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[81.2.115.148]) by smtp.gmail.com with ESMTPSA id v184sm39476572wma.6.2019.04.16.05.58.00 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 16 Apr 2019 05:58:01 -0700 (PDT) From: Peter Maydell To: qemu-arm@nongnu.org, qemu-devel@nongnu.org Date: Tue, 16 Apr 2019 13:57:26 +0100 Message-Id: <20190416125744.27770-9-peter.maydell@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190416125744.27770-1-peter.maydell@linaro.org> References: <20190416125744.27770-1-peter.maydell@linaro.org> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2a00:1450:4864:20::442 Subject: [Qemu-devel] [PATCH 08/26] target/arm: Handle SFPA and FPCA bits in reads and writes of CONTROL X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" The M-profile CONTROL register has two bits -- SFPA and FPCA -- which relate to floating-point support, and should be RES0 otherwise. Handle them correctly in the MSR/MRS register access code. Neither is banked between security states, so they are stored in v7m.control[M_REG_S] regardless of current security state. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson --- target/arm/helper.c | 57 ++++++++++++++++++++++++++++++++++++++------- 1 file changed, 49 insertions(+), 8 deletions(-) diff --git a/target/arm/helper.c b/target/arm/helper.c index b4f1609a1c6..297eb38fef0 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -12032,7 +12032,14 @@ uint32_t HELPER(v7m_mrs)(CPUARMState *env, uint32_t reg) return xpsr_read(env) & mask; break; case 20: /* CONTROL */ - return env->v7m.control[env->v7m.secure]; + { + uint32_t value = env->v7m.control[env->v7m.secure]; + if (!env->v7m.secure) { + /* SFPA is RAZ/WI from NS; FPCA is stored in the M_REG_S bank */ + value |= env->v7m.control[M_REG_S] & R_V7M_CONTROL_FPCA_MASK; + } + return value; + } case 0x94: /* CONTROL_NS */ /* We have to handle this here because unprivileged Secure code * can read the NS CONTROL register. @@ -12040,7 +12047,8 @@ uint32_t HELPER(v7m_mrs)(CPUARMState *env, uint32_t reg) if (!env->v7m.secure) { return 0; } - return env->v7m.control[M_REG_NS]; + return env->v7m.control[M_REG_NS] | + (env->v7m.control[M_REG_S] & R_V7M_CONTROL_FPCA_MASK); } if (el == 0) { @@ -12146,9 +12154,13 @@ void HELPER(v7m_msr)(CPUARMState *env, uint32_t maskreg, uint32_t val) */ uint32_t mask = extract32(maskreg, 8, 4); uint32_t reg = extract32(maskreg, 0, 8); + int cur_el = arm_current_el(env); - if (arm_current_el(env) == 0 && reg > 7) { - /* only xPSR sub-fields may be written by unprivileged */ + if (cur_el == 0 && reg > 7 && reg != 20) { + /* + * only xPSR sub-fields and CONTROL.SFPA may be written by + * unprivileged code + */ return; } @@ -12207,6 +12219,15 @@ void HELPER(v7m_msr)(CPUARMState *env, uint32_t maskreg, uint32_t val) env->v7m.control[M_REG_NS] &= ~R_V7M_CONTROL_NPRIV_MASK; env->v7m.control[M_REG_NS] |= val & R_V7M_CONTROL_NPRIV_MASK; } + /* + * SFPA is RAZ/WI from NS. FPCA is RO if NSACR.CP10 == 0, + * RES0 if the FPU is not present, and is stored in the S bank + */ + if (arm_feature(env, ARM_FEATURE_VFP) && + extract32(env->v7m.nsacr, 10, 1)) { + env->v7m.control[M_REG_S] &= ~R_V7M_CONTROL_FPCA_MASK; + env->v7m.control[M_REG_S] |= val & R_V7M_CONTROL_FPCA_MASK; + } return; case 0x98: /* SP_NS */ { @@ -12309,21 +12330,41 @@ void HELPER(v7m_msr)(CPUARMState *env, uint32_t maskreg, uint32_t val) env->v7m.faultmask[env->v7m.secure] = val & 1; break; case 20: /* CONTROL */ - /* Writing to the SPSEL bit only has an effect if we are in + /* + * Writing to the SPSEL bit only has an effect if we are in * thread mode; other bits can be updated by any privileged code. * write_v7m_control_spsel() deals with updating the SPSEL bit in * env->v7m.control, so we only need update the others. * For v7M, we must just ignore explicit writes to SPSEL in handler * mode; for v8M the write is permitted but will have no effect. + * All these bits are writes-ignored from non-privileged code, + * except for SFPA. */ - if (arm_feature(env, ARM_FEATURE_V8) || - !arm_v7m_is_handler_mode(env)) { + if (cur_el > 0 && (arm_feature(env, ARM_FEATURE_V8) || + !arm_v7m_is_handler_mode(env))) { write_v7m_control_spsel(env, (val & R_V7M_CONTROL_SPSEL_MASK) != 0); } - if (arm_feature(env, ARM_FEATURE_M_MAIN)) { + if (cur_el > 0 && arm_feature(env, ARM_FEATURE_M_MAIN)) { env->v7m.control[env->v7m.secure] &= ~R_V7M_CONTROL_NPRIV_MASK; env->v7m.control[env->v7m.secure] |= val & R_V7M_CONTROL_NPRIV_MASK; } + if (arm_feature(env, ARM_FEATURE_VFP)) { + /* + * SFPA is RAZ/WI from NS or if no FPU. + * FPCA is RO if NSACR.CP10 == 0, RES0 if the FPU is not present. + * Both are stored in the S bank. + */ + if (env->v7m.secure) { + env->v7m.control[M_REG_S] &= ~R_V7M_CONTROL_SFPA_MASK; + env->v7m.control[M_REG_S] |= val & R_V7M_CONTROL_SFPA_MASK; + } + if (cur_el > 0 && + (env->v7m.secure || !arm_feature(env, ARM_FEATURE_M_SECURITY) || + extract32(env->v7m.nsacr, 10, 1))) { + env->v7m.control[M_REG_S] &= ~R_V7M_CONTROL_FPCA_MASK; + env->v7m.control[M_REG_S] |= val & R_V7M_CONTROL_FPCA_MASK; + } + } break; default: bad_reg: