diff mbox series

[v3,1/2] powerpc/boot: add {get, put}_unaligned_be32 to xz_config.h

Message ID 20190705100144.28785-1-yamada.masahiro@socionext.com (mailing list archive)
State Accepted
Commit 9e005b761e7ad153dcf40a6cba1d681fe0830ac6
Headers show
Series [v3,1/2] powerpc/boot: add {get, put}_unaligned_be32 to xz_config.h | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch success Successfully applied on branch next (f531d5e8f55b3767217b5d1be0ce1f1acd10167c)
snowpatch_ozlabs/checkpatch warning total: 0 errors, 1 warnings, 0 checks, 30 lines checked

Commit Message

Masahiro Yamada July 5, 2019, 10:01 a.m. UTC
The next commit will make the way of passing CONFIG options more robust.
Unfortunately, it would uncover another hidden issue; without this
commit, skiroot_defconfig would be broken like this:

|   WRAP    arch/powerpc/boot/zImage.pseries
| arch/powerpc/boot/wrapper.a(decompress.o): In function `bcj_powerpc.isra.10':
| decompress.c:(.text+0x720): undefined reference to `get_unaligned_be32'
| decompress.c:(.text+0x7a8): undefined reference to `put_unaligned_be32'
| make[1]: *** [arch/powerpc/boot/Makefile;383: arch/powerpc/boot/zImage.pseries] Error 1
| make: *** [arch/powerpc/Makefile;295: zImage] Error 2

skiroot_defconfig is the only defconfig that enables CONFIG_KERNEL_XZ
for ppc, which has never been correctly built before.

I figured out the root cause in lib/decompress_unxz.c:

| #ifdef CONFIG_PPC
| #      define XZ_DEC_POWERPC
| #endif

CONFIG_PPC is undefined here in the ppc bootwrapper because autoconf.h
is not included except by arch/powerpc/boot/serial.c

XZ_DEC_POWERPC is not defined, therefore, bcj_powerpc() is not compiled
for the bootwrapper.

With the next commit passing CONFIG_PPC correctly, we would realize that
{get,put}_unaligned_be32 was missing.

Unlike the other decompressors, the ppc bootwrapper duplicates all the
necessary helpers in arch/powerpc/boot/.

The other architectures define __KERNEL__ and pull in helpers for
building the decompressors.

If ppc bootwrapper had defined __KERNEL__, lib/xz/xz_private.h would
have included <asm/unaligned.h>:

| #ifdef __KERNEL__
| #       include <linux/xz.h>
| #       include <linux/kernel.h>
| #       include <asm/unaligned.h>

However, doing so would cause tons of definition conflicts since the
bootwrapper has duplicated everything.

I just added copies of {get,put}_unaligned_be32, following the
bootwrapper coding convention.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

Changes in v3:
 - New patch to fix the potential issue of skiroot_defconfig

Changes in v2: None

 arch/powerpc/boot/xz_config.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Comments

Michael Ellerman July 10, 2019, 3:05 p.m. UTC | #1
On Fri, 2019-07-05 at 10:01:43 UTC, Masahiro Yamada wrote:
> The next commit will make the way of passing CONFIG options more robust.
> Unfortunately, it would uncover another hidden issue; without this
> commit, skiroot_defconfig would be broken like this:
> 
> |   WRAP    arch/powerpc/boot/zImage.pseries
> | arch/powerpc/boot/wrapper.a(decompress.o): In function `bcj_powerpc.isra.10':
> | decompress.c:(.text+0x720): undefined reference to `get_unaligned_be32'
> | decompress.c:(.text+0x7a8): undefined reference to `put_unaligned_be32'
> | make[1]: *** [arch/powerpc/boot/Makefile;383: arch/powerpc/boot/zImage.pseries] Error 1
> | make: *** [arch/powerpc/Makefile;295: zImage] Error 2
> 
> skiroot_defconfig is the only defconfig that enables CONFIG_KERNEL_XZ
> for ppc, which has never been correctly built before.
> 
> I figured out the root cause in lib/decompress_unxz.c:
> 
> | #ifdef CONFIG_PPC
> | #      define XZ_DEC_POWERPC
> | #endif
> 
> CONFIG_PPC is undefined here in the ppc bootwrapper because autoconf.h
> is not included except by arch/powerpc/boot/serial.c
> 
> XZ_DEC_POWERPC is not defined, therefore, bcj_powerpc() is not compiled
> for the bootwrapper.
> 
> With the next commit passing CONFIG_PPC correctly, we would realize that
> {get,put}_unaligned_be32 was missing.
> 
> Unlike the other decompressors, the ppc bootwrapper duplicates all the
> necessary helpers in arch/powerpc/boot/.
> 
> The other architectures define __KERNEL__ and pull in helpers for
> building the decompressors.
> 
> If ppc bootwrapper had defined __KERNEL__, lib/xz/xz_private.h would
> have included <asm/unaligned.h>:
> 
> | #ifdef __KERNEL__
> | #       include <linux/xz.h>
> | #       include <linux/kernel.h>
> | #       include <asm/unaligned.h>
> 
> However, doing so would cause tons of definition conflicts since the
> bootwrapper has duplicated everything.
> 
> I just added copies of {get,put}_unaligned_be32, following the
> bootwrapper coding convention.
> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/9e005b761e7ad153dcf40a6cba1d681fe0830ac6

cheers
diff mbox series

Patch

diff --git a/arch/powerpc/boot/xz_config.h b/arch/powerpc/boot/xz_config.h
index e22e5b3770dd..ebfadd39e192 100644
--- a/arch/powerpc/boot/xz_config.h
+++ b/arch/powerpc/boot/xz_config.h
@@ -20,10 +20,30 @@  static inline uint32_t swab32p(void *p)
 
 #ifdef __LITTLE_ENDIAN__
 #define get_le32(p) (*((uint32_t *) (p)))
+#define cpu_to_be32(x) swab32(x)
+static inline u32 be32_to_cpup(const u32 *p)
+{
+	return swab32p((u32 *)p);
+}
 #else
 #define get_le32(p) swab32p(p)
+#define cpu_to_be32(x) (x)
+static inline u32 be32_to_cpup(const u32 *p)
+{
+	return *p;
+}
 #endif
 
+static inline uint32_t get_unaligned_be32(const void *p)
+{
+	return be32_to_cpup(p);
+}
+
+static inline void put_unaligned_be32(u32 val, void *p)
+{
+	*((u32 *)p) = cpu_to_be32(val);
+}
+
 #define memeq(a, b, size) (memcmp(a, b, size) == 0)
 #define memzero(buf, size) memset(buf, 0, size)