RE: [PATCH v2 linux-next 1/3] x86, crash: don't nest CONFIG_CRASH_DUMP ifdef inside CONFIG_KEXEC_CODE ifdef scope

[Michael Kelley]

From: Baoquan He <bhe@xxxxxxxxxx> Sent: Monday, January 29, 2024 7:00 PM
> 
> Michael pointed out that the CONFIG_CRASH_DUMP ifdef is nested inside
> CONFIG_KEXEC_CODE ifdef scope in some XEN, Hyper-V codes.
> 
> Although the nesting works well too since CONFIG_CRASH_DUMP has
> dependency on CONFIG_KEXEC_CORE, it may cause confusion because there
> are places where it's not nested, and people may think it needs to be
> nested even though it doesn't have to.
> 
> Fix that by moving  CONFIG_CRASH_DUMP ifdeffery of codes out of
> CONFIG_KEXEC_CODE ifdeffery scope.
> 
> And also put function machine_crash_shutdown() definition inside
> CONFIG_CRASH_DUMP ifdef scope instead of CONFIG_KEXEC_CORE ifdef.
> 
> And also fix a building error Nathan reported as below by replacing
> CONFIG_KEXEC_CORE ifdef with CONFIG_VMCORE_INFO ifdef.
> 
> ====
> $ curl -LSso .config https://git.alpinelinux.org/aports/plain/community/linux-edge/config-edge.x86_64
> $ make -skj"$(nproc)" ARCH=x86_64 CROSS_COMPILE=x86_64-linux-
> olddefconfig all
> ...
> x86_64-linux-ld: arch/x86/xen/mmu_pv.o: in function
> `paddr_vmcoreinfo_note':
> mmu_pv.c:(.text+0x3af3): undefined reference to `vmcoreinfo_note'
> ====
> 
> Link: https://lore.kernel.org/all/SN6PR02MB4157931105FA68D72E3D3DB8D47B2@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/T/#u
> Link: https://lore.kernel.org/all/20240126045551.GA126645@dev-arch.thelio-3990X/T/#u
> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
> ---
> v1->v2:
> - Add missing words and fix typos in patch log pointed out by Michael.
> 
>  arch/x86/kernel/cpu/mshyperv.c | 10 ++++++----
>  arch/x86/kernel/reboot.c       |  2 +-
>  arch/x86/xen/enlighten_hvm.c   |  4 ++--
>  arch/x86/xen/mmu_pv.c          |  2 +-
>  4 files changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/mshyperv.c
> b/arch/x86/kernel/cpu/mshyperv.c
> index f8163a59026b..2e8cd5a4ae85 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -209,6 +209,7 @@ static void hv_machine_shutdown(void)
>  	if (kexec_in_progress)
>  		hyperv_cleanup();
>  }
> +#endif /* CONFIG_KEXEC_CORE */
> 
>  #ifdef CONFIG_CRASH_DUMP
>  static void hv_machine_crash_shutdown(struct pt_regs *regs)
> @@ -222,8 +223,7 @@ static void hv_machine_crash_shutdown(struct
> pt_regs *regs)
>  	/* Disable the hypercall page when there is only 1 active CPU. */
>  	hyperv_cleanup();
>  }
> -#endif
> -#endif /* CONFIG_KEXEC_CORE */
> +#endif /* CONFIG_CRASH_DUMP */
>  #endif /* CONFIG_HYPERV */
> 
>  static uint32_t  __init ms_hyperv_platform(void)
> @@ -497,9 +497,11 @@ static void __init ms_hyperv_init_platform(void)
>  	no_timer_check = 1;
>  #endif
> 
> -#if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
> +#if IS_ENABLED(CONFIG_HYPERV)
> +#if defined(CONFIG_KEXEC_CORE)
>  	machine_ops.shutdown = hv_machine_shutdown;
> -#ifdef CONFIG_CRASH_DUMP
> +#endif
> +#if defined(CONFIG_CRASH_DUMP)
>  	machine_ops.crash_shutdown = hv_machine_crash_shutdown;
>  #endif
>  #endif
> diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
> index 1287b0d5962f..f3130f762784 100644
> --- a/arch/x86/kernel/reboot.c
> +++ b/arch/x86/kernel/reboot.c
> @@ -826,7 +826,7 @@ void machine_halt(void)
>  	machine_ops.halt();
>  }
> 
> -#ifdef CONFIG_KEXEC_CORE
> +#ifdef CONFIG_CRASH_DUMP
>  void machine_crash_shutdown(struct pt_regs *regs)
>  {
>  	machine_ops.crash_shutdown(regs);
> diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
> index 09e3db7ff990..0b367c1e086d 100644
> --- a/arch/x86/xen/enlighten_hvm.c
> +++ b/arch/x86/xen/enlighten_hvm.c
> @@ -148,6 +148,7 @@ static void xen_hvm_shutdown(void)
>  	if (kexec_in_progress)
>  		xen_reboot(SHUTDOWN_soft_reset);
>  }
> +#endif
> 
>  #ifdef CONFIG_CRASH_DUMP
>  static void xen_hvm_crash_shutdown(struct pt_regs *regs)
> @@ -156,7 +157,6 @@ static void xen_hvm_crash_shutdown(struct pt_regs
> *regs)
>  	xen_reboot(SHUTDOWN_soft_reset);
>  }
>  #endif
> -#endif
> 
>  static int xen_cpu_up_prepare_hvm(unsigned int cpu)
>  {
> @@ -238,10 +238,10 @@ static void __init xen_hvm_guest_init(void)
> 
>  #ifdef CONFIG_KEXEC_CORE
>  	machine_ops.shutdown = xen_hvm_shutdown;
> +#endif
>  #ifdef CONFIG_CRASH_DUMP
>  	machine_ops.crash_shutdown = xen_hvm_crash_shutdown;
>  #endif
> -#endif
>  }
> 
>  static __init int xen_parse_nopv(char *arg)
> diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
> index 218773cfb009..e21974f2cf2d 100644
> --- a/arch/x86/xen/mmu_pv.c
> +++ b/arch/x86/xen/mmu_pv.c
> @@ -2520,7 +2520,7 @@ int xen_remap_pfn(struct vm_area_struct *vma,
> unsigned long addr,
>  }
>  EXPORT_SYMBOL_GPL(xen_remap_pfn);
> 
> -#ifdef CONFIG_KEXEC_CORE
> +#ifdef CONFIG_VMCORE_INFO
>  phys_addr_t paddr_vmcoreinfo_note(void)
>  {
>  	if (xen_pv_domain())
> --
> 2.41.0

Reviewed-by: Michael Kelley <mhklinux@xxxxxxxxxxx>