From d56974afe980b2bb8d60b17729483d80a7692400 Mon Sep 17 00:00:00 2001 From: Luc Michel Date: Thu, 19 Sep 2019 14:18:40 +0100 Subject: [PATCH] target/arm: fix CBAR register for AArch64 CPUs For AArch64 CPUs with a CBAR register, we have two views for it: - in AArch64 state, the CBAR_EL1 register (S3_1_C15_C3_0), returns the full 64 bits CBAR value - in AArch32 state, the CBAR register (cp15, opc1=1, CRn=15, CRm=3, opc2=0) returns a 32 bits view such that: CBAR = CBAR_EL1[31:18] 0..0 CBAR_EL1[43:32] This commit fixes the current implementation where: - CBAR_EL1 was returning the 32 bits view instead of the full 64 bits value, - CBAR was returning a truncated 32 bits version of the full 64 bits one, instead of the 32 bits view - CBAR was declared as cp15, opc1=4, CRn=15, CRm=0, opc2=0, which is the CBAR register found in the ARMv7 Cortex-Ax CPUs, but not in ARMv8 CPUs. Signed-off-by: Luc Michel Message-id: 20190912110103.1417887-1-luc.michel@greensocs.com [PMM: Added a comment about the two different kinds of CBAR] Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- target/arm/helper.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/target/arm/helper.c b/target/arm/helper.c index 507026c915..bc1130d989 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -6733,6 +6733,19 @@ void register_cp_regs_for_features(ARMCPU *cpu) } if (arm_feature(env, ARM_FEATURE_CBAR)) { + /* + * CBAR is IMPDEF, but common on Arm Cortex-A implementations. + * There are two flavours: + * (1) older 32-bit only cores have a simple 32-bit CBAR + * (2) 64-bit cores have a 64-bit CBAR visible to AArch64, plus a + * 32-bit register visible to AArch32 at a different encoding + * to the "flavour 1" register and with the bits rearranged to + * be able to squash a 64-bit address into the 32-bit view. + * We distinguish the two via the ARM_FEATURE_AARCH64 flag, but + * in future if we support AArch32-only configs of some of the + * AArch64 cores we might need to add a specific feature flag + * to indicate cores with "flavour 2" CBAR. + */ if (arm_feature(env, ARM_FEATURE_AARCH64)) { /* 32 bit view is [31:18] 0...0 [43:32]. */ uint32_t cbar32 = (extract64(cpu->reset_cbar, 18, 14) << 18) @@ -6740,12 +6753,12 @@ void register_cp_regs_for_features(ARMCPU *cpu) ARMCPRegInfo cbar_reginfo[] = { { .name = "CBAR", .type = ARM_CP_CONST, - .cp = 15, .crn = 15, .crm = 0, .opc1 = 4, .opc2 = 0, - .access = PL1_R, .resetvalue = cpu->reset_cbar }, + .cp = 15, .crn = 15, .crm = 3, .opc1 = 1, .opc2 = 0, + .access = PL1_R, .resetvalue = cbar32 }, { .name = "CBAR_EL1", .state = ARM_CP_STATE_AA64, .type = ARM_CP_CONST, .opc0 = 3, .opc1 = 1, .crn = 15, .crm = 3, .opc2 = 0, - .access = PL1_R, .resetvalue = cbar32 }, + .access = PL1_R, .resetvalue = cpu->reset_cbar }, REGINFO_SENTINEL }; /* We don't implement a r/w 64 bit CBAR currently */