[PATCH 3/4] powerpc/powernv: remove dead NPU DMA code

From: Christoph Hellwig
Date: Thu May 23 2019 - 03:52:32 EST

None of these routines were ever used since they were added to the
kernel.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
arch/powerpc/include/asm/book3s/64/mmu.h | 2 -
arch/powerpc/include/asm/powernv.h | 22 -
arch/powerpc/mm/book3s64/mmu_context.c | 1 -
arch/powerpc/platforms/powernv/npu-dma.c | 556 -----------------------
4 files changed, 581 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h
index 74d24201fc4f..23b83d3593e2 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu.h
@@ -116,8 +116,6 @@ typedef struct {
/* Number of users of the external (Nest) MMU */
atomic_t copros;

- /* NPU NMMU context */
- struct npu_context *npu_context;
struct hash_mm_context *hash_context;

unsigned long vdso_base;
diff --git a/arch/powerpc/include/asm/powernv.h b/arch/powerpc/include/asm/powernv.h
index 05b552418519..40f868c5e93c 100644
--- a/arch/powerpc/include/asm/powernv.h
+++ b/arch/powerpc/include/asm/powernv.h
@@ -11,35 +11,13 @@
#define _ASM_POWERNV_H

#ifdef CONFIG_PPC_POWERNV
-#define NPU2_WRITE 1
extern void powernv_set_nmmu_ptcr(unsigned long ptcr);
-extern struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
- unsigned long flags,
- void (*cb)(struct npu_context *, void *),
- void *priv);
-extern void pnv_npu2_destroy_context(struct npu_context *context,
- struct pci_dev *gpdev);
-extern int pnv_npu2_handle_fault(struct npu_context *context, uintptr_t *ea,
- unsigned long *flags, unsigned long *status,
- int count);

void pnv_program_cpu_hotplug_lpcr(unsigned int cpu, u64 lpcr_val);

void pnv_tm_init(void);
#else
static inline void powernv_set_nmmu_ptcr(unsigned long ptcr) { }
-static inline struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
- unsigned long flags,
- struct npu_context *(*cb)(struct npu_context *, void *),
- void *priv) { return ERR_PTR(-ENODEV); }
-static inline void pnv_npu2_destroy_context(struct npu_context *context,
- struct pci_dev *gpdev) { }
-
-static inline int pnv_npu2_handle_fault(struct npu_context *context,
- uintptr_t *ea, unsigned long *flags,
- unsigned long *status, int count) {
- return -ENODEV;
-}

static inline void pnv_tm_init(void) { }
#endif
diff --git a/arch/powerpc/mm/book3s64/mmu_context.c b/arch/powerpc/mm/book3s64/mmu_context.c
index cb2b08635508..0dd3e631cf3e 100644
--- a/arch/powerpc/mm/book3s64/mmu_context.c
+++ b/arch/powerpc/mm/book3s64/mmu_context.c
@@ -140,7 +140,6 @@ static int radix__init_new_context(struct mm_struct *mm)
*/
asm volatile("ptesync;isync" : : : "memory");

- mm->context.npu_context = NULL;
mm->context.hash_context = NULL;

return index;
diff --git a/arch/powerpc/platforms/powernv/npu-dma.c b/arch/powerpc/platforms/powernv/npu-dma.c
index 495550432f3d..4ed24132bb7c 100644
--- a/arch/powerpc/platforms/powernv/npu-dma.c
+++ b/arch/powerpc/platforms/powernv/npu-dma.c
@@ -22,12 +22,6 @@

#include "pci.h"

-/*
- * spinlock to protect initialisation of an npu_context for a particular
- * mm_struct.
- */
-static DEFINE_SPINLOCK(npu_context_lock);
-
static struct pci_dev *get_pci_dev(struct device_node *dn)
{
struct pci_dn *pdn = PCI_DN(dn);
@@ -362,15 +356,6 @@ struct npu_comp {
/* An NPU descriptor, valid for POWER9 only */
struct npu {
int index;
- __be64 *mmio_atsd_regs[NV_NMMU_ATSD_REGS];
- unsigned int mmio_atsd_count;
-
- /* Bitmask for MMIO register usage */
- unsigned long mmio_atsd_usage;
-
- /* Do we need to explicitly flush the nest mmu? */
- bool nmmu_flush;
-
struct npu_comp npucomp;
};

@@ -627,534 +612,8 @@ struct iommu_table_group *pnv_npu_compound_attach(struct pnv_ioda_pe *pe)
}
#endif /* CONFIG_IOMMU_API */

-/* Maximum number of nvlinks per npu */
-#define NV_MAX_LINKS 6
-
-/* Maximum index of npu2 hosts in the system. Always < NV_MAX_NPUS */
-static int max_npu2_index;
-
-struct npu_context {
- struct mm_struct *mm;
- struct pci_dev *npdev[NV_MAX_NPUS][NV_MAX_LINKS];
- struct mmu_notifier mn;
- struct kref kref;
- bool nmmu_flush;
-
- /* Callback to stop translation requests on a given GPU */
- void (*release_cb)(struct npu_context *context, void *priv);
-
- /*
- * Private pointer passed to the above callback for usage by
- * device drivers.
- */
- void *priv;
-};
-
-struct mmio_atsd_reg {
- struct npu *npu;
- int reg;
-};
-
-/*
- * Find a free MMIO ATSD register and mark it in use. Return -ENOSPC
- * if none are available.
- */
-static int get_mmio_atsd_reg(struct npu *npu)
-{
- int i;
-
- for (i = 0; i < npu->mmio_atsd_count; i++) {
- if (!test_bit(i, &npu->mmio_atsd_usage))
- if (!test_and_set_bit_lock(i, &npu->mmio_atsd_usage))
- return i;
- }
-
- return -ENOSPC;
-}
-
-static void put_mmio_atsd_reg(struct npu *npu, int reg)
-{
- clear_bit_unlock(reg, &npu->mmio_atsd_usage);
-}
-
-/* MMIO ATSD register offsets */
-#define XTS_ATSD_LAUNCH 0
-#define XTS_ATSD_AVA 1
-#define XTS_ATSD_STAT 2
-
-static unsigned long get_atsd_launch_val(unsigned long pid, unsigned long psize)
-{
- unsigned long launch = 0;
-
- if (psize == MMU_PAGE_COUNT) {
- /* IS set to invalidate entire matching PID */
- launch |= PPC_BIT(12);
- } else {
- /* AP set to invalidate region of psize */
- launch |= (u64)mmu_get_ap(psize) << PPC_BITLSHIFT(17);
- }
-
- /* PRS set to process-scoped */
- launch |= PPC_BIT(13);
-
- /* PID */
- launch |= pid << PPC_BITLSHIFT(38);
-
- /* Leave "No flush" (bit 39) 0 so every ATSD performs a flush */
-
- return launch;
-}
-
-static void mmio_atsd_regs_write(struct mmio_atsd_reg
- mmio_atsd_reg[NV_MAX_NPUS], unsigned long offset,
- unsigned long val)
-{
- struct npu *npu;
- int i, reg;
-
- for (i = 0; i <= max_npu2_index; i++) {
- reg = mmio_atsd_reg[i].reg;
- if (reg < 0)
- continue;
-
- npu = mmio_atsd_reg[i].npu;
- __raw_writeq_be(val, npu->mmio_atsd_regs[reg] + offset);
- }
-}
-
-static void mmio_invalidate_pid(struct mmio_atsd_reg mmio_atsd_reg[NV_MAX_NPUS],
- unsigned long pid)
-{
- unsigned long launch = get_atsd_launch_val(pid, MMU_PAGE_COUNT);
-
- /* Invalidating the entire process doesn't use a va */
- mmio_atsd_regs_write(mmio_atsd_reg, XTS_ATSD_LAUNCH, launch);
-}
-
-static void mmio_invalidate_range(struct mmio_atsd_reg
- mmio_atsd_reg[NV_MAX_NPUS], unsigned long pid,
- unsigned long start, unsigned long psize)
-{
- unsigned long launch = get_atsd_launch_val(pid, psize);
-
- /* Write all VAs first */
- mmio_atsd_regs_write(mmio_atsd_reg, XTS_ATSD_AVA, start);
-
- /* Issue one barrier for all address writes */
- eieio();
-
- /* Launch */
- mmio_atsd_regs_write(mmio_atsd_reg, XTS_ATSD_LAUNCH, launch);
-}
-
-#define mn_to_npu_context(x) container_of(x, struct npu_context, mn)
-
-static void mmio_invalidate_wait(
- struct mmio_atsd_reg mmio_atsd_reg[NV_MAX_NPUS])
-{
- struct npu *npu;
- int i, reg;
-
- /* Wait for all invalidations to complete */
- for (i = 0; i <= max_npu2_index; i++) {
- if (mmio_atsd_reg[i].reg < 0)
- continue;
-
- /* Wait for completion */
- npu = mmio_atsd_reg[i].npu;
- reg = mmio_atsd_reg[i].reg;
- while (__raw_readq(npu->mmio_atsd_regs[reg] + XTS_ATSD_STAT))
- cpu_relax();
- }
-}
-
-/*
- * Acquires all the address translation shootdown (ATSD) registers required to
- * launch an ATSD on all links this npu_context is active on.
- */
-static void acquire_atsd_reg(struct npu_context *npu_context,
- struct mmio_atsd_reg mmio_atsd_reg[NV_MAX_NPUS])
-{
- int i, j;
- struct npu *npu;
- struct pci_dev *npdev;
-
- for (i = 0; i <= max_npu2_index; i++) {
- mmio_atsd_reg[i].reg = -1;
- for (j = 0; j < NV_MAX_LINKS; j++) {
- /*
- * There are no ordering requirements with respect to
- * the setup of struct npu_context, but to ensure
- * consistent behaviour we need to ensure npdev[][] is
- * only read once.
- */
- npdev = READ_ONCE(npu_context->npdev[i][j]);
- if (!npdev)
- continue;
-
- npu = pci_bus_to_host(npdev->bus)->npu;
- if (!npu)
- continue;
-
- mmio_atsd_reg[i].npu = npu;
- mmio_atsd_reg[i].reg = get_mmio_atsd_reg(npu);
- while (mmio_atsd_reg[i].reg < 0) {
- mmio_atsd_reg[i].reg = get_mmio_atsd_reg(npu);
- cpu_relax();
- }
- break;
- }
- }
-}
-
-/*
- * Release previously acquired ATSD registers. To avoid deadlocks the registers
- * must be released in the same order they were acquired above in
- * acquire_atsd_reg.
- */
-static void release_atsd_reg(struct mmio_atsd_reg mmio_atsd_reg[NV_MAX_NPUS])
-{
- int i;
-
- for (i = 0; i <= max_npu2_index; i++) {
- /*
- * We can't rely on npu_context->npdev[][] being the same here
- * as when acquire_atsd_reg() was called, hence we use the
- * values stored in mmio_atsd_reg during the acquire phase
- * rather than re-reading npdev[][].
- */
- if (mmio_atsd_reg[i].reg < 0)
- continue;
-
- put_mmio_atsd_reg(mmio_atsd_reg[i].npu, mmio_atsd_reg[i].reg);
- }
-}
-
-/*
- * Invalidate a virtual address range
- */
-static void mmio_invalidate(struct npu_context *npu_context,
- unsigned long start, unsigned long size)
-{
- struct mmio_atsd_reg mmio_atsd_reg[NV_MAX_NPUS];
- unsigned long pid = npu_context->mm->context.id;
- unsigned long atsd_start = 0;
- unsigned long end = start + size - 1;
- int atsd_psize = MMU_PAGE_COUNT;
-
- /*
- * Convert the input range into one of the supported sizes. If the range
- * doesn't fit, use the next larger supported size. Invalidation latency
- * is high, so over-invalidation is preferred to issuing multiple
- * invalidates.
- *
- * A 4K page size isn't supported by NPU/GPU ATS, so that case is
- * ignored.
- */
- if (size == SZ_64K) {
- atsd_start = start;
- atsd_psize = MMU_PAGE_64K;
- } else if (ALIGN_DOWN(start, SZ_2M) == ALIGN_DOWN(end, SZ_2M)) {
- atsd_start = ALIGN_DOWN(start, SZ_2M);
- atsd_psize = MMU_PAGE_2M;
- } else if (ALIGN_DOWN(start, SZ_1G) == ALIGN_DOWN(end, SZ_1G)) {
- atsd_start = ALIGN_DOWN(start, SZ_1G);
- atsd_psize = MMU_PAGE_1G;
- }
-
- if (npu_context->nmmu_flush)
- /*
- * Unfortunately the nest mmu does not support flushing specific
- * addresses so we have to flush the whole mm once before
- * shooting down the GPU translation.
- */
- flush_all_mm(npu_context->mm);
-
- /*
- * Loop over all the NPUs this process is active on and launch
- * an invalidate.
- */
- acquire_atsd_reg(npu_context, mmio_atsd_reg);
-
- if (atsd_psize == MMU_PAGE_COUNT)
- mmio_invalidate_pid(mmio_atsd_reg, pid);
- else
- mmio_invalidate_range(mmio_atsd_reg, pid, atsd_start,
- atsd_psize);
-
- mmio_invalidate_wait(mmio_atsd_reg);
-
- /*
- * The GPU requires two flush ATSDs to ensure all entries have been
- * flushed. We use PID 0 as it will never be used for a process on the
- * GPU.
- */
- mmio_invalidate_pid(mmio_atsd_reg, 0);
- mmio_invalidate_wait(mmio_atsd_reg);
- mmio_invalidate_pid(mmio_atsd_reg, 0);
- mmio_invalidate_wait(mmio_atsd_reg);
-
- release_atsd_reg(mmio_atsd_reg);
-}
-
-static void pnv_npu2_mn_release(struct mmu_notifier *mn,
- struct mm_struct *mm)
-{
- struct npu_context *npu_context = mn_to_npu_context(mn);
-
- /* Call into device driver to stop requests to the NMMU */
- if (npu_context->release_cb)
- npu_context->release_cb(npu_context, npu_context->priv);
-
- /*
- * There should be no more translation requests for this PID, but we
- * need to ensure any entries for it are removed from the TLB.
- */
- mmio_invalidate(npu_context, 0, ~0UL);
-}
-
-static void pnv_npu2_mn_invalidate_range(struct mmu_notifier *mn,
- struct mm_struct *mm,
- unsigned long start, unsigned long end)
-{
- struct npu_context *npu_context = mn_to_npu_context(mn);
- mmio_invalidate(npu_context, start, end - start);
-}
-
-static const struct mmu_notifier_ops nv_nmmu_notifier_ops = {
- .release = pnv_npu2_mn_release,
- .invalidate_range = pnv_npu2_mn_invalidate_range,
-};
-
-/*
- * Call into OPAL to setup the nmmu context for the current task in
- * the NPU. This must be called to setup the context tables before the
- * GPU issues ATRs. pdev should be a pointed to PCIe GPU device.
- *
- * A release callback should be registered to allow a device driver to
- * be notified that it should not launch any new translation requests
- * as the final TLB invalidate is about to occur.
- *
- * Returns an error if there no contexts are currently available or a
- * npu_context which should be passed to pnv_npu2_handle_fault().
- *
- * mmap_sem must be held in write mode and must not be called from interrupt
- * context.
- */
-struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
- unsigned long flags,
- void (*cb)(struct npu_context *, void *),
- void *priv)
-{
- int rc;
- u32 nvlink_index;
- struct device_node *nvlink_dn;
- struct mm_struct *mm = current->mm;
- struct npu *npu;
- struct npu_context *npu_context;
- struct pci_controller *hose;
-
- /*
- * At present we don't support GPUs connected to multiple NPUs and I'm
- * not sure the hardware does either.
- */
- struct pci_dev *npdev = pnv_pci_get_npu_dev(gpdev, 0);
-
- if (!npdev)
- /* No nvlink associated with this GPU device */
- return ERR_PTR(-ENODEV);
-
- /* We only support DR/PR/HV in pnv_npu2_map_lpar_dev() */
- if (flags & ~(MSR_DR | MSR_PR | MSR_HV))
- return ERR_PTR(-EINVAL);
-
- nvlink_dn = of_parse_phandle(npdev->dev.of_node, "ibm,nvlink", 0);
- if (WARN_ON(of_property_read_u32(nvlink_dn, "ibm,npu-link-index",
- &nvlink_index)))
- return ERR_PTR(-ENODEV);
-
- if (!mm || mm->context.id == 0) {
- /*
- * Kernel thread contexts are not supported and context id 0 is
- * reserved on the GPU.
- */
- return ERR_PTR(-EINVAL);
- }
-
- hose = pci_bus_to_host(npdev->bus);
- npu = hose->npu;
- if (!npu)
- return ERR_PTR(-ENODEV);
-
- /*
- * We store the npu pci device so we can more easily get at the
- * associated npus.
- */
- spin_lock(&npu_context_lock);
- npu_context = mm->context.npu_context;
- if (npu_context) {
- if (npu_context->release_cb != cb ||
- npu_context->priv != priv) {
- spin_unlock(&npu_context_lock);
- return ERR_PTR(-EINVAL);
- }
-
- WARN_ON(!kref_get_unless_zero(&npu_context->kref));
- }
- spin_unlock(&npu_context_lock);
-
- if (!npu_context) {
- /*
- * We can set up these fields without holding the
- * npu_context_lock as the npu_context hasn't been returned to
- * the caller meaning it can't be destroyed. Parallel allocation
- * is protected against by mmap_sem.
- */
- rc = -ENOMEM;
- npu_context = kzalloc(sizeof(struct npu_context), GFP_KERNEL);
- if (npu_context) {
- kref_init(&npu_context->kref);
- npu_context->mm = mm;
- npu_context->mn.ops = &nv_nmmu_notifier_ops;
- rc = __mmu_notifier_register(&npu_context->mn, mm);
- }
-
- if (rc) {
- kfree(npu_context);
- return ERR_PTR(rc);
- }
-
- mm->context.npu_context = npu_context;
- }
-
- npu_context->release_cb = cb;
- npu_context->priv = priv;
-
- /*
- * npdev is a pci_dev pointer setup by the PCI code. We assign it to
- * npdev[][] to indicate to the mmu notifiers that an invalidation
- * should also be sent over this nvlink. The notifiers don't use any
- * other fields in npu_context, so we just need to ensure that when they
- * deference npu_context->npdev[][] it is either a valid pointer or
- * NULL.
- */
- WRITE_ONCE(npu_context->npdev[npu->index][nvlink_index], npdev);
-
- if (!npu->nmmu_flush) {
- /*
- * If we're not explicitly flushing ourselves we need to mark
- * the thread for global flushes
- */
- npu_context->nmmu_flush = false;
- mm_context_add_copro(mm);
- } else
- npu_context->nmmu_flush = true;
-
- return npu_context;
-}
-EXPORT_SYMBOL(pnv_npu2_init_context);
-
-static void pnv_npu2_release_context(struct kref *kref)
-{
- struct npu_context *npu_context =
- container_of(kref, struct npu_context, kref);
-
- if (!npu_context->nmmu_flush)
- mm_context_remove_copro(npu_context->mm);
-
- npu_context->mm->context.npu_context = NULL;
-}
-
-/*
- * Destroy a context on the given GPU. May free the npu_context if it is no
- * longer active on any GPUs. Must not be called from interrupt context.
- */
-void pnv_npu2_destroy_context(struct npu_context *npu_context,
- struct pci_dev *gpdev)
-{
- int removed;
- struct npu *npu;
- struct pci_dev *npdev = pnv_pci_get_npu_dev(gpdev, 0);
- struct device_node *nvlink_dn;
- u32 nvlink_index;
- struct pci_controller *hose;
-
- if (WARN_ON(!npdev))
- return;
-
- hose = pci_bus_to_host(npdev->bus);
- npu = hose->npu;
- if (!npu)
- return;
- nvlink_dn = of_parse_phandle(npdev->dev.of_node, "ibm,nvlink", 0);
- if (WARN_ON(of_property_read_u32(nvlink_dn, "ibm,npu-link-index",
- &nvlink_index)))
- return;
- WRITE_ONCE(npu_context->npdev[npu->index][nvlink_index], NULL);
- spin_lock(&npu_context_lock);
- removed = kref_put(&npu_context->kref, pnv_npu2_release_context);
- spin_unlock(&npu_context_lock);
-
- /*
- * We need to do this outside of pnv_npu2_release_context so that it is
- * outside the spinlock as mmu_notifier_destroy uses SRCU.
- */
- if (removed) {
- mmu_notifier_unregister(&npu_context->mn,
- npu_context->mm);
-
- kfree(npu_context);
- }
-
-}
-EXPORT_SYMBOL(pnv_npu2_destroy_context);
-
-/*
- * Assumes mmap_sem is held for the contexts associated mm.
- */
-int pnv_npu2_handle_fault(struct npu_context *context, uintptr_t *ea,
- unsigned long *flags, unsigned long *status, int count)
-{
- u64 rc = 0, result = 0;
- int i, is_write;
- struct page *page[1];
- const char __user *u;
- char c;
-
- /* mmap_sem should be held so the struct_mm must be present */
- struct mm_struct *mm = context->mm;
-
- WARN_ON(!rwsem_is_locked(&mm->mmap_sem));
-
- for (i = 0; i < count; i++) {
- is_write = flags[i] & NPU2_WRITE;
- rc = get_user_pages_remote(NULL, mm, ea[i], 1,
- is_write ? FOLL_WRITE : 0,
- page, NULL, NULL);
-
- if (rc != 1) {
- status[i] = rc;
- result = -EFAULT;
- continue;
- }
-
- /* Make sure partition scoped tree gets a pte */
- u = page_address(page[0]);
- if (__get_user(c, u))
- result = -EFAULT;
-
- status[i] = 0;
- put_page(page[0]);
- }
-
- return result;
-}
-EXPORT_SYMBOL(pnv_npu2_handle_fault);
-
int pnv_npu2_init(struct pci_controller *hose)
{
- unsigned int i;
- u64 mmio_atsd;
static int npu_index;
struct npu *npu;
int ret;
@@ -1163,33 +622,18 @@ int pnv_npu2_init(struct pci_controller *hose)
if (!npu)
return -ENOMEM;

- npu->nmmu_flush = of_property_read_bool(hose->dn, "ibm,nmmu-flush");
-
- for (i = 0; i < ARRAY_SIZE(npu->mmio_atsd_regs) &&
- !of_property_read_u64_index(hose->dn, "ibm,mmio-atsd",
- i, &mmio_atsd); i++)
- npu->mmio_atsd_regs[i] = ioremap(mmio_atsd, 32);
-
- pr_info("NPU%d: Found %d MMIO ATSD registers", hose->global_number, i);
- npu->mmio_atsd_count = i;
- npu->mmio_atsd_usage = 0;
npu_index++;
if (WARN_ON(npu_index >= NV_MAX_NPUS)) {
ret = -ENOSPC;
goto fail_exit;
}
- max_npu2_index = npu_index;
npu->index = npu_index;
hose->npu = npu;

return 0;

fail_exit:
- for (i = 0; i < npu->mmio_atsd_count; ++i)
- iounmap(npu->mmio_atsd_regs[i]);
-
kfree(npu);
-
return ret;
}

--
2.20.1