File arm-arm-powerctl-set-NSACR.-CP11-CP10-bi.patch of Package qemu

Overview Repositories Revisions Requests Users Attributes Meta

File arm-arm-powerctl-set-NSACR.-CP11-CP10-bi.patch of Package qemu (Revision 8478f801ae9684591fa54d43ea9c2404)

Currently displaying revision 8478f801ae9684591fa54d43ea9c2404 , Show latest

From: Niek Linnenbank <nieklinnenbank@gmail.com>
Date: Mon, 2 Dec 2019 22:09:43 +0100
Subject: arm/arm-powerctl: set NSACR.{CP11, CP10} bits in arm_set_cpu_on()

Git-commit: 0c7f8c43daf6556078e51de98aa13f069e505985

This change ensures that the FPU can be accessed in Non-Secure mode
when the CPU core is reset using the arm_set_cpu_on() function call.
The NSACR.{CP11,CP10} bits define the exception level required to
access the FPU in Non-Secure mode. Without these bits set, the CPU
will give an undefined exception trap on the first FPU access for the
secondary cores under Linux.

This is necessary because in this power-control codepath QEMU
is effectively emulating a bit of EL3 firmware, and has to set
the CPU up as the EL3 firmware would.

Fixes: fc1120a7f5
Cc: qemu-stable@nongnu.org
Signed-off-by: Niek Linnenbank <nieklinnenbank@gmail.com>
[PMM: added clarifying para to commit message]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 target/arm/arm-powerctl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/target/arm/arm-powerctl.c b/target/arm/arm-powerctl.c
index f77a950db67276513977af686aa9..b064513d44a86932bbd70b06b3ca 100644
--- a/target/arm/arm-powerctl.c
+++ b/target/arm/arm-powerctl.c
@@ -104,6 +104,9 @@ static void arm_set_cpu_on_async_work(CPUState *target_cpu_state,
         /* Processor is not in secure mode */
         target_cpu->env.cp15.scr_el3 |= SCR_NS;
 
+        /* Set NSACR.{CP11,CP10} so NS can access the FPU */
+        target_cpu->env.cp15.nsacr |= 3 << 10;
+
         /*
          * If QEMU is providing the equivalent of EL3 firmware, then we need
          * to make sure a CPU targeting EL2 comes out of reset with a

Places

File arm-arm-powerctl-set-NSACR.-CP11-CP10-bi.patch of Package qemu (Revision 8478f801ae9684591fa54d43ea9c2404)

Places