powerpc: Split ICSWX ACOP and PID processing

Some processors, like embedded, that already have a PID register that
is managed by the system.  This patch separates the ACOP and PID
processing into separate files so that the ACOP code can be shared.

Signed-off-by: Jimi Xenidis <jimix@pobox.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Jimi Xenidis 2011-09-29 10:55:12 +00:00 committed by Benjamin Herrenschmidt
parent 5182a131dd
commit 9d67028090
6 changed files with 297 additions and 194 deletions

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@ -21,6 +21,8 @@ obj-$(CONFIG_PPC_STD_MMU_32) += ppc_mmu_32.o
obj-$(CONFIG_PPC_STD_MMU) += hash_low_$(CONFIG_WORD_SIZE).o \
tlb_hash$(CONFIG_WORD_SIZE).o \
mmu_context_hash$(CONFIG_WORD_SIZE).o
obj-$(CONFIG_PPC_ICSWX) += icswx.o
obj-$(CONFIG_PPC_ICSWX_PID) += icswx_pid.o
obj-$(CONFIG_40x) += 40x_mmu.o
obj-$(CONFIG_44x) += 44x_mmu.o
obj-$(CONFIG_PPC_FSL_BOOK3E) += fsl_booke_mmu.o

160
arch/powerpc/mm/icswx.c Normal file
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@ -0,0 +1,160 @@
/*
* 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 "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_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);

39
arch/powerpc/mm/icswx.h Normal file
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@ -0,0 +1,39 @@
#ifndef _ARCH_POWERPC_MM_ICSWX_H_
#define _ARCH_POWERPC_MM_ICSWX_H_
/*
* 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 <asm/mmu_context.h>
/* also used to denote that PIDs are not used */
#define COP_PID_NONE 0
static inline void sync_cop(void *arg)
{
struct mm_struct *mm = arg;
if (mm == current->active_mm)
switch_cop(current->active_mm);
}
#ifdef CONFIG_PPC_ICSWX_PID
extern int get_cop_pid(struct mm_struct *mm);
extern int disable_cop_pid(struct mm_struct *mm);
extern void free_cop_pid(int free_pid);
#else
#define get_cop_pid(m) (COP_PID_NONE)
#define disable_cop_pid(m) (COP_PID_NONE)
#define free_cop_pid(p)
#endif
#endif /* !_ARCH_POWERPC_MM_ICSWX_H_ */

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@ -0,0 +1,87 @@
/*
* ICSWX and ACOP/PID 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/idr.h>
#include <linux/module.h>
#include "icswx.h"
#define COP_PID_MIN (COP_PID_NONE + 1)
#define COP_PID_MAX (0xFFFF)
static DEFINE_SPINLOCK(mmu_context_acop_lock);
static DEFINE_IDA(cop_ida);
static int new_cop_pid(struct ida *ida, int min_id, int max_id,
spinlock_t *lock)
{
int index;
int err;
again:
if (!ida_pre_get(ida, GFP_KERNEL))
return -ENOMEM;
spin_lock(lock);
err = ida_get_new_above(ida, min_id, &index);
spin_unlock(lock);
if (err == -EAGAIN)
goto again;
else if (err)
return err;
if (index > max_id) {
spin_lock(lock);
ida_remove(ida, index);
spin_unlock(lock);
return -ENOMEM;
}
return index;
}
int get_cop_pid(struct mm_struct *mm)
{
int pid;
if (mm->context.cop_pid == COP_PID_NONE) {
pid = new_cop_pid(&cop_ida, COP_PID_MIN, COP_PID_MAX,
&mmu_context_acop_lock);
if (pid >= 0)
mm->context.cop_pid = pid;
}
return mm->context.cop_pid;
}
int disable_cop_pid(struct mm_struct *mm)
{
int free_pid = COP_PID_NONE;
if ((!mm->context.acop) && (mm->context.cop_pid != COP_PID_NONE)) {
free_pid = mm->context.cop_pid;
mm->context.cop_pid = COP_PID_NONE;
}
return free_pid;
}
void free_cop_pid(int free_pid)
{
spin_lock(&mmu_context_acop_lock);
ida_remove(&cop_ida, free_pid);
spin_unlock(&mmu_context_acop_lock);
}

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@ -24,200 +24,7 @@
#include <asm/mmu_context.h>
#ifdef CONFIG_PPC_ICSWX
/*
* 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 and is
* placed in cacheable memory on a 128-byte cache line boundary.
*
* The task to use a coprocessor should use use_cop() to allocate
* a coprocessor PID before executing icswx instruction. use_cop()
* also enables the coprocessor context switching. 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.
*/
#define COP_PID_NONE 0
#define COP_PID_MIN (COP_PID_NONE + 1)
#define COP_PID_MAX (0xFFFF)
static DEFINE_SPINLOCK(mmu_context_acop_lock);
static DEFINE_IDA(cop_ida);
void switch_cop(struct mm_struct *next)
{
mtspr(SPRN_PID, next->context.cop_pid);
mtspr(SPRN_ACOP, next->context.acop);
}
static int new_cop_pid(struct ida *ida, int min_id, int max_id,
spinlock_t *lock)
{
int index;
int err;
again:
if (!ida_pre_get(ida, GFP_KERNEL))
return -ENOMEM;
spin_lock(lock);
err = ida_get_new_above(ida, min_id, &index);
spin_unlock(lock);
if (err == -EAGAIN)
goto again;
else if (err)
return err;
if (index > max_id) {
spin_lock(lock);
ida_remove(ida, index);
spin_unlock(lock);
return -ENOMEM;
}
return index;
}
static void sync_cop(void *arg)
{
struct mm_struct *mm = arg;
if (mm == current->active_mm)
switch_cop(current->active_mm);
}
/**
* 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);
if (mm->context.cop_pid == COP_PID_NONE) {
ret = new_cop_pid(&cop_ida, COP_PID_MIN, COP_PID_MAX,
&mmu_context_acop_lock);
if (ret < 0)
goto out;
mm->context.cop_pid = ret;
}
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);
ret = mm->context.cop_pid;
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 = COP_PID_NONE;
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;
if ((!mm->context.acop) && (mm->context.cop_pid != COP_PID_NONE)) {
free_pid = mm->context.cop_pid;
mm->context.cop_pid = COP_PID_NONE;
}
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) {
spin_lock(&mmu_context_acop_lock);
ida_remove(&cop_ida, free_pid);
spin_unlock(&mmu_context_acop_lock);
}
spin_unlock(mm->context.cop_lockp);
spin_unlock(&mm->page_table_lock);
}
EXPORT_SYMBOL_GPL(drop_cop);
#endif /* CONFIG_PPC_ICSWX */
#include "icswx.h"
static DEFINE_SPINLOCK(mmu_context_lock);
static DEFINE_IDA(mmu_context_ida);

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@ -252,6 +252,14 @@ config PPC_ICSWX
If in doubt, say N here.
config PPC_ICSWX_PID
bool "icswx requires direct PID management"
depends on PPC_ICSWX && POWER4
default y
---help---
PID register in server is used explicitly for ICSWX. In
embedded systems PID managment is done by the system.
config SPE
bool "SPE Support"
depends on E200 || (E500 && !PPC_E500MC)