linux-dev/arch/arm64/include/asm/kernel-pgtable.h, branch linus/master

arm64: head: avoid over-mapping in map_memory

2021-08-24T15:44:23Z

The `compute_indices` and `populate_entries` macros operate on inclusive bounds, and thus the `map_memory` macro which uses them also operates on inclusive bounds. We pass `_end` and `_idmap_text_end` to `map_memory`, but these are exclusive bounds, and if one of these is sufficiently aligned (as a result of kernel configuration, physical placement, and KASLR), then: * In `compute_indices`, the computed `iend` will be in the page/block *after* the final byte of the intended mapping. * In `populate_entries`, an unnecessary entry will be created at the end of each level of table. At the leaf level, this entry will map up to SWAPPER_BLOCK_SIZE bytes of physical addresses that we did not intend to map. As we may map up to SWAPPER_BLOCK_SIZE bytes more than intended, we may violate the boot protocol and map physical address past the 2MiB-aligned end address we are permitted to map. As we map these with Normal memory attributes, this may result in further problems depending on what these physical addresses correspond to. The final entry at each level may require an additional table at that level. As EARLY_ENTRIES() calculates an inclusive bound, we allocate enough memory for this. Avoid the extraneous mapping by having map_memory convert the exclusive end address to an inclusive end address by subtracting one, and do likewise in EARLY_ENTRIES() when calculating the number of required tables. For clarity, comments are updated to more clearly document which boundaries the macros operate on. For consistency with the other macros, the comments in map_memory are also updated to describe `vstart` and `vend` as virtual addresses. Fixes: 0370b31e4845 ("arm64: Extend early page table code to allow for larger kernels") Cc: # 4.16.x Signed-off-by: Mark Rutland Cc: Anshuman Khandual Cc: Ard Biesheuvel Cc: Steve Capper Cc: Will Deacon Acked-by: Will Deacon Link: https://lore.kernel.org/r/20210823101253.55567-1-mark.rutland@arm.com Signed-off-by: Catalin Marinas

arm64/mm: Rename ARM64_SWAPPER_USES_SECTION_MAPS

2021-06-21T17:22:23Z

ARM64_SWAPPER_USES_SECTION_MAPS implies that a PMD level huge page mappings are used for swapper, idmap and vmemmap. Lets make it PMD explicit removing any possible confusion with generic memory sections and also bit generic as it's applicable for idmap and vmemmap mappings as well. Hence rename it as ARM64_KERNEL_USES_PMD_MAPS instead. Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual Acked-by: Catalin Marinas Link: https://lore.kernel.org/r/1623991622-24294-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Will Deacon

arm64/mm: Drop SECTION_[SHIFT|SIZE|MASK]

2021-06-15T11:08:39Z

SECTION_[SHIFT|SIZE|MASK] are essentially PMD_[SHIFT|SIZE|MASK]. But these create confusion being similar to generic sparsemem memory sections, which are derived from SECTION_SIZE_BITS. Section references have always implied PMD level block mapping. Instead just use all PMD level macros which would make it explicit and also remove confusion with sparsmem memory sections. Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual Reviewed-by: Gavin Shan Acked-by: Catalin Marinas Link: https://lore.kernel.org/r/1623658706-7182-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Will Deacon

arm64/mm: Use CONT_PMD_SHIFT for ARM64_MEMSTART_SHIFT

2021-06-15T11:08:25Z

ARM64_MEMSTART_SIZE needs to be aligned with CONT_PMD_SIZE on 16K page size config. Hence just directly use CONT_PMD_SHIFT. Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual Reviewed-by: Gavin Shan Acked-by: Catalin Marinas Link: https://lore.kernel.org/r/1623663755-8949-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Will Deacon

arm64/mm: Drop SWAPPER_INIT_MAP_SIZE

2021-06-15T11:08:11Z

The commit cdef5f6e9e0e ("arm64: mm: allocate pagetables anywhere") had dropped the last reference to SWAPPER_INIT_MAP_SIZE. Hence just clean up. Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual Reviewed-by: Gavin Shan Link: https://lore.kernel.org/r/1623665411-20055-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Will Deacon

arm64: Force SPARSEMEM_VMEMMAP as the only memory management model

2021-04-23T13:18:21Z

Currently arm64 allows a choice of FLATMEM, SPARSEMEM and SPARSEMEM_VMEMMAP. However, only the latter is tested regularly. FLATMEM does not seem to boot in certain configurations (guest under KVM with Qemu as a VMM). Since the reduction of the SECTION_SIZE_BITS to 27 (4K pages) or 29 (64K page), there's little argument against the memory wasted by the mem_map array with SPARSEMEM. Make SPARSEMEM_VMEMMAP the only available option, non-selectable, and remove the corresponding #ifdefs under arch/arm64/. Signed-off-by: Catalin Marinas Cc: Will Deacon Acked-by: Will Deacon Acked-by: Ard Biesheuvel Acked-by: Marc Zyngier Reviewed-by: Anshuman Khandual Acked-by: Mike Rapoport Link: https://lore.kernel.org/r/20210420093559.23168-1-catalin.marinas@arm.com Signed-off-by: Catalin Marinas

arm64: consistently use reserved_pg_dir

2020-11-10T17:30:40Z

Depending on configuration options and specific code paths, we either use the empty_zero_page or the configuration-dependent reserved_ttbr0 as a reserved value for TTBR{0,1}_EL1. To simplify this code, let's always allocate and use the same reserved_pg_dir, replacing reserved_ttbr0. Note that this is allocated (and hence pre-zeroed), and is also marked as read-only in the kernel Image mapping. Keeping this separate from the empty_zero_page potentially helps with robustness as the empty_zero_page is used in a number of cases where a failure to map it read-only could allow it to become corrupted. The (presently unused) swapper_pg_end symbol is also removed, and comments are added wherever we rely on the offsets between the pre-allocated pg_dirs to keep these cases easily identifiable. Signed-off-by: Mark Rutland Cc: Will Deacon Link: https://lore.kernel.org/r/20201103102229.8542-1-mark.rutland@arm.com Signed-off-by: Catalin Marinas

arm64: get rid of TEXT_OFFSET

2020-09-07T14:00:52Z

TEXT_OFFSET serves no purpose, and for this reason, it was redefined as 0x0 in the v5.8 timeframe. Since this does not appear to have caused any issues that require us to revisit that decision, let's get rid of the macro entirely, along with any references to it. Signed-off-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20200825135440.11288-1-ardb@kernel.org Signed-off-by: Will Deacon

arm64: Reduce the number of header files pulled into vmlinux.lds.S

2020-07-21T09:50:37Z

Although vmlinux.lds.S smells like an assembly file and is compiled with __ASSEMBLY__ defined, it's actually just fed to the preprocessor to create our linker script. This means that any assembly macros defined by headers that it includes will result in a helpful link error: | aarch64-linux-gnu-ld:./arch/arm64/kernel/vmlinux.lds:1: syntax error In preparation for an arm64-private asm/rwonce.h implementation, which will end up pulling assembly macros into linux/compiler.h, reduce the number of headers we include directly and transitively in vmlinux.lds.S Acked-by: Peter Zijlstra (Intel) Signed-off-by: Will Deacon

mm: introduce include/linux/pgtable.h

2020-06-09T16:39:13Z

The include/linux/pgtable.h is going to be the home of generic page table manipulation functions. Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and make the latter include asm/pgtable.h. Signed-off-by: Mike Rapoport Signed-off-by: Andrew Morton Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Brian Cain Cc: Catalin Marinas Cc: Chris Zankel Cc: "David S. Miller" Cc: Geert Uytterhoeven Cc: Greentime Hu Cc: Greg Ungerer Cc: Guan Xuetao Cc: Guo Ren Cc: Heiko Carstens Cc: Helge Deller Cc: Ingo Molnar Cc: Ley Foon Tan Cc: Mark Salter Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Nick Hu Cc: Paul Walmsley Cc: Richard Weinberger Cc: Rich Felker Cc: Russell King Cc: Stafford Horne Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Tony Luck Cc: Vincent Chen Cc: Vineet Gupta Cc: Will Deacon Cc: Yoshinori Sato Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org Signed-off-by: Linus Torvalds