From 2f027fc52d4b444a47cb05a9c96697372a6b57d2 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Thu, 11 Feb 2016 11:17:31 +0000 Subject: [PATCH] target-arm: Implement NSACR trapping behaviour Implement some corner cases of the behaviour of the NSACR register on ARMv8: * if EL3 is AArch64 then accessing the NSACR from Secure EL1 with AArch32 should trap to EL3 * if EL3 is not present or is AArch64 then reads from NS EL1 and NS EL2 return constant 0xc00 It would in theory be possible to implement all these with a single reginfo definition, but for clarity we use three separate definitions for the three cases and install the right one based on the CPU feature flags. Signed-off-by: Peter Maydell Reviewed-by: Edgar E. Iglesias Message-id: 1454506721-11843-7-git-send-email-peter.maydell@linaro.org --- target-arm/helper.c | 62 ++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 58 insertions(+), 4 deletions(-) diff --git a/target-arm/helper.c b/target-arm/helper.c index 1db8de3ad3..2f9db72806 100644 --- a/target-arm/helper.c +++ b/target-arm/helper.c @@ -3563,6 +3563,25 @@ static const ARMCPRegInfo el2_cp_reginfo[] = { REGINFO_SENTINEL }; +static CPAccessResult nsacr_access(CPUARMState *env, const ARMCPRegInfo *ri, + bool isread) +{ + /* The NSACR is RW at EL3, and RO for NS EL1 and NS EL2. + * At Secure EL1 it traps to EL3. + */ + if (arm_current_el(env) == 3) { + return CP_ACCESS_OK; + } + if (arm_is_secure_below_el3(env)) { + return CP_ACCESS_TRAP_EL3; + } + /* Accesses from EL1 NS and EL2 NS are UNDEF for write but allow reads. */ + if (isread) { + return CP_ACCESS_OK; + } + return CP_ACCESS_TRAP_UNCATEGORIZED; +} + static const ARMCPRegInfo el3_cp_reginfo[] = { { .name = "SCR_EL3", .state = ARM_CP_STATE_AA64, .opc0 = 3, .opc1 = 6, .crn = 1, .crm = 1, .opc2 = 0, @@ -3589,10 +3608,6 @@ static const ARMCPRegInfo el3_cp_reginfo[] = { .cp = 15, .opc1 = 0, .crn = 1, .crm = 1, .opc2 = 1, .access = PL3_RW, .resetvalue = 0, .fieldoffset = offsetoflow32(CPUARMState, cp15.sder) }, - /* TODO: Implement NSACR trapping of secure EL1 accesses to EL3 */ - { .name = "NSACR", .cp = 15, .opc1 = 0, .crn = 1, .crm = 1, .opc2 = 2, - .access = PL3_W | PL1_R, .resetvalue = 0, - .fieldoffset = offsetof(CPUARMState, cp15.nsacr) }, { .name = "MVBAR", .cp = 15, .opc1 = 0, .crn = 12, .crm = 0, .opc2 = 1, .access = PL1_RW, .accessfn = access_trap_aa32s_el1, .writefn = vbar_write, .resetvalue = 0, @@ -4363,6 +4378,45 @@ void register_cp_regs_for_features(ARMCPU *cpu) }; define_one_arm_cp_reg(cpu, &rvbar); } + /* The behaviour of NSACR is sufficiently various that we don't + * try to describe it in a single reginfo: + * if EL3 is 64 bit, then trap to EL3 from S EL1, + * reads as constant 0xc00 from NS EL1 and NS EL2 + * if EL3 is 32 bit, then RW at EL3, RO at NS EL1 and NS EL2 + * if v7 without EL3, register doesn't exist + * if v8 without EL3, reads as constant 0xc00 from NS EL1 and NS EL2 + */ + if (arm_feature(env, ARM_FEATURE_EL3)) { + if (arm_feature(env, ARM_FEATURE_AARCH64)) { + ARMCPRegInfo nsacr = { + .name = "NSACR", .type = ARM_CP_CONST, + .cp = 15, .opc1 = 0, .crn = 1, .crm = 1, .opc2 = 2, + .access = PL1_RW, .accessfn = nsacr_access, + .resetvalue = 0xc00 + }; + define_one_arm_cp_reg(cpu, &nsacr); + } else { + ARMCPRegInfo nsacr = { + .name = "NSACR", + .cp = 15, .opc1 = 0, .crn = 1, .crm = 1, .opc2 = 2, + .access = PL3_RW | PL1_R, + .resetvalue = 0, + .fieldoffset = offsetof(CPUARMState, cp15.nsacr) + }; + define_one_arm_cp_reg(cpu, &nsacr); + } + } else { + if (arm_feature(env, ARM_FEATURE_V8)) { + ARMCPRegInfo nsacr = { + .name = "NSACR", .type = ARM_CP_CONST, + .cp = 15, .opc1 = 0, .crn = 1, .crm = 1, .opc2 = 2, + .access = PL1_R, + .resetvalue = 0xc00 + }; + define_one_arm_cp_reg(cpu, &nsacr); + } + } + if (arm_feature(env, ARM_FEATURE_MPU)) { if (arm_feature(env, ARM_FEATURE_V6)) { /* PMSAv6 not implemented */