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[v6,07/13] powerpc/rtas: Serialize firmware activation sequences

Message ID 20231212-papr-sys_rtas-vs-lockdown-v6-7-e9eafd0c8c6c@linux.ibm.com (mailing list archive)
State Accepted
Commit dc7637c402b90a197d3f21a3d78f2b00b67ea22a
Headers show
Series powerpc/pseries: New character devices for system parameters and VPD | expand

Commit Message

Nathan Lynch via B4 Relay Dec. 12, 2023, 5:01 p.m. UTC 
From: Nathan Lynch <nathanl@linux.ibm.com>

Use rtas_ibm_activate_firmware_lock 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.

Reviewed-by: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org>
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 4d28983e8b1d..72f6b5a402dd 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -1734,10 +1734,14 @@  void rtas_activate_firmware(void)
 		return;
 	}
 
+	mutex_lock(&rtas_ibm_activate_firmware_lock);
+
 	do {
 		fwrc = rtas_call(token, 0, 1, NULL);
 	} while (rtas_busy_delay(fwrc));
 
+	mutex_unlock(&rtas_ibm_activate_firmware_lock);
+
 	if (fwrc)
 		pr_err("ibm,activate-firmware failed (%i)\n", fwrc);
 }