On Tue, 2014-02-25 at 19:52 -0800, Ben Widawsky wrote:
> These page table helpers make the code much cleaner. There is some
> room to use the arch/x86 header files. The reason I've opted not to is
> in several cases, the definitions are dictated by the CONFIG_ options
> which do not always indicate the restrictions in the GPU.
>
> Signed-off-by: Ben Widawsky <ben@xxxxxxxxxxxx>
> ---
>
> I have this patch queued up for the next round of /stuff/ I am working on. If
> you want to pull it into this series, it's fine by me. As I deal with the code
> more, it does become more obvious what looks good, and what does not.
>
> ---
>
> drivers/gpu/drm/i915/i915_gem_gtt.c | 115 +++++++++++++++++++++++++-----------
> 1 file changed, 81 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index aa3ef7f..43d9129 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -30,8 +30,6 @@
> #include "i915_trace.h"
> #include "intel_drv.h"
>
> -#define GEN6_PPGTT_PD_ENTRIES 512
> -#define I915_PPGTT_PT_ENTRIES (PAGE_SIZE / sizeof(gen6_gtt_pte_t))
> typedef uint64_t gen8_gtt_pte_t;
> typedef gen8_gtt_pte_t gen8_ppgtt_pde_t;
>
> @@ -51,6 +49,27 @@ typedef gen8_gtt_pte_t gen8_ppgtt_pde_t;
> #define GEN6_PTE_ADDR_ENCODE(addr) GEN6_GTT_ADDR_ENCODE(addr)
> #define HSW_PTE_ADDR_ENCODE(addr) HSW_GTT_ADDR_ENCODE(addr)
>
> +/* GEN6 PPGTT resembles a 2 level page table:
> + * 31:22 | 21:12 | 11:0
> + * PDE | PTE | offset
> + */
> +#define GEN6_PDE_SHIFT 22
> +#define GEN6_PPGTT_PD_ENTRIES 512
> +#define GEN6_PDE_MASK (GEN6_PPGTT_PD_ENTRIES-1)
> +#define GEN6_PTE_SHIFT 12
> +#define GEN6_PPGTT_PT_ENTRIES (PAGE_SIZE / sizeof(gen6_gtt_pte_t))
> +#define GEN6_PTE_MASK (GEN6_PPGTT_PT_ENTRIES-1)
> +
> +static inline uint32_t gen6_pte_index(uint32_t address)
> +{
> + return (address >> GEN6_PTE_SHIFT) & GEN6_PTE_MASK;
> +}
> +
> +static inline uint32_t gen6_pde_index(uint32_t address)
> +{
> + return (address >> GEN6_PDE_SHIFT) & GEN6_PDE_MASK;
> +}
> +
> /* Cacheability Control is a 4-bit value. The low three bits are stored in *
> * bits 3:1 of the PTE, while the fourth bit is stored in bit 11 of the PTE.
> */
> @@ -63,6 +82,11 @@ typedef gen8_gtt_pte_t gen8_ppgtt_pde_t;
> #define HSW_WT_ELLC_LLC_AGE0 HSW_CACHEABILITY_CONTROL(0x6)
> #define HSW_WT_ELLC_LLC_AGE3 HSW_CACHEABILITY_CONTROL(0x7)
>
> +#define PPAT_UNCACHED_INDEX (_PAGE_PWT | _PAGE_PCD)
> +#define PPAT_CACHED_PDE_INDEX 0 /* WB LLC */
> +#define PPAT_CACHED_INDEX _PAGE_PAT /* WB LLCeLLC */
> +#define PPAT_DISPLAY_ELLC_INDEX _PAGE_PCD /* WT eLLC */
> +
> #define GEN8_PTES_PER_PAGE (PAGE_SIZE / sizeof(gen8_gtt_pte_t))
> #define GEN8_PDES_PER_PAGE (PAGE_SIZE / sizeof(gen8_ppgtt_pde_t))
>
> @@ -71,6 +95,10 @@ typedef gen8_gtt_pte_t gen8_ppgtt_pde_t;
> * PDPE | PDE | PTE | offset
> * The difference as compared to normal x86 3 level page table is the PDPEs are
> * programmed via register.
> + *
> + * The x86 pagetable code is flexible in its ability to handle varying page
> + * table depths via abstracted PGDIR/PUD/PMD/PTE. I've opted to not do this and
> + * instead replicate the interesting functionality.
> */
> #define GEN8_PDPE_SHIFT 30
> #define GEN8_PDPE_MASK 0x3
> @@ -79,10 +107,31 @@ typedef gen8_gtt_pte_t gen8_ppgtt_pde_t;
> #define GEN8_PTE_SHIFT 12
> #define GEN8_PTE_MASK 0x1ff
>
> -#define PPAT_UNCACHED_INDEX (_PAGE_PWT | _PAGE_PCD)
> -#define PPAT_CACHED_PDE_INDEX 0 /* WB LLC */
> -#define PPAT_CACHED_INDEX _PAGE_PAT /* WB LLCeLLC */
> -#define PPAT_DISPLAY_ELLC_INDEX _PAGE_PCD /* WT eLLC */
> +static inline uint32_t gen8_pte_index(uint64_t address)
> +{
> + return (address >> GEN8_PTE_SHIFT) & GEN8_PTE_MASK;
> +}
> +
> +static inline uint32_t gen8_pde_index(uint64_t address)
> +{
> + return (address >> GEN8_PDE_SHIFT) & GEN8_PDE_MASK;
> +}
> +
> +static inline uint32_t gen8_pdpe_index(uint64_t address)
> +{
> + return (address >> GEN8_PDPE_SHIFT) & GEN8_PDPE_MASK;
> +}
> +
> +static inline uint32_t gen8_pml4e_index(uint64_t address)
> +{
> + BUG();
> +}
Would be better to add this if/when it's first used.
> +
> +/* Useful for 3 level page table functions */
> +static inline uint32_t gen8_pde_count(uint64_t start, uint64_t length)
> +{
> + return ((length - start) / PAGE_SIZE) << GEN8_PDE_SHIFT;
> +}
This isn't used anywhere either and has the <start,length> vs.
<start,end> issue Daniel pointed out elsewhere.
Otherwise the patch looks good and makes things indeed clearer, so with
the above two functions removed:
Reviewed-by: Imre Deak <imre.deak@xxxxxxxxx>
>
> static void ppgtt_bind_vma(struct i915_vma *vma,
> enum i915_cache_level cache_level,
> @@ -274,9 +323,9 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
> struct i915_hw_ppgtt *ppgtt =
> container_of(vm, struct i915_hw_ppgtt, base);
> gen8_gtt_pte_t *pt_vaddr, scratch_pte;
> - unsigned pdpe = start >> GEN8_PDPE_SHIFT & GEN8_PDPE_MASK;
> - unsigned pde = start >> GEN8_PDE_SHIFT & GEN8_PDE_MASK;
> - unsigned pte = start >> GEN8_PTE_SHIFT & GEN8_PTE_MASK;
> + unsigned pdpe = gen8_pdpe_index(start);
> + unsigned pde = gen8_pde_index(start);
> + unsigned pte = gen8_pte_index(start);
> unsigned num_entries = (length - start) >> PAGE_SHIFT;
> unsigned last_pte, i;
>
> @@ -315,9 +364,9 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
> struct i915_hw_ppgtt *ppgtt =
> container_of(vm, struct i915_hw_ppgtt, base);
> gen8_gtt_pte_t *pt_vaddr;
> - unsigned pdpe = start >> GEN8_PDPE_SHIFT & GEN8_PDPE_MASK;
> - unsigned pde = start >> GEN8_PDE_SHIFT & GEN8_PDE_MASK;
> - unsigned pte = start >> GEN8_PTE_SHIFT & GEN8_PTE_MASK;
> + unsigned pdpe = gen8_pdpe_index(start);
> + unsigned pde = gen8_pde_index(start);
> + unsigned pte = gen8_pte_index(start);
> struct sg_page_iter sg_iter;
>
> pt_vaddr = NULL;
> @@ -661,9 +710,9 @@ static void gen6_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
> seq_printf(m, "\tPDE: %x\n", pd_entry);
>
> pt_vaddr = kmap_atomic(ppgtt->pt_pages[pde]);
> - for (pte = 0; pte < I915_PPGTT_PT_ENTRIES; pte+=4) {
> + for (pte = 0; pte < GEN6_PPGTT_PT_ENTRIES; pte+=4) {
> unsigned long va =
> - (pde * PAGE_SIZE * I915_PPGTT_PT_ENTRIES) +
> + (pde * PAGE_SIZE * GEN6_PPGTT_PT_ENTRIES) +
> (pte * PAGE_SIZE);
> int i;
> bool found = false;
> @@ -938,29 +987,28 @@ static void gen6_ppgtt_clear_range(struct i915_address_space *vm,
> struct i915_hw_ppgtt *ppgtt =
> container_of(vm, struct i915_hw_ppgtt, base);
> gen6_gtt_pte_t *pt_vaddr, scratch_pte;
> - unsigned first_entry = start >> PAGE_SHIFT;
> + unsigned pde = gen6_pde_index(start);
> unsigned num_entries = (length - start) >> PAGE_SHIFT;
> - unsigned act_pt = first_entry / I915_PPGTT_PT_ENTRIES;
> - unsigned first_pte = first_entry % I915_PPGTT_PT_ENTRIES;
> + unsigned pte = gen6_pte_index(start);
> unsigned last_pte, i;
>
> scratch_pte = vm->pte_encode(vm->scratch.addr, I915_CACHE_LLC, true);
>
> while (num_entries) {
> - last_pte = first_pte + num_entries;
> - if (last_pte > I915_PPGTT_PT_ENTRIES)
> - last_pte = I915_PPGTT_PT_ENTRIES;
> + last_pte = pte + num_entries;
> + if (last_pte > GEN6_PPGTT_PT_ENTRIES)
> + last_pte = GEN6_PPGTT_PT_ENTRIES;
>
> - pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pt]);
> + pt_vaddr = kmap_atomic(ppgtt->pt_pages[pde]);
>
> - for (i = first_pte; i < last_pte; i++)
> + for (i = pte; i < last_pte; i++)
> pt_vaddr[i] = scratch_pte;
>
> kunmap_atomic(pt_vaddr);
>
> - num_entries -= last_pte - first_pte;
> - first_pte = 0;
> - act_pt++;
> + num_entries -= last_pte - pte;
> + pte = 0;
> + pde++;
> }
> }
>
> @@ -972,24 +1020,23 @@ static void gen6_ppgtt_insert_entries(struct i915_address_space *vm,
> struct i915_hw_ppgtt *ppgtt =
> container_of(vm, struct i915_hw_ppgtt, base);
> gen6_gtt_pte_t *pt_vaddr;
> - unsigned first_entry = start >> PAGE_SHIFT;
> - unsigned act_pt = first_entry / I915_PPGTT_PT_ENTRIES;
> - unsigned act_pte = first_entry % I915_PPGTT_PT_ENTRIES;
> + unsigned pde = gen6_pde_index(start);
> + unsigned pte = gen6_pte_index(start);
> struct sg_page_iter sg_iter;
>
> pt_vaddr = NULL;
> for_each_sg_page(pages->sgl, &sg_iter, pages->nents, 0) {
> if (pt_vaddr == NULL)
> - pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pt]);
> + pt_vaddr = kmap_atomic(ppgtt->pt_pages[pde]);
>
> - pt_vaddr[act_pte] =
> + pt_vaddr[pte] =
> vm->pte_encode(sg_page_iter_dma_address(&sg_iter),
> cache_level, true);
> - if (++act_pte == I915_PPGTT_PT_ENTRIES) {
> + if (++pte == GEN6_PPGTT_PT_ENTRIES) {
> kunmap_atomic(pt_vaddr);
> pt_vaddr = NULL;
> - act_pt++;
> - act_pte = 0;
> + pde++;
> + pte = 0;
> }
> }
> if (pt_vaddr)
> @@ -1173,7 +1220,7 @@ static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
> ppgtt->base.cleanup = gen6_ppgtt_cleanup;
> ppgtt->base.scratch = dev_priv->gtt.base.scratch;
> ppgtt->base.start = 0;
> - ppgtt->base.total = GEN6_PPGTT_PD_ENTRIES * I915_PPGTT_PT_ENTRIES * PAGE_SIZE;
> + ppgtt->base.total = GEN6_PPGTT_PD_ENTRIES * GEN6_PPGTT_PT_ENTRIES * PAGE_SIZE;
> ppgtt->debug_dump = gen6_dump_ppgtt;
>
> ppgtt->pd_offset =
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