From ed1f13d607e2c64c66bea49d6f4edaf278d3d246 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Fri, 29 Aug 2014 15:00:28 +0100 Subject: [PATCH] target-arm: Fix regression that disabled VFP for ARMv5 CPUs Commit 2c7ffc414 added support for honouring the CPACR coprocessor access control register bits which may disable access to VFP and Neon instructions. However it failed to account for the fact that the CPACR is only present starting from the ARMv6 architecture version, so it accidentally disabled VFP completely for ARMv5 CPUs like the ARM926. Linux would detect this as "no VFP present" and probably fall back to its own emulation, but other guest OSes might crash or misbehave. This fixes bug LP:1359930. Reported-by: Jakub Jermar Signed-off-by: Peter Maydell Message-id: 1408714940-7192-1-git-send-email-peter.maydell@linaro.org Cc: qemu-stable@nongnu.org Signed-off-by: Peter Maydell --- target-arm/cpu.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/target-arm/cpu.h b/target-arm/cpu.h index 8098b8d357..659b104608 100644 --- a/target-arm/cpu.h +++ b/target-arm/cpu.h @@ -1255,7 +1255,14 @@ static inline bool arm_singlestep_active(CPUARMState *env) static inline void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, target_ulong *cs_base, int *flags) { - int fpen = extract32(env->cp15.c1_coproc, 20, 2); + int fpen; + + if (arm_feature(env, ARM_FEATURE_V6)) { + fpen = extract32(env->cp15.c1_coproc, 20, 2); + } else { + /* CPACR doesn't exist before v6, so VFP is always accessible */ + fpen = 3; + } if (is_a64(env)) { *pc = env->pc; -- GitLab