[PATCH] cxl: Add support for ASB_Notify on POWER9
Christophe Lombard
clombard at linux.vnet.ibm.com
Thu Nov 23 22:05:32 AEDT 2017
The POWER9 core supports a new feature: ASB_Notify which requires the
support of the Special Purpose Register: TIDR.
The ASB_Notify command, generated by the AFU, will attempt to
wake-up the host thread identified by the particular LPID:PID:TID.
This patch assign a unique TIDR (thread id) for the current thread which
will be used in the process element entry.
Signed-off-by: Christophe Lombard <clombard at linux.vnet.ibm.com>
---
arch/powerpc/kernel/process.c | 2 ++
drivers/misc/cxl/api.c | 9 +++++++++
drivers/misc/cxl/context.c | 21 +++++++++++++++++++++
drivers/misc/cxl/cxl.h | 6 ++++++
drivers/misc/cxl/cxllib.c | 2 +-
drivers/misc/cxl/file.c | 13 +++++++++++++
drivers/misc/cxl/native.c | 2 +-
include/uapi/misc/cxl.h | 3 ++-
8 files changed, 55 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index bfdd783..370fec9 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1557,6 +1557,7 @@ void clear_thread_tidr(struct task_struct *t)
free_thread_tidr(t->thread.tidr);
t->thread.tidr = 0;
}
+EXPORT_SYMBOL_GPL(clear_thread_tidr);
void arch_release_task_struct(struct task_struct *t)
{
@@ -1583,6 +1584,7 @@ int set_thread_tidr(struct task_struct *t)
return 0;
}
+EXPORT_SYMBOL_GPL(set_thread_tidr);
#endif /* CONFIG_PPC64 */
diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
index 7c11bad..121bfbc 100644
--- a/drivers/misc/cxl/api.c
+++ b/drivers/misc/cxl/api.c
@@ -684,3 +684,12 @@ void _cxl_cx4_teardown_msi_irqs(struct pci_dev *pdev)
}
}
/* Exported via cxl_base */
+
+int cxl_thread_tidr(struct cxl_context *ctx, int assign)
+{
+ if (!ctx)
+ return -EINVAL;
+
+ return cxl_context_thread_tidr(ctx, assign);
+}
+EXPORT_SYMBOL_GPL(cxl_thread_tidr);
diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c
index 12a41b2..6fd61a8 100644
--- a/drivers/misc/cxl/context.c
+++ b/drivers/misc/cxl/context.c
@@ -22,6 +22,7 @@
#include <asm/cputable.h>
#include <asm/current.h>
#include <asm/copro.h>
+#include <asm/switch_to.h>
#include "cxl.h"
@@ -42,6 +43,7 @@ int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master)
ctx->afu = afu;
ctx->master = master;
+ ctx->tid = 0;
ctx->pid = NULL; /* Set in start work ioctl */
mutex_init(&ctx->mapping_lock);
ctx->mapping = NULL;
@@ -362,3 +364,22 @@ void cxl_context_mm_count_put(struct cxl_context *ctx)
if (ctx->mm)
mmdrop(ctx->mm);
}
+
+int cxl_context_thread_tidr(struct cxl_context *ctx, int assign)
+{
+ int rc = 0;
+
+ /* Clear any TIDR value assigned to the current thread */
+ if (!assign) {
+ clear_thread_tidr(current);
+ ctx->tid = 0;
+ } else {
+ /* Assign a unique TIDR (thread id) for the current thread */
+ rc = set_thread_tidr(current);
+ if (!rc)
+ ctx->tid = current->thread.tidr;
+ }
+ pr_devel("%s: current tidr: %d\n", __func__, ctx->tid);
+
+ return rc;
+}
diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
index e46a406..5f8678f 100644
--- a/drivers/misc/cxl/cxl.h
+++ b/drivers/misc/cxl/cxl.h
@@ -561,6 +561,7 @@ struct cxl_context {
unsigned int sst_size, sst_lru;
wait_queue_head_t wq;
+ u32 tid;
/* use mm context associated with this pid for ds faults */
struct pid *pid;
spinlock_t lock; /* Protects pending_irq_mask, pending_fault and fault_addr */
@@ -1169,4 +1170,9 @@ void cxl_context_mm_count_get(struct cxl_context *ctx);
/* Decrements the reference count to "struct mm_struct" */
void cxl_context_mm_count_put(struct cxl_context *ctx);
+/* Clear any TIDR value or assign a unique TIDR (thread id) for the
+ * current thread
+ */
+int cxl_context_thread_tidr(struct cxl_context *ctx, int assign);
+
#endif
diff --git a/drivers/misc/cxl/cxllib.c b/drivers/misc/cxl/cxllib.c
index dc9bc18..126d988 100644
--- a/drivers/misc/cxl/cxllib.c
+++ b/drivers/misc/cxl/cxllib.c
@@ -202,7 +202,7 @@ int cxllib_get_PE_attributes(struct task_struct *task,
} else {
attr->pid = 0;
}
- attr->tid = 0;
+ attr->tid = current->thread.tidr;
return 0;
}
EXPORT_SYMBOL_GPL(cxllib_get_PE_attributes);
diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
index 76c0b0c..f0666ee 100644
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -300,6 +300,17 @@ static long afu_ioctl_get_afu_id(struct cxl_context *ctx,
return 0;
}
+static long afu_ioctl_thread_tidr(struct cxl_context *ctx,
+ int __user *uassign)
+{
+ int assign;
+
+ if (copy_from_user(&assign, uassign, sizeof(assign)))
+ return -EFAULT;
+
+ return cxl_context_thread_tidr(ctx, assign);
+}
+
long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct cxl_context *ctx = file->private_data;
@@ -319,6 +330,8 @@ long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case CXL_IOCTL_GET_AFU_ID:
return afu_ioctl_get_afu_id(ctx, (struct cxl_afu_id __user *)
arg);
+ case CXL_IOCTL_THREAD_TIDR:
+ return afu_ioctl_thread_tidr(ctx, (int __user *)arg);
}
return -EINVAL;
}
diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c
index 02b6b45..657c4a9 100644
--- a/drivers/misc/cxl/native.c
+++ b/drivers/misc/cxl/native.c
@@ -673,7 +673,7 @@ static int process_element_entry_psl9(struct cxl_context *ctx, u64 wed, u64 amr)
pid = ctx->mm->context.id;
}
- ctx->elem->common.tid = 0;
+ ctx->elem->common.tid = cpu_to_be32(ctx->tid);
ctx->elem->common.pid = cpu_to_be32(pid);
ctx->elem->sr = cpu_to_be64(calculate_sr(ctx));
diff --git a/include/uapi/misc/cxl.h b/include/uapi/misc/cxl.h
index 49e8fd0..78b5eb5 100644
--- a/include/uapi/misc/cxl.h
+++ b/include/uapi/misc/cxl.h
@@ -81,7 +81,8 @@ struct cxl_adapter_image {
/* AFU devices */
#define CXL_IOCTL_START_WORK _IOW(CXL_MAGIC, 0x00, struct cxl_ioctl_start_work)
#define CXL_IOCTL_GET_PROCESS_ELEMENT _IOR(CXL_MAGIC, 0x01, __u32)
-#define CXL_IOCTL_GET_AFU_ID _IOR(CXL_MAGIC, 0x02, struct cxl_afu_id)
+#define CXL_IOCTL_GET_AFU_ID _IOR(CXL_MAGIC, 0x02, struct cxl_afu_id)
+#define CXL_IOCTL_THREAD_TIDR _IOR(CXL_MAGIC, 0x03, int)
/* adapter devices */
#define CXL_IOCTL_DOWNLOAD_IMAGE _IOW(CXL_MAGIC, 0x0A, struct cxl_adapter_image)
#define CXL_IOCTL_VALIDATE_IMAGE _IOW(CXL_MAGIC, 0x0B, struct cxl_adapter_image)
--
2.7.4
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