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.
A next patch will handle a new kind of "compatible" property in the
device-tree (PHB DT node) indicating which version of CAPI and which
features are supported, instead of handling PVR values.
Signed-off-by: Christophe Lombard <clomb...@linux.vnet.ibm.com>
Reviewed-by: Philippe Bergheaud <fe...@linux.vnet.ibm.com>
---
Changelog[v4]
- Rebased to latest upstream.
- Updated the ioctl interface.
- Removed the field tid in the context structure.
Changelog[v3]
- Rebased to latest upstream.
- Updated attr->tid field in cxllib_get_PE_attributes().
Changelog[v2]
- Rebased to latest upstream.
- Updated the ioctl interface.
- Added a checking to allow updating the TIDR if a P9 chip is present.
---
arch/powerpc/kernel/process.c | 1 +
drivers/misc/cxl/context.c | 15 +++++++++++++++
drivers/misc/cxl/cxl.h | 3 +++
drivers/misc/cxl/cxllib.c | 3 ++-
drivers/misc/cxl/file.c | 7 +++++++
drivers/misc/cxl/native.c | 2 +-
include/uapi/misc/cxl.h | 4 +++-
7 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 5acb5a1..a6a70e2 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1589,6 +1589,7 @@ 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/context.c b/drivers/misc/cxl/context.c
index 12a41b2..e309d35 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"
@@ -362,3 +363,17 @@ 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 rc = 0;
+
+ if (!cxl_is_power9())
+ return -ENODEV;
+
+ rc = set_thread_tidr(current);
+ pr_devel("%s: current tidr: %ld\n", __func__,
+ current->thread.tidr);
+
+ return rc;
+}
diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
index e46a406..1a5db0b 100644
--- a/drivers/misc/cxl/cxl.h
+++ b/drivers/misc/cxl/cxl.h
@@ -1169,4 +1169,7 @@ 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);
+/* Handles an unique TIDR (thread id) for the current thread */
+int cxl_context_thread_tidr(struct cxl_context *ctx);
+
#endif
diff --git a/drivers/misc/cxl/cxllib.c b/drivers/misc/cxl/cxllib.c
index dc9bc18..30ccba4 100644
--- a/drivers/misc/cxl/cxllib.c
+++ b/drivers/misc/cxl/cxllib.c
@@ -199,10 +199,11 @@ int cxllib_get_PE_attributes(struct task_struct *task,
*/
attr->pid = mm->context.id;
mmput(mm);
+ attr->tid = task->thread.tidr;
} else {
attr->pid = 0;
+ attr->tid = 0;
}
- attr->tid = 0;
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..a823c76 100644
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -248,6 +248,13 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
*/
smp_mb();
+ /* Assign a unique TIDR (thread id) for the current thread */
+ if (work.flags & CXL_START_WORK_TID) {
+ rc = cxl_context_thread_tidr(ctx);
+ if (rc)
+ goto out;
+ }
+
trace_cxl_attach(ctx, work.work_element_descriptor,
work.num_interrupts, amr);
if ((rc = cxl_ops->attach_process(ctx, false,
work.work_element_descriptor,
diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c
index 02b6b45..036fe5b 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(current->thread.tidr);
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..980ee8f 100644
--- a/include/uapi/misc/cxl.h
+++ b/include/uapi/misc/cxl.h
@@ -31,9 +31,11 @@ struct cxl_ioctl_start_work {
#define CXL_START_WORK_AMR 0x0000000000000001ULL
#define CXL_START_WORK_NUM_IRQS 0x0000000000000002ULL
#define CXL_START_WORK_ERR_FF 0x0000000000000004ULL
+#define CXL_START_WORK_TID 0x0000000000000008ULL
#define CXL_START_WORK_ALL (CXL_START_WORK_AMR |\
CXL_START_WORK_NUM_IRQS |\
- CXL_START_WORK_ERR_FF)
+ CXL_START_WORK_ERR_FF |\
+ CXL_START_WORK_TID)
/* Possible modes that an afu can be in */
--
2.7.4
