linear_map_split_to_ptes() and __kpti_install_ng_mappings() are called as callback of stop_machine(). That means these functions context are preemption disabled. Unfortunately, under PREEMPT_RT, the pagetable_alloc() or __get_free_pages() couldn't be called in this context since spin lock that becomes sleepable on RT, potentially causing a sleep during page allocation. To address this, pagetable_alloc_nolock(). Signed-off-by: Yeoreum Yun --- arch/arm64/mm/mmu.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 2ba01dc8ef82..0e98606d8c4c 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -475,10 +475,15 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, static phys_addr_t __pgd_pgtable_alloc(struct mm_struct *mm, gfp_t gfp, enum pgtable_type pgtable_type) { - /* Page is zeroed by init_clear_pgtable() so don't duplicate effort. */ - struct ptdesc *ptdesc = pagetable_alloc(gfp & ~__GFP_ZERO, 0); + struct ptdesc *ptdesc; phys_addr_t pa; + /* Page is zeroed by init_clear_pgtable() so don't duplicate effort. */ + if (gfpflags_allow_spinning(gfp)) + ptdesc = pagetable_alloc(gfp & ~__GFP_ZERO, 0); + else + ptdesc = pagetable_alloc_nolock(gfp & ~__GFP_ZERO, 0); + if (!ptdesc) return INVALID_PHYS_ADDR; @@ -869,6 +874,7 @@ static int __init linear_map_split_to_ptes(void *__unused) unsigned long kstart = (unsigned long)lm_alias(_stext); unsigned long kend = (unsigned long)lm_alias(__init_begin); int ret; + gfp_t gfp = IS_ENABLED(CONFIG_PREEMPT_RT) ? __GFP_HIGH : GFP_ATOMIC; /* * Wait for all secondary CPUs to be put into the waiting area. @@ -881,9 +887,9 @@ static int __init linear_map_split_to_ptes(void *__unused) * PTE. The kernel alias remains static throughout runtime so * can continue to be safely mapped with large mappings. */ - ret = range_split_to_ptes(lstart, kstart, GFP_ATOMIC); + ret = range_split_to_ptes(lstart, kstart, gfp); if (!ret) - ret = range_split_to_ptes(kend, lend, GFP_ATOMIC); + ret = range_split_to_ptes(kend, lend, gfp); if (ret) panic("Failed to split linear map\n"); flush_tlb_kernel_range(lstart, lend); @@ -1207,7 +1213,14 @@ static int __init __kpti_install_ng_mappings(void *__unused) remap_fn = (void *)__pa_symbol(idmap_kpti_install_ng_mappings); if (!cpu) { - alloc = __get_free_pages(GFP_ATOMIC | __GFP_ZERO, order); + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + alloc = (u64) pagetable_alloc_nolock(__GFP_HIGH | __GFP_ZERO, order); + else + alloc = __get_free_pages(GFP_ATOMIC | __GFP_ZERO, order); + + if (!alloc) + panic("Failed to alloc kpti_ng_pgd\n"); + kpti_ng_temp_pgd = (pgd_t *)(alloc + (levels - 1) * PAGE_SIZE); kpti_ng_temp_alloc = kpti_ng_temp_pgd_pa = __pa(kpti_ng_temp_pgd); -- LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}