Re: [PATCH] add Altivec/VMX state to coredumps

On Thu, 2007-09-27 at 05:10 -0500, Kumar Gala wrote:

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You're probably right :)

What cores have SPE at the moment? Also, perhaps more importantly,
are there any plans to have Altivec and SPE in the same core?

The e500 cores's from Freescale.

No, they are pretty much mutually exclusive.

quoted

I've been working with Carlos Eduardo Seo (Cc'ed on this mail) on
the GDB side of this.

 From comments it looks like the expectation is that the combination
of note type and name which is expected to be unique.

I'm wondering if we should handle this via
elf_coredump_extra_notes_size() & elf_coredump_extra_notes_write().
Does GDB care about the order it sees the various sections in?

I don't think those callbacks will work in this case, they're only
called for the primary thread that's doing the coredump, not for each
thread. Perhaps there's a way to adapt it though.

I think the easiest solution for now is just to make the note type a
#define and create a new value for Altivec.

Oh, well.  It shouldn't be too difficult to abstract vector handler  
similar to how we do GPRs today to the core dump code.

I'm not sure I follow, you mean elf_core_copy_regs() ?

If so, that's basically what we've done, the problem is that as with
elf_core_copy_regs(), although the content is abstracted and overridden
by arch code, the note type is not. But making the vector note type
configurable seems easy enough.

eg:

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 4482a06..7c8a145 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c

@@ -1624,7 +1624,7 @@ static int elf_core_dump(long signr, struct pt_regs *regs,
 #ifdef ELF_CORE_COPY_XFPREGS
        if (elf_core_copy_task_xfpregs(current, xfpu))
                fill_note(notes + numnote++,
-                         "LINUX", NT_PRXFPREG, sizeof(*xfpu), xfpu);
+                         "LINUX", ELF_CORE_XFPREGS_TYPE, sizeof(*xfpu), xfpu);
 #endif 
   
        fs = get_fs();

cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

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