[PATCH] Fix ptrace compat wrapper for fpu register access
Michael Neuling
mikey at neuling.org
Tue Mar 31 09:53:59 EST 2009
In message <m2myb32rk8.fsf at igel.home> you wrote:
> Michael Neuling <mikey at neuling.org> writes:
>
> >> @@ -263,7 +263,9 @@ long compat_arch_ptrace(struct task_stru
> >> ret = ptrace_put_reg(child, numReg, freg);
> >> } else {
> >> flush_fp_to_thread(child);
> >> - ((unsigned int *)child->thread.regs)[index] = data;
> >> + ((unsigned int *)child->thread.fpr)
> >> + [TS_FPRWIDTH * (numReg - PT_FPR0) * 2 +
> >> + index % 2] = data;
> >
> > I think the indexing here should be the same as PEEKUSR_3264. This
> > looks better but all this magic indexing makes me want to vomit.
>
> How about this instead:
>
> @@ -241,6 +241,7 @@ long compat_arch_ptrace(struct task_stru
> case PPC_PTRACE_POKEUSR_3264: {
> u32 index;
> u32 numReg;
> + u32 *tmp;
>
> ret = -EIO;
> /* Determine which register the user wants */
> @@ -263,7 +264,8 @@ long compat_arch_ptrace(struct task_stru
> ret = ptrace_put_reg(child, numReg, freg);
> } else {
> flush_fp_to_thread(child);
> - ((unsigned int *)child->thread.regs)[index] = data;
> + tmp = (u32 *)child->thread.fpr[numReg - PT_FPR0];
> + tmp[index % 2] = data;
I do like this approach better (two arrays) but there is no accounting
for TS_WIDTH, so I'm not sure it works.
We *really* need a test case for this stuff :-)
Mikey
> ret = 0;
> }
> break;
>
> Andreas.
>
> --
> Andreas Schwab, schwab at linux-m68k.org
> GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
> "And now for something completely different."
>
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