From 0c7f8c43daf6556078e51de98aa13f069e505985 Mon Sep 17 00:00:00 2001 From: Niek Linnenbank Date: Mon, 2 Dec 2019 22:09:43 +0100 Subject: [PATCH] arm/arm-powerctl: set NSACR.{CP11, CP10} bits in arm_set_cpu_on() 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 [PMM: added clarifying para to commit message] Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- 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 f77a950db6..b064513d44 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