cxl: Remove unused values in bare-metal environment.

The two previously fields pid and tid, located in the structure
cxl_irq_info, are only used in the guest environment. To avoid confusion,
it's not necessary to fill the fields in the bare-metal environment.
Pid_tid is now renamed to 'reserved' to avoid undefined behavior on
bare-metal. The PSL Process and Thread Identification Register
(CXL_PSL_PID_TID_An) is only used when attaching a dedicated process
for PSL8 only. This register goes away in CAIA2.

Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

drivers/misc/cxl/cxl.h

@@ -888,27 +888,15 @@ int __detach_context(struct cxl_context *ctx);
 /*
  * This must match the layout of the H_COLLECT_CA_INT_INFO retbuf defined
  * in PAPR.
- * A word about endianness: a pointer to this structure is passed when
- * calling the hcall. However, it is not a block of memory filled up by
- * the hypervisor. The return values are found in registers, and copied
- * one by one when returning from the hcall. See the end of the call to
- * plpar_hcall9() in hvCall.S
- * As a consequence:
- * - we don't need to do any endianness conversion
- * - the pid and tid are an exception. They are 32-bit values returned in
- *   the same 64-bit register. So we do need to worry about byte ordering.
+ * Field pid_tid is now 'reserved' because it's no more used on bare-metal.
+ * On a guest environment, PSL_PID_An is located on the upper 32 bits and
+ * PSL_TID_An register in the lower 32 bits.
  */
 struct cxl_irq_info {
 	u64 dsisr;
 	u64 dar;
 	u64 dsr;
-#ifndef CONFIG_CPU_LITTLE_ENDIAN
-	u32 pid;
-	u32 tid;
-#else
-	u32 tid;
-	u32 pid;
-#endif
+	u64 reserved;
 	u64 afu_err;
 	u64 errstat;
 	u64 proc_handle;

drivers/misc/cxl/hcalls.c

@@ -413,9 +413,9 @@ long cxl_h_collect_int_info(u64 unit_address, u64 process_token,
 
 	switch (rc) {
 	case H_SUCCESS:     /* The interrupt info is returned in return registers. */
-		pr_devel("dsisr:%#llx, dar:%#llx, dsr:%#llx, pid:%u, tid:%u, afu_err:%#llx, errstat:%#llx\n",
-			info->dsisr, info->dar, info->dsr, info->pid,
-			info->tid, info->afu_err, info->errstat);
+		pr_devel("dsisr:%#llx, dar:%#llx, dsr:%#llx, pid_tid:%#llx, afu_err:%#llx, errstat:%#llx\n",
+			info->dsisr, info->dar, info->dsr, info->reserved,
+			info->afu_err, info->errstat);
 		return 0;
 	case H_PARAMETER:   /* An incorrect parameter was supplied. */
 		return -EINVAL;

drivers/misc/cxl/native.c

@@ -859,8 +859,6 @@ static int native_detach_process(struct cxl_context *ctx)
 
 static int native_get_irq_info(struct cxl_afu *afu, struct cxl_irq_info *info)
 {
-	u64 pidtid;
-
 	/* If the adapter has gone away, we can't get any meaningful
 	 * information.
 	 */
@@ -870,9 +868,6 @@ static int native_get_irq_info(struct cxl_afu *afu, struct cxl_irq_info *info)
 	info->dsisr = cxl_p2n_read(afu, CXL_PSL_DSISR_An);
 	info->dar = cxl_p2n_read(afu, CXL_PSL_DAR_An);
 	info->dsr = cxl_p2n_read(afu, CXL_PSL_DSR_An);
-	pidtid = cxl_p2n_read(afu, CXL_PSL_PID_TID_An);
-	info->pid = pidtid >> 32;
-	info->tid = pidtid & 0xffffffff;
 	info->afu_err = cxl_p2n_read(afu, CXL_AFU_ERR_An);
 	info->errstat = cxl_p2n_read(afu, CXL_PSL_ErrStat_An);
 	info->proc_handle = 0;