diff options
Diffstat (limited to 'drivers/misc/sgi-gru/grumain.c')
| -rw-r--r-- | drivers/misc/sgi-gru/grumain.c | 977 |
1 files changed, 977 insertions, 0 deletions
diff --git a/drivers/misc/sgi-gru/grumain.c b/drivers/misc/sgi-gru/grumain.c new file mode 100644 index 000000000..e2325e3d0 --- /dev/null +++ b/drivers/misc/sgi-gru/grumain.c @@ -0,0 +1,977 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * SN Platform GRU Driver + * + * DRIVER TABLE MANAGER + GRU CONTEXT LOAD/UNLOAD + * + * Copyright (c) 2008 Silicon Graphics, Inc. All Rights Reserved. + */ + +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/mm.h> +#include <linux/spinlock.h> +#include <linux/sched.h> +#include <linux/device.h> +#include <linux/list.h> +#include <linux/err.h> +#include <linux/prefetch.h> +#include <asm/uv/uv_hub.h> +#include "gru.h" +#include "grutables.h" +#include "gruhandles.h" + +unsigned long gru_options __read_mostly; + +static struct device_driver gru_driver = { + .name = "gru" +}; + +static struct device gru_device = { + .init_name = "", + .driver = &gru_driver, +}; + +struct device *grudev = &gru_device; + +/* + * Select a gru fault map to be used by the current cpu. Note that + * multiple cpus may be using the same map. + * ZZZ should be inline but did not work on emulator + */ +int gru_cpu_fault_map_id(void) +{ +#ifdef CONFIG_IA64 + return uv_blade_processor_id() % GRU_NUM_TFM; +#else + int cpu = smp_processor_id(); + int id, core; + + core = uv_cpu_core_number(cpu); + id = core + UV_MAX_INT_CORES * uv_cpu_socket_number(cpu); + return id; +#endif +} + +/*--------- ASID Management ------------------------------------------- + * + * Initially, assign asids sequentially from MIN_ASID .. MAX_ASID. + * Once MAX is reached, flush the TLB & start over. However, + * some asids may still be in use. There won't be many (percentage wise) still + * in use. Search active contexts & determine the value of the first + * asid in use ("x"s below). Set "limit" to this value. + * This defines a block of assignable asids. + * + * When "limit" is reached, search forward from limit+1 and determine the + * next block of assignable asids. + * + * Repeat until MAX_ASID is reached, then start over again. + * + * Each time MAX_ASID is reached, increment the asid generation. Since + * the search for in-use asids only checks contexts with GRUs currently + * assigned, asids in some contexts will be missed. Prior to loading + * a context, the asid generation of the GTS asid is rechecked. If it + * doesn't match the current generation, a new asid will be assigned. + * + * 0---------------x------------x---------------------x----| + * ^-next ^-limit ^-MAX_ASID + * + * All asid manipulation & context loading/unloading is protected by the + * gs_lock. + */ + +/* Hit the asid limit. Start over */ +static int gru_wrap_asid(struct gru_state *gru) +{ + gru_dbg(grudev, "gid %d\n", gru->gs_gid); + STAT(asid_wrap); + gru->gs_asid_gen++; + return MIN_ASID; +} + +/* Find the next chunk of unused asids */ +static int gru_reset_asid_limit(struct gru_state *gru, int asid) +{ + int i, gid, inuse_asid, limit; + + gru_dbg(grudev, "gid %d, asid 0x%x\n", gru->gs_gid, asid); + STAT(asid_next); + limit = MAX_ASID; + if (asid >= limit) + asid = gru_wrap_asid(gru); + gru_flush_all_tlb(gru); + gid = gru->gs_gid; +again: + for (i = 0; i < GRU_NUM_CCH; i++) { + if (!gru->gs_gts[i] || is_kernel_context(gru->gs_gts[i])) + continue; + inuse_asid = gru->gs_gts[i]->ts_gms->ms_asids[gid].mt_asid; + gru_dbg(grudev, "gid %d, gts %p, gms %p, inuse 0x%x, cxt %d\n", + gru->gs_gid, gru->gs_gts[i], gru->gs_gts[i]->ts_gms, + inuse_asid, i); + if (inuse_asid == asid) { + asid += ASID_INC; + if (asid >= limit) { + /* + * empty range: reset the range limit and + * start over + */ + limit = MAX_ASID; + if (asid >= MAX_ASID) + asid = gru_wrap_asid(gru); + goto again; + } + } + + if ((inuse_asid > asid) && (inuse_asid < limit)) + limit = inuse_asid; + } + gru->gs_asid_limit = limit; + gru->gs_asid = asid; + gru_dbg(grudev, "gid %d, new asid 0x%x, new_limit 0x%x\n", gru->gs_gid, + asid, limit); + return asid; +} + +/* Assign a new ASID to a thread context. */ +static int gru_assign_asid(struct gru_state *gru) +{ + int asid; + + gru->gs_asid += ASID_INC; + asid = gru->gs_asid; + if (asid >= gru->gs_asid_limit) + asid = gru_reset_asid_limit(gru, asid); + + gru_dbg(grudev, "gid %d, asid 0x%x\n", gru->gs_gid, asid); + return asid; +} + +/* + * Clear n bits in a word. Return a word indicating the bits that were cleared. + * Optionally, build an array of chars that contain the bit numbers allocated. + */ +static unsigned long reserve_resources(unsigned long *p, int n, int mmax, + char *idx) +{ + unsigned long bits = 0; + int i; + + while (n--) { + i = find_first_bit(p, mmax); + if (i == mmax) + BUG(); + __clear_bit(i, p); + __set_bit(i, &bits); + if (idx) + *idx++ = i; + } + return bits; +} + +unsigned long gru_reserve_cb_resources(struct gru_state *gru, int cbr_au_count, + char *cbmap) +{ + return reserve_resources(&gru->gs_cbr_map, cbr_au_count, GRU_CBR_AU, + cbmap); +} + +unsigned long gru_reserve_ds_resources(struct gru_state *gru, int dsr_au_count, + char *dsmap) +{ + return reserve_resources(&gru->gs_dsr_map, dsr_au_count, GRU_DSR_AU, + dsmap); +} + +static void reserve_gru_resources(struct gru_state *gru, + struct gru_thread_state *gts) +{ + gru->gs_active_contexts++; + gts->ts_cbr_map = + gru_reserve_cb_resources(gru, gts->ts_cbr_au_count, + gts->ts_cbr_idx); + gts->ts_dsr_map = + gru_reserve_ds_resources(gru, gts->ts_dsr_au_count, NULL); +} + +static void free_gru_resources(struct gru_state *gru, + struct gru_thread_state *gts) +{ + gru->gs_active_contexts--; + gru->gs_cbr_map |= gts->ts_cbr_map; + gru->gs_dsr_map |= gts->ts_dsr_map; +} + +/* + * Check if a GRU has sufficient free resources to satisfy an allocation + * request. Note: GRU locks may or may not be held when this is called. If + * not held, recheck after acquiring the appropriate locks. + * + * Returns 1 if sufficient resources, 0 if not + */ +static int check_gru_resources(struct gru_state *gru, int cbr_au_count, + int dsr_au_count, int max_active_contexts) +{ + return hweight64(gru->gs_cbr_map) >= cbr_au_count + && hweight64(gru->gs_dsr_map) >= dsr_au_count + && gru->gs_active_contexts < max_active_contexts; +} + +/* + * TLB manangment requires tracking all GRU chiplets that have loaded a GSEG + * context. + */ +static int gru_load_mm_tracker(struct gru_state *gru, + struct gru_thread_state *gts) +{ + struct gru_mm_struct *gms = gts->ts_gms; + struct gru_mm_tracker *asids = &gms->ms_asids[gru->gs_gid]; + unsigned short ctxbitmap = (1 << gts->ts_ctxnum); + int asid; + + spin_lock(&gms->ms_asid_lock); + asid = asids->mt_asid; + + spin_lock(&gru->gs_asid_lock); + if (asid == 0 || (asids->mt_ctxbitmap == 0 && asids->mt_asid_gen != + gru->gs_asid_gen)) { + asid = gru_assign_asid(gru); + asids->mt_asid = asid; + asids->mt_asid_gen = gru->gs_asid_gen; + STAT(asid_new); + } else { + STAT(asid_reuse); + } + spin_unlock(&gru->gs_asid_lock); + + BUG_ON(asids->mt_ctxbitmap & ctxbitmap); + asids->mt_ctxbitmap |= ctxbitmap; + if (!test_bit(gru->gs_gid, gms->ms_asidmap)) + __set_bit(gru->gs_gid, gms->ms_asidmap); + spin_unlock(&gms->ms_asid_lock); + + gru_dbg(grudev, + "gid %d, gts %p, gms %p, ctxnum %d, asid 0x%x, asidmap 0x%lx\n", + gru->gs_gid, gts, gms, gts->ts_ctxnum, asid, + gms->ms_asidmap[0]); + return asid; +} + +static void gru_unload_mm_tracker(struct gru_state *gru, + struct gru_thread_state *gts) +{ + struct gru_mm_struct *gms = gts->ts_gms; + struct gru_mm_tracker *asids; + unsigned short ctxbitmap; + + asids = &gms->ms_asids[gru->gs_gid]; + ctxbitmap = (1 << gts->ts_ctxnum); + spin_lock(&gms->ms_asid_lock); + spin_lock(&gru->gs_asid_lock); + BUG_ON((asids->mt_ctxbitmap & ctxbitmap) != ctxbitmap); + asids->mt_ctxbitmap ^= ctxbitmap; + gru_dbg(grudev, "gid %d, gts %p, gms %p, ctxnum %d, asidmap 0x%lx\n", + gru->gs_gid, gts, gms, gts->ts_ctxnum, gms->ms_asidmap[0]); + spin_unlock(&gru->gs_asid_lock); + spin_unlock(&gms->ms_asid_lock); +} + +/* + * Decrement the reference count on a GTS structure. Free the structure + * if the reference count goes to zero. + */ +void gts_drop(struct gru_thread_state *gts) +{ + if (gts && atomic_dec_return(>s->ts_refcnt) == 0) { + if (gts->ts_gms) + gru_drop_mmu_notifier(gts->ts_gms); + kfree(gts); + STAT(gts_free); + } +} + +/* + * Locate the GTS structure for the current thread. + */ +static struct gru_thread_state *gru_find_current_gts_nolock(struct gru_vma_data + *vdata, int tsid) +{ + struct gru_thread_state *gts; + + list_for_each_entry(gts, &vdata->vd_head, ts_next) + if (gts->ts_tsid == tsid) + return gts; + return NULL; +} + +/* + * Allocate a thread state structure. + */ +struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma, + int cbr_au_count, int dsr_au_count, + unsigned char tlb_preload_count, int options, int tsid) +{ + struct gru_thread_state *gts; + struct gru_mm_struct *gms; + int bytes; + + bytes = DSR_BYTES(dsr_au_count) + CBR_BYTES(cbr_au_count); + bytes += sizeof(struct gru_thread_state); + gts = kmalloc(bytes, GFP_KERNEL); + if (!gts) + return ERR_PTR(-ENOMEM); + + STAT(gts_alloc); + memset(gts, 0, sizeof(struct gru_thread_state)); /* zero out header */ + atomic_set(>s->ts_refcnt, 1); + mutex_init(>s->ts_ctxlock); + gts->ts_cbr_au_count = cbr_au_count; + gts->ts_dsr_au_count = dsr_au_count; + gts->ts_tlb_preload_count = tlb_preload_count; + gts->ts_user_options = options; + gts->ts_user_blade_id = -1; + gts->ts_user_chiplet_id = -1; + gts->ts_tsid = tsid; + gts->ts_ctxnum = NULLCTX; + gts->ts_tlb_int_select = -1; + gts->ts_cch_req_slice = -1; + gts->ts_sizeavail = GRU_SIZEAVAIL(PAGE_SHIFT); + if (vma) { + gts->ts_mm = current->mm; + gts->ts_vma = vma; + gms = gru_register_mmu_notifier(); + if (IS_ERR(gms)) + goto err; + gts->ts_gms = gms; + } + + gru_dbg(grudev, "alloc gts %p\n", gts); + return gts; + +err: + gts_drop(gts); + return ERR_CAST(gms); +} + +/* + * Allocate a vma private data structure. + */ +struct gru_vma_data *gru_alloc_vma_data(struct vm_area_struct *vma, int tsid) +{ + struct gru_vma_data *vdata = NULL; + + vdata = kmalloc(sizeof(*vdata), GFP_KERNEL); + if (!vdata) + return NULL; + + STAT(vdata_alloc); + INIT_LIST_HEAD(&vdata->vd_head); + spin_lock_init(&vdata->vd_lock); + gru_dbg(grudev, "alloc vdata %p\n", vdata); + return vdata; +} + +/* + * Find the thread state structure for the current thread. + */ +struct gru_thread_state *gru_find_thread_state(struct vm_area_struct *vma, + int tsid) +{ + struct gru_vma_data *vdata = vma->vm_private_data; + struct gru_thread_state *gts; + + spin_lock(&vdata->vd_lock); + gts = gru_find_current_gts_nolock(vdata, tsid); + spin_unlock(&vdata->vd_lock); + gru_dbg(grudev, "vma %p, gts %p\n", vma, gts); + return gts; +} + +/* + * Allocate a new thread state for a GSEG. Note that races may allow + * another thread to race to create a gts. + */ +struct gru_thread_state *gru_alloc_thread_state(struct vm_area_struct *vma, + int tsid) +{ + struct gru_vma_data *vdata = vma->vm_private_data; + struct gru_thread_state *gts, *ngts; + + gts = gru_alloc_gts(vma, vdata->vd_cbr_au_count, + vdata->vd_dsr_au_count, + vdata->vd_tlb_preload_count, + vdata->vd_user_options, tsid); + if (IS_ERR(gts)) + return gts; + + spin_lock(&vdata->vd_lock); + ngts = gru_find_current_gts_nolock(vdata, tsid); + if (ngts) { + gts_drop(gts); + gts = ngts; + STAT(gts_double_allocate); + } else { + list_add(>s->ts_next, &vdata->vd_head); + } + spin_unlock(&vdata->vd_lock); + gru_dbg(grudev, "vma %p, gts %p\n", vma, gts); + return gts; +} + +/* + * Free the GRU context assigned to the thread state. + */ +static void gru_free_gru_context(struct gru_thread_state *gts) +{ + struct gru_state *gru; + + gru = gts->ts_gru; + gru_dbg(grudev, "gts %p, gid %d\n", gts, gru->gs_gid); + + spin_lock(&gru->gs_lock); + gru->gs_gts[gts->ts_ctxnum] = NULL; + free_gru_resources(gru, gts); + BUG_ON(test_bit(gts->ts_ctxnum, &gru->gs_context_map) == 0); + __clear_bit(gts->ts_ctxnum, &gru->gs_context_map); + gts->ts_ctxnum = NULLCTX; + gts->ts_gru = NULL; + gts->ts_blade = -1; + spin_unlock(&gru->gs_lock); + + gts_drop(gts); + STAT(free_context); +} + +/* + * Prefetching cachelines help hardware performance. + * (Strictly a performance enhancement. Not functionally required). + */ +static void prefetch_data(void *p, int num, int stride) +{ + while (num-- > 0) { + prefetchw(p); + p += stride; + } +} + +static inline long gru_copy_handle(void *d, void *s) +{ + memcpy(d, s, GRU_HANDLE_BYTES); + return GRU_HANDLE_BYTES; +} + +static void gru_prefetch_context(void *gseg, void *cb, void *cbe, + unsigned long cbrmap, unsigned long length) +{ + int i, scr; + + prefetch_data(gseg + GRU_DS_BASE, length / GRU_CACHE_LINE_BYTES, + GRU_CACHE_LINE_BYTES); + + for_each_cbr_in_allocation_map(i, &cbrmap, scr) { + prefetch_data(cb, 1, GRU_CACHE_LINE_BYTES); + prefetch_data(cbe + i * GRU_HANDLE_STRIDE, 1, + GRU_CACHE_LINE_BYTES); + cb += GRU_HANDLE_STRIDE; + } +} + +static void gru_load_context_data(void *save, void *grubase, int ctxnum, + unsigned long cbrmap, unsigned long dsrmap, + int data_valid) +{ + void *gseg, *cb, *cbe; + unsigned long length; + int i, scr; + + gseg = grubase + ctxnum * GRU_GSEG_STRIDE; + cb = gseg + GRU_CB_BASE; + cbe = grubase + GRU_CBE_BASE; + length = hweight64(dsrmap) * GRU_DSR_AU_BYTES; + gru_prefetch_context(gseg, cb, cbe, cbrmap, length); + + for_each_cbr_in_allocation_map(i, &cbrmap, scr) { + if (data_valid) { + save += gru_copy_handle(cb, save); + save += gru_copy_handle(cbe + i * GRU_HANDLE_STRIDE, + save); + } else { + memset(cb, 0, GRU_CACHE_LINE_BYTES); + memset(cbe + i * GRU_HANDLE_STRIDE, 0, + GRU_CACHE_LINE_BYTES); + } + /* Flush CBE to hide race in context restart */ + mb(); + gru_flush_cache(cbe + i * GRU_HANDLE_STRIDE); + cb += GRU_HANDLE_STRIDE; + } + + if (data_valid) + memcpy(gseg + GRU_DS_BASE, save, length); + else + memset(gseg + GRU_DS_BASE, 0, length); +} + +static void gru_unload_context_data(void *save, void *grubase, int ctxnum, + unsigned long cbrmap, unsigned long dsrmap) +{ + void *gseg, *cb, *cbe; + unsigned long length; + int i, scr; + + gseg = grubase + ctxnum * GRU_GSEG_STRIDE; + cb = gseg + GRU_CB_BASE; + cbe = grubase + GRU_CBE_BASE; + length = hweight64(dsrmap) * GRU_DSR_AU_BYTES; + + /* CBEs may not be coherent. Flush them from cache */ + for_each_cbr_in_allocation_map(i, &cbrmap, scr) + gru_flush_cache(cbe + i * GRU_HANDLE_STRIDE); + mb(); /* Let the CL flush complete */ + + gru_prefetch_context(gseg, cb, cbe, cbrmap, length); + + for_each_cbr_in_allocation_map(i, &cbrmap, scr) { + save += gru_copy_handle(save, cb); + save += gru_copy_handle(save, cbe + i * GRU_HANDLE_STRIDE); + cb += GRU_HANDLE_STRIDE; + } + memcpy(save, gseg + GRU_DS_BASE, length); +} + +void gru_unload_context(struct gru_thread_state *gts, int savestate) +{ + struct gru_state *gru = gts->ts_gru; + struct gru_context_configuration_handle *cch; + int ctxnum = gts->ts_ctxnum; + + if (!is_kernel_context(gts)) + zap_vma_ptes(gts->ts_vma, UGRUADDR(gts), GRU_GSEG_PAGESIZE); + cch = get_cch(gru->gs_gru_base_vaddr, ctxnum); + + gru_dbg(grudev, "gts %p, cbrmap 0x%lx, dsrmap 0x%lx\n", + gts, gts->ts_cbr_map, gts->ts_dsr_map); + lock_cch_handle(cch); + if (cch_interrupt_sync(cch)) + BUG(); + + if (!is_kernel_context(gts)) + gru_unload_mm_tracker(gru, gts); + if (savestate) { + gru_unload_context_data(gts->ts_gdata, gru->gs_gru_base_vaddr, + ctxnum, gts->ts_cbr_map, + gts->ts_dsr_map); + gts->ts_data_valid = 1; + } + + if (cch_deallocate(cch)) + BUG(); + unlock_cch_handle(cch); + + gru_free_gru_context(gts); +} + +/* + * Load a GRU context by copying it from the thread data structure in memory + * to the GRU. + */ +void gru_load_context(struct gru_thread_state *gts) +{ + struct gru_state *gru = gts->ts_gru; + struct gru_context_configuration_handle *cch; + int i, err, asid, ctxnum = gts->ts_ctxnum; + + cch = get_cch(gru->gs_gru_base_vaddr, ctxnum); + lock_cch_handle(cch); + cch->tfm_fault_bit_enable = + (gts->ts_user_options == GRU_OPT_MISS_FMM_POLL + || gts->ts_user_options == GRU_OPT_MISS_FMM_INTR); + cch->tlb_int_enable = (gts->ts_user_options == GRU_OPT_MISS_FMM_INTR); + if (cch->tlb_int_enable) { + gts->ts_tlb_int_select = gru_cpu_fault_map_id(); + cch->tlb_int_select = gts->ts_tlb_int_select; + } + if (gts->ts_cch_req_slice >= 0) { + cch->req_slice_set_enable = 1; + cch->req_slice = gts->ts_cch_req_slice; + } else { + cch->req_slice_set_enable =0; + } + cch->tfm_done_bit_enable = 0; + cch->dsr_allocation_map = gts->ts_dsr_map; + cch->cbr_allocation_map = gts->ts_cbr_map; + + if (is_kernel_context(gts)) { + cch->unmap_enable = 1; + cch->tfm_done_bit_enable = 1; + cch->cb_int_enable = 1; + cch->tlb_int_select = 0; /* For now, ints go to cpu 0 */ + } else { + cch->unmap_enable = 0; + cch->tfm_done_bit_enable = 0; + cch->cb_int_enable = 0; + asid = gru_load_mm_tracker(gru, gts); + for (i = 0; i < 8; i++) { + cch->asid[i] = asid + i; + cch->sizeavail[i] = gts->ts_sizeavail; + } + } + + err = cch_allocate(cch); + if (err) { + gru_dbg(grudev, + "err %d: cch %p, gts %p, cbr 0x%lx, dsr 0x%lx\n", + err, cch, gts, gts->ts_cbr_map, gts->ts_dsr_map); + BUG(); + } + + gru_load_context_data(gts->ts_gdata, gru->gs_gru_base_vaddr, ctxnum, + gts->ts_cbr_map, gts->ts_dsr_map, gts->ts_data_valid); + + if (cch_start(cch)) + BUG(); + unlock_cch_handle(cch); + + gru_dbg(grudev, "gid %d, gts %p, cbrmap 0x%lx, dsrmap 0x%lx, tie %d, tis %d\n", + gts->ts_gru->gs_gid, gts, gts->ts_cbr_map, gts->ts_dsr_map, + (gts->ts_user_options == GRU_OPT_MISS_FMM_INTR), gts->ts_tlb_int_select); +} + +/* + * Update fields in an active CCH: + * - retarget interrupts on local blade + * - update sizeavail mask + */ +int gru_update_cch(struct gru_thread_state *gts) +{ + struct gru_context_configuration_handle *cch; + struct gru_state *gru = gts->ts_gru; + int i, ctxnum = gts->ts_ctxnum, ret = 0; + + cch = get_cch(gru->gs_gru_base_vaddr, ctxnum); + + lock_cch_handle(cch); + if (cch->state == CCHSTATE_ACTIVE) { + if (gru->gs_gts[gts->ts_ctxnum] != gts) + goto exit; + if (cch_interrupt(cch)) + BUG(); + for (i = 0; i < 8; i++) + cch->sizeavail[i] = gts->ts_sizeavail; + gts->ts_tlb_int_select = gru_cpu_fault_map_id(); + cch->tlb_int_select = gru_cpu_fault_map_id(); + cch->tfm_fault_bit_enable = + (gts->ts_user_options == GRU_OPT_MISS_FMM_POLL + || gts->ts_user_options == GRU_OPT_MISS_FMM_INTR); + if (cch_start(cch)) + BUG(); + ret = 1; + } +exit: + unlock_cch_handle(cch); + return ret; +} + +/* + * Update CCH tlb interrupt select. Required when all the following is true: + * - task's GRU context is loaded into a GRU + * - task is using interrupt notification for TLB faults + * - task has migrated to a different cpu on the same blade where + * it was previously running. + */ +static int gru_retarget_intr(struct gru_thread_state *gts) +{ + if (gts->ts_tlb_int_select < 0 + || gts->ts_tlb_int_select == gru_cpu_fault_map_id()) + return 0; + + gru_dbg(grudev, "retarget from %d to %d\n", gts->ts_tlb_int_select, + gru_cpu_fault_map_id()); + return gru_update_cch(gts); +} + +/* + * Check if a GRU context is allowed to use a specific chiplet. By default + * a context is assigned to any blade-local chiplet. However, users can + * override this. + * Returns 1 if assignment allowed, 0 otherwise + */ +static int gru_check_chiplet_assignment(struct gru_state *gru, + struct gru_thread_state *gts) +{ + int blade_id; + int chiplet_id; + + blade_id = gts->ts_user_blade_id; + if (blade_id < 0) + blade_id = uv_numa_blade_id(); + + chiplet_id = gts->ts_user_chiplet_id; + return gru->gs_blade_id == blade_id && + (chiplet_id < 0 || chiplet_id == gru->gs_chiplet_id); +} + +/* + * Unload the gru context if it is not assigned to the correct blade or + * chiplet. Misassignment can occur if the process migrates to a different + * blade or if the user changes the selected blade/chiplet. + */ +int gru_check_context_placement(struct gru_thread_state *gts) +{ + struct gru_state *gru; + int ret = 0; + + /* + * If the current task is the context owner, verify that the + * context is correctly placed. This test is skipped for non-owner + * references. Pthread apps use non-owner references to the CBRs. + */ + gru = gts->ts_gru; + /* + * If gru or gts->ts_tgid_owner isn't initialized properly, return + * success to indicate that the caller does not need to unload the + * gru context.The caller is responsible for their inspection and + * reinitialization if needed. + */ + if (!gru || gts->ts_tgid_owner != current->tgid) + return ret; + + if (!gru_check_chiplet_assignment(gru, gts)) { + STAT(check_context_unload); + ret = -EINVAL; + } else if (gru_retarget_intr(gts)) { + STAT(check_context_retarget_intr); + } + + return ret; +} + + +/* + * Insufficient GRU resources available on the local blade. Steal a context from + * a process. This is a hack until a _real_ resource scheduler is written.... + */ +#define next_ctxnum(n) ((n) < GRU_NUM_CCH - 2 ? (n) + 1 : 0) +#define next_gru(b, g) (((g) < &(b)->bs_grus[GRU_CHIPLETS_PER_BLADE - 1]) ? \ + ((g)+1) : &(b)->bs_grus[0]) + +static int is_gts_stealable(struct gru_thread_state *gts, + struct gru_blade_state *bs) +{ + if (is_kernel_context(gts)) + return down_write_trylock(&bs->bs_kgts_sema); + else + return mutex_trylock(>s->ts_ctxlock); +} + +static void gts_stolen(struct gru_thread_state *gts, + struct gru_blade_state *bs) +{ + if (is_kernel_context(gts)) { + up_write(&bs->bs_kgts_sema); + STAT(steal_kernel_context); + } else { + mutex_unlock(>s->ts_ctxlock); + STAT(steal_user_context); + } +} + +void gru_steal_context(struct gru_thread_state *gts) +{ + struct gru_blade_state *blade; + struct gru_state *gru, *gru0; + struct gru_thread_state *ngts = NULL; + int ctxnum, ctxnum0, flag = 0, cbr, dsr; + int blade_id; + + blade_id = gts->ts_user_blade_id; + if (blade_id < 0) + blade_id = uv_numa_blade_id(); + cbr = gts->ts_cbr_au_count; + dsr = gts->ts_dsr_au_count; + + blade = gru_base[blade_id]; + spin_lock(&blade->bs_lock); + + ctxnum = next_ctxnum(blade->bs_lru_ctxnum); + gru = blade->bs_lru_gru; + if (ctxnum == 0) + gru = next_gru(blade, gru); + blade->bs_lru_gru = gru; + blade->bs_lru_ctxnum = ctxnum; + ctxnum0 = ctxnum; + gru0 = gru; + while (1) { + if (gru_check_chiplet_assignment(gru, gts)) { + if (check_gru_resources(gru, cbr, dsr, GRU_NUM_CCH)) + break; + spin_lock(&gru->gs_lock); + for (; ctxnum < GRU_NUM_CCH; ctxnum++) { + if (flag && gru == gru0 && ctxnum == ctxnum0) + break; + ngts = gru->gs_gts[ctxnum]; + /* + * We are grabbing locks out of order, so trylock is + * needed. GTSs are usually not locked, so the odds of + * success are high. If trylock fails, try to steal a + * different GSEG. + */ + if (ngts && is_gts_stealable(ngts, blade)) + break; + ngts = NULL; + } + spin_unlock(&gru->gs_lock); + if (ngts || (flag && gru == gru0 && ctxnum == ctxnum0)) + break; + } + if (flag && gru == gru0) + break; + flag = 1; + ctxnum = 0; + gru = next_gru(blade, gru); + } + spin_unlock(&blade->bs_lock); + + if (ngts) { + gts->ustats.context_stolen++; + ngts->ts_steal_jiffies = jiffies; + gru_unload_context(ngts, is_kernel_context(ngts) ? 0 : 1); + gts_stolen(ngts, blade); + } else { + STAT(steal_context_failed); + } + gru_dbg(grudev, + "stole gid %d, ctxnum %d from gts %p. Need cb %d, ds %d;" + " avail cb %ld, ds %ld\n", + gru->gs_gid, ctxnum, ngts, cbr, dsr, hweight64(gru->gs_cbr_map), + hweight64(gru->gs_dsr_map)); +} + +/* + * Assign a gru context. + */ +static int gru_assign_context_number(struct gru_state *gru) +{ + int ctxnum; + + ctxnum = find_first_zero_bit(&gru->gs_context_map, GRU_NUM_CCH); + __set_bit(ctxnum, &gru->gs_context_map); + return ctxnum; +} + +/* + * Scan the GRUs on the local blade & assign a GRU context. + */ +struct gru_state *gru_assign_gru_context(struct gru_thread_state *gts) +{ + struct gru_state *gru, *grux; + int i, max_active_contexts; + int blade_id = gts->ts_user_blade_id; + + if (blade_id < 0) + blade_id = uv_numa_blade_id(); +again: + gru = NULL; + max_active_contexts = GRU_NUM_CCH; + for_each_gru_on_blade(grux, blade_id, i) { + if (!gru_check_chiplet_assignment(grux, gts)) + continue; + if (check_gru_resources(grux, gts->ts_cbr_au_count, + gts->ts_dsr_au_count, + max_active_contexts)) { + gru = grux; + max_active_contexts = grux->gs_active_contexts; + if (max_active_contexts == 0) + break; + } + } + + if (gru) { + spin_lock(&gru->gs_lock); + if (!check_gru_resources(gru, gts->ts_cbr_au_count, + gts->ts_dsr_au_count, GRU_NUM_CCH)) { + spin_unlock(&gru->gs_lock); + goto again; + } + reserve_gru_resources(gru, gts); + gts->ts_gru = gru; + gts->ts_blade = gru->gs_blade_id; + gts->ts_ctxnum = gru_assign_context_number(gru); + atomic_inc(>s->ts_refcnt); + gru->gs_gts[gts->ts_ctxnum] = gts; + spin_unlock(&gru->gs_lock); + + STAT(assign_context); + gru_dbg(grudev, + "gseg %p, gts %p, gid %d, ctx %d, cbr %d, dsr %d\n", + gseg_virtual_address(gts->ts_gru, gts->ts_ctxnum), gts, + gts->ts_gru->gs_gid, gts->ts_ctxnum, + gts->ts_cbr_au_count, gts->ts_dsr_au_count); + } else { + gru_dbg(grudev, "failed to allocate a GTS %s\n", ""); + STAT(assign_context_failed); + } + + return gru; +} + +/* + * gru_nopage + * + * Map the user's GRU segment + * + * Note: gru segments alway mmaped on GRU_GSEG_PAGESIZE boundaries. + */ +vm_fault_t gru_fault(struct vm_fault *vmf) +{ + struct vm_area_struct *vma = vmf->vma; + struct gru_thread_state *gts; + unsigned long paddr, vaddr; + unsigned long expires; + + vaddr = vmf->address; + gru_dbg(grudev, "vma %p, vaddr 0x%lx (0x%lx)\n", + vma, vaddr, GSEG_BASE(vaddr)); + STAT(nopfn); + + /* The following check ensures vaddr is a valid address in the VMA */ + gts = gru_find_thread_state(vma, TSID(vaddr, vma)); + if (!gts) + return VM_FAULT_SIGBUS; + +again: + mutex_lock(>s->ts_ctxlock); + preempt_disable(); + + if (gru_check_context_placement(gts)) { + preempt_enable(); + mutex_unlock(>s->ts_ctxlock); + gru_unload_context(gts, 1); + return VM_FAULT_NOPAGE; + } + + if (!gts->ts_gru) { + STAT(load_user_context); + if (!gru_assign_gru_context(gts)) { + preempt_enable(); + mutex_unlock(>s->ts_ctxlock); + set_current_state(TASK_INTERRUPTIBLE); + schedule_timeout(GRU_ASSIGN_DELAY); /* true hack ZZZ */ + expires = gts->ts_steal_jiffies + GRU_STEAL_DELAY; + if (time_before(expires, jiffies)) + gru_steal_context(gts); + goto again; + } + gru_load_context(gts); + paddr = gseg_physical_address(gts->ts_gru, gts->ts_ctxnum); + remap_pfn_range(vma, vaddr & ~(GRU_GSEG_PAGESIZE - 1), + paddr >> PAGE_SHIFT, GRU_GSEG_PAGESIZE, + vma->vm_page_prot); + } + + preempt_enable(); + mutex_unlock(>s->ts_ctxlock); + + return VM_FAULT_NOPAGE; +} + |