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    SubjectRE: [PATCH] clocksource/drivers/hyper-v: Include asm/hyperv-tlfs.h not asm/mshyperv.h
    Date
    On Sun, Nov 13 2022 at 10:50, Thomas Gleixner wrote:
    > On Sat, Nov 12 2022 at 21:55, Michael Kelley wrote:
    >> But I can see the problem with too much getting dragged into the VDSO
    >> builds. If hv_get_raw_timer() is added to hyperv_timer.h, it should
    >> be under #ifdef CONFIG_X86. Adding an #ifdef isn't ideal, and a more
    >> more proper solution might be to have a separate hyperv_timer.h include
    >> file under arch/x86/include/asm. But the latter seems like overkill for just
    >> hv_get_raw_timer(), so I'm OK with the #ifdef.
    >
    > We surely can have asm/hyperv_timer.h but TBH:
    >
    >>> static inline notrace u64
    >>> hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, u64 *cur_tsc)
    >>> {
    >
    > hv_read_tsc_page_tsc() does not look architecture agnostic either. TSC
    > is pretty x86 specific :)

    Though the below makes sense on its own because it ensures that msr.h is
    included, which is required for making clocksource/hyperv_timer.h self
    contained.

    Thanks,

    tglx
    ---
    Subject: clocksource/drivers/hyper-v: Include asm/hyperv-tlfs.h not asm/mshyperv.h
    From: Thomas Gleixner <tglx@linutronix.de>
    Date: Sat, 12 Nov 2022 19:08:15 +0100

    clocksource/hyperv_timer.h is included into the VDSO build. It includes
    asm/mshyperv.h which in turn includes the world and some more. This worked
    so far by chance, but any subtle change in the include chain results in a
    build breakage because VDSO builds are building user space libraries.

    Include asm/hyperv-tlfs.h instead which contains everything what the
    VDSO build needs and move the hv_get_raw_timer() define into a separate
    header file which also includes asm/msr.h to resolve rdtsc_ordered().

    Fixup drivers/hv/vmbus_drv.c which relies on the indirect include of
    asm/mshyperv.h.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    ---
    arch/x86/include/asm/hyperv_timer.h | 9 +++++++++
    arch/x86/include/asm/mshyperv.h | 2 --
    drivers/hv/vmbus_drv.c | 1 +
    include/clocksource/hyperv_timer.h | 2 +-
    4 files changed, 11 insertions(+), 3 deletions(-)

    --- /dev/null
    +++ b/arch/x86/include/asm/hyperv_timer.h
    @@ -0,0 +1,9 @@
    +/* SPDX-License-Identifier: GPL-2.0 */
    +#ifndef _ASM_X86_HYPERV_TIMER_H
    +#define _ASM_X86_HYPERV_TIMER_H
    +
    +#include <asm/msr.h>
    +
    +#define hv_get_raw_timer() rdtsc_ordered()
    +
    +#endif
    --- a/arch/x86/include/asm/mshyperv.h
    +++ b/arch/x86/include/asm/mshyperv.h
    @@ -19,8 +19,6 @@ typedef int (*hyperv_fill_flush_list_fun
    struct hv_guest_mapping_flush_list *flush,
    void *data);

    -#define hv_get_raw_timer() rdtsc_ordered()
    -
    void hyperv_vector_handler(struct pt_regs *regs);

    #if IS_ENABLED(CONFIG_HYPERV)
    --- a/drivers/hv/vmbus_drv.c
    +++ b/drivers/hv/vmbus_drv.c
    @@ -37,6 +37,7 @@
    #include <linux/dma-map-ops.h>
    #include <linux/pci.h>
    #include <clocksource/hyperv_timer.h>
    +#include <asm/mshyperv.h>
    #include "hyperv_vmbus.h"

    struct vmbus_dynid {
    --- a/include/clocksource/hyperv_timer.h
    +++ b/include/clocksource/hyperv_timer.h
    @@ -15,7 +15,7 @@

    #include <linux/clocksource.h>
    #include <linux/math64.h>
    -#include <asm/mshyperv.h>
    +#include <asm/hyperv-tlfs.h>

    #define HV_MAX_MAX_DELTA_TICKS 0xffffffff
    #define HV_MIN_DELTA_TICKS 1
    \
     
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