[PATCH 5.15 123/245] powerpc/pseries/lparcfg: add missing RTAS retry status handling

Greg Kroah-Hartman
2024-02-27T14:07:50Z

From: Nathan Lynch <nathanl@linux.ibm.com>

[ Upstream commit 5d08633e5f6564b60f1cbe09af3af40a74d66431 ]

The ibm,get-system-parameter RTAS function may return -2 or 990x,
which indicate that the caller should try again.

lparcfg's parse_system_parameter_string() ignores this, making it
possible to intermittently report incorrect SPLPAR characteristics.

Move the RTAS call into a coventional rtas_busy_delay()-based loop.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230125-b4-powerpc-rtas-queue-v3-4-26929c8cce78@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/platforms/pseries/lparcfg.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c
index 19503a8797823..a291b5a94d4da 100644
--- a/arch/powerpc/platforms/pseries/lparcfg.c
+++ b/arch/powerpc/platforms/pseries/lparcfg.c
@@ -322,6 +322,7 @@ static void parse_mpp_x_data(struct seq_file *m)
*/
static void parse_system_parameter_string(struct seq_file *m)
{
+ const s32 token = rtas_token("ibm,get-system-parameter");
int call_status;

unsigned char *local_buffer = kmalloc(SPLPAR_MAXLENGTH, GFP_KERNEL);
@@ -331,16 +332,15 @@ static void parse_system_parameter_string(struct seq_file *m)
return;
}

- spin_lock(&rtas_data_buf_lock);
- memset(rtas_data_buf, 0, SPLPAR_MAXLENGTH);
- call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
- NULL,
- SPLPAR_CHARACTERISTICS_TOKEN,
- __pa(rtas_data_buf),
- RTAS_DATA_BUF_SIZE);
- memcpy(local_buffer, rtas_data_buf, SPLPAR_MAXLENGTH);
- local_buffer[SPLPAR_MAXLENGTH - 1] = '\0';
- spin_unlock(&rtas_data_buf_lock);
+ do {
+ spin_lock(&rtas_data_buf_lock);
+ memset(rtas_data_buf, 0, SPLPAR_MAXLENGTH);
+ call_status = rtas_call(token, 3, 1, NULL, SPLPAR_CHARACTERISTICS_TOKEN,
+ __pa(rtas_data_buf), RTAS_DATA_BUF_SIZE);
+ memcpy(local_buffer, rtas_data_buf, SPLPAR_MAXLENGTH);
+ local_buffer[SPLPAR_MAXLENGTH - 1] = '\0';
+ spin_unlock(&rtas_data_buf_lock);
+ } while (rtas_busy_delay(call_status));

if (call_status != 0) {
printk(KERN_INFO
--
2.43.0