diff mbox series

[v3,03/10] powerpc/rtas: Serialize firmware activation sequences

Message ID 20231025-papr-sys_rtas-vs-lockdown-v3-3-5eb04559e7d8@linux.ibm.com (mailing list archive)
State Superseded, archived
Headers show
Series powerpc/pseries: New character devices for system parameters and VPD | expand

Commit Message

Nathan Lynch via B4 Relay Oct. 26, 2023, 3:24 a.m. UTC 
From: Nathan Lynch <nathanl@linux.ibm.com>

Use the function lock API to prevent interleaving call sequences of
the ibm,activate-firmware RTAS function, which typically requires
multiple calls to complete the update. While the spec does not
specifically prohibit interleaved sequences, there's almost certainly
no advantage to allowing them.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/kernel/rtas.c | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 579a2c475bb6..864d140e7247 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -1738,10 +1738,14 @@  void rtas_activate_firmware(void)
 		return;
 	}
 
+	rtas_function_lock(RTAS_FN_IBM_ACTIVATE_FIRMWARE);
+
 	do {
 		fwrc = rtas_call(token, 0, 1, NULL);
 	} while (rtas_busy_delay(fwrc));
 
+	rtas_function_unlock(RTAS_FN_IBM_ACTIVATE_FIRMWARE);
+
 	if (fwrc)
 		pr_err("ibm,activate-firmware failed (%i)\n", fwrc);
 }