[PATCH 5.7 148/393] powerpc/fixmap: Fix FIX_EARLY_DEBUG_BASE when page size is 256k

From: Greg Kroah-Hartman
Date: Mon Aug 17 2020 - 15:01:57 EST


From: Christophe Leroy <christophe.leroy@xxxxxxxxxx>

[ Upstream commit 03fd42d458fb9cb69e712600bd69ff77ff3a45a8 ]

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.

Fixes: b8e8efaa8639 ("powerpc: reserve fixmap entries for early debug")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/ca8c9f8249f523b1fab873e67b81b11989d46553.1592207216.git.christophe.leroy@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 2ef155a3c8214..77ab25a199740 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,
--
2.25.1