Re: [PATCH v2] xen: remove <asm/delay.h>

[Jan Beulich <jbeulich@xxxxxxxx>]

On 10.11.2023 10:30, Oleksii wrote:
> On Tue, 2023-10-31 at 16:28 +0200, Oleksii Kurochko wrote:
>> <asm/delay.h> only declares udelay() function so udelay()
>> declaration was moved to xen/delay.h.
>>
>> For x86, __udelay() was renamed to udelay() and removed
>> inclusion of <asm/delay.h> in x86 code.
>>
>> For ppc, udelay() stub definition was moved to ppc/stubs.c.
>>
>> Suggested-by: Jan Beulich <jbeulich@xxxxxxxx>
>> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
>> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
>> ---
>> Changes in v2:
>>  - rebase on top of the latest staging.
>>  - add Suggested-by:/Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>.
>>  - remove <asm/delay.h> for PPC.
>>  - remove changes related to RISC-V's <asm/delay.h> as they've not
>>    introduced in staging branch yet.
>> ---
>>  xen/arch/arm/include/asm/delay.h  | 14 --------------
>>  xen/arch/ppc/include/asm/delay.h  | 12 ------------
>>  xen/arch/ppc/stubs.c              |  7 +++++++
>>  xen/arch/x86/cpu/microcode/core.c |  2 +-
>>  xen/arch/x86/delay.c              |  2 +-
>>  xen/arch/x86/include/asm/delay.h  | 13 -------------
>>  xen/include/xen/delay.h           |  2 +-
>>  7 files changed, 10 insertions(+), 42 deletions(-)
>>  delete mode 100644 xen/arch/arm/include/asm/delay.h
>>  delete mode 100644 xen/arch/ppc/include/asm/delay.h
>>  delete mode 100644 xen/arch/x86/include/asm/delay.h
>>
>> diff --git a/xen/arch/arm/include/asm/delay.h
>> b/xen/arch/arm/include/asm/delay.h
>> deleted file mode 100644
>> index 042907d9d5..0000000000
>> --- a/xen/arch/arm/include/asm/delay.h
>> +++ /dev/null
>> @@ -1,14 +0,0 @@
>> -#ifndef _ARM_DELAY_H
>> -#define _ARM_DELAY_H
>> -
>> -extern void udelay(unsigned long usecs);
>> -
>> -#endif /* defined(_ARM_DELAY_H) */
>> -/*
>> - * Local variables:
>> - * mode: C
>> - * c-file-style: "BSD"
>> - * c-basic-offset: 4
>> - * indent-tabs-mode: nil
>> - * End:
>> - */
>> diff --git a/xen/arch/ppc/include/asm/delay.h
>> b/xen/arch/ppc/include/asm/delay.h
>> deleted file mode 100644
>> index da6635888b..0000000000
>> --- a/xen/arch/ppc/include/asm/delay.h
>> +++ /dev/null
>> @@ -1,12 +0,0 @@
>> -/* SPDX-License-Identifier: GPL-2.0-only */
>> -#ifndef __ASM_PPC_DELAY_H__
>> -#define __ASM_PPC_DELAY_H__
>> -
>> -#include <xen/lib.h>
>> -
>> -static inline void udelay(unsigned long usecs)
>> -{
>> -    BUG_ON("unimplemented");
>> -}
>> -
>> -#endif /* __ASM_PPC_DELAY_H__ */
>> diff --git a/xen/arch/ppc/stubs.c b/xen/arch/ppc/stubs.c
>> index 4c276b0e39..a96e45626d 100644
>> --- a/xen/arch/ppc/stubs.c
>> +++ b/xen/arch/ppc/stubs.c
>> @@ -337,3 +337,10 @@ int __init parse_arch_dom0_param(const char *s,
>> const char *e)
>>  {
>>      BUG_ON("unimplemented");
>>  }
>> +
>> +/* delay.c */
>> +
>> +void udelay(unsigned long usecs)
>> +{
>> +    BUG_ON("unimplemented");
>> +}
>> diff --git a/xen/arch/x86/cpu/microcode/core.c
>> b/xen/arch/x86/cpu/microcode/core.c
>> index 65ebeb50de..22d5e04552 100644
>> --- a/xen/arch/x86/cpu/microcode/core.c
>> +++ b/xen/arch/x86/cpu/microcode/core.c
>> @@ -23,6 +23,7 @@
>>  
>>  #include <xen/alternative-call.h>
>>  #include <xen/cpu.h>
>> +#include <xen/delay.h>
>>  #include <xen/earlycpio.h>
>>  #include <xen/err.h>
>>  #include <xen/guest_access.h>
>> @@ -35,7 +36,6 @@
>>  
>>  #include <asm/apic.h>
>>  #include <asm/cpu-policy.h>
>> -#include <asm/delay.h>
>>  #include <asm/nmi.h>
>>  #include <asm/processor.h>
>>  #include <asm/setup.h>
>> diff --git a/xen/arch/x86/delay.c b/xen/arch/x86/delay.c
>> index 2662c26272..b3a41881a1 100644
>> --- a/xen/arch/x86/delay.c
>> +++ b/xen/arch/x86/delay.c
>> @@ -15,7 +15,7 @@
>>  #include <asm/msr.h>
>>  #include <asm/processor.h>
>>  
>> -void __udelay(unsigned long usecs)
>> +void udelay(unsigned long usecs)
>>  {
>>      unsigned long ticks = usecs * (cpu_khz / 1000);
>>      unsigned long s, e;
>> diff --git a/xen/arch/x86/include/asm/delay.h
>> b/xen/arch/x86/include/asm/delay.h
>> deleted file mode 100644
>> index 9be2f46590..0000000000
>> --- a/xen/arch/x86/include/asm/delay.h
>> +++ /dev/null
>> @@ -1,13 +0,0 @@
>> -#ifndef _X86_DELAY_H
>> -#define _X86_DELAY_H
>> -
>> -/*
>> - * Copyright (C) 1993 Linus Torvalds
>> - *
>> - * Delay routines calling functions in arch/i386/lib/delay.c
>> - */
>> -
>> -extern void __udelay(unsigned long usecs);
>> -#define udelay(n) __udelay(n)
>> -
>> -#endif /* defined(_X86_DELAY_H) */
>> diff --git a/xen/include/xen/delay.h b/xen/include/xen/delay.h
>> index 9150226271..8fd3b8f99f 100644
>> --- a/xen/include/xen/delay.h
>> +++ b/xen/include/xen/delay.h
>> @@ -3,7 +3,7 @@
>>  
>>  /* Copyright (C) 1993 Linus Torvalds */
>>  
>> -#include <asm/delay.h>
>> +void udelay(unsigned long usecs);
>>  
>>  static inline void mdelay(unsigned long msec)
>>  {
> 
> I forgot to update xen/arch/{x86,arm,ppc}/include/asm/Makefile:
>     generic-y += delay.h
> 
> Should I send a new patch version or it can be updated durig merge?

My take is that such a change wouldn't be appropriate to do by the
committer. But: Why would this be needed? You're not introducing
asm-generic/delay.h. Everything is moved to just xen/delay.h.

Jan