Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 903 insertions, 0 deletions

diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
new file mode 100644
index 0000000000..629edb6486
--- /dev/null
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -0,0 +1,903 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * SN Platform GRU Driver
+ *
+ *              FAULT HANDLER FOR GRU DETECTED TLB MISSES
+ *
+ * This file contains code that handles TLB misses within the GRU.
+ * These misses are reported either via interrupts or user polling of
+ * the user CB.
+ *
+ *  Copyright (c) 2008 Silicon Graphics, Inc.  All Rights Reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/spinlock.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <linux/security.h>
+#include <linux/sync_core.h>
+#include <linux/prefetch.h>
+#include "gru.h"
+#include "grutables.h"
+#include "grulib.h"
+#include "gru_instructions.h"
+#include <asm/uv/uv_hub.h>
+
+/* Return codes for vtop functions */
+#define VTOP_SUCCESS               0
+#define VTOP_INVALID               -1
+#define VTOP_RETRY                 -2
+
+
+/*
+ * Test if a physical address is a valid GRU GSEG address
+ */
+static inline int is_gru_paddr(unsigned long paddr)
+{
+	return paddr >= gru_start_paddr && paddr < gru_end_paddr;
+}
+
+/*
+ * Find the vma of a GRU segment. Caller must hold mmap_lock.
+ */
+struct vm_area_struct *gru_find_vma(unsigned long vaddr)
+{
+	struct vm_area_struct *vma;
+
+	vma = vma_lookup(current->mm, vaddr);
+	if (vma && vma->vm_ops == &gru_vm_ops)
+		return vma;
+	return NULL;
+}
+
+/*
+ * Find and lock the gts that contains the specified user vaddr.
+ *
+ * Returns:
+ * 	- *gts with the mmap_lock locked for read and the GTS locked.
+ *	- NULL if vaddr invalid OR is not a valid GSEG vaddr.
+ */
+
+static struct gru_thread_state *gru_find_lock_gts(unsigned long vaddr)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	struct gru_thread_state *gts = NULL;
+
+	mmap_read_lock(mm);
+	vma = gru_find_vma(vaddr);
+	if (vma)
+		gts = gru_find_thread_state(vma, TSID(vaddr, vma));
+	if (gts)
+		mutex_lock(&gts->ts_ctxlock);
+	else
+		mmap_read_unlock(mm);
+	return gts;
+}
+
+static struct gru_thread_state *gru_alloc_locked_gts(unsigned long vaddr)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	struct gru_thread_state *gts = ERR_PTR(-EINVAL);
+
+	mmap_write_lock(mm);
+	vma = gru_find_vma(vaddr);
+	if (!vma)
+		goto err;
+
+	gts = gru_alloc_thread_state(vma, TSID(vaddr, vma));
+	if (IS_ERR(gts))
+		goto err;
+	mutex_lock(&gts->ts_ctxlock);
+	mmap_write_downgrade(mm);
+	return gts;
+
+err:
+	mmap_write_unlock(mm);
+	return gts;
+}
+
+/*
+ * Unlock a GTS that was previously locked with gru_find_lock_gts().
+ */
+static void gru_unlock_gts(struct gru_thread_state *gts)
+{
+	mutex_unlock(&gts->ts_ctxlock);
+	mmap_read_unlock(current->mm);
+}
+
+/*
+ * Set a CB.istatus to active using a user virtual address. This must be done
+ * just prior to a TFH RESTART. The new cb.istatus is an in-cache status ONLY.
+ * If the line is evicted, the status may be lost. The in-cache update
+ * is necessary to prevent the user from seeing a stale cb.istatus that will
+ * change as soon as the TFH restart is complete. Races may cause an
+ * occasional failure to clear the cb.istatus, but that is ok.
+ */
+static void gru_cb_set_istatus_active(struct gru_instruction_bits *cbk)
+{
+	if (cbk) {
+		cbk->istatus = CBS_ACTIVE;
+	}
+}
+
+/*
+ * Read & clear a TFM
+ *
+ * The GRU has an array of fault maps. A map is private to a cpu
+ * Only one cpu will be accessing a cpu's fault map.
+ *
+ * This function scans the cpu-private fault map & clears all bits that
+ * are set. The function returns a bitmap that indicates the bits that
+ * were cleared. Note that sense the maps may be updated asynchronously by
+ * the GRU, atomic operations must be used to clear bits.
+ */
+static void get_clear_fault_map(struct gru_state *gru,
+				struct gru_tlb_fault_map *imap,
+				struct gru_tlb_fault_map *dmap)
+{
+	unsigned long i, k;
+	struct gru_tlb_fault_map *tfm;
+
+	tfm = get_tfm_for_cpu(gru, gru_cpu_fault_map_id());
+	prefetchw(tfm);		/* Helps on hardware, required for emulator */
+	for (i = 0; i < BITS_TO_LONGS(GRU_NUM_CBE); i++) {
+		k = tfm->fault_bits[i];
+		if (k)
+			k = xchg(&tfm->fault_bits[i], 0UL);
+		imap->fault_bits[i] = k;
+		k = tfm->done_bits[i];
+		if (k)
+			k = xchg(&tfm->done_bits[i], 0UL);
+		dmap->fault_bits[i] = k;
+	}
+
+	/*
+	 * Not functionally required but helps performance. (Required
+	 * on emulator)
+	 */
+	gru_flush_cache(tfm);
+}
+
+/*
+ * Atomic (interrupt context) & non-atomic (user context) functions to
+ * convert a vaddr into a physical address. The size of the page
+ * is returned in pageshift.
+ * 	returns:
+ * 		  0 - successful
+ * 		< 0 - error code
+ * 		  1 - (atomic only) try again in non-atomic context
+ */
+static int non_atomic_pte_lookup(struct vm_area_struct *vma,
+				 unsigned long vaddr, int write,
+				 unsigned long *paddr, int *pageshift)
+{
+	struct page *page;
+
+#ifdef CONFIG_HUGETLB_PAGE
+	*pageshift = is_vm_hugetlb_page(vma) ? HPAGE_SHIFT : PAGE_SHIFT;
+#else
+	*pageshift = PAGE_SHIFT;
+#endif
+	if (get_user_pages(vaddr, 1, write ? FOLL_WRITE : 0, &page) <= 0)
+		return -EFAULT;
+	*paddr = page_to_phys(page);
+	put_page(page);
+	return 0;
+}
+
+/*
+ * atomic_pte_lookup
+ *
+ * Convert a user virtual address to a physical address
+ * Only supports Intel large pages (2MB only) on x86_64.
+ *	ZZZ - hugepage support is incomplete
+ *
+ * NOTE: mmap_lock is already held on entry to this function. This
+ * guarantees existence of the page tables.
+ */
+static int atomic_pte_lookup(struct vm_area_struct *vma, unsigned long vaddr,
+	int write, unsigned long *paddr, int *pageshift)
+{
+	pgd_t *pgdp;
+	p4d_t *p4dp;
+	pud_t *pudp;
+	pmd_t *pmdp;
+	pte_t pte;
+
+	pgdp = pgd_offset(vma->vm_mm, vaddr);
+	if (unlikely(pgd_none(*pgdp)))
+		goto err;
+
+	p4dp = p4d_offset(pgdp, vaddr);
+	if (unlikely(p4d_none(*p4dp)))
+		goto err;
+
+	pudp = pud_offset(p4dp, vaddr);
+	if (unlikely(pud_none(*pudp)))
+		goto err;
+
+	pmdp = pmd_offset(pudp, vaddr);
+	if (unlikely(pmd_none(*pmdp)))
+		goto err;
+#ifdef CONFIG_X86_64
+	if (unlikely(pmd_large(*pmdp)))
+		pte = ptep_get((pte_t *)pmdp);
+	else
+#endif
+		pte = *pte_offset_kernel(pmdp, vaddr);
+
+	if (unlikely(!pte_present(pte) ||
+		     (write && (!pte_write(pte) || !pte_dirty(pte)))))
+		return 1;
+
+	*paddr = pte_pfn(pte) << PAGE_SHIFT;
+#ifdef CONFIG_HUGETLB_PAGE
+	*pageshift = is_vm_hugetlb_page(vma) ? HPAGE_SHIFT : PAGE_SHIFT;
+#else
+	*pageshift = PAGE_SHIFT;
+#endif
+	return 0;
+
+err:
+	return 1;
+}
+
+static int gru_vtop(struct gru_thread_state *gts, unsigned long vaddr,
+		    int write, int atomic, unsigned long *gpa, int *pageshift)
+{
+	struct mm_struct *mm = gts->ts_mm;
+	struct vm_area_struct *vma;
+	unsigned long paddr;
+	int ret, ps;
+
+	vma = find_vma(mm, vaddr);
+	if (!vma)
+		goto inval;
+
+	/*
+	 * Atomic lookup is faster & usually works even if called in non-atomic
+	 * context.
+	 */
+	rmb();	/* Must/check ms_range_active before loading PTEs */
+	ret = atomic_pte_lookup(vma, vaddr, write, &paddr, &ps);
+	if (ret) {
+		if (atomic)
+			goto upm;
+		if (non_atomic_pte_lookup(vma, vaddr, write, &paddr, &ps))
+			goto inval;
+	}
+	if (is_gru_paddr(paddr))
+		goto inval;
+	paddr = paddr & ~((1UL << ps) - 1);
+	*gpa = uv_soc_phys_ram_to_gpa(paddr);
+	*pageshift = ps;
+	return VTOP_SUCCESS;
+
+inval:
+	return VTOP_INVALID;
+upm:
+	return VTOP_RETRY;
+}
+
+
+/*
+ * Flush a CBE from cache. The CBE is clean in the cache. Dirty the
+ * CBE cacheline so that the line will be written back to home agent.
+ * Otherwise the line may be silently dropped. This has no impact
+ * except on performance.
+ */
+static void gru_flush_cache_cbe(struct gru_control_block_extended *cbe)
+{
+	if (unlikely(cbe)) {
+		cbe->cbrexecstatus = 0;         /* make CL dirty */
+		gru_flush_cache(cbe);
+	}
+}
+
+/*
+ * Preload the TLB with entries that may be required. Currently, preloading
+ * is implemented only for BCOPY. Preload  <tlb_preload_count> pages OR to
+ * the end of the bcopy tranfer, whichever is smaller.
+ */
+static void gru_preload_tlb(struct gru_state *gru,
+			struct gru_thread_state *gts, int atomic,
+			unsigned long fault_vaddr, int asid, int write,
+			unsigned char tlb_preload_count,
+			struct gru_tlb_fault_handle *tfh,
+			struct gru_control_block_extended *cbe)
+{
+	unsigned long vaddr = 0, gpa;
+	int ret, pageshift;
+
+	if (cbe->opccpy != OP_BCOPY)
+		return;
+
+	if (fault_vaddr == cbe->cbe_baddr0)
+		vaddr = fault_vaddr + GRU_CACHE_LINE_BYTES * cbe->cbe_src_cl - 1;
+	else if (fault_vaddr == cbe->cbe_baddr1)
+		vaddr = fault_vaddr + (1 << cbe->xtypecpy) * cbe->cbe_nelemcur - 1;
+
+	fault_vaddr &= PAGE_MASK;
+	vaddr &= PAGE_MASK;
+	vaddr = min(vaddr, fault_vaddr + tlb_preload_count * PAGE_SIZE);
+
+	while (vaddr > fault_vaddr) {
+		ret = gru_vtop(gts, vaddr, write, atomic, &gpa, &pageshift);
+		if (ret || tfh_write_only(tfh, gpa, GAA_RAM, vaddr, asid, write,
+					  GRU_PAGESIZE(pageshift)))
+			return;
+		gru_dbg(grudev,
+			"%s: gid %d, gts 0x%p, tfh 0x%p, vaddr 0x%lx, asid 0x%x, rw %d, ps %d, gpa 0x%lx\n",
+			atomic ? "atomic" : "non-atomic", gru->gs_gid, gts, tfh,
+			vaddr, asid, write, pageshift, gpa);
+		vaddr -= PAGE_SIZE;
+		STAT(tlb_preload_page);
+	}
+}
+
+/*
+ * Drop a TLB entry into the GRU. The fault is described by info in an TFH.
+ *	Input:
+ *		cb    Address of user CBR. Null if not running in user context
+ * 	Return:
+ * 		  0 = dropin, exception, or switch to UPM successful
+ * 		  1 = range invalidate active
+ * 		< 0 = error code
+ *
+ */
+static int gru_try_dropin(struct gru_state *gru,
+			  struct gru_thread_state *gts,
+			  struct gru_tlb_fault_handle *tfh,
+			  struct gru_instruction_bits *cbk)
+{
+	struct gru_control_block_extended *cbe = NULL;
+	unsigned char tlb_preload_count = gts->ts_tlb_preload_count;
+	int pageshift = 0, asid, write, ret, atomic = !cbk, indexway;
+	unsigned long gpa = 0, vaddr = 0;
+
+	/*
+	 * NOTE: The GRU contains magic hardware that eliminates races between
+	 * TLB invalidates and TLB dropins. If an invalidate occurs
+	 * in the window between reading the TFH and the subsequent TLB dropin,
+	 * the dropin is ignored. This eliminates the need for additional locks.
+	 */
+
+	/*
+	 * Prefetch the CBE if doing TLB preloading
+	 */
+	if (unlikely(tlb_preload_count)) {
+		cbe = gru_tfh_to_cbe(tfh);
+		prefetchw(cbe);
+	}
+
+	/*
+	 * Error if TFH state is IDLE or FMM mode & the user issuing a UPM call.
+	 * Might be a hardware race OR a stupid user. Ignore FMM because FMM
+	 * is a transient state.
+	 */
+	if (tfh->status != TFHSTATUS_EXCEPTION) {
+		gru_flush_cache(tfh);
+		sync_core();
+		if (tfh->status != TFHSTATUS_EXCEPTION)
+			goto failnoexception;
+		STAT(tfh_stale_on_fault);
+	}
+	if (tfh->state == TFHSTATE_IDLE)
+		goto failidle;
+	if (tfh->state == TFHSTATE_MISS_FMM && cbk)
+		goto failfmm;
+
+	write = (tfh->cause & TFHCAUSE_TLB_MOD) != 0;
+	vaddr = tfh->missvaddr;
+	asid = tfh->missasid;
+	indexway = tfh->indexway;
+	if (asid == 0)
+		goto failnoasid;
+
+	rmb();	/* TFH must be cache resident before reading ms_range_active */
+
+	/*
+	 * TFH is cache resident - at least briefly. Fail the dropin
+	 * if a range invalidate is active.
+	 */
+	if (atomic_read(&gts->ts_gms->ms_range_active))
+		goto failactive;
+
+	ret = gru_vtop(gts, vaddr, write, atomic, &gpa, &pageshift);
+	if (ret == VTOP_INVALID)
+		goto failinval;
+	if (ret == VTOP_RETRY)
+		goto failupm;
+
+	if (!(gts->ts_sizeavail & GRU_SIZEAVAIL(pageshift))) {
+		gts->ts_sizeavail |= GRU_SIZEAVAIL(pageshift);
+		if (atomic || !gru_update_cch(gts)) {
+			gts->ts_force_cch_reload = 1;
+			goto failupm;
+		}
+	}
+
+	if (unlikely(cbe) && pageshift == PAGE_SHIFT) {
+		gru_preload_tlb(gru, gts, atomic, vaddr, asid, write, tlb_preload_count, tfh, cbe);
+		gru_flush_cache_cbe(cbe);
+	}
+
+	gru_cb_set_istatus_active(cbk);
+	gts->ustats.tlbdropin++;
+	tfh_write_restart(tfh, gpa, GAA_RAM, vaddr, asid, write,
+			  GRU_PAGESIZE(pageshift));
+	gru_dbg(grudev,
+		"%s: gid %d, gts 0x%p, tfh 0x%p, vaddr 0x%lx, asid 0x%x, indexway 0x%x,"
+		" rw %d, ps %d, gpa 0x%lx\n",
+		atomic ? "atomic" : "non-atomic", gru->gs_gid, gts, tfh, vaddr, asid,
+		indexway, write, pageshift, gpa);
+	STAT(tlb_dropin);
+	return 0;
+
+failnoasid:
+	/* No asid (delayed unload). */
+	STAT(tlb_dropin_fail_no_asid);
+	gru_dbg(grudev, "FAILED no_asid tfh: 0x%p, vaddr 0x%lx\n", tfh, vaddr);
+	if (!cbk)
+		tfh_user_polling_mode(tfh);
+	else
+		gru_flush_cache(tfh);
+	gru_flush_cache_cbe(cbe);
+	return -EAGAIN;
+
+failupm:
+	/* Atomic failure switch CBR to UPM */
+	tfh_user_polling_mode(tfh);
+	gru_flush_cache_cbe(cbe);
+	STAT(tlb_dropin_fail_upm);
+	gru_dbg(grudev, "FAILED upm tfh: 0x%p, vaddr 0x%lx\n", tfh, vaddr);
+	return 1;
+
+failfmm:
+	/* FMM state on UPM call */
+	gru_flush_cache(tfh);
+	gru_flush_cache_cbe(cbe);
+	STAT(tlb_dropin_fail_fmm);
+	gru_dbg(grudev, "FAILED fmm tfh: 0x%p, state %d\n", tfh, tfh->state);
+	return 0;
+
+failnoexception:
+	/* TFH status did not show exception pending */
+	gru_flush_cache(tfh);
+	gru_flush_cache_cbe(cbe);
+	if (cbk)
+		gru_flush_cache(cbk);
+	STAT(tlb_dropin_fail_no_exception);
+	gru_dbg(grudev, "FAILED non-exception tfh: 0x%p, status %d, state %d\n",
+		tfh, tfh->status, tfh->state);
+	return 0;
+
+failidle:
+	/* TFH state was idle  - no miss pending */
+	gru_flush_cache(tfh);
+	gru_flush_cache_cbe(cbe);
+	if (cbk)
+		gru_flush_cache(cbk);
+	STAT(tlb_dropin_fail_idle);
+	gru_dbg(grudev, "FAILED idle tfh: 0x%p, state %d\n", tfh, tfh->state);
+	return 0;
+
+failinval:
+	/* All errors (atomic & non-atomic) switch CBR to EXCEPTION state */
+	tfh_exception(tfh);
+	gru_flush_cache_cbe(cbe);
+	STAT(tlb_dropin_fail_invalid);
+	gru_dbg(grudev, "FAILED inval tfh: 0x%p, vaddr 0x%lx\n", tfh, vaddr);
+	return -EFAULT;
+
+failactive:
+	/* Range invalidate active. Switch to UPM iff atomic */
+	if (!cbk)
+		tfh_user_polling_mode(tfh);
+	else
+		gru_flush_cache(tfh);
+	gru_flush_cache_cbe(cbe);
+	STAT(tlb_dropin_fail_range_active);
+	gru_dbg(grudev, "FAILED range active: tfh 0x%p, vaddr 0x%lx\n",
+		tfh, vaddr);
+	return 1;
+}
+
+/*
+ * Process an external interrupt from the GRU. This interrupt is
+ * caused by a TLB miss.
+ * Note that this is the interrupt handler that is registered with linux
+ * interrupt handlers.
+ */
+static irqreturn_t gru_intr(int chiplet, int blade)
+{
+	struct gru_state *gru;
+	struct gru_tlb_fault_map imap, dmap;
+	struct gru_thread_state *gts;
+	struct gru_tlb_fault_handle *tfh = NULL;
+	struct completion *cmp;
+	int cbrnum, ctxnum;
+
+	STAT(intr);
+
+	gru = &gru_base[blade]->bs_grus[chiplet];
+	if (!gru) {
+		dev_err(grudev, "GRU: invalid interrupt: cpu %d, chiplet %d\n",
+			raw_smp_processor_id(), chiplet);
+		return IRQ_NONE;
+	}
+	get_clear_fault_map(gru, &imap, &dmap);
+	gru_dbg(grudev,
+		"cpu %d, chiplet %d, gid %d, imap %016lx %016lx, dmap %016lx %016lx\n",
+		smp_processor_id(), chiplet, gru->gs_gid,
+		imap.fault_bits[0], imap.fault_bits[1],
+		dmap.fault_bits[0], dmap.fault_bits[1]);
+
+	for_each_cbr_in_tfm(cbrnum, dmap.fault_bits) {
+		STAT(intr_cbr);
+		cmp = gru->gs_blade->bs_async_wq;
+		if (cmp)
+			complete(cmp);
+		gru_dbg(grudev, "gid %d, cbr_done %d, done %d\n",
+			gru->gs_gid, cbrnum, cmp ? cmp->done : -1);
+	}
+
+	for_each_cbr_in_tfm(cbrnum, imap.fault_bits) {
+		STAT(intr_tfh);
+		tfh = get_tfh_by_index(gru, cbrnum);
+		prefetchw(tfh);	/* Helps on hdw, required for emulator */
+
+		/*
+		 * When hardware sets a bit in the faultmap, it implicitly
+		 * locks the GRU context so that it cannot be unloaded.
+		 * The gts cannot change until a TFH start/writestart command
+		 * is issued.
+		 */
+		ctxnum = tfh->ctxnum;
+		gts = gru->gs_gts[ctxnum];
+
+		/* Spurious interrupts can cause this. Ignore. */
+		if (!gts) {
+			STAT(intr_spurious);
+			continue;
+		}
+
+		/*
+		 * This is running in interrupt context. Trylock the mmap_lock.
+		 * If it fails, retry the fault in user context.
+		 */
+		gts->ustats.fmm_tlbmiss++;
+		if (!gts->ts_force_cch_reload &&
+					mmap_read_trylock(gts->ts_mm)) {
+			gru_try_dropin(gru, gts, tfh, NULL);
+			mmap_read_unlock(gts->ts_mm);
+		} else {
+			tfh_user_polling_mode(tfh);
+			STAT(intr_mm_lock_failed);
+		}
+	}
+	return IRQ_HANDLED;
+}
+
+irqreturn_t gru0_intr(int irq, void *dev_id)
+{
+	return gru_intr(0, uv_numa_blade_id());
+}
+
+irqreturn_t gru1_intr(int irq, void *dev_id)
+{
+	return gru_intr(1, uv_numa_blade_id());
+}
+
+irqreturn_t gru_intr_mblade(int irq, void *dev_id)
+{
+	int blade;
+
+	for_each_possible_blade(blade) {
+		if (uv_blade_nr_possible_cpus(blade))
+			continue;
+		gru_intr(0, blade);
+		gru_intr(1, blade);
+	}
+	return IRQ_HANDLED;
+}
+
+
+static int gru_user_dropin(struct gru_thread_state *gts,
+			   struct gru_tlb_fault_handle *tfh,
+			   void *cb)
+{
+	struct gru_mm_struct *gms = gts->ts_gms;
+	int ret;
+
+	gts->ustats.upm_tlbmiss++;
+	while (1) {
+		wait_event(gms->ms_wait_queue,
+			   atomic_read(&gms->ms_range_active) == 0);
+		prefetchw(tfh);	/* Helps on hdw, required for emulator */
+		ret = gru_try_dropin(gts->ts_gru, gts, tfh, cb);
+		if (ret <= 0)
+			return ret;
+		STAT(call_os_wait_queue);
+	}
+}
+
+/*
+ * This interface is called as a result of a user detecting a "call OS" bit
+ * in a user CB. Normally means that a TLB fault has occurred.
+ * 	cb - user virtual address of the CB
+ */
+int gru_handle_user_call_os(unsigned long cb)
+{
+	struct gru_tlb_fault_handle *tfh;
+	struct gru_thread_state *gts;
+	void *cbk;
+	int ucbnum, cbrnum, ret = -EINVAL;
+
+	STAT(call_os);
+
+	/* sanity check the cb pointer */
+	ucbnum = get_cb_number((void *)cb);
+	if ((cb & (GRU_HANDLE_STRIDE - 1)) || ucbnum >= GRU_NUM_CB)
+		return -EINVAL;
+
+again:
+	gts = gru_find_lock_gts(cb);
+	if (!gts)
+		return -EINVAL;
+	gru_dbg(grudev, "address 0x%lx, gid %d, gts 0x%p\n", cb, gts->ts_gru ? gts->ts_gru->gs_gid : -1, gts);
+
+	if (ucbnum >= gts->ts_cbr_au_count * GRU_CBR_AU_SIZE)
+		goto exit;
+
+	if (gru_check_context_placement(gts)) {
+		gru_unlock_gts(gts);
+		gru_unload_context(gts, 1);
+		goto again;
+	}
+
+	/*
+	 * CCH may contain stale data if ts_force_cch_reload is set.
+	 */
+	if (gts->ts_gru && gts->ts_force_cch_reload) {
+		gts->ts_force_cch_reload = 0;
+		gru_update_cch(gts);
+	}
+
+	ret = -EAGAIN;
+	cbrnum = thread_cbr_number(gts, ucbnum);
+	if (gts->ts_gru) {
+		tfh = get_tfh_by_index(gts->ts_gru, cbrnum);
+		cbk = get_gseg_base_address_cb(gts->ts_gru->gs_gru_base_vaddr,
+				gts->ts_ctxnum, ucbnum);
+		ret = gru_user_dropin(gts, tfh, cbk);
+	}
+exit:
+	gru_unlock_gts(gts);
+	return ret;
+}
+
+/*
+ * Fetch the exception detail information for a CB that terminated with
+ * an exception.
+ */
+int gru_get_exception_detail(unsigned long arg)
+{
+	struct control_block_extended_exc_detail excdet;
+	struct gru_control_block_extended *cbe;
+	struct gru_thread_state *gts;
+	int ucbnum, cbrnum, ret;
+
+	STAT(user_exception);
+	if (copy_from_user(&excdet, (void __user *)arg, sizeof(excdet)))
+		return -EFAULT;
+
+	gts = gru_find_lock_gts(excdet.cb);
+	if (!gts)
+		return -EINVAL;
+
+	gru_dbg(grudev, "address 0x%lx, gid %d, gts 0x%p\n", excdet.cb, gts->ts_gru ? gts->ts_gru->gs_gid : -1, gts);
+	ucbnum = get_cb_number((void *)excdet.cb);
+	if (ucbnum >= gts->ts_cbr_au_count * GRU_CBR_AU_SIZE) {
+		ret = -EINVAL;
+	} else if (gts->ts_gru) {
+		cbrnum = thread_cbr_number(gts, ucbnum);
+		cbe = get_cbe_by_index(gts->ts_gru, cbrnum);
+		gru_flush_cache(cbe);	/* CBE not coherent */
+		sync_core();		/* make sure we are have current data */
+		excdet.opc = cbe->opccpy;
+		excdet.exopc = cbe->exopccpy;
+		excdet.ecause = cbe->ecause;
+		excdet.exceptdet0 = cbe->idef1upd;
+		excdet.exceptdet1 = cbe->idef3upd;
+		excdet.cbrstate = cbe->cbrstate;
+		excdet.cbrexecstatus = cbe->cbrexecstatus;
+		gru_flush_cache_cbe(cbe);
+		ret = 0;
+	} else {
+		ret = -EAGAIN;
+	}
+	gru_unlock_gts(gts);
+
+	gru_dbg(grudev,
+		"cb 0x%lx, op %d, exopc %d, cbrstate %d, cbrexecstatus 0x%x, ecause 0x%x, "
+		"exdet0 0x%lx, exdet1 0x%x\n",
+		excdet.cb, excdet.opc, excdet.exopc, excdet.cbrstate, excdet.cbrexecstatus,
+		excdet.ecause, excdet.exceptdet0, excdet.exceptdet1);
+	if (!ret && copy_to_user((void __user *)arg, &excdet, sizeof(excdet)))
+		ret = -EFAULT;
+	return ret;
+}
+
+/*
+ * User request to unload a context. Content is saved for possible reload.
+ */
+static int gru_unload_all_contexts(void)
+{
+	struct gru_thread_state *gts;
+	struct gru_state *gru;
+	int gid, ctxnum;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	foreach_gid(gid) {
+		gru = GID_TO_GRU(gid);
+		spin_lock(&gru->gs_lock);
+		for (ctxnum = 0; ctxnum < GRU_NUM_CCH; ctxnum++) {
+			gts = gru->gs_gts[ctxnum];
+			if (gts && mutex_trylock(&gts->ts_ctxlock)) {
+				spin_unlock(&gru->gs_lock);
+				gru_unload_context(gts, 1);
+				mutex_unlock(&gts->ts_ctxlock);
+				spin_lock(&gru->gs_lock);
+			}
+		}
+		spin_unlock(&gru->gs_lock);
+	}
+	return 0;
+}
+
+int gru_user_unload_context(unsigned long arg)
+{
+	struct gru_thread_state *gts;
+	struct gru_unload_context_req req;
+
+	STAT(user_unload_context);
+	if (copy_from_user(&req, (void __user *)arg, sizeof(req)))
+		return -EFAULT;
+
+	gru_dbg(grudev, "gseg 0x%lx\n", req.gseg);
+
+	if (!req.gseg)
+		return gru_unload_all_contexts();
+
+	gts = gru_find_lock_gts(req.gseg);
+	if (!gts)
+		return -EINVAL;
+
+	if (gts->ts_gru)
+		gru_unload_context(gts, 1);
+	gru_unlock_gts(gts);
+
+	return 0;
+}
+
+/*
+ * User request to flush a range of virtual addresses from the GRU TLB
+ * (Mainly for testing).
+ */
+int gru_user_flush_tlb(unsigned long arg)
+{
+	struct gru_thread_state *gts;
+	struct gru_flush_tlb_req req;
+	struct gru_mm_struct *gms;
+
+	STAT(user_flush_tlb);
+	if (copy_from_user(&req, (void __user *)arg, sizeof(req)))
+		return -EFAULT;
+
+	gru_dbg(grudev, "gseg 0x%lx, vaddr 0x%lx, len 0x%lx\n", req.gseg,
+		req.vaddr, req.len);
+
+	gts = gru_find_lock_gts(req.gseg);
+	if (!gts)
+		return -EINVAL;
+
+	gms = gts->ts_gms;
+	gru_unlock_gts(gts);
+	gru_flush_tlb_range(gms, req.vaddr, req.len);
+
+	return 0;
+}
+
+/*
+ * Fetch GSEG statisticss
+ */
+long gru_get_gseg_statistics(unsigned long arg)
+{
+	struct gru_thread_state *gts;
+	struct gru_get_gseg_statistics_req req;
+
+	if (copy_from_user(&req, (void __user *)arg, sizeof(req)))
+		return -EFAULT;
+
+	/*
+	 * The library creates arrays of contexts for threaded programs.
+	 * If no gts exists in the array, the context has never been used & all
+	 * statistics are implicitly 0.
+	 */
+	gts = gru_find_lock_gts(req.gseg);
+	if (gts) {
+		memcpy(&req.stats, &gts->ustats, sizeof(gts->ustats));
+		gru_unlock_gts(gts);
+	} else {
+		memset(&req.stats, 0, sizeof(gts->ustats));
+	}
+
+	if (copy_to_user((void __user *)arg, &req, sizeof(req)))
+		return -EFAULT;
+
+	return 0;
+}
+
+/*
+ * Register the current task as the user of the GSEG slice.
+ * Needed for TLB fault interrupt targeting.
+ */
+int gru_set_context_option(unsigned long arg)
+{
+	struct gru_thread_state *gts;
+	struct gru_set_context_option_req req;
+	int ret = 0;
+
+	STAT(set_context_option);
+	if (copy_from_user(&req, (void __user *)arg, sizeof(req)))
+		return -EFAULT;
+	gru_dbg(grudev, "op %d, gseg 0x%lx, value1 0x%lx\n", req.op, req.gseg, req.val1);
+
+	gts = gru_find_lock_gts(req.gseg);
+	if (!gts) {
+		gts = gru_alloc_locked_gts(req.gseg);
+		if (IS_ERR(gts))
+			return PTR_ERR(gts);
+	}
+
+	switch (req.op) {
+	case sco_blade_chiplet:
+		/* Select blade/chiplet for GRU context */
+		if (req.val0 < -1 || req.val0 >= GRU_CHIPLETS_PER_HUB ||
+		    req.val1 < -1 || req.val1 >= GRU_MAX_BLADES ||
+		    (req.val1 >= 0 && !gru_base[req.val1])) {
+			ret = -EINVAL;
+		} else {
+			gts->ts_user_blade_id = req.val1;
+			gts->ts_user_chiplet_id = req.val0;
+			if (gru_check_context_placement(gts)) {
+				gru_unlock_gts(gts);
+				gru_unload_context(gts, 1);
+				return ret;
+			}
+		}
+		break;
+	case sco_gseg_owner:
+ 		/* Register the current task as the GSEG owner */
+		gts->ts_tgid_owner = current->tgid;
+		break;
+	case sco_cch_req_slice:
+ 		/* Set the CCH slice option */
+		gts->ts_cch_req_slice = req.val1 & 3;
+		break;
+	default:
+		ret = -EINVAL;
+	}
+	gru_unlock_gts(gts);
+
+	return ret;
+}