git: ccaf78c962e8 - main - arm64: Move cpu0 dpcpu and msgbuf to the DMAP

The branch main has been updated by andrew:

URL: https://cgit.FreeBSD.org/src/commit/?id=ccaf78c962e85630298f068931862a3595e9bbdf

commit ccaf78c962e85630298f068931862a3595e9bbdf
Author:     Andrew Turner <andrew@FreeBSD.org>
AuthorDate: 2025-04-22 15:59:25 +0000
Commit:     Andrew Turner <andrew@FreeBSD.org>
CommitDate: 2025-04-22 16:08:57 +0000

    arm64: Move cpu0 dpcpu and msgbuf to the DMAP
    
    When these are allocated we already have the DMAP region mapped. Search
    for the largest region and use this to hold these.
    
    Pr:             269726
    Reviewed by:    markj
    Sponsored by:   Arm Ltd
    Differential Revision:  https://reviews.freebsd.org/D42734
---
 sys/arm64/arm64/pmap.c | 40 ++++++++++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 10 deletions(-)

diff --git a/sys/arm64/arm64/pmap.c b/sys/arm64/arm64/pmap.c
index 30efd40573d2..f4d6b1cfcb56 100644
--- a/sys/arm64/arm64/pmap.c
+++ b/sys/arm64/arm64/pmap.c
@@ -1332,6 +1332,7 @@ pmap_bootstrap(void)
 {
 	vm_offset_t dpcpu, msgbufpv;
 	vm_paddr_t start_pa, pa;
+	size_t largest_phys_size;
 
 	/* Set this early so we can use the pagetable walking functions */
 	kernel_pmap_store.pm_l0 = pagetable_l0_ttbr1;
@@ -1346,12 +1347,41 @@ pmap_bootstrap(void)
 	kernel_pmap->pm_ttbr = kernel_pmap->pm_l0_paddr;
 	kernel_pmap->pm_asid_set = &asids;
 
+	/* Reserve some VA space for early BIOS/ACPI mapping */
+	preinit_map_va = roundup2(bs_state.freemempos, L2_SIZE);
+
+	virtual_avail = preinit_map_va + PMAP_PREINIT_MAPPING_SIZE;
+	virtual_avail = roundup2(virtual_avail, L1_SIZE);
+	virtual_end = VM_MAX_KERNEL_ADDRESS - PMAP_MAPDEV_EARLY_SIZE;
+	kernel_vm_end = virtual_avail;
+
 	/*
 	 * We only use PXN when we know nothing will be executed from it, e.g.
 	 * the DMAP region.
 	 */
 	bs_state.table_attrs &= ~TATTR_PXN_TABLE;
 
+	/*
+	 * Find the physical memory we could use. This needs to be after we
+	 * exclude any memory that is mapped into the DMAP region but should
+	 * not be used by the kernel, e.g. some UEFI memory types.
+	 */
+	physmap_idx = physmem_avail(physmap, nitems(physmap));
+
+	/*
+	 * Find space for early allocations. We search for the largest
+	 * region. This is because the user may choose a large msgbuf.
+	 * This could be smarter, e.g. to allow multiple regions to be
+	 * used & switch to the next when one is full.
+	 */
+	largest_phys_size = 0;
+	for (int i = 0; i < physmap_idx; i += 2) {
+		if ((physmap[i + 1] - physmap[i]) > largest_phys_size) {
+			largest_phys_size = physmap[i + 1] - physmap[i];
+			bs_state.freemempos = PHYS_TO_DMAP(physmap[i]);
+		}
+	}
+
 	start_pa = pmap_early_vtophys(bs_state.freemempos);
 
 	/*
@@ -1378,19 +1408,9 @@ pmap_bootstrap(void)
 	alloc_pages(msgbufpv, round_page(msgbufsize) / PAGE_SIZE);
 	msgbufp = (void *)msgbufpv;
 
-	/* Reserve some VA space for early BIOS/ACPI mapping */
-	preinit_map_va = roundup2(bs_state.freemempos, L2_SIZE);
-
-	virtual_avail = preinit_map_va + PMAP_PREINIT_MAPPING_SIZE;
-	virtual_avail = roundup2(virtual_avail, L1_SIZE);
-	virtual_end = VM_MAX_KERNEL_ADDRESS - (PMAP_MAPDEV_EARLY_SIZE);
-	kernel_vm_end = virtual_avail;
-
 	pa = pmap_early_vtophys(bs_state.freemempos);
 
 	physmem_exclude_region(start_pa, pa - start_pa, EXFLAG_NOALLOC);
-
-	cpu_tlb_flushID();
 }
 
 #if defined(KASAN) || defined(KMSAN)