From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- arch/powerpc/platforms/powernv/vas-fault.c | 245 +++++++++++++++++++++++++++++ 1 file changed, 245 insertions(+) create mode 100644 arch/powerpc/platforms/powernv/vas-fault.c (limited to 'arch/powerpc/platforms/powernv/vas-fault.c') diff --git a/arch/powerpc/platforms/powernv/vas-fault.c b/arch/powerpc/platforms/powernv/vas-fault.c new file mode 100644 index 0000000000..2b47d5a863 --- /dev/null +++ b/arch/powerpc/platforms/powernv/vas-fault.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * VAS Fault handling. + * Copyright 2019, IBM Corporation + */ + +#define pr_fmt(fmt) "vas: " fmt + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "vas.h" + +/* + * The maximum FIFO size for fault window can be 8MB + * (VAS_RX_FIFO_SIZE_MAX). Using 4MB FIFO since each VAS + * instance will be having fault window. + * 8MB FIFO can be used if expects more faults for each VAS + * instance. + */ +#define VAS_FAULT_WIN_FIFO_SIZE (4 << 20) + +static void dump_fifo(struct vas_instance *vinst, void *entry) +{ + unsigned long *end = vinst->fault_fifo + vinst->fault_fifo_size; + unsigned long *fifo = entry; + int i; + + pr_err("Fault fifo size %d, Max crbs %d\n", vinst->fault_fifo_size, + vinst->fault_fifo_size / CRB_SIZE); + + /* Dump 10 CRB entries or until end of FIFO */ + pr_err("Fault FIFO Dump:\n"); + for (i = 0; i < 10*(CRB_SIZE/8) && fifo < end; i += 4, fifo += 4) { + pr_err("[%.3d, %p]: 0x%.16lx 0x%.16lx 0x%.16lx 0x%.16lx\n", + i, fifo, *fifo, *(fifo+1), *(fifo+2), *(fifo+3)); + } +} + +/* + * Process valid CRBs in fault FIFO. + * NX process user space requests, return credit and update the status + * in CRB. If it encounters transalation error when accessing CRB or + * request buffers, raises interrupt on the CPU to handle the fault. + * It takes credit on fault window, updates nx_fault_stamp in CRB with + * the following information and pastes CRB in fault FIFO. + * + * pswid - window ID of the window on which the request is sent. + * fault_storage_addr - fault address + * + * It can raise a single interrupt for multiple faults. Expects OS to + * process all valid faults and return credit for each fault on user + * space and fault windows. This fault FIFO control will be done with + * credit mechanism. NX can continuously paste CRBs until credits are not + * available on fault window. Otherwise, returns with RMA_reject. + * + * Total credits available on fault window: FIFO_SIZE(4MB)/CRBS_SIZE(128) + * + */ +irqreturn_t vas_fault_thread_fn(int irq, void *data) +{ + struct vas_instance *vinst = data; + struct coprocessor_request_block *crb, *entry; + struct coprocessor_request_block buf; + struct pnv_vas_window *window; + unsigned long flags; + void *fifo; + + crb = &buf; + + /* + * VAS can interrupt with multiple page faults. So process all + * valid CRBs within fault FIFO until reaches invalid CRB. + * We use CCW[0] and pswid to validate CRBs: + * + * CCW[0] Reserved bit. When NX pastes CRB, CCW[0]=0 + * OS sets this bit to 1 after reading CRB. + * pswid NX assigns window ID. Set pswid to -1 after + * reading CRB from fault FIFO. + * + * We exit this function if no valid CRBs are available to process. + * So acquire fault_lock and reset fifo_in_progress to 0 before + * exit. + * In case kernel receives another interrupt with different page + * fault, interrupt handler returns with IRQ_HANDLED if + * fifo_in_progress is set. Means these new faults will be + * handled by the current thread. Otherwise set fifo_in_progress + * and return IRQ_WAKE_THREAD to wake up thread. + */ + while (true) { + spin_lock_irqsave(&vinst->fault_lock, flags); + /* + * Advance the fault fifo pointer to next CRB. + * Use CRB_SIZE rather than sizeof(*crb) since the latter is + * aligned to CRB_ALIGN (256) but the CRB written to by VAS is + * only CRB_SIZE in len. + */ + fifo = vinst->fault_fifo + (vinst->fault_crbs * CRB_SIZE); + entry = fifo; + + if ((entry->stamp.nx.pswid == cpu_to_be32(FIFO_INVALID_ENTRY)) + || (entry->ccw & cpu_to_be32(CCW0_INVALID))) { + vinst->fifo_in_progress = 0; + spin_unlock_irqrestore(&vinst->fault_lock, flags); + return IRQ_HANDLED; + } + + spin_unlock_irqrestore(&vinst->fault_lock, flags); + vinst->fault_crbs++; + if (vinst->fault_crbs == (vinst->fault_fifo_size / CRB_SIZE)) + vinst->fault_crbs = 0; + + memcpy(crb, fifo, CRB_SIZE); + entry->stamp.nx.pswid = cpu_to_be32(FIFO_INVALID_ENTRY); + entry->ccw |= cpu_to_be32(CCW0_INVALID); + /* + * Return credit for the fault window. + */ + vas_return_credit(vinst->fault_win, false); + + pr_devel("VAS[%d] fault_fifo %p, fifo %p, fault_crbs %d\n", + vinst->vas_id, vinst->fault_fifo, fifo, + vinst->fault_crbs); + + vas_dump_crb(crb); + window = vas_pswid_to_window(vinst, + be32_to_cpu(crb->stamp.nx.pswid)); + + if (IS_ERR(window)) { + /* + * We got an interrupt about a specific send + * window but we can't find that window and we can't + * even clean it up (return credit on user space + * window). + * But we should not get here. + * TODO: Disable IRQ. + */ + dump_fifo(vinst, (void *)entry); + pr_err("VAS[%d] fault_fifo %p, fifo %p, pswid 0x%x, fault_crbs %d bad CRB?\n", + vinst->vas_id, vinst->fault_fifo, fifo, + be32_to_cpu(crb->stamp.nx.pswid), + vinst->fault_crbs); + + WARN_ON_ONCE(1); + } else { + /* + * NX sees faults only with user space windows. + */ + if (window->user_win) + vas_update_csb(crb, &window->vas_win.task_ref); + else + WARN_ON_ONCE(!window->user_win); + + /* + * Return credit for send window after processing + * fault CRB. + */ + vas_return_credit(window, true); + } + } +} + +irqreturn_t vas_fault_handler(int irq, void *dev_id) +{ + struct vas_instance *vinst = dev_id; + irqreturn_t ret = IRQ_WAKE_THREAD; + unsigned long flags; + + /* + * NX can generate an interrupt for multiple faults. So the + * fault handler thread process all CRBs until finds invalid + * entry. In case if NX sees continuous faults, it is possible + * that the thread function entered with the first interrupt + * can execute and process all valid CRBs. + * So wake up thread only if the fault thread is not in progress. + */ + spin_lock_irqsave(&vinst->fault_lock, flags); + + if (vinst->fifo_in_progress) + ret = IRQ_HANDLED; + else + vinst->fifo_in_progress = 1; + + spin_unlock_irqrestore(&vinst->fault_lock, flags); + + return ret; +} + +/* + * Fault window is opened per VAS instance. NX pastes fault CRB in fault + * FIFO upon page faults. + */ +int vas_setup_fault_window(struct vas_instance *vinst) +{ + struct vas_rx_win_attr attr; + struct vas_window *win; + + vinst->fault_fifo_size = VAS_FAULT_WIN_FIFO_SIZE; + vinst->fault_fifo = kzalloc(vinst->fault_fifo_size, GFP_KERNEL); + if (!vinst->fault_fifo) { + pr_err("Unable to alloc %d bytes for fault_fifo\n", + vinst->fault_fifo_size); + return -ENOMEM; + } + + /* + * Invalidate all CRB entries. NX pastes valid entry for each fault. + */ + memset(vinst->fault_fifo, FIFO_INVALID_ENTRY, vinst->fault_fifo_size); + vas_init_rx_win_attr(&attr, VAS_COP_TYPE_FAULT); + + attr.rx_fifo_size = vinst->fault_fifo_size; + attr.rx_fifo = __pa(vinst->fault_fifo); + + /* + * Max creds is based on number of CRBs can fit in the FIFO. + * (fault_fifo_size/CRB_SIZE). If 8MB FIFO is used, max creds + * will be 0xffff since the receive creds field is 16bits wide. + */ + attr.wcreds_max = vinst->fault_fifo_size / CRB_SIZE; + attr.lnotify_lpid = 0; + attr.lnotify_pid = mfspr(SPRN_PID); + attr.lnotify_tid = mfspr(SPRN_PID); + + win = vas_rx_win_open(vinst->vas_id, VAS_COP_TYPE_FAULT, &attr); + if (IS_ERR(win)) { + pr_err("VAS: Error %ld opening FaultWin\n", PTR_ERR(win)); + kfree(vinst->fault_fifo); + return PTR_ERR(win); + } + + vinst->fault_win = container_of(win, struct pnv_vas_window, vas_win); + + pr_devel("VAS: Created FaultWin %d, LPID/PID/TID [%d/%d/%d]\n", + vinst->fault_win->vas_win.winid, attr.lnotify_lpid, + attr.lnotify_pid, attr.lnotify_tid); + + return 0; +} -- cgit v1.2.3