[Skiboot] [PATCH 2/2] OPAL_REINIT_CPUS: clarify that for P9 and above, we can have other flags

[Stewart Smith]

On P8 we got it a bit wrong and would fall into a workaround for P8 DD1
HILE setting if other bits were set in the flags to OPAL_REINIT_CPUS,
limiting our opportunity to extend it in the future.

Signed-off-by: Stewart Smith <stewart at linux.vnet.ibm.com>
---
 core/cpu.c                           | 4 +++-
 doc/opal-api/opal-reinit-cpus-70.txt | 2 ++
 doc/opal-api/power9-changes.txt      | 5 +++++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/core/cpu.c b/core/cpu.c
index 20841509052d..f33ac4871614 100644
--- a/core/cpu.c
+++ b/core/cpu.c
@@ -879,8 +879,10 @@ static int64_t opal_reinit_cpus(uint64_t flags)
 	}
 
 	/* Any flags left ? */
-	if (flags != 0)
+	if (flags != 0 && proc_gen == proc_gen_p8)
 		rc = slw_reinit(flags);
+	else if (flags != 0)
+		rc = OPAL_UNSUPPORTED;
 
 	/* And undo the above */
 	lock(&reinit_lock);
diff --git a/doc/opal-api/opal-reinit-cpus-70.txt b/doc/opal-api/opal-reinit-cpus-70.txt
index 27f6f2e89ba4..bf9b238a628b 100644
--- a/doc/opal-api/opal-reinit-cpus-70.txt
+++ b/doc/opal-api/opal-reinit-cpus-70.txt
@@ -22,6 +22,8 @@ flags will return OPAL_UNSUPPORTED.
 On POWER8 CPUs, only OPAL_REINIT_CPUS_HILE_BE and OPAL_REINIT_CPUS_HILE_LE
 are support and other bits *MUST NOT* be set.
 
+On POWER9 CPUs, other flags may be supported in the future.
+
 Returns:
 - OPAL_SUCCESS
 - OPAL_UNSUPPORTED
diff --git a/doc/opal-api/power9-changes.txt b/doc/opal-api/power9-changes.txt
index 1935e1279147..cf354d60ac63 100644
--- a/doc/opal-api/power9-changes.txt
+++ b/doc/opal-api/power9-changes.txt
@@ -10,6 +10,11 @@ parts of the OPAL API.
 Eventually, when the kernel drops support for POWER8 and before, we can then
 remove the associated kernel code too.
 
+OPAL_REINIT_CPUS
+----------------
+Can now be extended beyond HILE BE/LE bits. If invalid flags are set on
+POWER9, OPAL_UNSUPPORTED will be returned.
+
 
 TODO
 ----
-- 
2.1.4