[PATCH V7] cxl: Add support for ASB_Notify on POWER9
Andrew Donnellan
andrew.donnellan at au1.ibm.com
Mon Jan 15 18:29:13 AEDT 2018
On 11/01/18 19:55, Christophe Lombard wrote:
> 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>
> Reviewed-by: Philippe Bergheaud <felix at linux.vnet.ibm.com>
Acked-by: Andrew Donnellan <andrew.donnellan at au1.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 */
>
--
Andrew Donnellan OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com IBM Australia Limited
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