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Simplify arm64's pmap_bootstrap() a bit.

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locore constructs an L2 page mapping the kernel and preloaded data
starting a KERNBASE (the same as VM_MIN_KERNEL_ADDRESS on arm64).
initarm() and pmap_bootstrap() use the preloaded metadata to
tell it where it can start allocating from.

pmap_bootstrap() currently iterates over the L2 page to find the last
valid entry, but doesn't do anything with the result.  Remove the loop
and zap some now-unused local variables.

MFC after:	2 weeks
Sponsored by:	Juniper Networks, Klara Inc.
Differential Revision:	https://reviews.freebsd.org/D24559
This commit is contained in:
Mark Johnston 2020-05-06 15:01:06 +00:00
parent 768c98a737
commit 1a5b3b5102
1 changed files with 6 additions and 32 deletions
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38
sys/arm64/arm64/pmap.c
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@ -831,9 +831,7 @@ void
pmap_bootstrap(vm_offset_t l0pt, vm_offset_t l1pt, vm_paddr_t kernstart,
vm_size_t kernlen)
{
u_int l1_slot, l2_slot;
pt_entry_t *l2;
vm_offset_t va, freemempos;
vm_offset_t freemempos;
vm_offset_t dpcpu, msgbufpv;
vm_paddr_t start_pa, pa, min_pa;
uint64_t kern_delta;
@ -867,7 +865,7 @@ pmap_bootstrap(vm_offset_t l0pt, vm_offset_t l1pt, vm_paddr_t kernstart,
* Find the minimum physical address. physmap is sorted,
* but may contain empty ranges.
*/
for (i = 0; i < (physmap_idx * 2); i += 2) {
for (i = 0; i < physmap_idx * 2; i += 2) {
if (physmap[i] == physmap[i + 1])
continue;
if (physmap[i] <= min_pa)
@ -880,38 +878,14 @@ pmap_bootstrap(vm_offset_t l0pt, vm_offset_t l1pt, vm_paddr_t kernstart,
/* Create a direct map region early so we can use it for pa -> va */
freemempos = pmap_bootstrap_dmap(l1pt, min_pa, freemempos);
va = KERNBASE;
start_pa = pa = KERNBASE - kern_delta;
/*
* Read the page table to find out what is already mapped.
* This assumes we have mapped a block of memory from KERNBASE
* using a single L1 entry.
* Create the l2 tables up to VM_MAX_KERNEL_ADDRESS. We assume that the
* loader allocated the first and only l2 page table page used to map
* the kernel, preloaded files and module metadata.
*/
l2 = pmap_early_page_idx(l1pt, KERNBASE, &l1_slot, &l2_slot);
/* Sanity check the index, KERNBASE should be the first VA */
KASSERT(l2_slot == 0, ("The L2 index is non-zero"));
/* Find how many pages we have mapped */
for (; l2_slot < Ln_ENTRIES; l2_slot++) {
if ((l2[l2_slot] & ATTR_DESCR_MASK) == 0)
break;
/* Check locore used L2 blocks */
KASSERT((l2[l2_slot] & ATTR_DESCR_MASK) == L2_BLOCK,
("Invalid bootstrap L2 table"));
KASSERT((l2[l2_slot] & ~ATTR_MASK) == pa,
("Incorrect PA in L2 table"));
va += L2_SIZE;
pa += L2_SIZE;
}
va = roundup2(va, L1_SIZE);
/* Create the l2 tables up to VM_MAX_KERNEL_ADDRESS */
freemempos = pmap_bootstrap_l2(l1pt, va, freemempos);
freemempos = pmap_bootstrap_l2(l1pt, KERNBASE + L1_SIZE, freemempos);
/* And the l3 tables for the early devmap */
freemempos = pmap_bootstrap_l3(l1pt,
VM_MAX_KERNEL_ADDRESS - (PMAP_MAPDEV_EARLY_SIZE), freemempos);