drm/i915/gtt: Use NULL to encode scratch shadow entries
We can simplify our gtt walking code by comparing against NULL for scratch entries as opposed to looking up the distinct per-level scratch pointer. The only caveat is to remember to protect external parties and map the NULL to the scratch top pd. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190712094327.24437-6-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson
parent
c03cbe4c0a
commit
6239901c57
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@ -710,7 +710,6 @@ static struct i915_page_table *alloc_pt(struct i915_address_space *vm)
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}
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atomic_set(&pt->used, 0);
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return pt;
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}
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@ -718,13 +717,11 @@ static struct i915_page_directory *__alloc_pd(void)
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{
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struct i915_page_directory *pd;
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pd = kmalloc(sizeof(*pd), I915_GFP_ALLOW_FAIL);
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pd = kzalloc(sizeof(*pd), I915_GFP_ALLOW_FAIL);
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if (unlikely(!pd))
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return NULL;
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atomic_set(px_used(pd), 0);
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spin_lock_init(&pd->lock);
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return pd;
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}
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@ -752,63 +749,56 @@ static void free_pd(struct i915_address_space *vm, struct i915_page_dma *pd)
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#define free_px(vm, px) free_pd(vm, px_base(px))
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static void init_pd(struct i915_page_directory *pd,
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struct i915_page_scratch *scratch)
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{
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fill_px(pd, scratch->encode);
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memset_p(pd->entry, scratch, 512);
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}
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static inline void
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write_dma_entry(struct i915_page_dma * const pdma,
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const unsigned short pde,
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const unsigned short idx,
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const u64 encoded_entry)
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{
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u64 * const vaddr = kmap_atomic(pdma->page);
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vaddr[pde] = encoded_entry;
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vaddr[idx] = encoded_entry;
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kunmap_atomic(vaddr);
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}
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static inline void
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__set_pd_entry(struct i915_page_directory * const pd,
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const unsigned short pde,
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const unsigned short idx,
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struct i915_page_dma * const to,
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u64 (*encode)(const dma_addr_t, const enum i915_cache_level))
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{
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GEM_BUG_ON(atomic_read(px_used(pd)) > 512);
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atomic_inc(px_used(pd));
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pd->entry[pde] = to;
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write_dma_entry(px_base(pd), pde, encode(to->daddr, I915_CACHE_LLC));
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pd->entry[idx] = to;
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write_dma_entry(px_base(pd), idx, encode(to->daddr, I915_CACHE_LLC));
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}
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#define set_pd_entry(pd, pde, to) \
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__set_pd_entry((pd), (pde), px_base(to), gen8_pde_encode)
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#define set_pd_entry(pd, idx, to) \
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__set_pd_entry((pd), (idx), px_base(to), gen8_pde_encode)
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static inline void
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clear_pd_entry(struct i915_page_directory * const pd,
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const unsigned short pde,
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struct i915_page_scratch * const scratch)
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const unsigned short idx,
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const struct i915_page_scratch * const scratch)
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{
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GEM_BUG_ON(atomic_read(px_used(pd)) == 0);
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write_dma_entry(px_base(pd), pde, scratch->encode);
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pd->entry[pde] = scratch;
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write_dma_entry(px_base(pd), idx, scratch->encode);
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pd->entry[idx] = NULL;
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atomic_dec(px_used(pd));
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}
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static bool
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release_pd_entry(struct i915_page_directory * const pd,
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const unsigned short pde,
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const unsigned short idx,
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struct i915_page_table * const pt,
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struct i915_page_scratch * const scratch)
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const struct i915_page_scratch * const scratch)
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{
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bool free = false;
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spin_lock(&pd->lock);
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if (atomic_dec_and_test(&pt->used)) {
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clear_pd_entry(pd, pde, scratch);
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clear_pd_entry(pd, idx, scratch);
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free = true;
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}
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spin_unlock(&pd->lock);
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@ -912,7 +902,7 @@ static void gen8_free_page_tables(struct i915_address_space *vm,
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int i;
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for (i = 0; i < I915_PDES; i++) {
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if (pd->entry[i] != &vm->scratch[1])
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if (pd->entry[i])
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free_pd(vm, pd->entry[i]);
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}
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}
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@ -924,7 +914,7 @@ static void gen8_ppgtt_cleanup_3lvl(struct i915_address_space *vm,
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int i;
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for (i = 0; i < pdpes; i++) {
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if (pdp->entry[i] == &vm->scratch[2])
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if (!pdp->entry[i])
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continue;
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gen8_free_page_tables(vm, pdp->entry[i]);
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@ -942,7 +932,7 @@ static void gen8_ppgtt_cleanup_4lvl(struct i915_ppgtt *ppgtt)
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for (i = 0; i < GEN8_PML4ES_PER_PML4; i++) {
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struct i915_page_directory *pdp = i915_pdp_entry(pml4, i);
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if (px_base(pdp) == px_base(&ppgtt->vm.scratch[3]))
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if (!pdp)
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continue;
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gen8_ppgtt_cleanup_3lvl(&ppgtt->vm, pdp);
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@ -996,8 +986,6 @@ static void gen8_ppgtt_clear_pd(struct i915_address_space *vm,
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u32 pde;
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gen8_for_each_pde(pt, pd, start, length, pde) {
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GEM_BUG_ON(px_base(pt) == px_base(&vm->scratch[1]));
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atomic_inc(&pt->used);
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gen8_ppgtt_clear_pt(vm, pt, start, length);
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if (release_pd_entry(pd, pde, pt, &vm->scratch[1]))
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@ -1016,8 +1004,6 @@ static void gen8_ppgtt_clear_pdp(struct i915_address_space *vm,
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unsigned int pdpe;
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gen8_for_each_pdpe(pd, pdp, start, length, pdpe) {
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GEM_BUG_ON(px_base(pd) == px_base(&vm->scratch[2]));
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atomic_inc(px_used(pd));
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gen8_ppgtt_clear_pd(vm, pd, start, length);
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if (release_pd_entry(pdp, pdpe, &pd->pt, &vm->scratch[2]))
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@ -1046,8 +1032,6 @@ static void gen8_ppgtt_clear_4lvl(struct i915_address_space *vm,
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GEM_BUG_ON(!i915_vm_is_4lvl(vm));
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gen8_for_each_pml4e(pdp, pml4, start, length, pml4e) {
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GEM_BUG_ON(px_base(pdp) == px_base(&vm->scratch[3]));
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atomic_inc(px_used(pdp));
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gen8_ppgtt_clear_pdp(vm, pdp, start, length);
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if (release_pd_entry(pml4, pml4e, &pdp->pt, &vm->scratch[3]))
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@ -1068,7 +1052,7 @@ static int gen8_ppgtt_alloc_pd(struct i915_address_space *vm,
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gen8_for_each_pde(pt, pd, start, length, pde) {
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const int count = gen8_pte_count(start, length);
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if (px_base(pt) == px_base(&vm->scratch[1])) {
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if (!pt) {
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spin_unlock(&pd->lock);
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pt = fetch_and_zero(&alloc);
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@ -1083,7 +1067,7 @@ static int gen8_ppgtt_alloc_pd(struct i915_address_space *vm,
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fill_px(pt, vm->scratch[0].encode);
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spin_lock(&pd->lock);
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if (pd->entry[pde] == &vm->scratch[1]) {
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if (!pd->entry[pde]) {
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set_pd_entry(pd, pde, pt);
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} else {
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alloc = pt;
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@ -1115,7 +1099,7 @@ static int gen8_ppgtt_alloc_pdp(struct i915_address_space *vm,
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spin_lock(&pdp->lock);
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gen8_for_each_pdpe(pd, pdp, start, length, pdpe) {
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if (px_base(pd) == px_base(&vm->scratch[2])) {
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if (!pd) {
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spin_unlock(&pdp->lock);
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pd = fetch_and_zero(&alloc);
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@ -1126,10 +1110,10 @@ static int gen8_ppgtt_alloc_pdp(struct i915_address_space *vm,
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goto unwind;
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}
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init_pd(pd, &vm->scratch[1]);
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fill_px(pd, vm->scratch[1].encode);
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spin_lock(&pdp->lock);
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if (pdp->entry[pdpe] == &vm->scratch[2]) {
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if (!pdp->entry[pdpe]) {
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set_pd_entry(pdp, pdpe, pd);
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} else {
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alloc = pd;
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@ -1179,7 +1163,7 @@ static int gen8_ppgtt_alloc_4lvl(struct i915_address_space *vm,
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spin_lock(&pml4->lock);
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gen8_for_each_pml4e(pdp, pml4, start, length, pml4e) {
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if (px_base(pdp) == px_base(&vm->scratch[3])) {
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if (!pdp) {
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spin_unlock(&pml4->lock);
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pdp = fetch_and_zero(&alloc);
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@ -1190,10 +1174,10 @@ static int gen8_ppgtt_alloc_4lvl(struct i915_address_space *vm,
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goto unwind;
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}
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init_pd(pdp, &vm->scratch[2]);
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fill_px(pdp, vm->scratch[2].encode);
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spin_lock(&pml4->lock);
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if (pml4->entry[pml4e] == &vm->scratch[3]) {
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if (!pml4->entry[pml4e]) {
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set_pd_entry(pml4, pml4e, pdp);
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} else {
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alloc = pdp;
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@ -1529,7 +1513,7 @@ static int gen8_preallocate_top_level_pdp(struct i915_ppgtt *ppgtt)
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if (IS_ERR(pd))
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goto unwind;
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init_pd(pd, &vm->scratch[1]);
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fill_px(pd, vm->scratch[1].encode);
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set_pd_entry(pdp, pdpe, pd);
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}
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@ -1558,46 +1542,19 @@ static void ppgtt_init(struct i915_ppgtt *ppgtt, struct intel_gt *gt)
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ppgtt->vm.vma_ops.clear_pages = clear_pages;
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}
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static void init_pd_n(struct i915_address_space *vm,
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struct i915_page_directory *pd,
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struct i915_page_scratch *scratch,
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const unsigned int entries)
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{
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u64 * const vaddr = kmap_atomic_px(pd);
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memset64(vaddr, scratch->encode, entries);
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kunmap_atomic(vaddr);
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memset_p(pd->entry, scratch, entries);
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}
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static struct i915_page_directory *
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gen8_alloc_top_pd(struct i915_address_space *vm)
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{
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const unsigned int count = vm->total >> __gen8_pte_shift(vm->top);
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struct i915_page_directory *pd;
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if (i915_vm_is_4lvl(vm)) {
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pd = alloc_pd(vm);
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if (!IS_ERR(pd))
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init_pd(pd, &vm->scratch[3]);
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GEM_BUG_ON(count > ARRAY_SIZE(pd->entry));
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pd = alloc_pd(vm);
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if (IS_ERR(pd))
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return pd;
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}
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/* 3lvl */
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pd = __alloc_pd();
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if (!pd)
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return ERR_PTR(-ENOMEM);
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pd->entry[GEN8_3LVL_PDPES] = NULL;
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if (unlikely(setup_page_dma(vm, px_base(pd)))) {
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kfree(pd);
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return ERR_PTR(-ENOMEM);
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}
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init_pd_n(vm, pd, &vm->scratch[2], GEN8_3LVL_PDPES);
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fill_page_dma(px_base(pd), vm->scratch[vm->top].encode, count);
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return pd;
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}
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@ -609,7 +609,7 @@ i915_page_dir_dma_addr(const struct i915_ppgtt *ppgtt, const unsigned int n)
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{
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struct i915_page_dma *pt = ppgtt->pd->entry[n];
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return px_dma(pt);
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return px_dma(pt ?: px_base(&ppgtt->vm.scratch[ppgtt->vm.top]));
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}
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static inline struct i915_ggtt *
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