This patchset is fixing compilation issues that are encountered in our usage of the Linux kernel.
Two patches are addressing compilation of eBPF related software with clang compiler on arm architecture.
The third patch resolves compilation of the perf tool in this specific scenario.
We are also interested in possible alternative approaches in fixing these compilation issues which could
then be incorporated into the mainline.
Ivan Khoronzhuk (2):
arm: include: asm: swab: mask rev16 instruction for clang
arm: include: asm: unified: mask .syntax unified for clang
Matt Redfearn (1):
include/uapi/linux/swab: Fix potentially missing __always_inline
arch/arm/include/asm/swab.h | 3 +++
arch/arm/include/asm/unified.h | 4 +++-
include/uapi/linux/swab.h | 2 +-
3 files changed, 7 insertions(+), 2 deletions(-)
--
2.32.0
From: Matt Redfearn <[email protected]>
Commit bc27fb68aaad ("include/uapi/linux/byteorder, swab: force inlining
of some byteswap operations") added __always_inline to swab functions
and commit 283d75737837 ("uapi/linux/stddef.h: Provide __always_inline to
userspace headers") added a definition of __always_inline for use in
exported headers when the kernel's compiler.h is not available.
However, since swab.h does not include stddef.h, if the header soup does
not indirectly include it, the definition of __always_inline is missing,
resulting in a compilation failure, which was observed compiling the
perf tool using exported headers containing this commit:
In file included from /usr/include/linux/byteorder/little_endian.h:12:0,
from /usr/include/asm/byteorder.h:14,
from tools/include/uapi/linux/perf_event.h:20,
from perf.h:8,
from builtin-bench.c:18:
/usr/include/linux/swab.h:160:8: error: unknown type name `__always_inline'
static __always_inline __u16 __swab16p(const __u16 *p)
Fix this by replacing the inclusion of linux/compiler.h with
linux/stddef.h to ensure that we pick up that definition if required,
without relying on it's indirect inclusion. compiler.h is then included
indirectly, via stddef.h.
Fixes: 283d75737837 ("uapi/linux/stddef.h: Provide __always_inline to userspace headers")
Signed-off-by: Matt Redfearn <[email protected]>
---
include/uapi/linux/swab.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/uapi/linux/swab.h b/include/uapi/linux/swab.h
index 7272f85d6d6a..3736f2fe1541 100644
--- a/include/uapi/linux/swab.h
+++ b/include/uapi/linux/swab.h
@@ -3,7 +3,7 @@
#define _UAPI_LINUX_SWAB_H
#include <linux/types.h>
-#include <linux/compiler.h>
+#include <linux/stddef.h>
#include <asm/bitsperlong.h>
#include <asm/swab.h>
--
2.32.0
On Tue, Jul 27, 2021 at 04:11:19PM +0200, Pavo Banicevic wrote:
> From: Matt Redfearn <[email protected]>
>
> Commit bc27fb68aaad ("include/uapi/linux/byteorder, swab: force inlining
> of some byteswap operations") added __always_inline to swab functions
> and commit 283d75737837 ("uapi/linux/stddef.h: Provide __always_inline to
> userspace headers") added a definition of __always_inline for use in
> exported headers when the kernel's compiler.h is not available.
>
> However, since swab.h does not include stddef.h, if the header soup does
> not indirectly include it, the definition of __always_inline is missing,
> resulting in a compilation failure, which was observed compiling the
> perf tool using exported headers containing this commit:
>
> In file included from /usr/include/linux/byteorder/little_endian.h:12:0,
> from /usr/include/asm/byteorder.h:14,
> from tools/include/uapi/linux/perf_event.h:20,
> from perf.h:8,
> from builtin-bench.c:18:
> /usr/include/linux/swab.h:160:8: error: unknown type name `__always_inline'
> static __always_inline __u16 __swab16p(const __u16 *p)
>
> Fix this by replacing the inclusion of linux/compiler.h with
> linux/stddef.h to ensure that we pick up that definition if required,
> without relying on it's indirect inclusion. compiler.h is then included
> indirectly, via stddef.h.
>
> Fixes: 283d75737837 ("uapi/linux/stddef.h: Provide __always_inline to userspace headers")
>
> Signed-off-by: Matt Redfearn <[email protected]>
> ---
I use this patch in order to fix __always_inline issue for kernels
5.12+, see https://lore.kernel.org/lkml/YPGXXt6Z3O1W0AYS@arkam/ .
I believe this is the correct solution.
Reviewed-by: Petr Vaněk <[email protected]>