* [PATCH] x86, pkeys: update documentation about availability
@ 2017-11-09 19:12 Dave Hansen
2017-11-10 6:12 ` Ingo Molnar
0 siblings, 1 reply; 4+ messages in thread
From: Dave Hansen @ 2017-11-09 19:12 UTC (permalink / raw)
To: linux-kernel; +Cc: x86, dave.hansen
From: Dave Hansen <dave.hansen@linux.intel.com>
Now that CPUs that implement Memory Protection Keys are publicly
available we can be a bit less oblique about where it is available.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
---
b/Documentation/x86/protection-keys.txt | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff -puN Documentation/x86/protection-keys.txt~pkeys-update Documentation/x86/protection-keys.txt
--- a/Documentation/x86/protection-keys.txt~pkeys-update 2017-11-09 10:36:53.381467202 -0800
+++ b/Documentation/x86/protection-keys.txt 2017-11-09 10:43:15.527466249 -0800
@@ -1,5 +1,10 @@
-Memory Protection Keys for Userspace (PKU aka PKEYs) is a CPU feature
-which will be found on future Intel CPUs.
+Memory Protection Keys for Userspace (PKU aka PKEYs) is a feature
+which is found on Intel's Skylake "Scalable Processor" Server CPUs.
+It will be avalable in future non-server parts.
+
+For anyone wishing to test or use this feature, it is available in
+Amazon's EC2 C5 instances and is known to work there using an Ubuntu
+17.04 image.
Memory Protection Keys provides a mechanism for enforcing page-based
protections, but without requiring modification of the page tables
_
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86, pkeys: update documentation about availability
2017-11-09 19:12 [PATCH] x86, pkeys: update documentation about availability Dave Hansen
@ 2017-11-10 6:12 ` Ingo Molnar
2017-11-10 6:41 ` Dave Hansen
0 siblings, 1 reply; 4+ messages in thread
From: Ingo Molnar @ 2017-11-10 6:12 UTC (permalink / raw)
To: Dave Hansen
Cc: linux-kernel, x86, Andy Lutomirski, Thomas Gleixner, H. Peter Anvin
* Dave Hansen <dave.hansen@linux.intel.com> wrote:
>
> From: Dave Hansen <dave.hansen@linux.intel.com>
>
> Now that CPUs that implement Memory Protection Keys are publicly
> available we can be a bit less oblique about where it is available.
>
> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
> ---
>
> b/Documentation/x86/protection-keys.txt | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff -puN Documentation/x86/protection-keys.txt~pkeys-update Documentation/x86/protection-keys.txt
> --- a/Documentation/x86/protection-keys.txt~pkeys-update 2017-11-09 10:36:53.381467202 -0800
> +++ b/Documentation/x86/protection-keys.txt 2017-11-09 10:43:15.527466249 -0800
> @@ -1,5 +1,10 @@
> -Memory Protection Keys for Userspace (PKU aka PKEYs) is a CPU feature
> -which will be found on future Intel CPUs.
> +Memory Protection Keys for Userspace (PKU aka PKEYs) is a feature
> +which is found on Intel's Skylake "Scalable Processor" Server CPUs.
> +It will be avalable in future non-server parts.
> +
> +For anyone wishing to test or use this feature, it is available in
> +Amazon's EC2 C5 instances and is known to work there using an Ubuntu
> +17.04 image.
>
> Memory Protection Keys provides a mechanism for enforcing page-based
> protections, but without requiring modification of the page tables
Could we please first fix the pkeys self-test? One of the testcases doesn't build
at all:
gcc -m32 -o /home/mingo/tip/tools/testing/selftests/x86/protection_keys_32 -O2 -g -std=gnu99 -pthread -Wall -no-pie protection_keys.c -lrt -ldl -lm
In file included from /usr/include/signal.h:57:0,
from protection_keys.c:33:
protection_keys.c: In function ‘signal_handler’:
protection_keys.c:253:6: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’
before ‘.’ token
u64 si_pkey;
^
plus, on a related note, the MPX testcase produces annoying warnings:
gcc -m32 -o /home/mingo/tip/tools/testing/selftests/x86/mpx-mini-test_32 -O2 -g -std=gnu99 -pthread -Wall -no-pie mpx-mini-test.c -lrt -ldl -lm
mpx-mini-test.c: In function ‘insn_test_failed’:
mpx-mini-test.c:1406:3: warning: array subscript is above array bounds
[-Warray-bounds]
printf("bte[1]: %lx\n", bte->contents[1]);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mpx-mini-test.c:1407:3: warning: array subscript is above array bounds
[-Warray-bounds]
printf("bte[2]: %lx\n", bte->contents[2]);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mpx-mini-test.c:1408:3: warning: array subscript is above array bounds
[-Warray-bounds]
printf("bte[3]: %lx\n", bte->contents[3]);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Thanks,
Ingo
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86, pkeys: update documentation about availability
2017-11-10 6:12 ` Ingo Molnar
@ 2017-11-10 6:41 ` Dave Hansen
2017-11-10 7:17 ` Ingo Molnar
0 siblings, 1 reply; 4+ messages in thread
From: Dave Hansen @ 2017-11-10 6:41 UTC (permalink / raw)
To: Ingo Molnar
Cc: linux-kernel, x86, Andy Lutomirski, Thomas Gleixner, H. Peter Anvin
On 11/09/2017 10:12 PM, Ingo Molnar wrote:
>
> * Dave Hansen <dave.hansen@linux.intel.com> wrote:
>
>>
>> From: Dave Hansen <dave.hansen@linux.intel.com>
>>
>> Now that CPUs that implement Memory Protection Keys are publicly
>> available we can be a bit less oblique about where it is available.
>>
>> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
>> ---
>>
>> b/Documentation/x86/protection-keys.txt | 9 +++++++--
>> 1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff -puN Documentation/x86/protection-keys.txt~pkeys-update Documentation/x86/protection-keys.txt
>> --- a/Documentation/x86/protection-keys.txt~pkeys-update 2017-11-09 10:36:53.381467202 -0800
>> +++ b/Documentation/x86/protection-keys.txt 2017-11-09 10:43:15.527466249 -0800
>> @@ -1,5 +1,10 @@
>> -Memory Protection Keys for Userspace (PKU aka PKEYs) is a CPU feature
>> -which will be found on future Intel CPUs.
>> +Memory Protection Keys for Userspace (PKU aka PKEYs) is a feature
>> +which is found on Intel's Skylake "Scalable Processor" Server CPUs.
>> +It will be avalable in future non-server parts.
>> +
>> +For anyone wishing to test or use this feature, it is available in
>> +Amazon's EC2 C5 instances and is known to work there using an Ubuntu
>> +17.04 image.
>>
>> Memory Protection Keys provides a mechanism for enforcing page-based
>> protections, but without requiring modification of the page tables
>
> Could we please first fix the pkeys self-test? One of the testcases doesn't build
> at all:
>
> gcc -m32 -o /home/mingo/tip/tools/testing/selftests/x86/protection_keys_32 -O2 -g -std=gnu99 -pthread -Wall -no-pie protection_keys.c -lrt -ldl -lm
> In file included from /usr/include/signal.h:57:0,
> from protection_keys.c:33:
> protection_keys.c: In function ‘signal_handler’:
> protection_keys.c:253:6: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’
> before ‘.’ token
> u64 si_pkey;
That's odd. I build them all the time. I compiled it just now with
4.14-rc8 and gcc 4.8.4.
I wonder if this is more fallout from the glibc headers getting updated
to now contain pkey-related stuff. si_pkey might be getting #defined
over for the siginfo si_pkey.
What distro are you seeing this on?
> plus, on a related note, the MPX testcase produces annoying warnings:
>
> gcc -m32 -o /home/mingo/tip/tools/testing/selftests/x86/mpx-mini-test_32 -O2 -g -std=gnu99 -pthread -Wall -no-pie mpx-mini-test.c -lrt -ldl -lm
> mpx-mini-test.c: In function ‘insn_test_failed’:
> mpx-mini-test.c:1406:3: warning: array subscript is above array bounds
> [-Warray-bounds]
> printf("bte[1]: %lx\n", bte->contents[1]);
This is kinda a weird structure:
> struct mpx_bt_entry {
> union {
> char x[MPX_BOUNDS_TABLE_ENTRY_SIZE_BYTES];
> unsigned long contents[1];
> };
> } __attribute__((packed));
I guess it should either be contents[0] or
contents[MPX_BOUNDS_TABLE_ENTRY_SIZE_BYTE/sizeof(long)]. But, the
warning is harmless at least.
What gcc is this, btw? I must be behind the times.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86, pkeys: update documentation about availability
2017-11-10 6:41 ` Dave Hansen
@ 2017-11-10 7:17 ` Ingo Molnar
0 siblings, 0 replies; 4+ messages in thread
From: Ingo Molnar @ 2017-11-10 7:17 UTC (permalink / raw)
To: Dave Hansen
Cc: linux-kernel, x86, Andy Lutomirski, Thomas Gleixner, H. Peter Anvin
* Dave Hansen <dave.hansen@linux.intel.com> wrote:
> On 11/09/2017 10:12 PM, Ingo Molnar wrote:
> >
> > * Dave Hansen <dave.hansen@linux.intel.com> wrote:
> >
> >>
> >> From: Dave Hansen <dave.hansen@linux.intel.com>
> >>
> >> Now that CPUs that implement Memory Protection Keys are publicly
> >> available we can be a bit less oblique about where it is available.
> >>
> >> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
> >> ---
> >>
> >> b/Documentation/x86/protection-keys.txt | 9 +++++++--
> >> 1 file changed, 7 insertions(+), 2 deletions(-)
> >>
> >> diff -puN Documentation/x86/protection-keys.txt~pkeys-update Documentation/x86/protection-keys.txt
> >> --- a/Documentation/x86/protection-keys.txt~pkeys-update 2017-11-09 10:36:53.381467202 -0800
> >> +++ b/Documentation/x86/protection-keys.txt 2017-11-09 10:43:15.527466249 -0800
> >> @@ -1,5 +1,10 @@
> >> -Memory Protection Keys for Userspace (PKU aka PKEYs) is a CPU feature
> >> -which will be found on future Intel CPUs.
> >> +Memory Protection Keys for Userspace (PKU aka PKEYs) is a feature
> >> +which is found on Intel's Skylake "Scalable Processor" Server CPUs.
> >> +It will be avalable in future non-server parts.
> >> +
> >> +For anyone wishing to test or use this feature, it is available in
> >> +Amazon's EC2 C5 instances and is known to work there using an Ubuntu
> >> +17.04 image.
> >>
> >> Memory Protection Keys provides a mechanism for enforcing page-based
> >> protections, but without requiring modification of the page tables
> >
> > Could we please first fix the pkeys self-test? One of the testcases doesn't build
> > at all:
> >
> > gcc -m32 -o /home/mingo/tip/tools/testing/selftests/x86/protection_keys_32 -O2 -g -std=gnu99 -pthread -Wall -no-pie protection_keys.c -lrt -ldl -lm
> > In file included from /usr/include/signal.h:57:0,
> > from protection_keys.c:33:
> > protection_keys.c: In function ‘signal_handler’:
> > protection_keys.c:253:6: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’
> > before ‘.’ token
> > u64 si_pkey;
>
> That's odd. I build them all the time. I compiled it just now with
> 4.14-rc8 and gcc 4.8.4.
>
> I wonder if this is more fallout from the glibc headers getting updated
> to now contain pkey-related stuff. si_pkey might be getting #defined
> over for the siginfo si_pkey.
>
> What distro are you seeing this on?
Latest Ubuntu, 17.10:
triton:~/tip> cat /etc/os-release
NAME="Ubuntu"
VERSION="17.10 (Artful Aardvark)"
triton:~/tip> apt-file find /usr/include/signal.h
libc6-dev: /usr/include/signal.h
triton:~/tip> dpkg -l libc6-dev
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-=======================================-========================-========================-====================================================================================
ii libc6-dev:amd64 2.26-0ubuntu2 amd64 GNU C Library: Development Libraries and Header Files
> > plus, on a related note, the MPX testcase produces annoying warnings:
> >
> > gcc -m32 -o /home/mingo/tip/tools/testing/selftests/x86/mpx-mini-test_32 -O2 -g -std=gnu99 -pthread -Wall -no-pie mpx-mini-test.c -lrt -ldl -lm
> > mpx-mini-test.c: In function ‘insn_test_failed’:
> > mpx-mini-test.c:1406:3: warning: array subscript is above array bounds
> > [-Warray-bounds]
> > printf("bte[1]: %lx\n", bte->contents[1]);
>
> This is kinda a weird structure:
>
> > struct mpx_bt_entry {
> > union {
> > char x[MPX_BOUNDS_TABLE_ENTRY_SIZE_BYTES];
> > unsigned long contents[1];
> > };
> > } __attribute__((packed));
>
> I guess it should either be contents[0] or
> contents[MPX_BOUNDS_TABLE_ENTRY_SIZE_BYTE/sizeof(long)]. But, the
> warning is harmless at least.
>
> What gcc is this, btw? I must be behind the times.
gcc version 7.2.0 (Ubuntu 7.2.0-8ubuntu3)
Thanks,
Ingo
^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-11-09 19:12 [PATCH] x86, pkeys: update documentation about availability Dave Hansen
2017-11-10 6:12 ` Ingo Molnar
2017-11-10 6:41 ` Dave Hansen
2017-11-10 7:17 ` Ingo Molnar
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