c83557859e
Enabling KASLR forces the use of non-global page-table entries for kernel mappings, as this is a decision that we have to make very early on before mapping the kernel proper. When used in conjunction with the "kpti=off" command-line option, it is possible to use non-global kernel mappings but with the kpti trampoline disabled. Since commit09e3c22a86
("arm64: Use a variable to store non-global mappings decision"), arm64_kernel_unmapped_at_el0() reflects only the use of non-global mappings and does not take into account whether the kpti trampoline is enabled. This breaks context switching of the TPIDRRO_EL0 register for 64-bit tasks, where the clearing of the register is deferred to the ret-to-user code, but it also breaks the ARM SPE PMU driver which helpfully recommends passing "kpti=off" on the command line! Report whether or not KPTI is actually enabled in arm64_kernel_unmapped_at_el0() and check the 'arm64_use_ng_mappings' global variable directly when determining the protection flags for kernel mappings. Cc: Mark Brown <broonie@kernel.org> Reported-by: Hongbo Yao <yaohongbo@huawei.com> Tested-by: Hongbo Yao <yaohongbo@huawei.com> Fixes:09e3c22a86
("arm64: Use a variable to store non-global mappings decision") Signed-off-by: Will Deacon <will@kernel.org>
112 lines
4.3 KiB
C
112 lines
4.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2016 ARM Ltd.
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*/
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#ifndef __ASM_PGTABLE_PROT_H
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#define __ASM_PGTABLE_PROT_H
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#include <asm/memory.h>
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#include <asm/pgtable-hwdef.h>
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#include <linux/const.h>
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/*
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* Software defined PTE bits definition.
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*/
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#define PTE_WRITE (PTE_DBM) /* same as DBM (51) */
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#define PTE_DIRTY (_AT(pteval_t, 1) << 55)
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#define PTE_SPECIAL (_AT(pteval_t, 1) << 56)
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#define PTE_DEVMAP (_AT(pteval_t, 1) << 57)
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#define PTE_PROT_NONE (_AT(pteval_t, 1) << 58) /* only when !PTE_VALID */
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#ifndef __ASSEMBLY__
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#include <asm/pgtable-types.h>
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extern bool arm64_use_ng_mappings;
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#define _PROT_DEFAULT (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
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#define _PROT_SECT_DEFAULT (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
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#define PTE_MAYBE_NG (arm64_use_ng_mappings ? PTE_NG : 0)
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#define PMD_MAYBE_NG (arm64_use_ng_mappings ? PMD_SECT_NG : 0)
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#define PROT_DEFAULT (_PROT_DEFAULT | PTE_MAYBE_NG)
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#define PROT_SECT_DEFAULT (_PROT_SECT_DEFAULT | PMD_MAYBE_NG)
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#define PROT_DEVICE_nGnRnE (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_WRITE | PTE_ATTRINDX(MT_DEVICE_nGnRnE))
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#define PROT_DEVICE_nGnRE (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_WRITE | PTE_ATTRINDX(MT_DEVICE_nGnRE))
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#define PROT_NORMAL_NC (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_WRITE | PTE_ATTRINDX(MT_NORMAL_NC))
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#define PROT_NORMAL_WT (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_WRITE | PTE_ATTRINDX(MT_NORMAL_WT))
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#define PROT_NORMAL (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_WRITE | PTE_ATTRINDX(MT_NORMAL))
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#define PROT_SECT_DEVICE_nGnRE (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_DEVICE_nGnRE))
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#define PROT_SECT_NORMAL (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
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#define PROT_SECT_NORMAL_EXEC (PROT_SECT_DEFAULT | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
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#define _PAGE_DEFAULT (_PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL))
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#define _HYP_PAGE_DEFAULT _PAGE_DEFAULT
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#define PAGE_KERNEL __pgprot(PROT_NORMAL)
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#define PAGE_KERNEL_RO __pgprot((PROT_NORMAL & ~PTE_WRITE) | PTE_RDONLY)
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#define PAGE_KERNEL_ROX __pgprot((PROT_NORMAL & ~(PTE_WRITE | PTE_PXN)) | PTE_RDONLY)
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#define PAGE_KERNEL_EXEC __pgprot(PROT_NORMAL & ~PTE_PXN)
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#define PAGE_KERNEL_EXEC_CONT __pgprot((PROT_NORMAL & ~PTE_PXN) | PTE_CONT)
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#define PAGE_HYP __pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_HYP_XN)
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#define PAGE_HYP_EXEC __pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY)
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#define PAGE_HYP_RO __pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY | PTE_HYP_XN)
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#define PAGE_HYP_DEVICE __pgprot(PROT_DEVICE_nGnRE | PTE_HYP)
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#define PAGE_S2_MEMATTR(attr) \
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({ \
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u64 __val; \
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if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) \
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__val = PTE_S2_MEMATTR(MT_S2_FWB_ ## attr); \
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else \
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__val = PTE_S2_MEMATTR(MT_S2_ ## attr); \
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__val; \
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})
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#define PAGE_S2_XN \
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({ \
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u64 __val; \
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if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC)) \
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__val = 0; \
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else \
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__val = PTE_S2_XN; \
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__val; \
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})
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#define PAGE_S2 __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(NORMAL) | PTE_S2_RDONLY | PAGE_S2_XN)
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#define PAGE_S2_DEVICE __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_S2_XN)
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#define PAGE_NONE __pgprot(((_PAGE_DEFAULT) & ~PTE_VALID) | PTE_PROT_NONE | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN)
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/* shared+writable pages are clean by default, hence PTE_RDONLY|PTE_WRITE */
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#define PAGE_SHARED __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)
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#define PAGE_SHARED_EXEC __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_WRITE)
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#define PAGE_READONLY __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN)
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#define PAGE_READONLY_EXEC __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN)
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#define __P000 PAGE_NONE
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#define __P001 PAGE_READONLY
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#define __P010 PAGE_READONLY
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#define __P011 PAGE_READONLY
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#define __P100 PAGE_READONLY_EXEC
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#define __P101 PAGE_READONLY_EXEC
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#define __P110 PAGE_READONLY_EXEC
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#define __P111 PAGE_READONLY_EXEC
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#define __S000 PAGE_NONE
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#define __S001 PAGE_READONLY
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#define __S010 PAGE_SHARED
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#define __S011 PAGE_SHARED
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#define __S100 PAGE_READONLY_EXEC
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#define __S101 PAGE_READONLY_EXEC
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#define __S110 PAGE_SHARED_EXEC
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#define __S111 PAGE_SHARED_EXEC
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_PGTABLE_PROT_H */
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