Kevin Brodsky 778f4e1730 arm64: poe: Handle spurious Overlay faults ... [ Upstream commit 22f3a4f608 ] We do not currently issue an ISB after updating POR_EL0 when context-switching it, for instance. The rationale is that if the old value of POR_EL0 is more restrictive and causes a fault during uaccess, the access will be retried [1]. In other words, we are trading an ISB on every context-switching for the (unlikely) possibility of a spurious fault. We may also miss faults if the new value of POR_EL0 is more restrictive, but that's considered acceptable. However, as things stand, a spurious Overlay fault results in uaccess failing right away since it causes fault_from_pkey() to return true. If an Overlay fault is reported, we therefore need to double check POR_EL0 against vma_pkey(vma) - this is what arch_vma_access_permitted() already does. As it turns out, we already perform that explicit check if no Overlay fault is reported, and we need to keep that check (see comment added in fault_from_pkey()). Net result: the Overlay ISS2 bit isn't of much help to decide whether a pkey fault occurred. Remove the check for the Overlay bit from fault_from_pkey() and add a comment to try and explain the situation. While at it, also add a comment to permission_overlay_switch() in case anyone gets surprised by the lack of ISB. [1] https://lore.kernel.org/linux-arm-kernel/ZtYNGBrcE-j35fpw@arm.com/ Fixes: 160a8e13de ("arm64: context switch POR_EL0 register") Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com> Link: https://lore.kernel.org/r/20250619160042.2499290-2-kevin.brodsky@arm.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2025-07-17 18:37:04 +02:00
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cache.S
context.c	arm64: Ensure bits ASID[15:8] are masked out when the kernel uses 8-bit ASIDs	2024-12-14 20:03:22 +01:00
contpte.c	mm: arm64: document why pte is not advanced in contpte_ptep_set_access_flags()	2024-09-06 12:28:33 +01:00
copypage.c
dma-mapping.c	arm64: Properly clean up iommu-dma remnants	2024-05-10 09:04:25 +02:00
extable.c
fault.c	arm64: poe: Handle spurious Overlay faults	2025-07-17 18:37:04 +02:00
fixmap.c	- Sumanth Korikkar has taught s390 to allocate hotplug-time page frames	2024-03-14 17:43:30 -07:00
flush.c
hugetlbpage.c	arm64: hugetlb: Fix huge_ptep_get_and_clear() for non-present ptes	2025-03-13 13:02:17 +01:00
init.c	arm64/mm: Fix Boot panic on Ampere Altra	2025-03-07 18:25:39 +01:00
ioremap.c	arm64: mm: Add confidential computing hook to ioremap_prot()	2024-08-30 16:30:41 +01:00
kasan_init.c	- Sumanth Korikkar has taught s390 to allocate hotplug-time page frames	2024-03-14 17:43:30 -07:00
Makefile	arm64: mm: Add top-level dispatcher for internal mem_encrypt API	2024-08-30 16:30:41 +01:00
mem_encrypt.c	arm64: mm: Add top-level dispatcher for internal mem_encrypt API	2024-08-30 16:30:41 +01:00
mmap.c	arm64: convert protection key into vm_flags and pgprot values	2024-09-04 12:52:41 +01:00
mmu.c	arm64: Restrict pagetable teardown to avoid false warning	2025-06-27 11:11:39 +01:00
mteswap.c	arm64: mm: swap: support THP_SWAP on hardware with MTE	2024-04-25 20:56:07 -07:00
pageattr.c	arm64: hibernate: Fix level3 translation fault in swsusp_save()	2024-04-19 16:33:00 +01:00
pgd.c	arm64: mm: Add support for folding PUDs at runtime	2024-02-16 12:42:41 +00:00
physaddr.c
proc.S	arm64/mm: Drop TCR_SMP_FLAGS	2024-08-16 11:24:55 +01:00
ptdump_debugfs.c
ptdump.c	arm64: ptdump: Don't override the level when operating on the stage-2 tables	2024-09-10 21:32:51 +01:00
trans_pgd-asm.S
trans_pgd.c	arm64: trans_pgd: mark PTEs entries as valid to avoid dead kexec()	2024-09-04 16:30:23 +01:00