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    SubjectRe: [PATCH net-next 1/2] tools: add missing infrastructure for building ptr_ring.h
    On Tue, Jul 06, 2021 at 10:04:02AM +0800, Yunsheng Lin wrote:
    > On 2021/7/6 2:39, Michael S. Tsirkin wrote:
    > > On Mon, Jul 05, 2021 at 11:57:34AM +0800, Yunsheng Lin wrote:
    > >> In order to build ptr_ring.h in userspace, the cacheline
    > >> aligning, cpu_relax() and slab related infrastructure is
    > >> needed, so add them in this patch.
    > >>
    > >> As L1_CACHE_BYTES may be different for different arch, which
    > >> is mostly defined in include/generated/autoconf.h, so user may
    > >> need to do "make defconfig" before building a tool using the
    > >> API in linux/cache.h.
    > >>
    > >> Also "linux/lockdep.h" is not added in "tools/include" yet,
    > >> so remove it in "linux/spinlock.h", and the only place using
    > >> "linux/spinlock.h" is tools/testing/radix-tree, removing that
    > >> does not break radix-tree testing.
    > >>
    > >> Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
    > >
    > > This is hard to review.
    > > Try to split this please. Functional changes separate from
    > > merely moving code around.
    >
    > Sure.
    >
    > >
    > >
    > >> ---
    > >> tools/include/asm/cache.h | 56 ++++++++++++++++++++++++
    > >> tools/include/asm/processor.h | 36 ++++++++++++++++
    > >> tools/include/generated/autoconf.h | 1 +
    > >> tools/include/linux/align.h | 15 +++++++
    > >> tools/include/linux/cache.h | 87 ++++++++++++++++++++++++++++++++++++++
    > >> tools/include/linux/gfp.h | 4 ++
    > >> tools/include/linux/slab.h | 46 ++++++++++++++++++++
    > >> tools/include/linux/spinlock.h | 2 -
    > >> 8 files changed, 245 insertions(+), 2 deletions(-)
    > >> create mode 100644 tools/include/asm/cache.h
    > >> create mode 100644 tools/include/asm/processor.h
    > >> create mode 100644 tools/include/generated/autoconf.h
    > >> create mode 100644 tools/include/linux/align.h
    > >> create mode 100644 tools/include/linux/cache.h
    > >> create mode 100644 tools/include/linux/slab.h
    > >>
    > >> diff --git a/tools/include/asm/cache.h b/tools/include/asm/cache.h
    > >> new file mode 100644
    > >> index 0000000..071e310
    > >> --- /dev/null
    > >> +++ b/tools/include/asm/cache.h
    > >> @@ -0,0 +1,56 @@
    > >> +/* SPDX-License-Identifier: GPL-2.0 */
    > >> +
    > >> +#ifndef __TOOLS_LINUX_ASM_CACHE_H
    > >> +#define __TOOLS_LINUX_ASM_CACHE_H
    > >> +
    > >> +#include <generated/autoconf.h>
    > >> +
    > >> +#if defined(__i386__) || defined(__x86_64__)
    > >> +#define L1_CACHE_SHIFT (CONFIG_X86_L1_CACHE_SHIFT)
    > >> +#elif defined(__arm__)
    > >> +#define L1_CACHE_SHIFT (CONFIG_ARM_L1_CACHE_SHIFT)
    > >> +#elif defined(__aarch64__)
    > >> +#define L1_CACHE_SHIFT (6)
    > >> +#elif defined(__powerpc__)
    > >> +
    > >> +/* bytes per L1 cache line */
    > >> +#if defined(CONFIG_PPC_8xx)
    > >> +#define L1_CACHE_SHIFT 4
    > >> +#elif defined(CONFIG_PPC_E500MC)
    > >> +#define L1_CACHE_SHIFT 6
    > >> +#elif defined(CONFIG_PPC32)
    > >> +#if defined(CONFIG_PPC_47x)
    > >> +#define L1_CACHE_SHIFT 7
    > >> +#else
    > >> +#define L1_CACHE_SHIFT 5
    > >> +#endif
    > >> +#else /* CONFIG_PPC64 */
    > >> +#define L1_CACHE_SHIFT 7
    > >> +#endif
    > >> +
    > >> +#elif defined(__sparc__)
    > >> +#define L1_CACHE_SHIFT 5
    > >> +#elif defined(__alpha__)
    > >> +
    > >> +#if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_EV6)
    > >> +#define L1_CACHE_SHIFT 6
    > >> +#else
    > >> +/* Both EV4 and EV5 are write-through, read-allocate,
    > >> + direct-mapped, physical.
    > >> +*/
    > >> +#define L1_CACHE_SHIFT 5
    > >> +#endif
    > >> +
    > >> +#elif defined(__mips__)
    > >> +#define L1_CACHE_SHIFT CONFIG_MIPS_L1_CACHE_SHIFT
    > >> +#elif defined(__ia64__)
    > >> +#define L1_CACHE_SHIFT CONFIG_IA64_L1_CACHE_SHIFT
    > >> +#elif defined(__nds32__)
    > >> +#define L1_CACHE_SHIFT 5
    > >> +#else
    > >> +#define L1_CACHE_SHIFT 5
    > >> +#endif
    > >> +
    > >> +#define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT)
    > >> +
    > >> +#endif
    > >> diff --git a/tools/include/asm/processor.h b/tools/include/asm/processor.h
    > >> new file mode 100644
    > >> index 0000000..3198ad6
    > >> --- /dev/null
    > >> +++ b/tools/include/asm/processor.h
    > >> @@ -0,0 +1,36 @@
    > >> +/* SPDX-License-Identifier: GPL-2.0 */
    > >> +
    > >> +#ifndef __TOOLS_LINUX_ASM_PROCESSOR_H
    > >> +#define __TOOLS_LINUX_ASM_PROCESSOR_H
    > >> +
    > >> +#include <pthread.h>
    > >> +
    > >> +#if defined(__i386__) || defined(__x86_64__)
    > >> +#include "../../arch/x86/include/asm/vdso/processor.h"
    > >> +#elif defined(__arm__)
    > >> +#include "../../arch/arm/include/asm/vdso/processor.h"
    > >> +#elif defined(__aarch64__)
    > >> +#include "../../arch/arm64/include/asm/vdso/processor.h"
    > >> +#elif defined(__powerpc__)
    > >> +#include "../../arch/powerpc/include/vdso/processor.h"
    > >> +#elif defined(__s390__)
    > >> +#include "../../arch/s390/include/vdso/processor.h"
    > >> +#elif defined(__sh__)
    > >> +#include "../../arch/sh/include/asm/processor.h"
    > >> +#elif defined(__sparc__)
    > >> +#include "../../arch/sparc/include/asm/processor.h"
    > >> +#elif defined(__alpha__)
    > >> +#include "../../arch/alpha/include/asm/processor.h"
    > >> +#elif defined(__mips__)
    > >> +#include "../../arch/mips/include/asm/vdso/processor.h"
    > >> +#elif defined(__ia64__)
    > >> +#include "../../arch/ia64/include/asm/processor.h"
    > >> +#elif defined(__xtensa__)
    > >> +#include "../../arch/xtensa/include/asm/processor.h"
    > >> +#elif defined(__nds32__)
    > >> +#include "../../arch/nds32/include/asm/processor.h"
    > >> +#else
    > >> +#define cpu_relax() sched_yield()
    > >
    > > Does this have a chance to work outside of kernel?
    >
    > I am not sure I understand what you meant here.
    > sched_yield() is a pthread API, so it should work in the
    > user space.
    > And it allow the rigntest to compile when it is built on
    > the arch which is not handled as above.

    It might compile but is likely too heavy to behave
    reasonably.

    Also, given you did not actually test it I don't
    think you should add such arch code.
    Note you broke at least s390 here:
    ../../arch/s390/include/vdso/processor.h
    does not actually exist. Where these headers
    do exit they tend to include lots of code which won't
    build out of kernel.

    All this is just for cpu_relax - open coding that seems way easier.


    > >
    > >> +#endif
    > >
    > > did you actually test or even test build all these arches?
    > > Not sure we need to bother with hacks like these.
    >
    > Only x86_64 and arm64 arches have been built and tested.

    In that case I think you should not add code that you
    have not even built let alone tested.


    > This is added referring the tools/include/asm/barrier.h.
    >
    > >
    > >
    > >> +

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