The branch stable/13 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=79e0f742da9b7fab40de4f1309e864340451c0a3
commit 79e0f742da9b7fab40de4f1309e864340451c0a3 Author: Mark Johnston <[email protected]> AuthorDate: 2022-03-01 14:06:31 +0000 Commit: Mark Johnston <[email protected]> CommitDate: 2022-03-14 14:45:43 +0000 riscv: Maintain the allpmaps list only in SV39 mode When four-level page tables are used, there is no need to distribute updates to the top-level page to all pmaps. Reviewed by: jhb Sponsored by: The FreeBSD Foundation (cherry picked from commit ceed61483ca9c3c0bf44e37118ae9c8377e6b9ff) --- sys/riscv/riscv/pmap.c | 48 +++++++++++++++++++++++++++++++----------------- 1 file changed, 31 insertions(+), 17 deletions(-) diff --git a/sys/riscv/riscv/pmap.c b/sys/riscv/riscv/pmap.c index 74192a16341c..71957b235e70 100644 --- a/sys/riscv/riscv/pmap.c +++ b/sys/riscv/riscv/pmap.c @@ -486,8 +486,13 @@ pmap_distribute_l1(struct pmap *pmap, vm_pindex_t l1index, struct pmap *user_pmap; pd_entry_t *l1; - /* Distribute new kernel L1 entry to all the user pmaps */ - if (pmap != kernel_pmap) + /* + * Distribute new kernel L1 entry to all the user pmaps. This is only + * necessary with three-level paging configured: with four-level paging + * the kernel's half of the top-level page table page is static and can + * simply be copied at pmap initialization time. + */ + if (pmap != kernel_pmap || pmap_mode != PMAP_MODE_SV39) return; mtx_lock(&allpmaps_lock); @@ -1266,6 +1271,7 @@ pmap_pinit(pmap_t pmap) { vm_paddr_t topphys; vm_page_t mtop; + size_t i; mtop = vm_page_alloc_noobj(VM_ALLOC_WIRED | VM_ALLOC_ZERO | VM_ALLOC_WAITOK); @@ -1278,19 +1284,25 @@ pmap_pinit(pmap_t pmap) CPU_ZERO(&pmap->pm_active); - /* - * Copy L1 entries from the kernel pmap. This must be done with the - * allpmaps lock held to avoid races with pmap_distribute_l1(). - */ - mtx_lock(&allpmaps_lock); - LIST_INSERT_HEAD(&allpmaps, pmap, pm_list); - for (size_t i = pmap_l1_index(VM_MIN_KERNEL_ADDRESS); - i < pmap_l1_index(VM_MAX_KERNEL_ADDRESS); i++) - pmap->pm_top[i] = kernel_pmap->pm_top[i]; - for (size_t i = pmap_l1_index(DMAP_MIN_ADDRESS); - i < pmap_l1_index(DMAP_MAX_ADDRESS); i++) + if (pmap_mode == PMAP_MODE_SV39) { + /* + * Copy L1 entries from the kernel pmap. This must be done with + * the allpmaps lock held to avoid races with + * pmap_distribute_l1(). + */ + mtx_lock(&allpmaps_lock); + LIST_INSERT_HEAD(&allpmaps, pmap, pm_list); + for (i = pmap_l1_index(VM_MIN_KERNEL_ADDRESS); + i < pmap_l1_index(VM_MAX_KERNEL_ADDRESS); i++) + pmap->pm_top[i] = kernel_pmap->pm_top[i]; + for (i = pmap_l1_index(DMAP_MIN_ADDRESS); + i < pmap_l1_index(DMAP_MAX_ADDRESS); i++) + pmap->pm_top[i] = kernel_pmap->pm_top[i]; + mtx_unlock(&allpmaps_lock); + } else { + i = pmap_l0_index(VM_MIN_KERNEL_ADDRESS); pmap->pm_top[i] = kernel_pmap->pm_top[i]; - mtx_unlock(&allpmaps_lock); + } vm_radix_init(&pmap->pm_root); @@ -1480,9 +1492,11 @@ pmap_release(pmap_t pmap) KASSERT(CPU_EMPTY(&pmap->pm_active), ("releasing active pmap %p", pmap)); - mtx_lock(&allpmaps_lock); - LIST_REMOVE(pmap, pm_list); - mtx_unlock(&allpmaps_lock); + if (pmap_mode == PMAP_MODE_SV39) { + mtx_lock(&allpmaps_lock); + LIST_REMOVE(pmap, pm_list); + mtx_unlock(&allpmaps_lock); + } m = PHYS_TO_VM_PAGE(DMAP_TO_PHYS((vm_offset_t)pmap->pm_top)); vm_page_unwire_noq(m);
