with 32-bit rootfs, the offset may out of range when set it
to 0xc0010299, define it as "unsigned long long" type and
call pread64 directly in kernel.
Signed-off-by: Liwei Song <[email protected]>
---
tools/power/x86/turbostat/turbostat.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 33b370865d16..4c5cdfcb5721 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -33,6 +33,7 @@
#include <sys/capability.h>
#include <errno.h>
#include <math.h>
+#include <sys/syscall.h>
char *proc_stat = "/proc/stat";
FILE *outf;
@@ -381,11 +382,11 @@ int get_msr_fd(int cpu)
return fd;
}
-int get_msr(int cpu, off_t offset, unsigned long long *msr)
+int get_msr(int cpu, unsigned long long offset, unsigned long long *msr)
{
ssize_t retval;
- retval = pread(get_msr_fd(cpu), msr, sizeof(*msr), offset);
+ retval = syscall(SYS_pread64, get_msr_fd(cpu), msr, sizeof(*msr), offset);
if (retval != sizeof *msr)
err(-1, "cpu%d: msr offset 0x%llx read failed", cpu, (unsigned long long)offset);
--
2.17.1
Huh?
On Fri, Jul 17, 2020 at 2:09 AM Liwei Song <[email protected]> wrote:
>
> with 32-bit rootfs, the offset may out of range when set it
> to 0xc0010299, define it as "unsigned long long" type and
> call pread64 directly in kernel.
>
> Signed-off-by: Liwei Song <[email protected]>
> ---
> tools/power/x86/turbostat/turbostat.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
> index 33b370865d16..4c5cdfcb5721 100644
> --- a/tools/power/x86/turbostat/turbostat.c
> +++ b/tools/power/x86/turbostat/turbostat.c
> @@ -33,6 +33,7 @@
> #include <sys/capability.h>
> #include <errno.h>
> #include <math.h>
> +#include <sys/syscall.h>
>
> char *proc_stat = "/proc/stat";
> FILE *outf;
> @@ -381,11 +382,11 @@ int get_msr_fd(int cpu)
> return fd;
> }
>
> -int get_msr(int cpu, off_t offset, unsigned long long *msr)
> +int get_msr(int cpu, unsigned long long offset, unsigned long long *msr)
> {
> ssize_t retval;
>
> - retval = pread(get_msr_fd(cpu), msr, sizeof(*msr), offset);
> + retval = syscall(SYS_pread64, get_msr_fd(cpu), msr, sizeof(*msr), offset);
>
> if (retval != sizeof *msr)
> err(-1, "cpu%d: msr offset 0x%llx read failed", cpu, (unsigned long long)offset);
> --
> 2.17.1
>
--
Len Brown, Intel Open Source Technology Center
with multilib lib32 support, the rootfs will be 32-bit,
the kernel is still 64-bit, in this case run turbostat
will failed with "out of range" error.
Thanks,
Liwei.
On 8/14/20 05:43, Len Brown wrote:
> Huh?
>
> On Fri, Jul 17, 2020 at 2:09 AM Liwei Song <[email protected]> wrote:
>>
>> with 32-bit rootfs, the offset may out of range when set it
>> to 0xc0010299, define it as "unsigned long long" type and
>> call pread64 directly in kernel.
>>
>> Signed-off-by: Liwei Song <[email protected]>
>> ---
>> tools/power/x86/turbostat/turbostat.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
>> index 33b370865d16..4c5cdfcb5721 100644
>> --- a/tools/power/x86/turbostat/turbostat.c
>> +++ b/tools/power/x86/turbostat/turbostat.c
>> @@ -33,6 +33,7 @@
>> #include <sys/capability.h>
>> #include <errno.h>
>> #include <math.h>
>> +#include <sys/syscall.h>
>>
>> char *proc_stat = "/proc/stat";
>> FILE *outf;
>> @@ -381,11 +382,11 @@ int get_msr_fd(int cpu)
>> return fd;
>> }
>>
>> -int get_msr(int cpu, off_t offset, unsigned long long *msr)
>> +int get_msr(int cpu, unsigned long long offset, unsigned long long *msr)
>> {
>> ssize_t retval;
>>
>> - retval = pread(get_msr_fd(cpu), msr, sizeof(*msr), offset);
>> + retval = syscall(SYS_pread64, get_msr_fd(cpu), msr, sizeof(*msr), offset);
>>
>> if (retval != sizeof *msr)
>> err(-1, "cpu%d: msr offset 0x%llx read failed", cpu, (unsigned long long)offset);
>> --
>> 2.17.1
>>
>
>
Re: offset size
The offsets on this file are the MSR offsets.
What MSR are you trying to access at offset 0xc0010299?
Re: pread vs pread64
If I take on faith that you have some kind of 32-bit execution
environment that makes pread into pread32 instead of pread64, and that
truncates an off_t to 32-bits from 64-bits, and it actually makes
sense to request a read at this large offset...
would we really have to invoke syscall() directly -- couldn't we
invoke pread64() directly? (eg. below)
thanks,
-Len
@@ -490,11 +491,12 @@ int get_msr_fd(int cpu)
return fd;
}
-int get_msr(int cpu, off_t offset, unsigned long long *msr)
+int get_msr(int cpu, unsigned long long offset, unsigned long long *msr)
{
ssize_t retval;
- retval = pread(get_msr_fd(cpu), msr, sizeof(*msr), offset);
+ retval = pread64(get_msr_fd(cpu), msr, sizeof(*msr), offset);
if (retval != sizeof *msr)
err(-1, "cpu%d: msr offset 0x%llx read failed", cpu,
(unsigned long long)offset);
On Thu, Aug 13, 2020 at 10:17 PM Liwei Song <[email protected]> wrote:
>
> with multilib lib32 support, the rootfs will be 32-bit,
> the kernel is still 64-bit, in this case run turbostat
> will failed with "out of range" error.
>
> Thanks,
> Liwei.
>
> On 8/14/20 05:43, Len Brown wrote:
> > Huh?
> >
> > On Fri, Jul 17, 2020 at 2:09 AM Liwei Song <[email protected]> wrote:
> >>
> >> with 32-bit rootfs, the offset may out of range when set it
> >> to 0xc0010299, define it as "unsigned long long" type and
> >> call pread64 directly in kernel.
> >>
> >> Signed-off-by: Liwei Song <[email protected]>
> >> ---
> >> tools/power/x86/turbostat/turbostat.c | 5 +++--
> >> 1 file changed, 3 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
> >> index 33b370865d16..4c5cdfcb5721 100644
> >> --- a/tools/power/x86/turbostat/turbostat.c
> >> +++ b/tools/power/x86/turbostat/turbostat.c
> >> @@ -33,6 +33,7 @@
> >> #include <sys/capability.h>
> >> #include <errno.h>
> >> #include <math.h>
> >> +#include <sys/syscall.h>
> >>
> >> char *proc_stat = "/proc/stat";
> >> FILE *outf;
> >> @@ -381,11 +382,11 @@ int get_msr_fd(int cpu)
> >> return fd;
> >> }
> >>
> >> -int get_msr(int cpu, off_t offset, unsigned long long *msr)
> >> +int get_msr(int cpu, unsigned long long offset, unsigned long long *msr)
> >> {
> >> ssize_t retval;
> >>
> >> - retval = pread(get_msr_fd(cpu), msr, sizeof(*msr), offset);
> >> + retval = syscall(SYS_pread64, get_msr_fd(cpu), msr, sizeof(*msr), offset);
> >>
> >> if (retval != sizeof *msr)
> >> err(-1, "cpu%d: msr offset 0x%llx read failed", cpu, (unsigned long long)offset);
> >> --
> >> 2.17.1
> >>
> >
> >
--
Len Brown, Intel Open Source Technology Center
Hi,
I am not the original submitter, but I have answers and a proper patch :)
On Fri, 21 Aug 2020, Len Brown wrote:
> Re: offset size
>
> The offsets on this file are the MSR offsets.
> What MSR are you trying to access at offset 0xc0010299?
This MSR is particular is part of AMD RAPL (energy measurements) interface.
> Re: pread vs pread64
>
> If I take on faith that you have some kind of 32-bit execution
> environment that makes pread into pread32 instead of pread64, and that
> truncates an off_t to 32-bits from 64-bits, and it actually makes
> sense to request a read at this large offset...
The problem here stems from the backward compatibility in Glibc: off_t is
32-bit on 32-bit x86, unless compiled with -D_FILE_OFFSET_BITS=64. This
macro should be used for all new code. Distros should enable it for all
builds, but when one builds turbostat 'by hand', they hit the issue.
> would we really have to invoke syscall() directly -- couldn't we
> invoke pread64() directly? (eg. below)
No, the proper fix is to pass -D_FILE_OFFSET_BITS=64 to the compiler.
Here's the patch:
---8<---
From: Alexander Monakov <[email protected]>
Date: Sun, 23 Aug 2020 23:27:02 +0300
Subject: [PATCH] turbostat: build with _FILE_OFFSET_BITS=64
For compatibility reasons, Glibc off_t is a 32-bit type on 32-bit x86
unless _FILE_OFFSET_BITS=64 is defined. Add this define, as otherwise
reading MSRs with index 0x80000000 and above attempts a pread with a
negative offset, which fails.
Signed-off-by: Alexander Monakov <[email protected]>
---
tools/power/x86/turbostat/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/tools/power/x86/turbostat/Makefile b/tools/power/x86/turbostat/Makefile
index 2b6551269e43..40ae44402eec 100644
--- a/tools/power/x86/turbostat/Makefile
+++ b/tools/power/x86/turbostat/Makefile
@@ -12,6 +12,7 @@ turbostat : turbostat.c
override CFLAGS += -O2 -Wall -I../../../include
override CFLAGS += -DMSRHEADER='"../../../../arch/x86/include/asm/msr-index.h"'
override CFLAGS += -DINTEL_FAMILY_HEADER='"../../../../arch/x86/include/asm/intel-family.h"'
+override CFLAGS += -D_FILE_OFFSET_BITS=64
override CFLAGS += -D_FORTIFY_SOURCE=2
%: %.c
--
2.26.2
On 8/24/20 04:54, Alexander Monakov wrote:
> Hi,
>
> I am not the original submitter, but I have answers and a proper patch :)
>
> On Fri, 21 Aug 2020, Len Brown wrote:
>
>> Re: offset size
>>
>> The offsets on this file are the MSR offsets.
>> What MSR are you trying to access at offset 0xc0010299?
>
> This MSR is particular is part of AMD RAPL (energy measurements) interface.
>
>> Re: pread vs pread64
>>
>> If I take on faith that you have some kind of 32-bit execution
>> environment that makes pread into pread32 instead of pread64, and that
>> truncates an off_t to 32-bits from 64-bits, and it actually makes
>> sense to request a read at this large offset...
>
> The problem here stems from the backward compatibility in Glibc: off_t is
> 32-bit on 32-bit x86, unless compiled with -D_FILE_OFFSET_BITS=64. This
> macro should be used for all new code. Distros should enable it for all
> builds, but when one builds turbostat 'by hand', they hit the issue.
>
>> would we really have to invoke syscall() directly -- couldn't we
>> invoke pread64() directly? (eg. below)
>
> No, the proper fix is to pass -D_FILE_OFFSET_BITS=64 to the compiler.
>
> Here's the patch:
This path works with my case.
Thanks,
Liwei.
>
> ---8<---
>
> From: Alexander Monakov <[email protected]>
> Date: Sun, 23 Aug 2020 23:27:02 +0300
> Subject: [PATCH] turbostat: build with _FILE_OFFSET_BITS=64
>
> For compatibility reasons, Glibc off_t is a 32-bit type on 32-bit x86
> unless _FILE_OFFSET_BITS=64 is defined. Add this define, as otherwise
> reading MSRs with index 0x80000000 and above attempts a pread with a
> negative offset, which fails.
>
> Signed-off-by: Alexander Monakov <[email protected]>
> ---
> tools/power/x86/turbostat/Makefile | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/tools/power/x86/turbostat/Makefile b/tools/power/x86/turbostat/Makefile
> index 2b6551269e43..40ae44402eec 100644
> --- a/tools/power/x86/turbostat/Makefile
> +++ b/tools/power/x86/turbostat/Makefile
> @@ -12,6 +12,7 @@ turbostat : turbostat.c
> override CFLAGS += -O2 -Wall -I../../../include
> override CFLAGS += -DMSRHEADER='"../../../../arch/x86/include/asm/msr-index.h"'
> override CFLAGS += -DINTEL_FAMILY_HEADER='"../../../../arch/x86/include/asm/intel-family.h"'
> +override CFLAGS += -D_FILE_OFFSET_BITS=64
> override CFLAGS += -D_FORTIFY_SOURCE=2
>
> %: %.c
>
> -D_FILE_OFFSET_BITS=64
Applied.
thanks!
-Len
On Mon, Aug 24, 2020 at 12:09 AM Liwei Song <[email protected]> wrote:
>
>
>
> On 8/24/20 04:54, Alexander Monakov wrote:
> > Hi,
> >
> > I am not the original submitter, but I have answers and a proper patch :)
> >
> > On Fri, 21 Aug 2020, Len Brown wrote:
> >
> >> Re: offset size
> >>
> >> The offsets on this file are the MSR offsets.
> >> What MSR are you trying to access at offset 0xc0010299?
> >
> > This MSR is particular is part of AMD RAPL (energy measurements) interface.
> >
> >> Re: pread vs pread64
> >>
> >> If I take on faith that you have some kind of 32-bit execution
> >> environment that makes pread into pread32 instead of pread64, and that
> >> truncates an off_t to 32-bits from 64-bits, and it actually makes
> >> sense to request a read at this large offset...
> >
> > The problem here stems from the backward compatibility in Glibc: off_t is
> > 32-bit on 32-bit x86, unless compiled with -D_FILE_OFFSET_BITS=64. This
> > macro should be used for all new code. Distros should enable it for all
> > builds, but when one builds turbostat 'by hand', they hit the issue.
> >
> >> would we really have to invoke syscall() directly -- couldn't we
> >> invoke pread64() directly? (eg. below)
> >
> > No, the proper fix is to pass -D_FILE_OFFSET_BITS=64 to the compiler.
> >
> > Here's the patch:
>
> This path works with my case.
>
> Thanks,
> Liwei.
>
>
> >
> > ---8<---
> >
> > From: Alexander Monakov <[email protected]>
> > Date: Sun, 23 Aug 2020 23:27:02 +0300
> > Subject: [PATCH] turbostat: build with _FILE_OFFSET_BITS=64
> >
> > For compatibility reasons, Glibc off_t is a 32-bit type on 32-bit x86
> > unless _FILE_OFFSET_BITS=64 is defined. Add this define, as otherwise
> > reading MSRs with index 0x80000000 and above attempts a pread with a
> > negative offset, which fails.
> >
> > Signed-off-by: Alexander Monakov <[email protected]>
> > ---
> > tools/power/x86/turbostat/Makefile | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/tools/power/x86/turbostat/Makefile b/tools/power/x86/turbostat/Makefile
> > index 2b6551269e43..40ae44402eec 100644
> > --- a/tools/power/x86/turbostat/Makefile
> > +++ b/tools/power/x86/turbostat/Makefile
> > @@ -12,6 +12,7 @@ turbostat : turbostat.c
> > override CFLAGS += -O2 -Wall -I../../../include
> > override CFLAGS += -DMSRHEADER='"../../../../arch/x86/include/asm/msr-index.h"'
> > override CFLAGS += -DINTEL_FAMILY_HEADER='"../../../../arch/x86/include/asm/intel-family.h"'
> > +override CFLAGS += -D_FILE_OFFSET_BITS=64
> > override CFLAGS += -D_FORTIFY_SOURCE=2
> >
> > %: %.c
> >
--
Len Brown, Intel Open Source Technology Center