[PATCH 1/3 v2] powerpc: Split ICSWX ACOP and PID processing
Jimi Xenidis
jimix at pobox.com
Sat Sep 24 01:59:52 EST 2011
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 at pobox.com>
---
Re: galak at kernel.crashing.org
Fix typo in arch/powerpc/mm/Makefile
Re: anton at samba.org
merge in: powerpc: Fix deadlock in icswx code
---
arch/powerpc/mm/Makefile | 2 +
arch/powerpc/mm/icswx.c | 162 ++++++++++++++++++++++++++
arch/powerpc/mm/icswx.h | 34 ++++++
arch/powerpc/mm/icswx_pid.c | 87 ++++++++++++++
arch/powerpc/mm/mmu_context_hash64.c | 195 --------------------------------
arch/powerpc/platforms/Kconfig.cputype | 10 ++-
6 files changed, 294 insertions(+), 196 deletions(-)
create mode 100644 arch/powerpc/mm/icswx.c
create mode 100644 arch/powerpc/mm/icswx.h
create mode 100644 arch/powerpc/mm/icswx_pid.c
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index bdca46e..fb7976f 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -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
diff --git a/arch/powerpc/mm/icswx.c b/arch/powerpc/mm/icswx.c
new file mode 100644
index 0000000..2f1dd29
--- /dev/null
+++ b/arch/powerpc/mm/icswx.c
@@ -0,0 +1,162 @@
+/*
+ * ICSWX and ACOP Management
+ *
+ * Copyright (C) 2011 Anton Blanchard, IBM Corp. <anton at 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 cache block or less, typically 64 or 128 bytes in
+ * size, and is placed in cacheable memory on a 128-byte boundary
+ * _always_.
+ *
+ * The task to use a coprocessor should use use_cop() mark the use of
+ * the coprocessor type (CT) and context swithing. On a server
+ * 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 resources created by
+ * use_cop().
+ *
+ * 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);
diff --git a/arch/powerpc/mm/icswx.h b/arch/powerpc/mm/icswx.h
new file mode 100644
index 0000000..5121ddd
--- /dev/null
+++ b/arch/powerpc/mm/icswx.h
@@ -0,0 +1,34 @@
+/*
+ * ICSWX and ACOP Management
+ *
+ * Copyright (C) 2011 Anton Blanchard, IBM Corp. <anton at 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
diff --git a/arch/powerpc/mm/icswx_pid.c b/arch/powerpc/mm/icswx_pid.c
new file mode 100644
index 0000000..91e30eb
--- /dev/null
+++ b/arch/powerpc/mm/icswx_pid.c
@@ -0,0 +1,87 @@
+/*
+ * ICSWX and ACOP/PID Management
+ *
+ * Copyright (C) 2011 Anton Blanchard, IBM Corp. <anton at 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);
+}
diff --git a/arch/powerpc/mm/mmu_context_hash64.c b/arch/powerpc/mm/mmu_context_hash64.c
index 3bafc3d..a75832c 100644
--- a/arch/powerpc/mm/mmu_context_hash64.c
+++ b/arch/powerpc/mm/mmu_context_hash64.c
@@ -24,201 +24,6 @@
#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;
-
- /* We need to make sure mm_users doesn't change */
- down_read(&mm->mmap_sem);
- 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);
- up_read(&mm->mmap_sem);
-
- 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;
-
- /* We need to make sure mm_users doesn't change */
- down_read(&mm->mmap_sem);
- 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);
- up_read(&mm->mmap_sem);
-}
-EXPORT_SYMBOL_GPL(drop_cop);
-
-#endif /* CONFIG_PPC_ICSWX */
-
static DEFINE_SPINLOCK(mmu_context_lock);
static DEFINE_IDA(mmu_context_ida);
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index e06e395..3cd22e5 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -234,7 +234,7 @@ config VSX
config PPC_ICSWX
bool "Support for PowerPC icswx coprocessor instruction"
- depends on POWER4
+ depends on POWER4 || PPC_A2
default n
---help---
@@ -250,6 +250,14 @@ 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)
--
1.7.0.4
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