From 36a24df84a4728b1cd7425af24c0d30cd65a51b5 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Sat, 9 Jul 2016 13:41:31 +1000 Subject: [PATCH] ppc: Fix support for odd MSR combinations MacOS uses an architecturally illegal MSR combination that seems nonetheless supported by 32-bit processors, which is to have MSR[PR]=1 and one or more of MSR[DR/IR/EE]=0. This adds support for it. To work properly we need to also properly include support for PR=1,{I,D}R=0 to the MMU index used by the qemu TLB. Signed-off-by: Benjamin Herrenschmidt Tested-by: Mark Cave-Ayland Signed-off-by: David Gibson --- target-ppc/helper_regs.h | 46 +++++++++++++++++++--------------------- 1 file changed, 22 insertions(+), 24 deletions(-) diff --git a/target-ppc/helper_regs.h b/target-ppc/helper_regs.h index 8d38828936..3d279f1d8a 100644 --- a/target-ppc/helper_regs.h +++ b/target-ppc/helper_regs.h @@ -41,17 +41,19 @@ static inline void hreg_swap_gpr_tgpr(CPUPPCState *env) static inline void hreg_compute_mem_idx(CPUPPCState *env) { - /* This is our encoding for server processors + /* This is our encoding for server processors. The architecture + * specifies that there is no such thing as userspace with + * translation off, however it appears that MacOS does it and + * some 32-bit CPUs support it. Weird... * * 0 = Guest User space virtual mode * 1 = Guest Kernel space virtual mode - * 2 = Guest Kernel space real mode - * 3 = HV User space virtual mode - * 4 = HV Kernel space virtual mode - * 5 = HV Kernel space real mode - * - * The combination PR=1 IR&DR=0 is invalid, we will treat - * it as IR=DR=1 + * 2 = Guest User space real mode + * 3 = Guest Kernel space real mode + * 4 = HV User space virtual mode + * 5 = HV Kernel space virtual mode + * 6 = HV User space real mode + * 7 = HV Kernel space real mode * * For BookE, we need 8 MMU modes as follow: * @@ -71,20 +73,11 @@ static inline void hreg_compute_mem_idx(CPUPPCState *env) env->immu_idx += msr_gs ? 4 : 0; env->dmmu_idx += msr_gs ? 4 : 0; } else { - /* First calucalte a base value independent of HV */ - if (msr_pr != 0) { - /* User space, ignore IR and DR */ - env->immu_idx = env->dmmu_idx = 0; - } else { - /* Kernel, setup a base I/D value */ - env->immu_idx = msr_ir ? 1 : 2; - env->dmmu_idx = msr_dr ? 1 : 2; - } - /* Then offset it for HV */ - if (msr_hv) { - env->immu_idx += 3; - env->dmmu_idx += 3; - } + env->immu_idx = env->dmmu_idx = msr_pr ? 0 : 1; + env->immu_idx += msr_ir ? 0 : 2; + env->dmmu_idx += msr_dr ? 0 : 2; + env->immu_idx += msr_hv ? 4 : 0; + env->dmmu_idx += msr_hv ? 4 : 0; } } @@ -136,8 +129,13 @@ static inline int hreg_store_msr(CPUPPCState *env, target_ulong value, /* Change the exception prefix on PowerPC 601 */ env->excp_prefix = ((value >> MSR_EP) & 1) * 0xFFF00000; } - /* If PR=1 then EE, IR and DR must be 1 */ - if ((value >> MSR_PR) & 1) { + /* If PR=1 then EE, IR and DR must be 1 + * + * Note: We only enforce this on 64-bit processors. It appears that + * 32-bit implementations supports PR=1 and EE/DR/IR=0 and MacOS + * exploits it. + */ + if ((env->insns_flags & PPC_64B) && ((value >> MSR_PR) & 1)) { value |= (1 << MSR_EE) | (1 << MSR_DR) | (1 << MSR_IR); } #endif -- GitLab