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![Florian Fainelli](/assets/img/avatar_default.png)
x86 has an option: CONFIG_DEBUG_VIRTUAL to do additional checks on virt_to_phys calls. The goal is to catch users who are calling virt_to_phys on non-linear addresses immediately. This includes caller using __virt_to_phys() on image addresses instead of __pa_symbol(). This is a generally useful debug feature to spot bad code (particulary in drivers). Acked-by: Russell King <rmk+kernel@armlinux.org.uk> Acked-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
57 lines
1.4 KiB
C
57 lines
1.4 KiB
C
#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/memory.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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