^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * linux/arch/arm/mm/fault-armv.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Copyright (C) 1995 Linus Torvalds
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * Modifications for ARM processor (c) 1995-2002 Russell King
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/mm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/bitops.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <linux/vmalloc.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/pagemap.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <linux/gfp.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #include <asm/bugs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #include <asm/cacheflush.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #include <asm/cachetype.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) #include <asm/tlbflush.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) #include "mm.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) static pteval_t shared_pte_mask = L_PTE_MT_BUFFERABLE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) #if __LINUX_ARM_ARCH__ < 6
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) * We take the easy way out of this problem - we make the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) * PTE uncacheable. However, we leave the write buffer on.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) * Note that the pte lock held when calling update_mmu_cache must also
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) * guard the pte (somewhere else in the same mm) that we modify here.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) * Therefore those configurations which might call adjust_pte (those
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) * without CONFIG_CPU_CACHE_VIPT) cannot support split page_table_lock.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) static int do_adjust_pte(struct vm_area_struct *vma, unsigned long address,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) unsigned long pfn, pte_t *ptep)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) pte_t entry = *ptep;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) * If this page is present, it's actually being shared.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) ret = pte_present(entry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) * If this page isn't present, or is already setup to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) * fault (ie, is old), we can safely ignore any issues.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) if (ret && (pte_val(entry) & L_PTE_MT_MASK) != shared_pte_mask) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) flush_cache_page(vma, address, pfn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) outer_flush_range((pfn << PAGE_SHIFT),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) (pfn << PAGE_SHIFT) + PAGE_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) pte_val(entry) &= ~L_PTE_MT_MASK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) pte_val(entry) |= shared_pte_mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) set_pte_at(vma->vm_mm, address, ptep, entry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) flush_tlb_page(vma, address);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) #if USE_SPLIT_PTE_PTLOCKS
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) * If we are using split PTE locks, then we need to take the page
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) * lock here. Otherwise we are using shared mm->page_table_lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) * which is already locked, thus cannot take it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) static inline void do_pte_lock(spinlock_t *ptl)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) * Use nested version here to indicate that we are already
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) * holding one similar spinlock.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) spin_lock_nested(ptl, SINGLE_DEPTH_NESTING);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) static inline void do_pte_unlock(spinlock_t *ptl)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) spin_unlock(ptl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) #else /* !USE_SPLIT_PTE_PTLOCKS */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) static inline void do_pte_lock(spinlock_t *ptl) {}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) static inline void do_pte_unlock(spinlock_t *ptl) {}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) #endif /* USE_SPLIT_PTE_PTLOCKS */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) static int adjust_pte(struct vm_area_struct *vma, unsigned long address,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) unsigned long pfn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) spinlock_t *ptl;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) pgd_t *pgd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) p4d_t *p4d;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) pud_t *pud;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) pmd_t *pmd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) pte_t *pte;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) pgd = pgd_offset(vma->vm_mm, address);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) if (pgd_none_or_clear_bad(pgd))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) p4d = p4d_offset(pgd, address);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) if (p4d_none_or_clear_bad(p4d))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) pud = pud_offset(p4d, address);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) if (pud_none_or_clear_bad(pud))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) pmd = pmd_offset(pud, address);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) if (pmd_none_or_clear_bad(pmd))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) * This is called while another page table is mapped, so we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) * must use the nested version. This also means we need to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) * open-code the spin-locking.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) ptl = pte_lockptr(vma->vm_mm, pmd);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) pte = pte_offset_map(pmd, address);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) do_pte_lock(ptl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) ret = do_adjust_pte(vma, address, pfn, pte);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) do_pte_unlock(ptl);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) pte_unmap(pte);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) static void
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) make_coherent(struct address_space *mapping, struct vm_area_struct *vma,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) unsigned long addr, pte_t *ptep, unsigned long pfn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) struct mm_struct *mm = vma->vm_mm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) struct vm_area_struct *mpnt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) unsigned long offset;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) pgoff_t pgoff;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) int aliases = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) pgoff = vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) * If we have any shared mappings that are in the same mm
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) * space, then we need to handle them specially to maintain
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) * cache coherency.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) flush_dcache_mmap_lock(mapping);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) vma_interval_tree_foreach(mpnt, &mapping->i_mmap, pgoff, pgoff) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) * If this VMA is not in our MM, we can ignore it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) * Note that we intentionally mask out the VMA
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) * that we are fixing up.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) if (mpnt->vm_mm != mm || mpnt == vma)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) if (!(mpnt->vm_flags & VM_MAYSHARE))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) aliases += adjust_pte(mpnt, mpnt->vm_start + offset, pfn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) flush_dcache_mmap_unlock(mapping);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) if (aliases)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) do_adjust_pte(vma, addr, pfn, ptep);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) * Take care of architecture specific things when placing a new PTE into
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) * a page table, or changing an existing PTE. Basically, there are two
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) * things that we need to take care of:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) * 1. If PG_dcache_clean is not set for the page, we need to ensure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) * that any cache entries for the kernels virtual memory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) * range are written back to the page.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) * 2. If we have multiple shared mappings of the same space in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) * an object, we need to deal with the cache aliasing issues.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) * Note that the pte lock will be held.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) pte_t *ptep)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) unsigned long pfn = pte_pfn(*ptep);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) struct address_space *mapping;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) struct page *page;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) if (!pfn_valid(pfn))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) * The zero page is never written to, so never has any dirty
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) * cache lines, and therefore never needs to be flushed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) page = pfn_to_page(pfn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) if (page == ZERO_PAGE(0))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) mapping = page_mapping_file(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) if (!test_and_set_bit(PG_dcache_clean, &page->flags))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) __flush_dcache_page(mapping, page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) if (mapping) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) if (cache_is_vivt())
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) make_coherent(mapping, vma, addr, ptep, pfn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) else if (vma->vm_flags & VM_EXEC)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) __flush_icache_all();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) #endif /* __LINUX_ARM_ARCH__ < 6 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) * Check whether the write buffer has physical address aliasing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) * issues. If it has, we need to avoid them for the case where
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) * we have several shared mappings of the same object in user
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) * space.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) static int __init check_writebuffer(unsigned long *p1, unsigned long *p2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) register unsigned long zero = 0, one = 1, val;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) local_irq_disable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) mb();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) *p1 = one;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) mb();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) *p2 = zero;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) mb();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) val = *p1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) mb();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) local_irq_enable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) return val != zero;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) void __init check_writebuffer_bugs(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) struct page *page;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) const char *reason;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) unsigned long v = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) pr_info("CPU: Testing write buffer coherency: ");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) page = alloc_page(GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) if (page) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) unsigned long *p1, *p2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) pgprot_t prot = __pgprot_modify(PAGE_KERNEL,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) L_PTE_MT_MASK, L_PTE_MT_BUFFERABLE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) p1 = vmap(&page, 1, VM_IOREMAP, prot);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) p2 = vmap(&page, 1, VM_IOREMAP, prot);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) if (p1 && p2) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) v = check_writebuffer(p1, p2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) reason = "enabling work-around";
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) reason = "unable to map memory\n";
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) vunmap(p1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) vunmap(p2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) put_page(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) reason = "unable to grab page\n";
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) if (v) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) pr_cont("failed, %s\n", reason);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) shared_pte_mask = L_PTE_MT_UNCACHED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) pr_cont("ok\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) }
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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