From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- arch/xtensa/mm/cache.c | 335 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 335 insertions(+) create mode 100644 arch/xtensa/mm/cache.c (limited to 'arch/xtensa/mm/cache.c') diff --git a/arch/xtensa/mm/cache.c b/arch/xtensa/mm/cache.c new file mode 100644 index 000000000..5354df52d --- /dev/null +++ b/arch/xtensa/mm/cache.c @@ -0,0 +1,335 @@ +/* + * arch/xtensa/mm/cache.c + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2001-2006 Tensilica Inc. + * + * Chris Zankel + * Joe Taylor + * Marc Gauthier + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +/* + * Note: + * The kernel provides one architecture bit PG_arch_1 in the page flags that + * can be used for cache coherency. + * + * I$-D$ coherency. + * + * The Xtensa architecture doesn't keep the instruction cache coherent with + * the data cache. We use the architecture bit to indicate if the caches + * are coherent. The kernel clears this bit whenever a page is added to the + * page cache. At that time, the caches might not be in sync. We, therefore, + * define this flag as 'clean' if set. + * + * D-cache aliasing. + * + * With cache aliasing, we have to always flush the cache when pages are + * unmapped (see tlb_start_vma(). So, we use this flag to indicate a dirty + * page. + * + * + * + */ + +#if (DCACHE_WAY_SIZE > PAGE_SIZE) +static inline void kmap_invalidate_coherent(struct page *page, + unsigned long vaddr) +{ + if (!DCACHE_ALIAS_EQ(page_to_phys(page), vaddr)) { + unsigned long kvaddr; + + if (!PageHighMem(page)) { + kvaddr = (unsigned long)page_to_virt(page); + + __invalidate_dcache_page(kvaddr); + } else { + kvaddr = TLBTEMP_BASE_1 + + (page_to_phys(page) & DCACHE_ALIAS_MASK); + + preempt_disable(); + __invalidate_dcache_page_alias(kvaddr, + page_to_phys(page)); + preempt_enable(); + } + } +} + +static inline void *coherent_kvaddr(struct page *page, unsigned long base, + unsigned long vaddr, unsigned long *paddr) +{ + *paddr = page_to_phys(page); + return (void *)(base + (vaddr & DCACHE_ALIAS_MASK)); +} + +void clear_user_highpage(struct page *page, unsigned long vaddr) +{ + struct folio *folio = page_folio(page); + unsigned long paddr; + void *kvaddr = coherent_kvaddr(page, TLBTEMP_BASE_1, vaddr, &paddr); + + preempt_disable(); + kmap_invalidate_coherent(page, vaddr); + set_bit(PG_arch_1, folio_flags(folio, 0)); + clear_page_alias(kvaddr, paddr); + preempt_enable(); +} +EXPORT_SYMBOL(clear_user_highpage); + +void copy_user_highpage(struct page *dst, struct page *src, + unsigned long vaddr, struct vm_area_struct *vma) +{ + struct folio *folio = page_folio(dst); + unsigned long dst_paddr, src_paddr; + void *dst_vaddr = coherent_kvaddr(dst, TLBTEMP_BASE_1, vaddr, + &dst_paddr); + void *src_vaddr = coherent_kvaddr(src, TLBTEMP_BASE_2, vaddr, + &src_paddr); + + preempt_disable(); + kmap_invalidate_coherent(dst, vaddr); + set_bit(PG_arch_1, folio_flags(folio, 0)); + copy_page_alias(dst_vaddr, src_vaddr, dst_paddr, src_paddr); + preempt_enable(); +} +EXPORT_SYMBOL(copy_user_highpage); + +/* + * Any time the kernel writes to a user page cache page, or it is about to + * read from a page cache page this routine is called. + * + */ + +void flush_dcache_folio(struct folio *folio) +{ + struct address_space *mapping = folio_flush_mapping(folio); + + /* + * If we have a mapping but the page is not mapped to user-space + * yet, we simply mark this page dirty and defer flushing the + * caches until update_mmu(). + */ + + if (mapping && !mapping_mapped(mapping)) { + if (!test_bit(PG_arch_1, &folio->flags.f)) + set_bit(PG_arch_1, &folio->flags.f); + return; + + } else { + unsigned long phys = folio_pfn(folio) * PAGE_SIZE; + unsigned long temp = folio_pos(folio); + unsigned int i, nr = folio_nr_pages(folio); + unsigned long alias = !(DCACHE_ALIAS_EQ(temp, phys)); + unsigned long virt; + + /* + * Flush the page in kernel space and user space. + * Note that we can omit that step if aliasing is not + * an issue, but we do have to synchronize I$ and D$ + * if we have a mapping. + */ + + if (!alias && !mapping) + return; + + preempt_disable(); + for (i = 0; i < nr; i++) { + virt = TLBTEMP_BASE_1 + (phys & DCACHE_ALIAS_MASK); + __flush_invalidate_dcache_page_alias(virt, phys); + + virt = TLBTEMP_BASE_1 + (temp & DCACHE_ALIAS_MASK); + + if (alias) + __flush_invalidate_dcache_page_alias(virt, phys); + + if (mapping) + __invalidate_icache_page_alias(virt, phys); + phys += PAGE_SIZE; + temp += PAGE_SIZE; + } + preempt_enable(); + } + + /* There shouldn't be an entry in the cache for this page anymore. */ +} +EXPORT_SYMBOL(flush_dcache_folio); + +/* + * For now, flush the whole cache. FIXME?? + */ + +void local_flush_cache_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end) +{ + __flush_invalidate_dcache_all(); + __invalidate_icache_all(); +} +EXPORT_SYMBOL(local_flush_cache_range); + +/* + * Remove any entry in the cache for this page. + * + * Note that this function is only called for user pages, so use the + * alias versions of the cache flush functions. + */ + +void local_flush_cache_page(struct vm_area_struct *vma, unsigned long address, + unsigned long pfn) +{ + /* Note that we have to use the 'alias' address to avoid multi-hit */ + + unsigned long phys = page_to_phys(pfn_to_page(pfn)); + unsigned long virt = TLBTEMP_BASE_1 + (address & DCACHE_ALIAS_MASK); + + preempt_disable(); + __flush_invalidate_dcache_page_alias(virt, phys); + __invalidate_icache_page_alias(virt, phys); + preempt_enable(); +} +EXPORT_SYMBOL(local_flush_cache_page); + +#endif /* DCACHE_WAY_SIZE > PAGE_SIZE */ + +void update_mmu_cache_range(struct vm_fault *vmf, struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, unsigned int nr) +{ + unsigned long pfn = pte_pfn(*ptep); + struct folio *folio; + unsigned int i; + + if (!pfn_valid(pfn)) + return; + + folio = page_folio(pfn_to_page(pfn)); + + /* Invalidate old entries in TLBs */ + for (i = 0; i < nr; i++) + flush_tlb_page(vma, addr + i * PAGE_SIZE); + nr = folio_nr_pages(folio); + +#if (DCACHE_WAY_SIZE > PAGE_SIZE) + + if (!folio_test_reserved(folio) && test_bit(PG_arch_1, &folio->flags.f)) { + unsigned long phys = folio_pfn(folio) * PAGE_SIZE; + unsigned long tmp; + + preempt_disable(); + for (i = 0; i < nr; i++) { + tmp = TLBTEMP_BASE_1 + (phys & DCACHE_ALIAS_MASK); + __flush_invalidate_dcache_page_alias(tmp, phys); + tmp = TLBTEMP_BASE_1 + (addr & DCACHE_ALIAS_MASK); + __flush_invalidate_dcache_page_alias(tmp, phys); + __invalidate_icache_page_alias(tmp, phys); + phys += PAGE_SIZE; + } + preempt_enable(); + + clear_bit(PG_arch_1, &folio->flags.f); + } +#else + if (!folio_test_reserved(folio) && !test_bit(PG_arch_1, &folio->flags.f) + && (vma->vm_flags & VM_EXEC) != 0) { + for (i = 0; i < nr; i++) { + void *paddr = kmap_local_folio(folio, i * PAGE_SIZE); + __flush_dcache_page((unsigned long)paddr); + __invalidate_icache_page((unsigned long)paddr); + kunmap_local(paddr); + } + set_bit(PG_arch_1, &folio->flags.f); + } +#endif +} + +/* + * access_process_vm() has called get_user_pages(), which has done a + * flush_dcache_page() on the page. + */ + +#if (DCACHE_WAY_SIZE > PAGE_SIZE) + +void copy_to_user_page(struct vm_area_struct *vma, struct page *page, + unsigned long vaddr, void *dst, const void *src, + unsigned long len) +{ + unsigned long phys = page_to_phys(page); + unsigned long alias = !(DCACHE_ALIAS_EQ(vaddr, phys)); + + /* Flush and invalidate user page if aliased. */ + + if (alias) { + unsigned long t = TLBTEMP_BASE_1 + (vaddr & DCACHE_ALIAS_MASK); + preempt_disable(); + __flush_invalidate_dcache_page_alias(t, phys); + preempt_enable(); + } + + /* Copy data */ + + memcpy(dst, src, len); + + /* + * Flush and invalidate kernel page if aliased and synchronize + * data and instruction caches for executable pages. + */ + + if (alias) { + unsigned long t = TLBTEMP_BASE_1 + (vaddr & DCACHE_ALIAS_MASK); + + preempt_disable(); + __flush_invalidate_dcache_range((unsigned long) dst, len); + if ((vma->vm_flags & VM_EXEC) != 0) + __invalidate_icache_page_alias(t, phys); + preempt_enable(); + + } else if ((vma->vm_flags & VM_EXEC) != 0) { + __flush_dcache_range((unsigned long)dst,len); + __invalidate_icache_range((unsigned long) dst, len); + } +} + +extern void copy_from_user_page(struct vm_area_struct *vma, struct page *page, + unsigned long vaddr, void *dst, const void *src, + unsigned long len) +{ + unsigned long phys = page_to_phys(page); + unsigned long alias = !(DCACHE_ALIAS_EQ(vaddr, phys)); + + /* + * Flush user page if aliased. + * (Note: a simply flush would be sufficient) + */ + + if (alias) { + unsigned long t = TLBTEMP_BASE_1 + (vaddr & DCACHE_ALIAS_MASK); + preempt_disable(); + __flush_invalidate_dcache_page_alias(t, phys); + preempt_enable(); + } + + memcpy(dst, src, len); +} + +#endif -- cgit v1.3.1