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arm/arm-powerctl: set NSACR.{CP11, CP10} bits in arm_set_cpu_on()

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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

Backports commit 0c7f8c43daf6556078e51de98aa13f069e505985 from qemu
This commit is contained in:
Niek Linnenbank 2020-01-07 18:10:19 -05:00 committed by Lioncash
parent 9c3e512479
commit 998714db1f
1 changed files with 3 additions and 0 deletions
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3
qemu/target/arm/arm-powerctl.c
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@ -156,6 +156,9 @@ int arm_set_cpu_on(struct uc_struct *uc,
/* 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