[PATCH 5.7 046/204] powerpc: Fix circular dependency between percpu.h and mmu.h

Greg Kroah-Hartman
2020-08-20T13:13:36Z

From: Michael Ellerman <mpe@ellerman.id.au>

commit 0c83b277ada72b585e6a3e52b067669df15bcedb upstream.

Recently random.h started including percpu.h (see commit
f227e3ec3b5c ("random32: update the net random state on interrupt and
activity")), which broke corenet64_smp_defconfig:

In file included from /linux/arch/powerpc/include/asm/paca.h:18,
from /linux/arch/powerpc/include/asm/percpu.h:13,
from /linux/include/linux/random.h:14,
from /linux/lib/uuid.c:14:
/linux/arch/powerpc/include/asm/mmu.h:139:22: error: unknown type name 'next_tlbcam_idx'
139 | DECLARE_PER_CPU(int, next_tlbcam_idx);

This is due to a circular header dependency:
asm/mmu.h includes asm/percpu.h, which includes asm/paca.h, which
includes asm/mmu.h

Which means DECLARE_PER_CPU() isn't defined when mmu.h needs it.

We can fix it by moving the include of paca.h below the include of
asm-generic/percpu.h.

This moves the include of paca.h out of the #ifdef __powerpc64__, but
that is OK because paca.h is almost entirely inside #ifdef
CONFIG_PPC64 anyway.

It also moves the include of paca.h out of the #ifdef CONFIG_SMP,
which could possibly break something, but seems to have no ill
effects.

Fixes: f227e3ec3b5c ("random32: update the net random state on interrupt and activity")
Cc: stable@vger.kernel.org # v5.8
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804130558.292328-1-mpe@ellerman.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/powerpc/include/asm/percpu.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/powerpc/include/asm/percpu.h
+++ b/arch/powerpc/include/asm/percpu.h
@@ -10,8 +10,6 @@

#ifdef CONFIG_SMP

-#include <asm/paca.h>
-
#define __my_cpu_offset local_paca->data_offset

#endif /* CONFIG_SMP */
@@ -19,4 +17,6 @@

#include <asm-generic/percpu.h>

+#include <asm/paca.h>
+
#endif /* _ASM_POWERPC_PERCPU_H_ */