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a9ff696160
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>
58 lines
1.4 KiB
C
58 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/bug.h>
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#include <linux/export.h>
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#include <linux/types.h>
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#include <linux/mmdebug.h>
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#include <linux/mm.h>
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#include <asm/sections.h>
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#include <asm/page.h>
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#include <asm/fixmap.h>
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#include <asm/dma.h>
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#include "mm.h"
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static inline bool __virt_addr_valid(unsigned long x)
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{
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/*
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* high_memory does not get immediately defined, and there
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* are early callers of __pa() against PAGE_OFFSET
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*/
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if (!high_memory && x >= PAGE_OFFSET)
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return true;
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if (high_memory && x >= PAGE_OFFSET && x < (unsigned long)high_memory)
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return true;
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/*
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* MAX_DMA_ADDRESS is a virtual address that may not correspond to an
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* actual physical address. Enough code relies on __pa(MAX_DMA_ADDRESS)
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* that we just need to work around it and always return true.
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*/
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if (x == MAX_DMA_ADDRESS)
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return true;
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return false;
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}
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phys_addr_t __virt_to_phys(unsigned long x)
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{
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WARN(!__virt_addr_valid(x),
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"virt_to_phys used for non-linear address: %pK (%pS)\n",
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(void *)x, (void *)x);
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return __virt_to_phys_nodebug(x);
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}
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EXPORT_SYMBOL(__virt_to_phys);
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phys_addr_t __phys_addr_symbol(unsigned long x)
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{
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/* This is bounds checking against the kernel image only.
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* __pa_symbol should only be used on kernel symbol addresses.
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*/
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VIRTUAL_BUG_ON(x < (unsigned long)KERNEL_START ||
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x > (unsigned long)KERNEL_END);
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return __pa_symbol_nodebug(x);
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}
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EXPORT_SYMBOL(__phys_addr_symbol);
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