2020-06-15 08:28:50

by Christophe Leroy

Subject: [PATCH] powerpc/fixmap: Fix FIX_EARLY_DEBUG_BASE when page size is 256k

FIX_EARLY_DEBUG_BASE reserves a 128k area for debuging.

When page size is 256k, the calculation results in a 0 number of
pages, leading to the following failure:

CC arch/powerpc/kernel/asm-offsets.s
In file included from ./arch/powerpc/include/asm/nohash/32/pgtable.h:77:0,
from ./arch/powerpc/include/asm/nohash/pgtable.h:8,
from ./arch/powerpc/include/asm/pgtable.h:20,
from ./include/linux/pgtable.h:6,
from ./arch/powerpc/include/asm/kup.h:42,
from ./arch/powerpc/include/asm/uaccess.h:9,
from ./include/linux/uaccess.h:11,
from ./include/linux/crypto.h:21,
from ./include/crypto/hash.h:11,
from ./include/linux/uio.h:10,
from ./include/linux/socket.h:8,
from ./include/linux/compat.h:15,
from arch/powerpc/kernel/asm-offsets.c:14:
./arch/powerpc/include/asm/fixmap.h:75:2: error: overflow in enumeration values
__end_of_permanent_fixed_addresses,
^
make[2]: *** [arch/powerpc/kernel/asm-offsets.s] Error 1

Ensure the debug area is at least one page.

Reported-by: kernel test robot <[email protected]>
Fixes: b8e8efaa8639 ("powerpc: reserve fixmap entries for early debug")
Cc: [email protected]
Cc: Albert Herranz <[email protected]>
Signed-off-by: Christophe Leroy <[email protected]>
---
arch/powerpc/include/asm/fixmap.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/fixmap.h b/arch/powerpc/include/asm/fixmap.h
index 29188810ba30..925cf89cbf4b 100644
--- a/arch/powerpc/include/asm/fixmap.h
+++ b/arch/powerpc/include/asm/fixmap.h
@@ -52,7 +52,7 @@ enum fixed_addresses {
FIX_HOLE,
/* reserve the top 128K for early debugging purposes */
FIX_EARLY_DEBUG_TOP = FIX_HOLE,
- FIX_EARLY_DEBUG_BASE = FIX_EARLY_DEBUG_TOP+((128*1024)/PAGE_SIZE)-1,
+ FIX_EARLY_DEBUG_BASE = FIX_EARLY_DEBUG_TOP+(ALIGN(SZ_128, PAGE_SIZE)/PAGE_SIZE)-1,
#ifdef CONFIG_HIGHMEM
FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
--
2.25.0

2020-06-26 04:56:09

by Michael Ellerman

Subject: Re: [PATCH] powerpc/fixmap: Fix FIX_EARLY_DEBUG_BASE when page size is 256k

On Mon, 15 Jun 2020 07:48:25 +0000 (UTC), Christophe Leroy wrote:
> FIX_EARLY_DEBUG_BASE reserves a 128k area for debuging.
>
> When page size is 256k, the calculation results in a 0 number of
> pages, leading to the following failure:
>
> CC arch/powerpc/kernel/asm-offsets.s
> In file included from ./arch/powerpc/include/asm/nohash/32/pgtable.h:77:0,
> from ./arch/powerpc/include/asm/nohash/pgtable.h:8,
> from ./arch/powerpc/include/asm/pgtable.h:20,
> from ./include/linux/pgtable.h:6,
> from ./arch/powerpc/include/asm/kup.h:42,
> from ./arch/powerpc/include/asm/uaccess.h:9,
> from ./include/linux/uaccess.h:11,
> from ./include/linux/crypto.h:21,
> from ./include/crypto/hash.h:11,
> from ./include/linux/uio.h:10,
> from ./include/linux/socket.h:8,
> from ./include/linux/compat.h:15,
> from arch/powerpc/kernel/asm-offsets.c:14:
> ./arch/powerpc/include/asm/fixmap.h:75:2: error: overflow in enumeration values
> __end_of_permanent_fixed_addresses,
> ^
> make[2]: *** [arch/powerpc/kernel/asm-offsets.s] Error 1
>
> [...]

Applied to powerpc/next.

[1/1] powerpc/fixmap: Fix FIX_EARLY_DEBUG_BASE when page size is 256k
https://git.kernel.org/powerpc/c/03fd42d458fb9cb69e712600bd69ff77ff3a45a8

cheers