Commitd57c33c5da(add generic fixmap.h) added (among other similar things) set_fixmap_io to deal with early ioremap of devices. More recently, commitbf4b558eba(arm64: add early_ioremap support) converted the arm64 earlyprintk to use set_fixmap_io. A side effect of this conversion is that my virtual machines have stopped booting when I pass "earlyprintk=uart8250-8bit,0x3f8" to the guest kernel. Turns out that the new earlyprintk code doesn't care at all about sub-page offsets, and just assumes that the earlyprintk device will be page-aligned. Obviously, that doesn't play well with the above example. Further investigation shows that set_fixmap_io uses __set_fixmap instead of __set_fixmap_offset. A fix is to introduce a set_fixmap_offset_io that uses the latter, and to remove the superflous call to fix_to_virt (which only returns the value that set_fixmap_io has already given us). With this applied, my VMs are back in business. Tested on a Cortex-A57 platform with kvmtool as platform emulation. Cc: Will Deacon <will.deacon@arm.com> Acked-by: Mark Salter <msalter@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
		
			
				
	
	
		
			100 lines
		
	
	
	
		
			2.7 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			100 lines
		
	
	
	
		
			2.7 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * fixmap.h: compile-time virtual memory allocation
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 *
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 * This file is subject to the terms and conditions of the GNU General Public
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 * License.  See the file "COPYING" in the main directory of this archive
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 * for more details.
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 *
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 * Copyright (C) 1998 Ingo Molnar
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 *
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 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
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 * x86_32 and x86_64 integration by Gustavo F. Padovan, February 2009
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 * Break out common bits to asm-generic by Mark Salter, November 2013
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 */
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#ifndef __ASM_GENERIC_FIXMAP_H
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#define __ASM_GENERIC_FIXMAP_H
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#include <linux/bug.h>
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#define __fix_to_virt(x)	(FIXADDR_TOP - ((x) << PAGE_SHIFT))
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#define __virt_to_fix(x)	((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
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#ifndef __ASSEMBLY__
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/*
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 * 'index to address' translation. If anyone tries to use the idx
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 * directly without translation, we catch the bug with a NULL-deference
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 * kernel oops. Illegal ranges of incoming indices are caught too.
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 */
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static __always_inline unsigned long fix_to_virt(const unsigned int idx)
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{
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	BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
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	return __fix_to_virt(idx);
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}
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static inline unsigned long virt_to_fix(const unsigned long vaddr)
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{
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	BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
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	return __virt_to_fix(vaddr);
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}
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/*
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 * Provide some reasonable defaults for page flags.
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 * Not all architectures use all of these different types and some
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 * architectures use different names.
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 */
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#ifndef FIXMAP_PAGE_NORMAL
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#define FIXMAP_PAGE_NORMAL PAGE_KERNEL
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#endif
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#ifndef FIXMAP_PAGE_NOCACHE
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#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE
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#endif
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#ifndef FIXMAP_PAGE_IO
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#define FIXMAP_PAGE_IO PAGE_KERNEL_IO
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#endif
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#ifndef FIXMAP_PAGE_CLEAR
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#define FIXMAP_PAGE_CLEAR __pgprot(0)
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#endif
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#ifndef set_fixmap
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#define set_fixmap(idx, phys)				\
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	__set_fixmap(idx, phys, FIXMAP_PAGE_NORMAL)
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#endif
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#ifndef clear_fixmap
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#define clear_fixmap(idx)			\
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	__set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR)
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#endif
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/* Return a pointer with offset calculated */
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#define __set_fixmap_offset(idx, phys, flags)		      \
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({							      \
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	unsigned long addr;				      \
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	__set_fixmap(idx, phys, flags);			      \
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	addr = fix_to_virt(idx) + ((phys) & (PAGE_SIZE - 1)); \
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	addr;						      \
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})
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#define set_fixmap_offset(idx, phys) \
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	__set_fixmap_offset(idx, phys, FIXMAP_PAGE_NORMAL)
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/*
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 * Some hardware wants to get fixmapped without caching.
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 */
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#define set_fixmap_nocache(idx, phys) \
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	__set_fixmap(idx, phys, FIXMAP_PAGE_NOCACHE)
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#define set_fixmap_offset_nocache(idx, phys) \
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	__set_fixmap_offset(idx, phys, FIXMAP_PAGE_NOCACHE)
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/*
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 * Some fixmaps are for IO
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 */
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#define set_fixmap_io(idx, phys) \
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	__set_fixmap(idx, phys, FIXMAP_PAGE_IO)
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#define set_fixmap_offset_io(idx, phys) \
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	__set_fixmap_offset(idx, phys, FIXMAP_PAGE_IO)
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_GENERIC_FIXMAP_H */
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