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Subject[PATCH v6 04/15] habanalabs: add context and ASID modules
Date
This patch adds two modules - ASID and context.

Each user process that opens a device's file must have at least one
context before it is able to "work" with the device. Each context has its
own device address-space and contains information about its runtime state
(its active command submissions).

To have address-space separation between contexts, each context is assigned
a unique ASID, which stands for "address-space id". Goya supports up to
1024 ASIDs.

Currently, the driver doesn't support multiple contexts. Therefore, the
user doesn't need to actively create a context. A "primary context" is
created automatically when the user opens the device's file.

Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
---
Changes in v6:
- Only include headers needed for compilation
- Update copyright years

drivers/misc/habanalabs/Makefile | 2 +-
drivers/misc/habanalabs/asid.c | 57 +++++++++
drivers/misc/habanalabs/context.c | 154 +++++++++++++++++++++++
drivers/misc/habanalabs/device.c | 47 +++++++
drivers/misc/habanalabs/habanalabs.h | 71 +++++++++++
drivers/misc/habanalabs/habanalabs_drv.c | 46 ++++++-
6 files changed, 374 insertions(+), 3 deletions(-)
create mode 100644 drivers/misc/habanalabs/asid.c
create mode 100644 drivers/misc/habanalabs/context.c

diff --git a/drivers/misc/habanalabs/Makefile b/drivers/misc/habanalabs/Makefile
index 6f1ead69bd77..3ffbadc2ca01 100644
--- a/drivers/misc/habanalabs/Makefile
+++ b/drivers/misc/habanalabs/Makefile
@@ -4,7 +4,7 @@

obj-m := habanalabs.o

-habanalabs-y := habanalabs_drv.o device.o
+habanalabs-y := habanalabs_drv.o device.o context.o asid.o

include $(src)/goya/Makefile
habanalabs-y += $(HL_GOYA_FILES)
diff --git a/drivers/misc/habanalabs/asid.c b/drivers/misc/habanalabs/asid.c
new file mode 100644
index 000000000000..f54e7971a762
--- /dev/null
+++ b/drivers/misc/habanalabs/asid.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright 2016-2019 HabanaLabs, Ltd.
+ * All Rights Reserved.
+ */
+
+#include "habanalabs.h"
+
+#include <linux/slab.h>
+
+int hl_asid_init(struct hl_device *hdev)
+{
+ hdev->asid_bitmap = kcalloc(BITS_TO_LONGS(hdev->asic_prop.max_asid),
+ sizeof(*hdev->asid_bitmap), GFP_KERNEL);
+ if (!hdev->asid_bitmap)
+ return -ENOMEM;
+
+ mutex_init(&hdev->asid_mutex);
+
+ /* ASID 0 is reserved for KMD */
+ set_bit(0, hdev->asid_bitmap);
+
+ return 0;
+}
+
+void hl_asid_fini(struct hl_device *hdev)
+{
+ mutex_destroy(&hdev->asid_mutex);
+ kfree(hdev->asid_bitmap);
+}
+
+unsigned long hl_asid_alloc(struct hl_device *hdev)
+{
+ unsigned long found;
+
+ mutex_lock(&hdev->asid_mutex);
+
+ found = find_first_zero_bit(hdev->asid_bitmap,
+ hdev->asic_prop.max_asid);
+ if (found == hdev->asic_prop.max_asid)
+ found = 0;
+ else
+ set_bit(found, hdev->asid_bitmap);
+
+ mutex_unlock(&hdev->asid_mutex);
+
+ return found;
+}
+
+void hl_asid_free(struct hl_device *hdev, unsigned long asid)
+{
+ if (WARN((asid == 0 || asid >= hdev->asic_prop.max_asid),
+ "Invalid ASID %lu", asid))
+ return;
+ clear_bit(asid, hdev->asid_bitmap);
+}
diff --git a/drivers/misc/habanalabs/context.c b/drivers/misc/habanalabs/context.c
new file mode 100644
index 000000000000..de1258e7a6e6
--- /dev/null
+++ b/drivers/misc/habanalabs/context.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright 2016-2019 HabanaLabs, Ltd.
+ * All Rights Reserved.
+ */
+
+#include "habanalabs.h"
+
+#include <linux/slab.h>
+
+static void hl_ctx_fini(struct hl_ctx *ctx)
+{
+ struct hl_device *hdev = ctx->hdev;
+
+ if (ctx->asid != HL_KERNEL_ASID_ID)
+ hl_asid_free(hdev, ctx->asid);
+}
+
+void hl_ctx_do_release(struct kref *ref)
+{
+ struct hl_ctx *ctx;
+
+ ctx = container_of(ref, struct hl_ctx, refcount);
+
+ dev_dbg(ctx->hdev->dev, "Now really releasing context %d\n", ctx->asid);
+
+ hl_ctx_fini(ctx);
+
+ if (ctx->hpriv)
+ hl_hpriv_put(ctx->hpriv);
+
+ kfree(ctx);
+}
+
+int hl_ctx_create(struct hl_device *hdev, struct hl_fpriv *hpriv)
+{
+ struct hl_ctx_mgr *mgr = &hpriv->ctx_mgr;
+ struct hl_ctx *ctx;
+ int rc;
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+ if (!ctx) {
+ rc = -ENOMEM;
+ goto out_err;
+ }
+
+ rc = hl_ctx_init(hdev, ctx, false);
+ if (rc)
+ goto free_ctx;
+
+ hl_hpriv_get(hpriv);
+ ctx->hpriv = hpriv;
+
+ /* TODO: remove for multiple contexts */
+ hpriv->ctx = ctx;
+ hdev->user_ctx = ctx;
+
+ mutex_lock(&mgr->ctx_lock);
+ rc = idr_alloc(&mgr->ctx_handles, ctx, 1, 0, GFP_KERNEL);
+ mutex_unlock(&mgr->ctx_lock);
+
+ if (rc < 0) {
+ dev_err(hdev->dev, "Failed to allocate IDR for a new CTX\n");
+ hl_ctx_free(hdev, ctx);
+ goto out_err;
+ }
+
+ return 0;
+
+free_ctx:
+ kfree(ctx);
+out_err:
+ return rc;
+}
+
+void hl_ctx_free(struct hl_device *hdev, struct hl_ctx *ctx)
+{
+ if (kref_put(&ctx->refcount, hl_ctx_do_release) == 1)
+ return;
+
+ dev_warn(hdev->dev,
+ "Context %d closed or terminated but its CS are executing\n",
+ ctx->asid);
+}
+
+int hl_ctx_init(struct hl_device *hdev, struct hl_ctx *ctx, bool is_kernel_ctx)
+{
+ ctx->hdev = hdev;
+
+ kref_init(&ctx->refcount);
+
+ if (is_kernel_ctx) {
+ ctx->asid = HL_KERNEL_ASID_ID; /* KMD gets ASID 0 */
+ } else {
+ ctx->asid = hl_asid_alloc(hdev);
+ if (!ctx->asid) {
+ dev_err(hdev->dev, "No free ASID, failed to create context\n");
+ return -ENOMEM;
+ }
+ }
+
+ dev_dbg(hdev->dev, "Created context with ASID %u\n", ctx->asid);
+
+ return 0;
+}
+
+void hl_ctx_get(struct hl_device *hdev, struct hl_ctx *ctx)
+{
+ kref_get(&ctx->refcount);
+}
+
+int hl_ctx_put(struct hl_ctx *ctx)
+{
+ return kref_put(&ctx->refcount, hl_ctx_do_release);
+}
+
+/*
+ * hl_ctx_mgr_init - initialize the context manager
+ *
+ * @mgr: pointer to context manager structure
+ *
+ * This manager is an object inside the hpriv object of the user process.
+ * The function is called when a user process opens the FD.
+ */
+void hl_ctx_mgr_init(struct hl_ctx_mgr *mgr)
+{
+ mutex_init(&mgr->ctx_lock);
+ idr_init(&mgr->ctx_handles);
+}
+
+/*
+ * hl_ctx_mgr_fini - finalize the context manager
+ *
+ * @hdev: pointer to device structure
+ * @mgr: pointer to context manager structure
+ *
+ * This function goes over all the contexts in the manager and frees them.
+ * It is called when a process closes the FD.
+ */
+void hl_ctx_mgr_fini(struct hl_device *hdev, struct hl_ctx_mgr *mgr)
+{
+ struct hl_ctx *ctx;
+ struct idr *idp;
+ u32 id;
+
+ idp = &mgr->ctx_handles;
+
+ idr_for_each_entry(idp, ctx, id)
+ hl_ctx_free(hdev, ctx);
+
+ idr_destroy(&mgr->ctx_handles);
+ mutex_destroy(&mgr->ctx_lock);
+}
diff --git a/drivers/misc/habanalabs/device.c b/drivers/misc/habanalabs/device.c
index a4feaa784db3..2423588ecf22 100644
--- a/drivers/misc/habanalabs/device.c
+++ b/drivers/misc/habanalabs/device.c
@@ -22,6 +22,12 @@ static void hpriv_release(struct kref *ref)
put_pid(hpriv->taskpid);

kfree(hpriv);
+
+ /* Now the FD is really closed */
+ atomic_dec(&hdev->fd_open_cnt);
+
+ /* This allows a new user context to open the device */
+ hdev->user_ctx = NULL;
}

void hl_hpriv_get(struct hl_fpriv *hpriv)
@@ -46,6 +52,8 @@ static int hl_device_release(struct inode *inode, struct file *filp)
{
struct hl_fpriv *hpriv = filp->private_data;

+ hl_ctx_mgr_fini(hpriv->hdev, &hpriv->ctx_mgr);
+
filp->private_data = NULL;

hl_hpriv_put(hpriv);
@@ -137,7 +145,20 @@ static int device_early_init(struct hl_device *hdev)
if (rc)
return rc;

+ rc = hl_asid_init(hdev);
+ if (rc)
+ goto early_fini;
+
+ mutex_init(&hdev->fd_open_cnt_lock);
+ atomic_set(&hdev->fd_open_cnt, 0);
+
return 0;
+
+early_fini:
+ if (hdev->asic_funcs->early_fini)
+ hdev->asic_funcs->early_fini(hdev);
+
+ return rc;
}

/*
@@ -149,9 +170,12 @@ static int device_early_init(struct hl_device *hdev)
static void device_early_fini(struct hl_device *hdev)
{

+ hl_asid_fini(hdev);
+
if (hdev->asic_funcs->early_fini)
hdev->asic_funcs->early_fini(hdev);

+ mutex_destroy(&hdev->fd_open_cnt_lock);
}

/*
@@ -245,11 +269,30 @@ int hl_device_init(struct hl_device *hdev, struct class *hclass)
if (rc)
goto early_fini;

+ /* Allocate the kernel context */
+ hdev->kernel_ctx = kzalloc(sizeof(*hdev->kernel_ctx), GFP_KERNEL);
+ if (!hdev->kernel_ctx) {
+ rc = -ENOMEM;
+ goto sw_fini;
+ }
+
+ hdev->user_ctx = NULL;
+
+ rc = hl_ctx_init(hdev, hdev->kernel_ctx, true);
+ if (rc) {
+ dev_err(hdev->dev, "failed to initialize kernel context\n");
+ goto free_ctx;
+ }
+
dev_notice(hdev->dev,
"Successfully added device to habanalabs driver\n");

return 0;

+free_ctx:
+ kfree(hdev->kernel_ctx);
+sw_fini:
+ hdev->asic_funcs->sw_fini(hdev);
early_fini:
device_early_fini(hdev);
release_device:
@@ -282,6 +325,10 @@ void hl_device_fini(struct hl_device *hdev)
/* Mark device as disabled */
hdev->disabled = true;

+ /* Release kernel context */
+ if ((hdev->kernel_ctx) && (hl_ctx_put(hdev->kernel_ctx) != 1))
+ dev_err(hdev->dev, "kernel ctx is still alive\n");
+
/* Call ASIC S/W finalize function */
hdev->asic_funcs->sw_fini(hdev);

diff --git a/drivers/misc/habanalabs/habanalabs.h b/drivers/misc/habanalabs/habanalabs.h
index 5076e680a73c..ca8171ca3a04 100644
--- a/drivers/misc/habanalabs/habanalabs.h
+++ b/drivers/misc/habanalabs/habanalabs.h
@@ -70,6 +70,8 @@ struct asic_fixed_properties {


#define HL_QUEUE_LENGTH 256
+
+
/*
* ASICs
*/
@@ -117,6 +119,39 @@ struct hl_asic_funcs {
void *cpu_addr, dma_addr_t dma_handle);
};

+
+/*
+ * CONTEXTS
+ */
+
+#define HL_KERNEL_ASID_ID 0
+
+/**
+ * struct hl_ctx - user/kernel context.
+ * @hpriv: pointer to the private (KMD) data of the process (fd).
+ * @hdev: pointer to the device structure.
+ * @refcount: reference counter for the context. Context is released only when
+ * this hits 0l. It is incremented on CS and CS_WAIT.
+ * @asid: context's unique address space ID in the device's MMU.
+ */
+struct hl_ctx {
+ struct hl_fpriv *hpriv;
+ struct hl_device *hdev;
+ struct kref refcount;
+ u32 asid;
+};
+
+/**
+ * struct hl_ctx_mgr - for handling multiple contexts.
+ * @ctx_lock: protects ctx_handles.
+ * @ctx_handles: idr to hold all ctx handles.
+ */
+struct hl_ctx_mgr {
+ struct mutex ctx_lock;
+ struct idr ctx_handles;
+};
+
+
/*
* FILE PRIVATE STRUCTURE
*/
@@ -126,12 +161,16 @@ struct hl_asic_funcs {
* @hdev: habanalabs device structure.
* @filp: pointer to the given file structure.
* @taskpid: current process ID.
+ * @ctx: current executing context.
+ * @ctx_mgr: context manager to handle multiple context for this FD.
* @refcount: number of related contexts.
*/
struct hl_fpriv {
struct hl_device *hdev;
struct file *filp;
struct pid *taskpid;
+ struct hl_ctx *ctx; /* TODO: remove for multiple ctx */
+ struct hl_ctx_mgr ctx_mgr;
struct kref refcount;
};

@@ -185,13 +224,24 @@ void hl_wreg(struct hl_device *hdev, u32 reg, u32 val);
* @dev: realted kernel basic device structure.
* @asic_name: ASIC specific nmae.
* @asic_type: ASIC specific type.
+ * @kernel_ctx: KMD context structure.
* @dma_pool: DMA pool for small allocations.
* @cpu_accessible_dma_mem: KMD <-> ArmCP shared memory CPU address.
* @cpu_accessible_dma_address: KMD <-> ArmCP shared memory DMA address.
* @cpu_accessible_dma_pool: KMD <-> ArmCP shared memory pool.
+ * @asid_bitmap: holds used/available ASIDs.
+ * @asid_mutex: protects asid_bitmap.
+ * @fd_open_cnt_lock: lock for updating fd_open_cnt in hl_device_open. Although
+ * fd_open_cnt is atomic, we need this lock to serialize
+ * the open function because the driver currently supports
+ * only a single process at a time. In addition, we need a
+ * lock here so we can flush user processes which are opening
+ * the device while we are trying to hard reset it
* @asic_prop: ASIC specific immutable properties.
* @asic_funcs: ASIC specific functions.
* @asic_specific: ASIC specific information to use only from ASIC files.
+ * @user_ctx: current user context executing.
+ * @fd_open_cnt: number of open user processes.
* @major: habanalabs KMD major.
* @id: device minor.
* @disabled: is device disabled.
@@ -204,13 +254,21 @@ struct hl_device {
struct device *dev;
char asic_name[16];
enum hl_asic_type asic_type;
+ struct hl_ctx *kernel_ctx;
struct dma_pool *dma_pool;
void *cpu_accessible_dma_mem;
dma_addr_t cpu_accessible_dma_address;
struct gen_pool *cpu_accessible_dma_pool;
+ unsigned long *asid_bitmap;
+ struct mutex asid_mutex;
+ /* TODO: remove fd_open_cnt_lock for multiple process support */
+ struct mutex fd_open_cnt_lock;
struct asic_fixed_properties asic_prop;
const struct hl_asic_funcs *asic_funcs;
void *asic_specific;
+ /* TODO: remove user_ctx for multiple process support */
+ struct hl_ctx *user_ctx;
+ atomic_t fd_open_cnt;
u32 major;
u16 id;
u8 disabled;
@@ -258,10 +316,23 @@ int hl_poll_timeout_memory(struct hl_device *hdev, u64 addr, u32 timeout_us,
int hl_poll_timeout_device_memory(struct hl_device *hdev, void __iomem *addr,
u32 timeout_us, u32 *val);

+int hl_asid_init(struct hl_device *hdev);
+void hl_asid_fini(struct hl_device *hdev);
+unsigned long hl_asid_alloc(struct hl_device *hdev);
+void hl_asid_free(struct hl_device *hdev, unsigned long asid);
+
+int hl_ctx_create(struct hl_device *hdev, struct hl_fpriv *hpriv);
+void hl_ctx_free(struct hl_device *hdev, struct hl_ctx *ctx);
+int hl_ctx_init(struct hl_device *hdev, struct hl_ctx *ctx, bool is_kernel_ctx);
+int hl_ctx_put(struct hl_ctx *ctx);
+void hl_ctx_mgr_init(struct hl_ctx_mgr *mgr);
+void hl_ctx_mgr_fini(struct hl_device *hdev, struct hl_ctx_mgr *mgr);
int hl_device_init(struct hl_device *hdev, struct class *hclass);
void hl_device_fini(struct hl_device *hdev);
int hl_device_suspend(struct hl_device *hdev);
int hl_device_resume(struct hl_device *hdev);
+void hl_hpriv_get(struct hl_fpriv *hpriv);
+void hl_hpriv_put(struct hl_fpriv *hpriv);

void goya_set_asic_funcs(struct hl_device *hdev);

diff --git a/drivers/misc/habanalabs/habanalabs_drv.c b/drivers/misc/habanalabs/habanalabs_drv.c
index edf626b2b7b1..6fddd801aca3 100644
--- a/drivers/misc/habanalabs/habanalabs_drv.c
+++ b/drivers/misc/habanalabs/habanalabs_drv.c
@@ -70,6 +70,7 @@ int hl_device_open(struct inode *inode, struct file *filp)
{
struct hl_device *hdev;
struct hl_fpriv *hpriv;
+ int rc;

mutex_lock(&hl_devs_idr_lock);
hdev = idr_find(&hl_devs_idr, iminor(inode));
@@ -81,9 +82,33 @@ int hl_device_open(struct inode *inode, struct file *filp)
return -ENXIO;
}

+ mutex_lock(&hdev->fd_open_cnt_lock);
+
+ if (hdev->disabled) {
+ dev_err_ratelimited(hdev->dev,
+ "Can't open %s because it is disabled\n",
+ dev_name(hdev->dev));
+ mutex_unlock(&hdev->fd_open_cnt_lock);
+ return -EPERM;
+ }
+
+ if (atomic_read(&hdev->fd_open_cnt)) {
+ dev_info_ratelimited(hdev->dev,
+ "Device %s is already attached to application\n",
+ dev_name(hdev->dev));
+ mutex_unlock(&hdev->fd_open_cnt_lock);
+ return -EBUSY;
+ }
+
+ atomic_inc(&hdev->fd_open_cnt);
+
+ mutex_unlock(&hdev->fd_open_cnt_lock);
+
hpriv = kzalloc(sizeof(*hpriv), GFP_KERNEL);
- if (!hpriv)
- return -ENOMEM;
+ if (!hpriv) {
+ rc = -ENOMEM;
+ goto close_device;
+ }

hpriv->hdev = hdev;
filp->private_data = hpriv;
@@ -91,9 +116,26 @@ int hl_device_open(struct inode *inode, struct file *filp)
kref_init(&hpriv->refcount);
nonseekable_open(inode, filp);

+ hl_ctx_mgr_init(&hpriv->ctx_mgr);
+
+ rc = hl_ctx_create(hdev, hpriv);
+ if (rc) {
+ dev_err(hdev->dev, "Failed to open FD (CTX fail)\n");
+ goto out_err;
+ }
+
hpriv->taskpid = find_get_pid(current->pid);

return 0;
+
+out_err:
+ filp->private_data = NULL;
+ hl_ctx_mgr_fini(hpriv->hdev, &hpriv->ctx_mgr);
+ kfree(hpriv);
+
+close_device:
+ atomic_dec(&hdev->fd_open_cnt);
+ return rc;
}

/*
--
2.18.0
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