Re: MPC5200 does not boot

On Tue, 02 Aug 2016 12:44:33 +1000
Benjamin Herrenschmidt [off-list ref] wrote:

On Tue, 2016-08-02 at 00:44 +0200, Michal Sojka wrote:

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Hi Benjamin,
=20
the following commit causes my MPC5200 not to boot.
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=C2=A0=C2=A0=C2=A0=C2=A0commit 9402c684613163888714df0955fa1f17142b08bf=

 =20

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=C2=A0=C2=A0=C2=A0=C2=A0Author: Benjamin Herrenschmidt <benh@kernel.c=

rashing.org> =20

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=C2=A0=C2=A0=C2=A0=C2=A0Date:=C2=A0=C2=A0=C2=A0Tue Jul 5 15:03:41 2016 =

+1000

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=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0powerpc: Factor do_feat=

ure_fixup calls

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=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A032 and 64-bit do a simi=

lar set of calls early on, we move it all to

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=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0a single common functio=

n to make the boot code more readable.

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=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0Signed-off-by: Benjamin=

 Herrenschmidt [off-list ref] =20

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=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0Signed-off-by: Michae=

l Ellerman [off-list ref] =20

quoted

=20
I suspect that the cause will be similar as described in commit
1cd03890ea64795e53f17a94928cca22495acb2a. Unfortunately, I don't have
much time to debug this, but I can easily test patches. =20

=20
Are you sure of your bisection ? Did you verify that reverting that one
patch fixes it ? Because all this does is move code to a function,
the code is functionally the same and called in the same place...

+	struct cpu_spec *spec =3D *PTRRELOC(&cur_cpu_spec);
+
+	/*
+	 * Apply the CPU-specific and firmware specific fixups to kernel text
+	 * (nop out sections not relevant to this CPU or this firmware).
+	 */
+	do_feature_fixups(spec->cpu_features,
+			  PTRRELOC(&__start___ftr_fixup),
+			  PTRRELOC(&__stop___ftr_fixup));

Shouldn't these be PTRRELOC(spec)->cpu_features ? You are relocating
access to the pointer word, but not the address it contains.
identify_cpu() returns the relocated pointer which is what 32-bit used
to use.

Thanks,
Nick