From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- drivers/misc/cxl/fault.c | 310 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 310 insertions(+) create mode 100644 drivers/misc/cxl/fault.c (limited to 'drivers/misc/cxl/fault.c') diff --git a/drivers/misc/cxl/fault.c b/drivers/misc/cxl/fault.c new file mode 100644 index 000000000..5286b8b70 --- /dev/null +++ b/drivers/misc/cxl/fault.c @@ -0,0 +1,310 @@ +/* + * Copyright 2014 IBM Corp. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include +#include +#include +#include +#include + +#undef MODULE_PARAM_PREFIX +#define MODULE_PARAM_PREFIX "cxl" "." +#include +#include +#include + +#include "cxl.h" +#include "trace.h" + +static bool sste_matches(struct cxl_sste *sste, struct copro_slb *slb) +{ + return ((sste->vsid_data == cpu_to_be64(slb->vsid)) && + (sste->esid_data == cpu_to_be64(slb->esid))); +} + +/* + * This finds a free SSTE for the given SLB, or returns NULL if it's already in + * the segment table. + */ +static struct cxl_sste* find_free_sste(struct cxl_context *ctx, + struct copro_slb *slb) +{ + struct cxl_sste *primary, *sste, *ret = NULL; + unsigned int mask = (ctx->sst_size >> 7) - 1; /* SSTP0[SegTableSize] */ + unsigned int entry; + unsigned int hash; + + if (slb->vsid & SLB_VSID_B_1T) + hash = (slb->esid >> SID_SHIFT_1T) & mask; + else /* 256M */ + hash = (slb->esid >> SID_SHIFT) & mask; + + primary = ctx->sstp + (hash << 3); + + for (entry = 0, sste = primary; entry < 8; entry++, sste++) { + if (!ret && !(be64_to_cpu(sste->esid_data) & SLB_ESID_V)) + ret = sste; + if (sste_matches(sste, slb)) + return NULL; + } + if (ret) + return ret; + + /* Nothing free, select an entry to cast out */ + ret = primary + ctx->sst_lru; + ctx->sst_lru = (ctx->sst_lru + 1) & 0x7; + + return ret; +} + +static void cxl_load_segment(struct cxl_context *ctx, struct copro_slb *slb) +{ + /* mask is the group index, we search primary and secondary here. */ + struct cxl_sste *sste; + unsigned long flags; + + spin_lock_irqsave(&ctx->sste_lock, flags); + sste = find_free_sste(ctx, slb); + if (!sste) + goto out_unlock; + + pr_devel("CXL Populating SST[%li]: %#llx %#llx\n", + sste - ctx->sstp, slb->vsid, slb->esid); + trace_cxl_ste_write(ctx, sste - ctx->sstp, slb->esid, slb->vsid); + + sste->vsid_data = cpu_to_be64(slb->vsid); + sste->esid_data = cpu_to_be64(slb->esid); +out_unlock: + spin_unlock_irqrestore(&ctx->sste_lock, flags); +} + +static int cxl_fault_segment(struct cxl_context *ctx, struct mm_struct *mm, + u64 ea) +{ + struct copro_slb slb = {0,0}; + int rc; + + if (!(rc = copro_calculate_slb(mm, ea, &slb))) { + cxl_load_segment(ctx, &slb); + } + + return rc; +} + +static void cxl_ack_ae(struct cxl_context *ctx) +{ + unsigned long flags; + + cxl_ack_irq(ctx, CXL_PSL_TFC_An_AE, 0); + + spin_lock_irqsave(&ctx->lock, flags); + ctx->pending_fault = true; + ctx->fault_addr = ctx->dar; + ctx->fault_dsisr = ctx->dsisr; + spin_unlock_irqrestore(&ctx->lock, flags); + + wake_up_all(&ctx->wq); +} + +static int cxl_handle_segment_miss(struct cxl_context *ctx, + struct mm_struct *mm, u64 ea) +{ + int rc; + + pr_devel("CXL interrupt: Segment fault pe: %i ea: %#llx\n", ctx->pe, ea); + trace_cxl_ste_miss(ctx, ea); + + if ((rc = cxl_fault_segment(ctx, mm, ea))) + cxl_ack_ae(ctx); + else { + + mb(); /* Order seg table write to TFC MMIO write */ + cxl_ack_irq(ctx, CXL_PSL_TFC_An_R, 0); + } + + return IRQ_HANDLED; +} + +static void cxl_handle_page_fault(struct cxl_context *ctx, + struct mm_struct *mm, u64 dsisr, u64 dar) +{ + unsigned flt = 0; + int result; + unsigned long access, flags, inv_flags = 0; + + trace_cxl_pte_miss(ctx, dsisr, dar); + + if ((result = copro_handle_mm_fault(mm, dar, dsisr, &flt))) { + pr_devel("copro_handle_mm_fault failed: %#x\n", result); + return cxl_ack_ae(ctx); + } + + /* + * update_mmu_cache() will not have loaded the hash since current->trap + * is not a 0x400 or 0x300, so just call hash_page_mm() here. + */ + access = _PAGE_PRESENT; + if (dsisr & CXL_PSL_DSISR_An_S) + access |= _PAGE_RW; + if ((!ctx->kernel) || ~(dar & (1ULL << 63))) + access |= _PAGE_USER; + + if (dsisr & DSISR_NOHPTE) + inv_flags |= HPTE_NOHPTE_UPDATE; + + local_irq_save(flags); + hash_page_mm(mm, dar, access, 0x300, inv_flags); + local_irq_restore(flags); + + pr_devel("Page fault successfully handled for pe: %i!\n", ctx->pe); + cxl_ack_irq(ctx, CXL_PSL_TFC_An_R, 0); +} + +void cxl_handle_fault(struct work_struct *fault_work) +{ + struct cxl_context *ctx = + container_of(fault_work, struct cxl_context, fault_work); + u64 dsisr = ctx->dsisr; + u64 dar = ctx->dar; + struct task_struct *task; + struct mm_struct *mm; + + if (cxl_p2n_read(ctx->afu, CXL_PSL_DSISR_An) != dsisr || + cxl_p2n_read(ctx->afu, CXL_PSL_DAR_An) != dar || + cxl_p2n_read(ctx->afu, CXL_PSL_PEHandle_An) != ctx->pe) { + /* Most likely explanation is harmless - a dedicated process + * has detached and these were cleared by the PSL purge, but + * warn about it just in case */ + dev_notice(&ctx->afu->dev, "cxl_handle_fault: Translation fault regs changed\n"); + return; + } + + /* Early return if the context is being / has been detached */ + if (ctx->status == CLOSED) { + cxl_ack_ae(ctx); + return; + } + + pr_devel("CXL BOTTOM HALF handling fault for afu pe: %i. " + "DSISR: %#llx DAR: %#llx\n", ctx->pe, dsisr, dar); + + if (!(task = get_pid_task(ctx->pid, PIDTYPE_PID))) { + pr_devel("cxl_handle_fault unable to get task %i\n", + pid_nr(ctx->pid)); + cxl_ack_ae(ctx); + return; + } + if (!(mm = get_task_mm(task))) { + pr_devel("cxl_handle_fault unable to get mm %i\n", + pid_nr(ctx->pid)); + cxl_ack_ae(ctx); + goto out; + } + + if (dsisr & CXL_PSL_DSISR_An_DS) + cxl_handle_segment_miss(ctx, mm, dar); + else if (dsisr & CXL_PSL_DSISR_An_DM) + cxl_handle_page_fault(ctx, mm, dsisr, dar); + else + WARN(1, "cxl_handle_fault has nothing to handle\n"); + + mmput(mm); +out: + put_task_struct(task); +} + +static void cxl_prefault_one(struct cxl_context *ctx, u64 ea) +{ + int rc; + struct task_struct *task; + struct mm_struct *mm; + + if (!(task = get_pid_task(ctx->pid, PIDTYPE_PID))) { + pr_devel("cxl_prefault_one unable to get task %i\n", + pid_nr(ctx->pid)); + return; + } + if (!(mm = get_task_mm(task))) { + pr_devel("cxl_prefault_one unable to get mm %i\n", + pid_nr(ctx->pid)); + put_task_struct(task); + return; + } + + rc = cxl_fault_segment(ctx, mm, ea); + + mmput(mm); + put_task_struct(task); +} + +static u64 next_segment(u64 ea, u64 vsid) +{ + if (vsid & SLB_VSID_B_1T) + ea |= (1ULL << 40) - 1; + else + ea |= (1ULL << 28) - 1; + + return ea + 1; +} + +static void cxl_prefault_vma(struct cxl_context *ctx) +{ + u64 ea, last_esid = 0; + struct copro_slb slb; + struct vm_area_struct *vma; + int rc; + struct task_struct *task; + struct mm_struct *mm; + + if (!(task = get_pid_task(ctx->pid, PIDTYPE_PID))) { + pr_devel("cxl_prefault_vma unable to get task %i\n", + pid_nr(ctx->pid)); + return; + } + if (!(mm = get_task_mm(task))) { + pr_devel("cxl_prefault_vm unable to get mm %i\n", + pid_nr(ctx->pid)); + goto out1; + } + + down_read(&mm->mmap_sem); + for (vma = mm->mmap; vma; vma = vma->vm_next) { + for (ea = vma->vm_start; ea < vma->vm_end; + ea = next_segment(ea, slb.vsid)) { + rc = copro_calculate_slb(mm, ea, &slb); + if (rc) + continue; + + if (last_esid == slb.esid) + continue; + + cxl_load_segment(ctx, &slb); + last_esid = slb.esid; + } + } + up_read(&mm->mmap_sem); + + mmput(mm); +out1: + put_task_struct(task); +} + +void cxl_prefault(struct cxl_context *ctx, u64 wed) +{ + switch (ctx->afu->prefault_mode) { + case CXL_PREFAULT_WED: + cxl_prefault_one(ctx, wed); + break; + case CXL_PREFAULT_ALL: + cxl_prefault_vma(ctx); + break; + default: + break; + } +} -- cgit v1.2.3-54-g00ecf