[RFC/PATCH 3/3] spufs: enable SPE problem state MMIO access.

From: Arnd Bergmann
Date: Tue Jan 17 2006 - 15:20:36 EST

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This patch is layered on top of CONFIG_SPARSEMEM
and is patterned after direct mapping of LS.

This patch allows mmap() of the following regions:
"mfc", which represents the area from [0x0000 - 0x0fff];
"cntl", which represents the area from [0x4000 - 0x5fff];
"signal1" which begins at offset 0x14000; "signal2" which
begins at offset 0x1c000.

The signal1 & signal2 files may be mmap()'d by regular user
processes. The cntl and mfc file, on the other hand, may
only be accessed if the owning process has CAP_SYS_RAWIO,
because they have the potential to confuse the kernel
with regard to parallel access to the same files with
regular file operations: the kernel always holds a spinlock
when accessing registers in these areas to serialize them,
which can not be guaranteed with user mmaps,

From: Mark Nutter <mnutter@xxxxxxxxxx>
Signed-off-by: Arnd Bergmann <arndb@xxxxxxxxxx>

Index: linux-2.6.16-rc/arch/powerpc/platforms/cell/spu_base.c
===================================================================
--- linux-2.6.16-rc.orig/arch/powerpc/platforms/cell/spu_base.c
+++ linux-2.6.16-rc/arch/powerpc/platforms/cell/spu_base.c
@@ -570,6 +570,11 @@ static int __init spu_map_device(struct
if (!spu->local_store)
goto out;

+ prop = get_property(spe, "problem", NULL);
+ if (!prop)
+ goto out_unmap;
+ spu->problem_phys = *(unsigned long *)prop;
+
spu->problem= map_spe_prop(spe, "problem");
if (!spu->problem)
goto out_unmap;
Index: linux-2.6.16-rc/arch/powerpc/platforms/cell/spufs/context.c
===================================================================
--- linux-2.6.16-rc.orig/arch/powerpc/platforms/cell/spufs/context.c
+++ linux-2.6.16-rc/arch/powerpc/platforms/cell/spufs/context.c
@@ -27,7 +27,7 @@
#include <asm/spu_csa.h>
#include "spufs.h"

-struct spu_context *alloc_spu_context(struct address_space *local_store)
+struct spu_context *alloc_spu_context(void)
{
struct spu_context *ctx;
ctx = kmalloc(sizeof *ctx, GFP_KERNEL);
@@ -53,7 +53,10 @@ struct spu_context *alloc_spu_context(st
ctx->mfc_fasync = NULL;
ctx->tagwait = 0;
ctx->state = SPU_STATE_SAVED;
- ctx->local_store = local_store;
+ ctx->local_store = NULL;
+ ctx->cntl = NULL;
+ ctx->signal1 = NULL;
+ ctx->signal2 = NULL;
ctx->spu = NULL;
ctx->ops = &spu_backing_ops;
ctx->owner = get_task_mm(current);
@@ -110,7 +113,16 @@ void spu_release(struct spu_context *ctx

void spu_unmap_mappings(struct spu_context *ctx)
{
- unmap_mapping_range(ctx->local_store, 0, LS_SIZE, 1);
+ if (ctx->local_store)
+ unmap_mapping_range(ctx->local_store, 0, LS_SIZE, 1);
+ if (ctx->mfc)
+ unmap_mapping_range(ctx->mfc, 0, 0x1000, 1);
+ if (ctx->cntl)
+ unmap_mapping_range(ctx->cntl, 0, 0x1000, 1);
+ if (ctx->signal1)
+ unmap_mapping_range(ctx->signal1, 0, 0x1000, 1);
+ if (ctx->signal2)
+ unmap_mapping_range(ctx->signal2, 0, 0x1000, 1);
}

int spu_acquire_runnable(struct spu_context *ctx)
Index: linux-2.6.16-rc/arch/powerpc/platforms/cell/spufs/file.c
===================================================================
--- linux-2.6.16-rc.orig/arch/powerpc/platforms/cell/spufs/file.c
+++ linux-2.6.16-rc/arch/powerpc/platforms/cell/spufs/file.c
@@ -41,8 +41,10 @@ static int
spufs_mem_open(struct inode *inode, struct file *file)
{
struct spufs_inode_info *i = SPUFS_I(inode);
- file->private_data = i->i_ctx;
- file->f_mapping = i->i_ctx->local_store;
+ struct spu_context *ctx = i->i_ctx;
+ file->private_data = ctx;
+ file->f_mapping = inode->i_mapping;
+ ctx->local_store = inode->i_mapping;
return 0;
}

@@ -86,7 +88,7 @@ spufs_mem_write(struct file *file, const
return ret;
}

-#ifdef CONFIG_SPARSEMEM
+#ifdef CONFIG_SPUFS_MMAP
static struct page *
spufs_mem_mmap_nopage(struct vm_area_struct *vma,
unsigned long address, int *type)
@@ -138,11 +140,113 @@ static struct file_operations spufs_mem_
.read = spufs_mem_read,
.write = spufs_mem_write,
.llseek = generic_file_llseek,
-#ifdef CONFIG_SPARSEMEM
+#ifdef CONFIG_SPUFS_MMAP
.mmap = spufs_mem_mmap,
#endif
};

+#ifdef CONFIG_SPUFS_MMAP
+static struct page *spufs_ps_nopage(struct vm_area_struct *vma,
+ unsigned long address,
+ int *type, unsigned long ps_offs)
+{
+ struct page *page = NOPAGE_SIGBUS;
+ int fault_type = VM_FAULT_SIGBUS;
+ struct spu_context *ctx = vma->vm_file->private_data;
+ unsigned long offset = address - vma->vm_start;
+ unsigned long area;
+ int ret;
+
+ offset += vma->vm_pgoff << PAGE_SHIFT;
+ if (offset > 0x1000)
+ goto out;
+
+ ret = spu_acquire_runnable(ctx);
+ if (ret)
+ goto out;
+
+ area = ctx->spu->problem_phys + ps_offs;
+ page = pfn_to_page((area + offset) >> PAGE_SHIFT);
+ fault_type = VM_FAULT_MINOR;
+ page_cache_get(page);
+
+ spu_release(ctx);
+
+ out:
+ if (type)
+ *type = fault_type;
+
+ return page;
+}
+
+static struct page *spufs_cntl_mmap_nopage(struct vm_area_struct *vma,
+ unsigned long address, int *type)
+{
+ return spufs_ps_nopage(vma, address, type, 0x4000);
+}
+
+static struct vm_operations_struct spufs_cntl_mmap_vmops = {
+ .nopage = spufs_cntl_mmap_nopage,
+};
+
+/*
+ * mmap support for problem state control area [0x4000 - 0x4fff].
+ * Mapping this area requires that the application have CAP_SYS_RAWIO,
+ * as these registers require special care when read/writing.
+ */
+static int spufs_cntl_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ if (!(vma->vm_flags & VM_SHARED))
+ return -EINVAL;
+
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+
+ vma->vm_flags |= VM_RESERVED;
+ vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
+ | _PAGE_NO_CACHE);
+
+ vma->vm_ops = &spufs_cntl_mmap_vmops;
+ return 0;
+}
+#endif
+
+static int spufs_cntl_open(struct inode *inode, struct file *file)
+{
+ struct spufs_inode_info *i = SPUFS_I(inode);
+ struct spu_context *ctx = i->i_ctx;
+
+ file->private_data = ctx;
+ file->f_mapping = inode->i_mapping;
+ ctx->cntl = inode->i_mapping;
+ return 0;
+}
+
+static ssize_t
+spufs_cntl_read(struct file *file, char __user *buffer,
+ size_t size, loff_t *pos)
+{
+ /* FIXME: read from spu status */
+ return -EINVAL;
+}
+
+static ssize_t
+spufs_cntl_write(struct file *file, const char __user *buffer,
+ size_t size, loff_t *pos)
+{
+ /* FIXME: write to runctl bit */
+ return -EINVAL;
+}
+
+static struct file_operations spufs_cntl_fops = {
+ .open = spufs_cntl_open,
+ .read = spufs_cntl_read,
+ .write = spufs_cntl_write,
+#ifdef CONFIG_SPUFS_MMAP
+ .mmap = spufs_cntl_mmap,
+#endif
+};
+
static int
spufs_regs_open(struct inode *inode, struct file *file)
{
@@ -503,6 +607,16 @@ static struct file_operations spufs_wbox
.read = spufs_wbox_stat_read,
};

+static int spufs_signal1_open(struct inode *inode, struct file *file)
+{
+ struct spufs_inode_info *i = SPUFS_I(inode);
+ struct spu_context *ctx = i->i_ctx;
+ file->private_data = ctx;
+ file->f_mapping = inode->i_mapping;
+ ctx->signal1 = inode->i_mapping;
+ return nonseekable_open(inode, file);
+}
+
static ssize_t spufs_signal1_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
@@ -543,12 +657,50 @@ static ssize_t spufs_signal1_write(struc
return 4;
}

+#ifdef CONFIG_SPUFS_MMAP
+static struct page *spufs_signal1_mmap_nopage(struct vm_area_struct *vma,
+ unsigned long address, int *type)
+{
+ return spufs_ps_nopage(vma, address, type, 0x14000);
+}
+
+static struct vm_operations_struct spufs_signal1_mmap_vmops = {
+ .nopage = spufs_signal1_mmap_nopage,
+};
+
+static int spufs_signal1_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ if (!(vma->vm_flags & VM_SHARED))
+ return -EINVAL;
+
+ vma->vm_flags |= VM_RESERVED;
+ vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
+ | _PAGE_NO_CACHE);
+
+ vma->vm_ops = &spufs_signal1_mmap_vmops;
+ return 0;
+}
+#endif
+
static struct file_operations spufs_signal1_fops = {
- .open = spufs_pipe_open,
+ .open = spufs_signal1_open,
.read = spufs_signal1_read,
.write = spufs_signal1_write,
+#ifdef CONFIG_SPUFS_MMAP
+ .mmap = spufs_signal1_mmap,
+#endif
};

+static int spufs_signal2_open(struct inode *inode, struct file *file)
+{
+ struct spufs_inode_info *i = SPUFS_I(inode);
+ struct spu_context *ctx = i->i_ctx;
+ file->private_data = ctx;
+ file->f_mapping = inode->i_mapping;
+ ctx->signal2 = inode->i_mapping;
+ return nonseekable_open(inode, file);
+}
+
static ssize_t spufs_signal2_read(struct file *file, char __user *buf,
size_t len, loff_t *pos)
{
@@ -591,10 +743,39 @@ static ssize_t spufs_signal2_write(struc
return 4;
}

+#ifdef CONFIG_SPUFS_MMAP
+static struct page *spufs_signal2_mmap_nopage(struct vm_area_struct *vma,
+ unsigned long address, int *type)
+{
+ return spufs_ps_nopage(vma, address, type, 0x1c000);
+}
+
+static struct vm_operations_struct spufs_signal2_mmap_vmops = {
+ .nopage = spufs_signal2_mmap_nopage,
+};
+
+static int spufs_signal2_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ if (!(vma->vm_flags & VM_SHARED))
+ return -EINVAL;
+
+ /* FIXME: */
+ vma->vm_flags |= VM_RESERVED;
+ vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
+ | _PAGE_NO_CACHE);
+
+ vma->vm_ops = &spufs_signal2_mmap_vmops;
+ return 0;
+}
+#endif
+
static struct file_operations spufs_signal2_fops = {
- .open = spufs_pipe_open,
+ .open = spufs_signal2_open,
.read = spufs_signal2_read,
.write = spufs_signal2_write,
+#ifdef CONFIG_SPUFS_MMAP
+ .mmap = spufs_signal2_mmap,
+#endif
};

static void spufs_signal1_type_set(void *data, u64 val)
@@ -643,6 +824,38 @@ static u64 spufs_signal2_type_get(void *
DEFINE_SIMPLE_ATTRIBUTE(spufs_signal2_type, spufs_signal2_type_get,
spufs_signal2_type_set, "%llu");

+#ifdef CONFIG_SPUFS_MMAP
+static struct page *spufs_mfc_mmap_nopage(struct vm_area_struct *vma,
+ unsigned long address, int *type)
+{
+ return spufs_ps_nopage(vma, address, type, 0x0000);
+}
+
+static struct vm_operations_struct spufs_mfc_mmap_vmops = {
+ .nopage = spufs_mfc_mmap_nopage,
+};
+
+/*
+ * mmap support for problem state MFC DMA area [0x0000 - 0x0fff].
+ * Mapping this area requires that the application have CAP_SYS_RAWIO,
+ * as these registers require special care when read/writing.
+ */
+static int spufs_mfc_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ if (!(vma->vm_flags & VM_SHARED))
+ return -EINVAL;
+
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+
+ vma->vm_flags |= VM_RESERVED;
+ vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
+ | _PAGE_NO_CACHE);
+
+ vma->vm_ops = &spufs_mfc_mmap_vmops;
+ return 0;
+}
+#endif

static int spufs_mfc_open(struct inode *inode, struct file *file)
{
@@ -932,6 +1145,9 @@ static struct file_operations spufs_mfc_
.flush = spufs_mfc_flush,
.fsync = spufs_mfc_fsync,
.fasync = spufs_mfc_fasync,
+#ifdef CONFIG_SPUFS_MMAP
+ .mmap = spufs_mfc_mmap,
+#endif
};

static void spufs_npc_set(void *data, u64 val)
@@ -1077,6 +1293,7 @@ struct tree_descr spufs_dir_contents[] =
{ "signal1_type", &spufs_signal1_type, 0666, },
{ "signal2_type", &spufs_signal2_type, 0666, },
{ "mfc", &spufs_mfc_fops, 0666, },
+ { "cntl", &spufs_cntl_fops, 0666, },
{ "npc", &spufs_npc_ops, 0666, },
{ "fpcr", &spufs_fpcr_fops, 0666, },
{ "decr", &spufs_decr_ops, 0666, },
Index: linux-2.6.16-rc/arch/powerpc/platforms/cell/spufs/inode.c
===================================================================
--- linux-2.6.16-rc.orig/arch/powerpc/platforms/cell/spufs/inode.c
+++ linux-2.6.16-rc/arch/powerpc/platforms/cell/spufs/inode.c
@@ -241,7 +241,7 @@ spufs_mkdir(struct inode *dir, struct de
inode->i_gid = dir->i_gid;
inode->i_mode &= S_ISGID;
}
- ctx = alloc_spu_context(inode->i_mapping);
+ ctx = alloc_spu_context();
SPUFS_I(inode)->i_ctx = ctx;
if (!ctx)
goto out_iput;
Index: linux-2.6.16-rc/arch/powerpc/platforms/cell/spufs/spufs.h
===================================================================
--- linux-2.6.16-rc.orig/arch/powerpc/platforms/cell/spufs/spufs.h
+++ linux-2.6.16-rc/arch/powerpc/platforms/cell/spufs/spufs.h
@@ -43,7 +43,11 @@ struct spu_context {
struct spu *spu; /* pointer to a physical SPU */
struct spu_state csa; /* SPU context save area. */
spinlock_t mmio_lock; /* protects mmio access */
- struct address_space *local_store;/* local store backing store */
+ struct address_space *local_store; /* local store mapping. */
+ struct address_space *mfc; /* 'mfc' area mappings. */
+ struct address_space *cntl; /* 'control' area mappings. */
+ struct address_space *signal1; /* 'signal1' area mappings. */
+ struct address_space *signal2; /* 'signal2' area mappings. */

enum { SPU_STATE_RUNNABLE, SPU_STATE_SAVED } state;
struct rw_semaphore state_sema;
@@ -125,7 +129,7 @@ long spufs_create_thread(struct nameidat
extern struct file_operations spufs_context_fops;

/* context management */
-struct spu_context * alloc_spu_context(struct address_space *local_store);
+struct spu_context * alloc_spu_context(void);
void destroy_spu_context(struct kref *kref);
struct spu_context * get_spu_context(struct spu_context *ctx);
int put_spu_context(struct spu_context *ctx);
Index: linux-2.6.16-rc/include/asm-powerpc/spu.h
===================================================================
--- linux-2.6.16-rc.orig/include/asm-powerpc/spu.h
+++ linux-2.6.16-rc/include/asm-powerpc/spu.h
@@ -110,6 +110,7 @@ struct spu {
char *name;
unsigned long local_store_phys;
u8 *local_store;
+ unsigned long problem_phys;
struct spu_problem __iomem *problem;
struct spu_priv1 __iomem *priv1;
struct spu_priv2 __iomem *priv2;
Index: linux-2.6.16-rc/arch/powerpc/platforms/cell/Kconfig
===================================================================
--- linux-2.6.16-rc.orig/arch/powerpc/platforms/cell/Kconfig
+++ linux-2.6.16-rc/arch/powerpc/platforms/cell/Kconfig
@@ -10,4 +10,9 @@ config SPU_FS
Units on machines implementing the Broadband Processor
Architecture.

+config SPUFS_MMAP
+ bool
+ depends on SPU_FS && SPARSEMEM && !PPC_64K_PAGES
+ default y
+
endmenu

--

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Next message: Jesper Juhl: "Re: [PATCH] TIPC: add Kconfig help text"
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