From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- arch/hexagon/mm/cache.c | 126 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 126 insertions(+) create mode 100644 arch/hexagon/mm/cache.c (limited to 'arch/hexagon/mm/cache.c') diff --git a/arch/hexagon/mm/cache.c b/arch/hexagon/mm/cache.c new file mode 100644 index 000000000..7e46f40c8 --- /dev/null +++ b/arch/hexagon/mm/cache.c @@ -0,0 +1,126 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Cache management functions for Hexagon + * + * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. + */ + +#include +#include +#include + +#define spanlines(start, end) \ + (((end - (start & ~(LINESIZE - 1))) >> LINEBITS) + 1) + +void flush_dcache_range(unsigned long start, unsigned long end) +{ + unsigned long lines = spanlines(start, end-1); + unsigned long i, flags; + + start &= ~(LINESIZE - 1); + + local_irq_save(flags); + + for (i = 0; i < lines; i++) { + __asm__ __volatile__ ( + " dccleaninva(%0); " + : + : "r" (start) + ); + start += LINESIZE; + } + local_irq_restore(flags); +} + +void flush_icache_range(unsigned long start, unsigned long end) +{ + unsigned long lines = spanlines(start, end-1); + unsigned long i, flags; + + start &= ~(LINESIZE - 1); + + local_irq_save(flags); + + for (i = 0; i < lines; i++) { + __asm__ __volatile__ ( + " dccleana(%0); " + " icinva(%0); " + : + : "r" (start) + ); + start += LINESIZE; + } + __asm__ __volatile__ ( + "isync" + ); + local_irq_restore(flags); +} +EXPORT_SYMBOL(flush_icache_range); + +void hexagon_clean_dcache_range(unsigned long start, unsigned long end) +{ + unsigned long lines = spanlines(start, end-1); + unsigned long i, flags; + + start &= ~(LINESIZE - 1); + + local_irq_save(flags); + + for (i = 0; i < lines; i++) { + __asm__ __volatile__ ( + " dccleana(%0); " + : + : "r" (start) + ); + start += LINESIZE; + } + local_irq_restore(flags); +} + +void hexagon_inv_dcache_range(unsigned long start, unsigned long end) +{ + unsigned long lines = spanlines(start, end-1); + unsigned long i, flags; + + start &= ~(LINESIZE - 1); + + local_irq_save(flags); + + for (i = 0; i < lines; i++) { + __asm__ __volatile__ ( + " dcinva(%0); " + : + : "r" (start) + ); + start += LINESIZE; + } + local_irq_restore(flags); +} + + + + +/* + * This is just really brutal and shouldn't be used anyways, + * especially on V2. Left here just in case. + */ +void flush_cache_all_hexagon(void) +{ + unsigned long flags; + local_irq_save(flags); + __vmcache_ickill(); + __vmcache_dckill(); + __vmcache_l2kill(); + local_irq_restore(flags); + mb(); +} + +void copy_to_user_page(struct vm_area_struct *vma, struct page *page, + unsigned long vaddr, void *dst, void *src, int len) +{ + memcpy(dst, src, len); + if (vma->vm_flags & VM_EXEC) { + flush_icache_range((unsigned long) dst, + (unsigned long) dst + len); + } +} -- cgit v1.3.1