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Diffstat (limited to 'arch/powerpc/mm/icswx.c')
| -rw-r--r-- | arch/powerpc/mm/icswx.c | 292 |
1 files changed, 0 insertions, 292 deletions
diff --git a/arch/powerpc/mm/icswx.c b/arch/powerpc/mm/icswx.c deleted file mode 100644 index 1fa794d7d59f..000000000000 --- a/arch/powerpc/mm/icswx.c +++ /dev/null @@ -1,292 +0,0 @@ -/* - * ICSWX and ACOP Management - * - * Copyright (C) 2011 Anton Blanchard, IBM Corp. <anton@samba.org> - * - * 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 <linux/sched.h> -#include <linux/kernel.h> -#include <linux/errno.h> -#include <linux/types.h> -#include <linux/mm.h> -#include <linux/spinlock.h> -#include <linux/module.h> -#include <linux/uaccess.h> - -#include "icswx.h" - -/* - * The processor and its L2 cache cause the icswx instruction to - * generate a COP_REQ transaction on PowerBus. The transaction has no - * address, and the processor does not perform an MMU access to - * authenticate the transaction. The command portion of the PowerBus - * COP_REQ transaction includes the LPAR_ID (LPID) and the coprocessor - * Process ID (PID), which the coprocessor compares to the authorized - * LPID and PID held in the coprocessor, to determine if the process - * is authorized to generate the transaction. The data of the COP_REQ - * transaction is 128-byte or less in size and is placed in cacheable - * memory on a 128-byte cache line boundary. - * - * The task to use a coprocessor should use use_cop() to mark the use - * of the Coprocessor Type (CT) and context switching. On a server - * class processor, the PID register is used only for coprocessor - * management + * and so a coprocessor PID is allocated before - * executing icswx + * instruction. Drop_cop() is used to free the - * coprocessor PID. - * - * Example: - * Host Fabric Interface (HFI) is a PowerPC network coprocessor. - * Each HFI have multiple windows. Each HFI window serves as a - * network device sending to and receiving from HFI network. - * HFI immediate send function uses icswx instruction. The immediate - * send function allows small (single cache-line) packets be sent - * without using the regular HFI send FIFO and doorbell, which are - * much slower than immediate send. - * - * For each task intending to use HFI immediate send, the HFI driver - * calls use_cop() to obtain a coprocessor PID for the task. - * The HFI driver then allocate a free HFI window and save the - * coprocessor PID to the HFI window to allow the task to use the - * HFI window. - * - * The HFI driver repeatedly creates immediate send packets and - * issues icswx instruction to send data through the HFI window. - * The HFI compares the coprocessor PID in the CPU PID register - * to the PID held in the HFI window to determine if the transaction - * is allowed. - * - * When the task to release the HFI window, the HFI driver calls - * drop_cop() to release the coprocessor PID. - */ - -void switch_cop(struct mm_struct *next) -{ -#ifdef CONFIG_PPC_ICSWX_PID - mtspr(SPRN_PID, next->context.cop_pid); -#endif - mtspr(SPRN_ACOP, next->context.acop); -} - -/** - * Start using a coprocessor. - * @acop: mask of coprocessor to be used. - * @mm: The mm the coprocessor to associate with. Most likely current mm. - * - * Return a positive PID if successful. Negative errno otherwise. - * The returned PID will be fed to the coprocessor to determine if an - * icswx transaction is authenticated. - */ -int use_cop(unsigned long acop, struct mm_struct *mm) -{ - int ret; - - if (!cpu_has_feature(CPU_FTR_ICSWX)) - return -ENODEV; - - if (!mm || !acop) - return -EINVAL; - - /* The page_table_lock ensures mm_users won't change under us */ - spin_lock(&mm->page_table_lock); - spin_lock(mm->context.cop_lockp); - - ret = get_cop_pid(mm); - if (ret < 0) - goto out; - - /* update acop */ - mm->context.acop |= acop; - - sync_cop(mm); - - /* - * If this is a threaded process then there might be other threads - * running. We need to send an IPI to force them to pick up any - * change in PID and ACOP. - */ - if (atomic_read(&mm->mm_users) > 1) - smp_call_function(sync_cop, mm, 1); - -out: - spin_unlock(mm->context.cop_lockp); - spin_unlock(&mm->page_table_lock); - - return ret; -} -EXPORT_SYMBOL_GPL(use_cop); - -/** - * Stop using a coprocessor. - * @acop: mask of coprocessor to be stopped. - * @mm: The mm the coprocessor associated with. - */ -void drop_cop(unsigned long acop, struct mm_struct *mm) -{ - int free_pid; - - if (!cpu_has_feature(CPU_FTR_ICSWX)) - return; - - if (WARN_ON_ONCE(!mm)) - return; - - /* The page_table_lock ensures mm_users won't change under us */ - spin_lock(&mm->page_table_lock); - spin_lock(mm->context.cop_lockp); - - mm->context.acop &= ~acop; - - free_pid = disable_cop_pid(mm); - sync_cop(mm); - - /* - * If this is a threaded process then there might be other threads - * running. We need to send an IPI to force them to pick up any - * change in PID and ACOP. - */ - if (atomic_read(&mm->mm_users) > 1) - smp_call_function(sync_cop, mm, 1); - - if (free_pid != COP_PID_NONE) - free_cop_pid(free_pid); - - spin_unlock(mm->context.cop_lockp); - spin_unlock(&mm->page_table_lock); -} -EXPORT_SYMBOL_GPL(drop_cop); - -static int acop_use_cop(int ct) -{ - /* There is no alternate policy, yet */ - return -1; -} - -/* - * Get the instruction word at the NIP - */ -static u32 acop_get_inst(struct pt_regs *regs) -{ - u32 inst; - u32 __user *p; - - p = (u32 __user *)regs->nip; - if (!access_ok(VERIFY_READ, p, sizeof(*p))) - return 0; - - if (__get_user(inst, p)) - return 0; - - return inst; -} - -/** - * @regs: registers at time of interrupt - * @address: storage address - * @error_code: Fault code, usually the DSISR or ESR depending on - * processor type - * - * Return 0 if we are able to resolve the data storage fault that - * results from a CT miss in the ACOP register. - */ -int acop_handle_fault(struct pt_regs *regs, unsigned long address, - unsigned long error_code) -{ - int ct; - u32 inst = 0; - - if (!cpu_has_feature(CPU_FTR_ICSWX)) { - pr_info("No coprocessors available"); - _exception(SIGILL, regs, ILL_ILLOPN, address); - } - - if (!user_mode(regs)) { - /* this could happen if the HV denies the - * kernel access, for now we just die */ - die("ICSWX from kernel failed", regs, SIGSEGV); - } - - /* Some implementations leave us a hint for the CT */ - ct = ICSWX_GET_CT_HINT(error_code); - if (ct < 0) { - /* we have to peek at the instruction word to figure out CT */ - u32 ccw; - u32 rs; - - inst = acop_get_inst(regs); - if (inst == 0) - return -1; - - rs = (inst >> (31 - 10)) & 0x1f; - ccw = regs->gpr[rs]; - ct = (ccw >> 16) & 0x3f; - } - - /* - * We could be here because another thread has enabled acop - * but the ACOP register has yet to be updated. - * - * This should have been taken care of by the IPI to sync all - * the threads (see smp_call_function(sync_cop, mm, 1)), but - * that could take forever if there are a significant amount - * of threads. - * - * Given the number of threads on some of these systems, - * perhaps this is the best way to sync ACOP rather than whack - * every thread with an IPI. - */ - if ((acop_copro_type_bit(ct) & current->active_mm->context.acop) != 0) { - sync_cop(current->active_mm); - return 0; - } - - /* check for alternate policy */ - if (!acop_use_cop(ct)) - return 0; - - /* at this point the CT is unknown to the system */ - pr_warn("%s[%d]: Coprocessor %d is unavailable\n", - current->comm, current->pid, ct); - - /* get inst if we don't already have it */ - if (inst == 0) { - inst = acop_get_inst(regs); - if (inst == 0) - return -1; - } - - /* Check if the instruction is the "record form" */ - if (inst & 1) { - /* - * the instruction is "record" form so we can reject - * using CR0 - */ - regs->ccr &= ~(0xful << 28); - regs->ccr |= ICSWX_RC_NOT_FOUND << 28; - - /* Move on to the next instruction */ - regs->nip += 4; - } else { - /* - * There is no architected mechanism to report a bad - * CT so we could either SIGILL or report nothing. - * Since the non-record version should only bu used - * for "hints" or "don't care" we should probably do - * nothing. However, I could see how some people - * might want an SIGILL so it here if you want it. - */ -#ifdef CONFIG_PPC_ICSWX_USE_SIGILL - _exception(SIGILL, regs, ILL_ILLOPN, address); -#else - regs->nip += 4; -#endif - } - - return 0; -} -EXPORT_SYMBOL_GPL(acop_handle_fault); |