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 <clomb...@linux.vnet.ibm.com>
Reviewed-by: Philippe Bergheaud <fe...@linux.vnet.ibm.com>
---
Changelog[v7]
- Rebased to latest upstream.
- Added boolean: "need to allocate a TIDR"
- Released the mutex and mark the context as STARTED in case of error.
Changelog[v6]
- Rebased to latest upstream.
- Updated the ioctl interface.
- Removed the updated ptrace.
- Assigned a unique TIDR for the current thread at a lower level.
Changelog[v5]
- Rebased to latest upstream.
- Updated the ioctl interface.
- Returned the tid in the ioctl structure.
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 | 2 ++
drivers/misc/cxl/cxl.h | 3 +++
drivers/misc/cxl/cxllib.c | 3 ++-
drivers/misc/cxl/file.c | 15 +++++++++++++--
drivers/misc/cxl/native.c | 13 ++++++++++++-
include/uapi/misc/cxl.h | 10 ++++++----
7 files changed, 39 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 72be0c3..1dc39dd 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..7ff315a 100644
--- a/drivers/misc/cxl/context.c
+++ b/drivers/misc/cxl/context.c
@@ -45,6 +45,8 @@ int cxl_context_init(struct cxl_context *ctx, struct cxl_afu
*afu, bool master)
ctx->pid = NULL; /* Set in start work ioctl */
mutex_init(&ctx->mapping_lock);
ctx->mapping = NULL;
+ ctx->tidr = 0;
+ ctx->assign_tidr = false;
if (cxl_is_power8()) {
spin_lock_init(&ctx->sste_lock);
diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
index e46a406..53149fb 100644
--- a/drivers/misc/cxl/cxl.h
+++ b/drivers/misc/cxl/cxl.h
@@ -630,6 +630,9 @@ struct cxl_context {
struct list_head extra_irq_contexts;
struct mm_struct *mm;
+
+ u16 tidr;
+ bool assign_tidr;
};
struct cxl_irq_info;
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..93fd381 100644
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -173,7 +173,7 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
* flags are set it's invalid
*/
if (work.reserved1 || work.reserved2 || work.reserved3 ||
- work.reserved4 || work.reserved5 || work.reserved6 ||
+ work.reserved4 || work.reserved5 ||
(work.flags & ~CXL_START_WORK_ALL)) {
rc = -EINVAL;
goto out;
@@ -186,12 +186,16 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
rc = -EINVAL;
goto out;
}
+
if ((rc = afu_register_irqs(ctx, work.num_interrupts)))
goto out;
if (work.flags & CXL_START_WORK_AMR)
amr = work.amr & mfspr(SPRN_UAMOR);
+ if (work.flags & CXL_START_WORK_TID)
+ ctx->assign_tidr = true;
+
ctx->mmio_err_ff = !!(work.flags & CXL_START_WORK_ERR_FF);
/*
@@ -263,8 +267,15 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
goto out;
}
- ctx->status = STARTED;
rc = 0;
+ if (work.flags & CXL_START_WORK_TID) {
+ work.tid = ctx->tidr;
+ if (copy_to_user(uwork, &work, sizeof(work)))
+ rc = -EFAULT;
+ }
+
+ ctx->status = STARTED;
+
out:
mutex_unlock(&ctx->status_mutex);
return rc;
diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c
index 02b6b45..1b3d7c6 100644
--- a/drivers/misc/cxl/native.c
+++ b/drivers/misc/cxl/native.c
@@ -16,6 +16,7 @@
#include <linux/uaccess.h>
#include <linux/delay.h>
#include <asm/synch.h>
+#include <asm/switch_to.h>
#include <misc/cxl-base.h>
#include "cxl.h"
@@ -655,6 +656,7 @@ static void update_ivtes_directed(struct cxl_context *ctx)
static int process_element_entry_psl9(struct cxl_context *ctx, u64 wed, u64
amr)
{
u32 pid;
+ int rc;
cxl_assign_psn_space(ctx);
@@ -673,7 +675,16 @@ static int process_element_entry_psl9(struct cxl_context
*ctx, u64 wed, u64 amr)
pid = ctx->mm->context.id;
}
- ctx->elem->common.tid = 0;
+ /* Assign a unique TIDR (thread id) for the current thread */
+ if (!(ctx->tidr) && (ctx->assign_tidr)) {
+ rc = set_thread_tidr(current);
+ if (rc)
+ return -ENODEV;
+ ctx->tidr = current->thread.tidr;
+ pr_devel("%s: current tidr: %d\n", __func__, ctx->tidr);
+ }
+
+ ctx->elem->common.tid = cpu_to_be32(ctx->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..56376d3 100644
--- a/include/uapi/misc/cxl.h
+++ b/include/uapi/misc/cxl.h
@@ -20,20 +20,22 @@ struct cxl_ioctl_start_work {
__u64 work_element_descriptor;
__u64 amr;
__s16 num_interrupts;
- __s16 reserved1;
- __s32 reserved2;
+ __u16 tid;
+ __s32 reserved1;
+ __u64 reserved2;
__u64 reserved3;
__u64 reserved4;
__u64 reserved5;
- __u64 reserved6;
};
#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
