Hi, after the recent issue with vmalloc and tracing code[1] on x86 and a long history of previous issues related to the vmalloc_sync_mappings() interface, I thought the time has come to remove it. Please see [2], [3], and [4] for some other issues in the past. The patches are based on v5.7-rc4 and add tracking of page-table directory changes to the vmalloc and ioremap code. Depending on which page-table levels changes have been made, a new per-arch function is called: arch_sync_kernel_mappings(). On x86-64 with 4-level paging, this function will not be called more than 64 times in a systems runtime (because vmalloc-space takes 64 PGD entries which are only populated, but never cleared). As a side effect this also allows to get rid of vmalloc faults on x86, making it safe to touch vmalloc'ed memory in the page-fault handler. Note that this potentially includes per-cpu memory. The code is tested on x86-64, x86-32 with and without PAE. It also fixes the issue described in [1]. Additionally this code has been compile-tested on almost all architectures supported by Linux. I couldn't find working compilers for hexagon and unicore32, so these are not tested. Please review. Regards, Joerg [1] https://lore.kernel.org/lkml/20200430141120.GA8135@xxxxxxx/ [2] https://lore.kernel.org/lkml/20191009124418.8286-1-joro@xxxxxxxxxx/ [3] https://lore.kernel.org/lkml/20190719184652.11391-1-joro@xxxxxxxxxx/ [4] https://lore.kernel.org/lkml/20191126111119.GA110513@xxxxxxxxx/ Joerg Roedel (7): mm: Add functions to track page directory modifications mm/vmalloc: Track which page-table levels were modified mm/ioremap: Track which page-table levels were modified x86/mm/64: Implement arch_sync_kernel_mappings() x86/mm/32: Implement arch_sync_kernel_mappings() mm: Remove vmalloc_sync_(un)mappings() x86/mm: Remove vmalloc faulting arch/x86/include/asm/pgtable-2level_types.h | 2 + arch/x86/include/asm/pgtable-3level_types.h | 2 + arch/x86/include/asm/pgtable_64_types.h | 2 + arch/x86/include/asm/switch_to.h | 23 --- arch/x86/kernel/setup_percpu.c | 6 +- arch/x86/mm/fault.c | 176 +------------------- arch/x86/mm/init_64.c | 5 + arch/x86/mm/pti.c | 8 +- drivers/acpi/apei/ghes.c | 6 - include/asm-generic/5level-fixup.h | 5 +- include/asm-generic/pgtable.h | 23 +++ include/linux/mm.h | 46 +++++ include/linux/vmalloc.h | 13 +- kernel/notifier.c | 1 - lib/ioremap.c | 46 +++-- mm/nommu.c | 12 -- mm/vmalloc.c | 109 +++++++----- 17 files changed, 199 insertions(+), 286 deletions(-) -- 2.17.1
