Re: Prelinking on ARM with Debug Link

[Torsten Polle <Torsten dot Polle at gmx dot de>]

Hi David,

David Smith writes:
 > On 11/27/2015 02:01 PM, Torsten Polle wrote:
 >> Hi Mark,
 >> 
 >>> Mark Wielaard writes:
 >>> >> WARNING: tapset "/opt/tooling/adit/systemtap/share/systemtap/tapset/linux/arm/syscalls.stp" has errors, and will be skipped
 >>> 
 >>> > You might want to look into why that is.
 >>> 
 >>> Yes, I know. I had re-added support of a system call (execve), which
 >>> does not work since some time in SystemTap. But since the support
 >>> depends on the kernel version, I get a warning about an empty file when
 >>> the kernel version is greater than 3.7.

 > In kernel versions less than 3.7, the execve syscall was in
 > arch-specific code. So, each arch has their own implementation of
 > [nd_]syscall.execve in tapsets/linux/ARCH/[nd_]syscalls.stp.

 > In kernel versions >= 3.7, the execve syscall was moved to generic
 > kernel code, and support for it is located in
 > tapset/linux/[nd_]syscalls.stp.

 > I don't believe we've ever supported an arm/arm64 kernel less than 3.7,

I'm using SystemTap successfully with a 2.6.34 kernel on ARM since 4
years now. So far it worked without much problems.

 > so there isn't arch-specific execve support for arm/arm64. But, if you
 > have got working execve support for arm/arm64 kernels less than 3.7, I
 > don't see a real problem with checking it in (assuming it looks reasonable).

I've support that is working in my environment. At least the defined
variables give some decent result. Please judge the quality for yourself.

The error message reported comes from the fact that the file
syscalls.stp is regarded as empty by SystemTap if the kernel version is
greater then 3.7. I could not find a nice solution so far.

 > -- 
 > David Smith
 > dsmith@redhat.com
 > Red Hat
 > http://www.redhat.com
 > 256.217.0141 (direct)
 > 256.837.0057 (fax)

Kind Regards,
Torsten

Attachment: 0001-Fix-Kernel-2.6.34-no-longer-supported.patch
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