kernel.git/arch/arm64/include/asm/fixmap.h, branch linux-4.19.y

arm64: entry: Allow the trampoline text to occupy multiple pages

2022-03-23T08:10:43Z

commit a9c406e6462ff14956d690de7bbe5131a5677dc9 upstream. Adding a second set of vectors to .entry.tramp.text will make it larger than a single 4K page. Allow the trampoline text to occupy up to three pages by adding two more fixmap slots. Previous changes to tramp_valias allowed it to reach beyond a single page. Reviewed-by: Catalin Marinas Signed-off-by: James Morse Signed-off-by: Greg Kroah-Hartman

arm64: entry: Move the trampoline data page before the text page

2022-03-23T08:10:42Z

commit c091fb6ae059cda563b2a4d93fdbc548ef34e1d6 upstream. The trampoline code has a data page that holds the address of the vectors, which is unmapped when running in user-space. This ensures that with CONFIG_RANDOMIZE_BASE, the randomised address of the kernel can't be discovered until after the kernel has been mapped. If the trampoline text page is extended to include multiple sets of vectors, it will be larger than a single page, making it tricky to find the data page without knowing the size of the trampoline text pages, which will vary with PAGE_SIZE. Move the data page to appear before the text page. This allows the data page to be found without knowing the size of the trampoline text pages. 'tramp_vectors' is used to refer to the beginning of the .entry.tramp.text section, do that explicitly. Reviewed-by: Russell King (Oracle) Reviewed-by: Catalin Marinas Signed-off-by: James Morse Signed-off-by: Greg Kroah-Hartman

arm64: kaslr: Put kernel vectors address in separate data page

2017-12-11T13:41:20Z

The literal pool entry for identifying the vectors base is the only piece of information in the trampoline page that identifies the true location of the kernel. This patch moves it into a page-aligned region of the .rodata section and maps this adjacent to the trampoline text via an additional fixmap entry, which protects against any accidental leakage of the trampoline contents. Suggested-by: Ard Biesheuvel Tested-by: Laura Abbott Tested-by: Shanker Donthineni Signed-off-by: Will Deacon

arm64: mm: Map entry trampoline into trampoline and kernel page tables

2017-12-11T13:40:50Z

The exception entry trampoline needs to be mapped at the same virtual address in both the trampoline page table (which maps nothing else) and also the kernel page table, so that we can swizzle TTBR1_EL1 on exceptions from and return to EL0. This patch maps the trampoline at a fixed virtual address in the fixmap area of the kernel virtual address space, which allows the kernel proper to be randomized with respect to the trampoline when KASLR is enabled. Reviewed-by: Mark Rutland Tested-by: Laura Abbott Tested-by: Shanker Donthineni Signed-off-by: Will Deacon

ACPI / APEI: Replace ioremap_page_range() with fixmap

2017-11-07T11:12:44Z

Replace ghes_io{re,un}map_pfn_{nmi,irq}()s use of ioremap_page_range() with __set_fixmap() as ioremap_page_range() may sleep to allocate a new level of page-table, even if its passed an existing final-address to use in the mapping. The GHES driver can only be enabled for architectures that select HAVE_ACPI_APEI: Add fixmap entries to both x86 and arm64. clear_fixmap() does the TLB invalidation in __set_fixmap() for arm64 and __set_pte_vaddr() for x86. In each case its the same as the respective arch_apei_flush_tlb_one(). Reported-by: Fengguang Wu Suggested-by: Linus Torvalds Signed-off-by: James Morse Reviewed-by: Borislav Petkov Tested-by: Tyler Baicar Tested-by: Toshi Kani [ For the arm64 bits: ] Acked-by: Will Deacon [ For the x86 bits: ] Acked-by: Ingo Molnar Signed-off-by: Rafael J. Wysocki Cc: All applicable

arm64: Remove fixmap include fragility

2016-02-26T15:22:53Z

The asm-generic fixmap.h depends on each architecture's fixmap.h to pull in the definition of PAGE_KERNEL_RO, if this exists. In the absence of this, FIXMAP_PAGE_RO will not be defined. In mm/early_ioremap.c the definition of early_memremap_ro is predicated on FIXMAP_PAGE_RO being defined. Currently, the arm64 fixmap.h doesn't include pgtable.h for the definition of PAGE_KERNEL_RO, and as a knock-on effect early_memremap_ro is not always defined, leading to link-time failures when it is used. This has been observed with defconfig on next-20160226. Unfortunately, as pgtable.h includes fixmap.h, adding the include introduces a circular dependency, which is just as fragile. Instead, this patch factors out PAGE_KERNEL_RO and other prot definitions into a new pgtable-prot header which can be included by poth pgtable.h and fixmap.h, avoiding the circular dependency, and ensuring that early_memremap_ro is alwyas defined where it is used. Signed-off-by: Mark Rutland Reported-by: Ard Biesheuvel Acked-by: Ard Biesheuvel Cc: Will Deacon Signed-off-by: Catalin Marinas

arm64: mm: add functions to walk tables in fixmap

2016-02-16T15:10:46Z

As a preparatory step to allow us to allocate early page tables from unmapped memory using memblock_alloc, add new p??_{set,clear}_fixmap* functions which can be used to walk page tables outside of the linear mapping by using fixmap slots. Signed-off-by: Mark Rutland Reviewed-by: Catalin Marinas Tested-by: Ard Biesheuvel Reviewed-by: Ard Biesheuvel Tested-by: Jeremy Linton Cc: Laura Abbott Cc: Will Deacon Signed-off-by: Catalin Marinas

arm64: Simplify NR_FIX_BTMAPS calculation

2015-10-19T16:54:07Z

We choose NR_FIX_BTMAPS such that each slot (NR_FIX_BTMAPS * PAGE_SIZE) can address 256K. Use division to derive NR_FIX_BTMAPS rather than defining it for each page size. Signed-off-by: Mark Rutland Signed-off-by: Suzuki K. Poulose Signed-off-by: Catalin Marinas

arm64: Fix source code file path in comments

2015-08-24T09:18:11Z

Architecture specific code for i386 and x86_64 was unified and merged to the arch/x86. This patch fix old path of x86 architecture in a comment from the arch/arm64/include/asm/fixmap.h. Signed-off-by: Alexander Kuleshov Signed-off-by: Will Deacon

arm64: use fixmap region for permanent FDT mapping

2015-06-02T15:31:33Z

Currently, the FDT blob needs to be in the same 512 MB region as the kernel, so that it can be mapped into the kernel virtual memory space very early on using a minimal set of statically allocated translation tables. Now that we have early fixmap support, we can relax this restriction, by moving the permanent FDT mapping to the fixmap region instead. This way, the FDT blob may be anywhere in memory. This also moves the vetting of the FDT to mmu.c, since the early init code in head.S does not handle mapping of the FDT anymore. At the same time, fix up some comments in head.S that have gone stale. Reviewed-by: Mark Rutland Tested-by: Mark Rutland Signed-off-by: Ard Biesheuvel Signed-off-by: Catalin Marinas