From: Nicolas Pitre <nicolas.pitre@linaro.org>
Date: Mon, 27 Nov 2017 20:51:04 +0000 (-0500)
Subject: percpu: hack to let the CRIS architecture to boot until they clean up
X-Git-Tag: v4.15-rc4~38^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=abee210500ed15a22787009d9210b9a34911afcc;p=thirdparty%2Fkernel%2Flinux.git

percpu: hack to let the CRIS architecture to boot until they clean up

Commit 438a506180 ("percpu: don't forget to free the temporary struct
pcpu_alloc_info") uncovered a problem on the CRIS architecture where
the bootmem allocator is initialized with virtual addresses. Given it
has:

    #define __va(x) ((void *)((unsigned long)(x) | 0x80000000))

then things just work out because the end result is the same whether you
give this a physical or a virtual address.

Untill you call memblock_free_early(__pa(address)) that is, because
values from __pa() don't match with the virtual addresses stuffed in the
bootmem allocator anymore.

Avoid freeing the temporary pcpu_alloc_info memory on that architecture
until they fix things up to let the kernel boot like it did before.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 438a506180 ("percpu: don't forget to free the temporary struct pcpu_alloc_info")
---

diff --git a/mm/percpu.c b/mm/percpu.c
index 79e3549cab0f4..50e7fdf840551 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -2719,7 +2719,11 @@ void __init setup_per_cpu_areas(void)
 
 	if (pcpu_setup_first_chunk(ai, fc) < 0)
 		panic("Failed to initialize percpu areas.");
+#ifdef CONFIG_CRIS
+#warning "the CRIS architecture has physical and virtual addresses confused"
+#else
 	pcpu_free_alloc_info(ai);
+#endif
 }
 
 #endif	/* CONFIG_SMP */