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2015-08-20mm: provide early_memremap_ro to establish read-only mappingJuergen Gross
During early boot as Xen pv domain the kernel needs to map some page tables supplied by the hypervisor read only. This is needed to be able to relocate some data structures conflicting with the physical memory map especially on systems with huge RAM (above 512GB). Provide the function early_memremap_ro() to provide this read only mapping. Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: Konrad Rzeszutek Wilk <Konrad.wilk@oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-05-03arm64: fixmap: fix missing sub-page offset for earlyprintkMarc Zyngier
Commit d57c33c5daa4 (add generic fixmap.h) added (among other similar things) set_fixmap_io to deal with early ioremap of devices. More recently, commit bf4b558eba92 (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>
2014-01-23add generic fixmap.hMark Salter
Many architectures provide an asm/fixmap.h which defines support for compile-time 'special' virtual mappings which need to be made before paging_init() has run. This support is also used for early ioremap on x86. Much of this support is identical across the architectures. This patch consolidates all of the common bits into asm-generic/fixmap.h which is intended to be included from arch/*/include/asm/fixmap.h. Signed-off-by: Mark Salter <msalter@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: James Hogan <james.hogan@imgtec.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jonas Bonn <jonas.bonn@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>