi-bits include/uapi/asm-generic/mman-common.h >> --- a/include/uapi/asm-generic/mman-common.h~pkeys-11-user-abi-bits 2015-05-07 10:31:43.367276719 -0700 >> +++ b/include/uapi/asm-generic/mman-common.h 2015-05-07 10:31:43.370276855 -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) */ > > Thats leaking deep Intelisms into asm-generic which makes me very > uncomfortable. Whether we need to reserve some bits for "arch specific" > is one question, what we do with them ought not to be leaking out. > > To start with trying to port code people will want to do > > #define PROT_PKEY0 0 > #define PROT_PKEY1 0
Yeah, I feel pretty uncomfortable with it as well. I really don't expect these to live like this in asm-generic when I submit this.
Powerpc and ia64 have _something_ resembling protection keys, so the concept isn't entirely x86 or Intel-specific. My hope would be that we do this in a way that other architectures can use.
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