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Commit 36aa1b18 authored by Ulrich Weigand's avatar Ulrich Weigand Committed by Benjamin Herrenschmidt
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powerpc: PTRACE_PEEKUSR always returns FPR0 



There is a bug in using ptrace to access FPRs via PTRACE_PEEKUSR /
PTRACE_POKEUSR. In effect, trying to access any of the FPRs always
really accesses FPR0, which does seriously break debugging :-)

The problem seems to have been introduced by commit 3ad26e5c
(Merge branch 'for-kvm' into next).

[ It is indeed a merge conflict between Paul's FPU/VSX state rework
and my LE patches - Anton ]

Signed-off-by: default avatarUlrich Weigand <Ulrich.Weigand@de.ibm.com>
Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent e641eb03

arch/powerpc/kernel/ptrace.c

+2 −2
Original line number Diff line number Diff line
@@ -1555,7 +1555,7 @@ long arch_ptrace(struct task_struct *child, long request, 


			flush_fp_to_thread(child);

			if (fpidx < (PT_FPSCR - PT_FPR0))

				memcpy(&tmp, &child->thread.fp_state.fpr,

				memcpy(&tmp, &child->thread.TS_FPR(fpidx),

				       sizeof(long));

			else

				tmp = child->thread.fp_state.fpscr;
@@ -1588,7 +1588,7 @@ long arch_ptrace(struct task_struct *child, long request, 


			flush_fp_to_thread(child);

			if (fpidx < (PT_FPSCR - PT_FPR0))

				memcpy(&child->thread.fp_state.fpr, &data,

				memcpy(&child->thread.TS_FPR(fpidx), &data,

				       sizeof(long));

			else

				child->thread.fp_state.fpscr = data;