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50c6dbdfd1
Allowing iounmap() on memory that was not ioremap()'d in the first place is obviously a bad idea. There is currently a feeble attempt to avoid errant iounmap()s by checking to see if the address is below "high_memory". But that's imprecise at best because there are plenty of high addresses that are also invalid to call iounmap() on. Thankfully, there is a more precise helper: is_ioremap_addr(). x86 just does not use it in iounmap(). Restrict iounmap() to addresses in the ioremap region, by using is_ioremap_addr(). This aligns x86 closer to the generic iounmap() implementation. Additionally, add a warning in case there is an attempt to iounmap() invalid memory. This replaces an existing silent return and will help alert folks to any incorrect usage of iounmap(). Due to VMALLOC_START on i386 not being present in asm/pgtable.h, include for asm/vmalloc.h had to be added to include/linux/ioremap.h. [ dhansen: tweak subject and changelog ] Signed-off-by: Max Ramanouski <max8rr8@gmail.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Alistair Popple <apopple@nvidia.com> Link: https://lore.kernel.org/all/20240824220111.84441-1-max8rr8%40gmail.com
32 lines
744 B
C
32 lines
744 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_IOREMAP_H
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#define _LINUX_IOREMAP_H
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#include <linux/kasan.h>
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#include <asm/pgtable.h>
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#include <asm/vmalloc.h>
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#if defined(CONFIG_HAS_IOMEM) || defined(CONFIG_GENERIC_IOREMAP)
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/*
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* Ioremap often, but not always uses the generic vmalloc area. E.g on
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* Power ARCH, it could have different ioremap space.
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*/
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#ifndef IOREMAP_START
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#define IOREMAP_START VMALLOC_START
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#define IOREMAP_END VMALLOC_END
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#endif
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static inline bool is_ioremap_addr(const void *x)
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{
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unsigned long addr = (unsigned long)kasan_reset_tag(x);
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return addr >= IOREMAP_START && addr < IOREMAP_END;
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}
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#else
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static inline bool is_ioremap_addr(const void *x)
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{
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return false;
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}
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#endif
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#endif /* _LINUX_IOREMAP_H */
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