Re: [PATCH] [v3] x86: xen: add missing prototypes

[Juergen Gross <jgross@xxxxxxxx>]

On 23.05.23 22:56, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> These function are all called from assembler files, or from inline assembler,
> so there is no immediate need for a prototype in a header, but if 
> -Wmissing-prototypes
> is enabled, the compiler warns about them:
>
> arch/x86/xen/efi.c:130:13: error: no previous prototype for 'xen_efi_init' 
> [-Werror=missing-prototypes]
> arch/x86/platform/pvh/enlighten.c:120:13: error: no previous prototype for 
> 'xen_prepare_pvh' [-Werror=missing-prototypes]
> arch/x86/xen/mmu_pv.c:358:20: error: no previous prototype for 'xen_pte_val' 
> [-Werror=missing-prototypes]
> arch/x86/xen/mmu_pv.c:366:20: error: no previous prototype for 'xen_pgd_val' 
> [-Werror=missing-prototypes]
> arch/x86/xen/mmu_pv.c:372:17: error: no previous prototype for 'xen_make_pte' 
> [-Werror=missing-prototypes]
> arch/x86/xen/mmu_pv.c:380:17: error: no previous prototype for 'xen_make_pgd' 
> [-Werror=missing-prototypes]
> arch/x86/xen/mmu_pv.c:387:20: error: no previous prototype for 'xen_pmd_val' 
> [-Werror=missing-prototypes]
> arch/x86/xen/mmu_pv.c:425:17: error: no previous prototype for 'xen_make_pmd' 
> [-Werror=missing-prototypes]
> arch/x86/xen/mmu_pv.c:432:20: error: no previous prototype for 'xen_pud_val' 
> [-Werror=missing-prototypes]
> arch/x86/xen/mmu_pv.c:438:17: error: no previous prototype for 'xen_make_pud' 
> [-Werror=missing-prototypes]
> arch/x86/xen/mmu_pv.c:522:20: error: no previous prototype for 'xen_p4d_val' 
> [-Werror=missing-prototypes]
> arch/x86/xen/mmu_pv.c:528:17: error: no previous prototype for 'xen_make_p4d' 
> [-Werror=missing-prototypes]
> arch/x86/xen/mmu_pv.c:1442:17: error: no previous prototype for 
> 'xen_make_pte_init' [-Werror=missing-prototypes]
I'd suggest to add the prototypes of the functions defined in
arch/x86/xen/mmu_pv.c to the same source, as they are referenced
nowhere else. This avoids the need of #ifdefs for those functions.

> arch/x86/xen/enlighten_pv.c:1233:34: error: no previous prototype for 
> 'xen_start_kernel' [-Werror=missing-prototypes]
> arch/x86/xen/irq.c:22:14: error: no previous prototype for 
> 'xen_force_evtchn_callback' [-Werror=missing-prototypes]
> arch/x86/entry/common.c:302:24: error: no previous prototype for 
> 'xen_pv_evtchn_do_upcall' [-Werror=missing-prototypes]
>
> Declare all of them in an appropriate header file to avoid the warnings.
> For consistency, also move the asm_cpu_bringup_and_idle() declaration out of
> smp_pv.c.
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> v3: move declations of conditional function in an #ifdef with a stub
> v2: fix up changelog
> ---
>   arch/x86/xen/efi.c     |  2 ++
>   arch/x86/xen/smp.h     | 11 +++++++++++
>   arch/x86/xen/smp_pv.c  |  1 -
>   arch/x86/xen/xen-ops.h | 26 ++++++++++++++++++++++++++
>   include/xen/xen.h      |  3 +++
>   5 files changed, 42 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/xen/efi.c b/arch/x86/xen/efi.c
> index 7d7ffb9c826a..863d0d6b3edc 100644
> --- a/arch/x86/xen/efi.c
> +++ b/arch/x86/xen/efi.c
> @@ -16,6 +16,8 @@
>   #include <asm/setup.h>
>   #include <asm/xen/hypercall.h>
>   
> +#include "xen-ops.h"
> +
>   static efi_char16_t vendor[100] __initdata;
>   
>   static efi_system_table_t efi_systab_xen __initdata = {
> diff --git a/arch/x86/xen/smp.h b/arch/x86/xen/smp.h
> index 22fb982ff971..9367502281dc 100644
> --- a/arch/x86/xen/smp.h
> +++ b/arch/x86/xen/smp.h
> @@ -2,6 +2,10 @@
>   #ifndef _XEN_SMP_H
>   
>   #ifdef CONFIG_SMP
> +
> +void asm_cpu_bringup_and_idle(void);
> +asmlinkage void cpu_bringup_and_idle(void);
> +
>   extern void xen_send_IPI_mask(const struct cpumask *mask,
>                               int vector);
>   extern void xen_send_IPI_mask_allbutself(const struct cpumask *mask,
> @@ -29,6 +33,13 @@ struct xen_common_irq {
>   };
>   #else /* CONFIG_SMP */
>   
> +static inline void asm_cpu_bringup_and_idle(void)
> +{
> +}
> +static inline void cpu_bringup_and_idle(void)
> +{
> +}
> +
No need for above stubs, as there is no way they can get called
without CONFIG_SMP.

>   static inline int xen_smp_intr_init(unsigned int cpu)
>   {
>         return 0;
> diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
> index a92e8002b5cf..d5ae5de2daa2 100644
> --- a/arch/x86/xen/smp_pv.c
> +++ b/arch/x86/xen/smp_pv.c
> @@ -55,7 +55,6 @@ static DEFINE_PER_CPU(struct xen_common_irq, xen_irq_work) = 
> { .irq = -1 };
>   static DEFINE_PER_CPU(struct xen_common_irq, xen_pmu_irq) = { .irq = -1 };
>   
>   static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id);
> -void asm_cpu_bringup_and_idle(void);
>   
>   static void cpu_bringup(void)
>   {
> diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
> index 6d7f6318fc07..eb4cb30570c7 100644
> --- a/arch/x86/xen/xen-ops.h
> +++ b/arch/x86/xen/xen-ops.h
> @@ -146,12 +146,38 @@ int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned 
> int),
>   void xen_pin_vcpu(int cpu);
>   
>   void xen_emergency_restart(void);
> +void xen_force_evtchn_callback(void);
> +
>   #ifdef CONFIG_XEN_PV
>   void xen_pv_pre_suspend(void);
>   void xen_pv_post_suspend(int suspend_cancelled);
> +pteval_t xen_pte_val(pte_t pte);
> +pgdval_t xen_pgd_val(pgd_t pgd);
> +pmdval_t xen_pmd_val(pmd_t pmd);
> +pudval_t xen_pud_val(pud_t pud);
> +p4dval_t xen_p4d_val(p4d_t p4d);
> +pte_t xen_make_pte(pteval_t pte);
> +pgd_t xen_make_pgd(pgdval_t pgd);
> +pmd_t xen_make_pmd(pmdval_t pmd);
> +pud_t xen_make_pud(pudval_t pud);
> +p4d_t xen_make_p4d(p4dval_t p4d);
> +pte_t xen_make_pte_init(pteval_t pte);
See above.

> +void xen_start_kernel(struct start_info *si);
>   #else
>   static inline void xen_pv_pre_suspend(void) {}
>   static inline void xen_pv_post_suspend(int suspend_cancelled) {}
> +static inline pteval_t xen_pte_val(pte_t pte)  { return pte.pte; }
> +static inline pgdval_t xen_pgd_val(pgd_t pgd)  { return pgd.pgd; }
> +static inline pmdval_t xen_pmd_val(pmd_t pmd)  { return pmd.pmd; }
> +static inline pudval_t xen_pud_val(pud_t pud)  { return pud.pud; }
> +static inline p4dval_t xen_p4d_val(p4d_t p4d)  { return p4d.p4d; }
> +static inline pte_t xen_make_pte(pteval_t pte) { return (pte_t){pte}; }
> +static inline pgd_t xen_make_pgd(pgdval_t pgd) { return (pgd_t){pgd}; }
> +static inline pmd_t xen_make_pmd(pmdval_t pmd) { return (pmd_t){pmd}; }
> +static inline pud_t xen_make_pud(pudval_t pud) { return (pud_t){pud}; }
> +static inline p4d_t xen_make_p4d(p4dval_t p4d) { return (p4d_t){p4d}; }
> +static inline pte_t xen_make_pte_init(pteval_t pte)    { return (pte_t){pte}; }
> +static inline void xen_start_kernel(struct start_info *si) {}
Drop those stubs, they are not used without CONFIG_XEN_PV, and
they shouldn't be used in this case anyway.

>   #endif
>   
>   #ifdef CONFIG_XEN_PVHVM
> diff --git a/include/xen/xen.h b/include/xen/xen.h
> index 0efeb652f9b8..f989162983c3 100644
> --- a/include/xen/xen.h
> +++ b/include/xen/xen.h
> @@ -31,6 +31,9 @@ extern uint32_t xen_start_flags;
>   
>   #include <xen/interface/hvm/start_info.h>
>   extern struct hvm_start_info pvh_start_info;
> +void xen_prepare_pvh(void);
> +struct pt_regs;
> +void xen_pv_evtchn_do_upcall(struct pt_regs *regs);
>   
>   #ifdef CONFIG_XEN_DOM0
>   #include <xen/interface/xen.h>

Juergen

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