ocxl: Add an IOCTL so userspace knows what OCXL features are available

BugLink: http://bugs.launchpad.net/bugs/1775786
In order for a userspace AFU driver to call the POWER9 specific
OCXL_IOCTL_ENABLE_P9_WAIT, it needs to verify that it can actually
make that call.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
(cherry picked from commit 02a8e5bc1c06045f36423bd9632ad9f40da18d3f)
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index e1012abf3050b6e4c57a85a96cb266690227e528..0fb521feb567fe72a3cc4b70853556c3fdae617e 100644 (file)
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -168,12 +168,32 @@ static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
 }
 #endif
 
+
+static long afu_ioctl_get_features(struct ocxl_context *ctx,
+               struct ocxl_ioctl_features __user *uarg)
+{
+       struct ocxl_ioctl_features arg;
+
+       memset(&arg, 0, sizeof(arg));
+
+#ifdef CONFIG_PPC64
+       if (cpu_has_feature(CPU_FTR_P9_TIDR))
+               arg.flags[0] |= OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT;
+#endif
+
+       if (copy_to_user(uarg, &arg, sizeof(arg)))
+               return -EFAULT;
+
+       return 0;
+}
+
 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :                        \
                        x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :       \
                        x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" :         \
                        x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" :     \
                        x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
                        x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" :     \
+                       x == OCXL_IOCTL_GET_FEATURES ? "GET_FEATURES" : \
                        "UNKNOWN")
 
 static long afu_ioctl(struct file *file, unsigned int cmd,
@@ -239,6 +259,11 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
                break;
 #endif
 
+       case OCXL_IOCTL_GET_FEATURES:
+               rc = afu_ioctl_get_features(ctx,
+                               (struct ocxl_ioctl_features __user *) args);
+               break;
+
        default:
                rc = -EINVAL;
        }

diff --git a/include/uapi/misc/ocxl.h b/include/uapi/misc/ocxl.h
index 561e6f0dfcb76b27013c7c82d47c32dd28778a61..97937cfa3baae3ebc334fbb668806774a3542b85 100644 (file)
--- a/include/uapi/misc/ocxl.h
+++ b/include/uapi/misc/ocxl.h
@@ -55,6 +55,11 @@ struct ocxl_ioctl_p9_wait {
        __u64 reserved3[3];
 };
 
+#define OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT     0x01
+struct ocxl_ioctl_features {
+       __u64 flags[4];
+};
+
 struct ocxl_ioctl_irq_fd {
        __u64 irq_offset;
        __s32 eventfd;
@@ -70,5 +75,6 @@ struct ocxl_ioctl_irq_fd {
 #define OCXL_IOCTL_IRQ_SET_FD  _IOW(OCXL_MAGIC, 0x13, struct ocxl_ioctl_irq_fd)
 #define OCXL_IOCTL_GET_METADATA _IOR(OCXL_MAGIC, 0x14, struct ocxl_ioctl_metadata)
 #define OCXL_IOCTL_ENABLE_P9_WAIT      _IOR(OCXL_MAGIC, 0x15, struct ocxl_ioctl_p9_wait)
+#define OCXL_IOCTL_GET_FEATURES _IOR(OCXL_MAGIC, 0x16, struct ocxl_ioctl_features)
 
 #endif /* _UAPI_MISC_OCXL_H */