Messages in this thread | | | Subject | Re: [V6,1/9] elf: Add new powerpc specifc core note sections | From | Ulrich Weigand <> | Date | Wed, 8 Apr 2015 19:50:50 +0200 |
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Anshuman Khandual <khandual@linux.vnet.ibm.com> wrote on 23.03.2015 11:34:30:
> > With that in mind, do we have a way to set the top 32bits of the MSR > > (which contain the TM bits) when ptracing 32 bit processes? I can't > > find anything like that in this patch set. > > No, we dont have that yet. When ptracing in 32-bit mode the MSR value > which can be viewed or set from the user space through PTRACE_GETREGS > PTRACE_SETREGS call is it's lower 32 bits only. Either we can club > the upper 32 bits of MSR as part of one of the ELF core notes we are > adding in the patch series or we can create one more separate ELF core > note for that purpose. Let me know your opinion on this.
I'm not sure I understand this. I thought we had the following:
- If the process calling ptrace is itself 64-bit (which is how GDB is built on all current Linux distributions), then PTRACE_GETREGS etc. will *always* operate on 64-bit register sets, even if the target process is 32-bit.
- If the process calling ptrace is 32-bit, then PTRACE_GETREGS will operate on 32-bit register sets. However, there is a separate PTRACE_GETREGS64 / PTRACE_SETREGS64 call that will also provide the opportunity to operate on the full 64-bit register set. Both apply independently of whether the target process is 32-bit or 64-bit.
Is this not correct?
Bye, Ulrich
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