mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2026-07-25 16:19:48 +02:00
Christophe LeroyandGreg Kroah-Hartman
99bdd0580d
[ Upstream commit 9316512b71 ]
PAGE_KERNEL_TEXT is an old macro that is used to tell kernel whether
kernel text has to be mapped read-only or read-write based on build
time options.
But nowadays, with functionnalities like jump_labels, static links,
etc ... more only less all kernels need to be read-write at some
point, and some combinations of configs failed to work due to
innacurate setting of PAGE_KERNEL_TEXT. On the other hand, today
we have CONFIG_STRICT_KERNEL_RWX which implements a more controlled
access to kernel modifications.
Instead of trying to keep PAGE_KERNEL_TEXT accurate with all
possible options that may imply kernel text modification, always
set kernel text read-write at startup and rely on
CONFIG_STRICT_KERNEL_RWX to provide accurate protection.
Do this by passing PAGE_KERNEL_X to map_kernel_page() in
__maping_ram_chunk() instead of passing PAGE_KERNEL_TEXT. Once
this is done, the only remaining user of PAGE_KERNEL_TEXT is
mmu_mark_initmem_nx() which uses it in a call to setibat().
As setibat() ignores the RW/RO, we can seamlessly replace
PAGE_KERNEL_TEXT by PAGE_KERNEL_X here as well and get rid of
PAGE_KERNEL_TEXT completely.
Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Closes: https://lore.kernel.org/all/342b4120-911c-4723-82ec-d8c9b03a8aef@mailbox.org/
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/8e2d793abf87ae3efb8f6dce10f974ac0eda61b8.1757412205.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin <sashal@kernel.org>
190 lines
4.4 KiB
C
190 lines
4.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_PGTABLE_H
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#define _ASM_POWERPC_PGTABLE_H
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#ifndef __ASSEMBLY__
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#include <linux/mmdebug.h>
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#include <linux/mmzone.h>
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#include <asm/processor.h> /* For TASK_SIZE */
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#include <asm/mmu.h>
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#include <asm/page.h>
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#include <asm/tlbflush.h>
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struct mm_struct;
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#endif /* !__ASSEMBLY__ */
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#ifdef CONFIG_PPC_BOOK3S
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#include <asm/book3s/pgtable.h>
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#else
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#include <asm/nohash/pgtable.h>
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#endif /* !CONFIG_PPC_BOOK3S */
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/* Make modules code happy. We don't set RO yet */
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#define PAGE_KERNEL_EXEC PAGE_KERNEL_X
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/* Advertise special mapping type for AGP */
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#define PAGE_AGP (PAGE_KERNEL_NC)
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#define HAVE_PAGE_AGP
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#ifndef __ASSEMBLY__
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void set_ptes(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
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pte_t pte, unsigned int nr);
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#define set_ptes set_ptes
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#define update_mmu_cache(vma, addr, ptep) \
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update_mmu_cache_range(NULL, vma, addr, ptep, 1)
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#ifndef MAX_PTRS_PER_PGD
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#define MAX_PTRS_PER_PGD PTRS_PER_PGD
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#endif
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/* Keep these as a macros to avoid include dependency mess */
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#define pte_page(x) pfn_to_page(pte_pfn(x))
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#define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot))
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static inline unsigned long pte_pfn(pte_t pte)
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{
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return (pte_val(pte) & PTE_RPN_MASK) >> PTE_RPN_SHIFT;
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}
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/*
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* Select all bits except the pfn
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*/
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static inline pgprot_t pte_pgprot(pte_t pte)
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{
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unsigned long pte_flags;
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pte_flags = pte_val(pte) & ~PTE_RPN_MASK;
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return __pgprot(pte_flags);
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}
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#ifndef pmd_page_vaddr
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static inline const void *pmd_page_vaddr(pmd_t pmd)
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{
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return __va(pmd_val(pmd) & ~PMD_MASKED_BITS);
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}
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#define pmd_page_vaddr pmd_page_vaddr
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#endif
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/*
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* ZERO_PAGE is a global shared page that is always zero: used
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* for zero-mapped memory areas etc..
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*/
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extern unsigned long empty_zero_page[];
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#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
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extern pgd_t swapper_pg_dir[];
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extern void paging_init(void);
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void poking_init(void);
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extern unsigned long ioremap_bot;
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extern const pgprot_t protection_map[16];
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#ifndef CONFIG_TRANSPARENT_HUGEPAGE
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#define pmd_large(pmd) 0
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#endif
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/* can we use this in kvm */
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unsigned long vmalloc_to_phys(void *vmalloc_addr);
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void pgtable_cache_add(unsigned int shift);
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pte_t *early_pte_alloc_kernel(pmd_t *pmdp, unsigned long va);
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#if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_PPC32)
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void mark_initmem_nx(void);
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#else
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static inline void mark_initmem_nx(void) { }
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#endif
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/*
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* When used, PTE_FRAG_NR is defined in subarch pgtable.h
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* so we are sure it is included when arriving here.
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*/
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#ifdef PTE_FRAG_NR
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static inline void *pte_frag_get(mm_context_t *ctx)
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{
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return ctx->pte_frag;
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}
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static inline void pte_frag_set(mm_context_t *ctx, void *p)
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{
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ctx->pte_frag = p;
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}
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#else
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#define PTE_FRAG_NR 1
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#define PTE_FRAG_SIZE_SHIFT PAGE_SHIFT
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#define PTE_FRAG_SIZE (1UL << PTE_FRAG_SIZE_SHIFT)
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static inline void *pte_frag_get(mm_context_t *ctx)
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{
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return NULL;
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}
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static inline void pte_frag_set(mm_context_t *ctx, void *p)
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{
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}
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#endif
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#ifndef pmd_is_leaf
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#define pmd_is_leaf pmd_is_leaf
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static inline bool pmd_is_leaf(pmd_t pmd)
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{
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return false;
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}
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#endif
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#ifndef pud_is_leaf
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#define pud_is_leaf pud_is_leaf
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static inline bool pud_is_leaf(pud_t pud)
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{
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return false;
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}
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#endif
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#ifndef p4d_is_leaf
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#define p4d_is_leaf p4d_is_leaf
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static inline bool p4d_is_leaf(p4d_t p4d)
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{
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return false;
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}
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#endif
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#define pmd_pgtable pmd_pgtable
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static inline pgtable_t pmd_pgtable(pmd_t pmd)
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{
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return (pgtable_t)pmd_page_vaddr(pmd);
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}
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#ifdef CONFIG_PPC64
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int __meminit vmemmap_populated(unsigned long vmemmap_addr, int vmemmap_map_size);
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bool altmap_cross_boundary(struct vmem_altmap *altmap, unsigned long start,
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unsigned long page_size);
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/*
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* mm/memory_hotplug.c:mhp_supports_memmap_on_memory goes into details
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* some of the restrictions. We don't check for PMD_SIZE because our
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* vmemmap allocation code can fallback correctly. The pageblock
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* alignment requirement is met using altmap->reserve blocks.
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*/
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#define arch_supports_memmap_on_memory arch_supports_memmap_on_memory
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static inline bool arch_supports_memmap_on_memory(unsigned long vmemmap_size)
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{
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if (!radix_enabled())
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return false;
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/*
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* With 4K page size and 2M PMD_SIZE, we can align
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* things better with memory block size value
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* starting from 128MB. Hence align things with PMD_SIZE.
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*/
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if (IS_ENABLED(CONFIG_PPC_4K_PAGES))
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return IS_ALIGNED(vmemmap_size, PMD_SIZE);
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return true;
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}
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#endif /* CONFIG_PPC64 */
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_POWERPC_PGTABLE_H */
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