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linux/arch/arm/include/asm/proc-fns.h
Linus Walleij a9ff696160 ARM: mm: Make virt_to_pfn() a static inline 
Making virt_to_pfn() a static inline taking a strongly typed
(const void *) makes the contract of a passing a pointer of that
type to the function explicit and exposes any misuse of the
macro virt_to_pfn() acting polymorphic and accepting many types
such as (void *), (unitptr_t) or (unsigned long) as arguments
without warnings.

Doing this is a bit intrusive: virt_to_pfn() requires
PHYS_PFN_OFFSET and PAGE_SHIFT to be defined, and this is defined in
<asm/page.h>, so this must be included *before* <asm/memory.h>.

The use of macros were obscuring the unclear inclusion order here,
as the macros would eventually be resolved, but a static inline
like this cannot be compiled with unresolved macros.

The naive solution to include <asm/page.h> at the top of
<asm/memory.h> does not work, because <asm/memory.h> sometimes
includes <asm/page.h> at the end of itself, which would create a
confusing inclusion loop. So instead, take the approach to always
unconditionally include <asm/page.h> at the end of <asm/memory.h>

arch/arm uses <asm/memory.h> explicitly in a lot of places,
however it turns out that if we just unconditionally include
<asm/memory.h> into <asm/page.h> and switch all inclusions of
<asm/memory.h> to <asm/page.h> instead, we enforce the right
order and <asm/memory.h> will always have access to the
definitions.

Put an inclusion guard in place making it impossible to include
<asm/memory.h> explicitly.

Link: https://lore.kernel.org/linux-mm/20220701160004.2ffff4e5ab59a55499f4c736@linux-foundation.org/
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2023-05-29 11:27:08 +02:00

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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* arch/arm/include/asm/proc-fns.h
*
* Copyright (C) 1997-1999 Russell King
* Copyright (C) 2000 Deep Blue Solutions Ltd
*/
#ifndef __ASM_PROCFNS_H
#define __ASM_PROCFNS_H
#ifdef __KERNEL__
#include <asm/glue-proc.h>
#include <asm/page.h>
#ifndef __ASSEMBLY__
struct mm_struct;
/*
* Don't change this structure - ASM code relies on it.
*/
struct processor {
/* MISC
* get data abort address/flags
*/
void (*_data_abort)(unsigned long pc);
/*
* Retrieve prefetch fault address
*/
unsigned long (*_prefetch_abort)(unsigned long lr);
/*
* Set up any processor specifics
*/
void (*_proc_init)(void);
/*
* Check for processor bugs
*/
void (*check_bugs)(void);
/*
* Disable any processor specifics
*/
void (*_proc_fin)(void);
/*
* Special stuff for a reset
*/
void (*reset)(unsigned long addr, bool hvc) __attribute__((noreturn));
/*
* Idle the processor
*/
int (*_do_idle)(void);
/*
* Processor architecture specific
*/
/*
* clean a virtual address range from the
* D-cache without flushing the cache.
*/
void (*dcache_clean_area)(void *addr, int size);
/*
* Set the page table
*/
void (*switch_mm)(phys_addr_t pgd_phys, struct mm_struct *mm);
/*
* Set a possibly extended PTE. Non-extended PTEs should
* ignore 'ext'.
*/
#ifdef CONFIG_ARM_LPAE
void (*set_pte_ext)(pte_t *ptep, pte_t pte);
#else
void (*set_pte_ext)(pte_t *ptep, pte_t pte, unsigned int ext);
#endif
/* Suspend/resume */
unsigned int suspend_size;
void (*do_suspend)(void *);
void (*do_resume)(void *);
};
#ifndef MULTI_CPU
static inline void init_proc_vtable(const struct processor *p)
{
}
extern void cpu_proc_init(void);
extern void cpu_proc_fin(void);
extern int cpu_do_idle(void);
extern void cpu_dcache_clean_area(void *, int);
extern void cpu_do_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm);
#ifdef CONFIG_ARM_LPAE
extern void cpu_set_pte_ext(pte_t *ptep, pte_t pte);
#else
extern void cpu_set_pte_ext(pte_t *ptep, pte_t pte, unsigned int ext);
#endif
extern void cpu_reset(unsigned long addr, bool hvc) __attribute__((noreturn));
/* These three are private to arch/arm/kernel/suspend.c */
extern void cpu_do_suspend(void *);
extern void cpu_do_resume(void *);
#else
extern struct processor processor;
#if defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR)
#include <linux/smp.h>
/*
* This can't be a per-cpu variable because we need to access it before
* per-cpu has been initialised. We have a couple of functions that are
* called in a pre-emptible context, and so can't use smp_processor_id()
* there, hence PROC_TABLE(). We insist in init_proc_vtable() that the
* function pointers for these are identical across all CPUs.
*/
extern struct processor *cpu_vtable[];
#define PROC_VTABLE(f) cpu_vtable[smp_processor_id()]->f
#define PROC_TABLE(f) cpu_vtable[0]->f
static inline void init_proc_vtable(const struct processor *p)
{
unsigned int cpu = smp_processor_id();
*cpu_vtable[cpu] = *p;
WARN_ON_ONCE(cpu_vtable[cpu]->dcache_clean_area !=
cpu_vtable[0]->dcache_clean_area);
WARN_ON_ONCE(cpu_vtable[cpu]->set_pte_ext !=
cpu_vtable[0]->set_pte_ext);
}
#else
#define PROC_VTABLE(f) processor.f
#define PROC_TABLE(f) processor.f
static inline void init_proc_vtable(const struct processor *p)
{
processor = *p;
}
#endif
#define cpu_proc_init PROC_VTABLE(_proc_init)
#define cpu_check_bugs PROC_VTABLE(check_bugs)
#define cpu_proc_fin PROC_VTABLE(_proc_fin)
#define cpu_reset PROC_VTABLE(reset)
#define cpu_do_idle PROC_VTABLE(_do_idle)
#define cpu_dcache_clean_area PROC_TABLE(dcache_clean_area)
#define cpu_set_pte_ext PROC_TABLE(set_pte_ext)
#define cpu_do_switch_mm PROC_VTABLE(switch_mm)
/* These two are private to arch/arm/kernel/suspend.c */
#define cpu_do_suspend PROC_VTABLE(do_suspend)
#define cpu_do_resume PROC_VTABLE(do_resume)
#endif
extern void cpu_resume(void);
#ifdef CONFIG_MMU
#define cpu_switch_mm(pgd,mm) cpu_do_switch_mm(virt_to_phys(pgd),mm)
#ifdef CONFIG_ARM_LPAE
#define cpu_get_ttbr(nr) \
({ \
u64 ttbr; \
__asm__("mrrc p15, " #nr ", %Q0, %R0, c2" \
: "=r" (ttbr)); \
ttbr; \
})
#define cpu_get_pgd() \
({ \
u64 pg = cpu_get_ttbr(0); \
pg &= ~(PTRS_PER_PGD*sizeof(pgd_t)-1); \
(pgd_t *)phys_to_virt(pg); \
})
#else
#define cpu_get_pgd() \
({ \
unsigned long pg; \
__asm__("mrc p15, 0, %0, c2, c0, 0" \
: "=r" (pg) : : "cc"); \
pg &= ~0x3fff; \
(pgd_t *)phys_to_virt(pg); \
})
#endif
#else /*!CONFIG_MMU */
#define cpu_switch_mm(pgd,mm) { }
#endif
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* __ASM_PROCFNS_H */
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