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[2403:580a:f89b:0:d09c:46ba:97a2:4a99]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7127af1999fsm1688425b3a.169.2024.08.15.19.56.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 15 Aug 2024 19:56:23 -0700 (PDT) Message-ID: <3e23b4a1-d05a-4189-aaf2-3ee75b154945@linaro.org> Date: Fri, 16 Aug 2024 12:56:13 +1000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 02/16] target/riscv: Introduce elp state and enabling controls for zicfilp To: Deepak Gupta , qemu-riscv@nongnu.org, qemu-devel@nongnu.org Cc: palmer@dabbelt.com, Alistair.Francis@wdc.com, bmeng.cn@gmail.com, liwei1518@gmail.com, dbarboza@ventanamicro.com, zhiwei_liu@linux.alibaba.com, pbonzini@redhat.com, jim.shu@sifive.com, andy.chiu@sifive.com, kito.cheng@sifive.com References: <20240816010711.3055425-1-debug@rivosinc.com> <20240816010711.3055425-3-debug@rivosinc.com> Content-Language: en-US From: Richard Henderson In-Reply-To: <20240816010711.3055425-3-debug@rivosinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2001:4860:4864:20::30; envelope-from=richard.henderson@linaro.org; helo=mail-oa1-x30.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 8/16/24 11:06, Deepak Gupta wrote: > zicfilp introduces a new state elp ("expected landing pad") in cpu. > During normal execution, elp is idle (NO_LP_EXPECTED) i.e not expecting > landing pad. On an indirect call, elp moves LP_EXPECTED. When elp is > LP_EXPECTED, only a subsquent landing pad instruction can set state back > to NO_LP_EXPECTED. On reset, elp is set to NO_LP_EXPECTED. > > zicfilp is enabled via bit2 in *envcfg CSRs. Enabling control for M-mode > is in mseccfg CSR at bit position 10. > > On trap, elp state is saved away in *status. > > Signed-off-by: Deepak Gupta > Co-developed-by: Jim Shu > Co-developed-by: Andy Chiu > --- > target/riscv/cpu.c | 3 +++ > target/riscv/cpu.h | 2 ++ > target/riscv/cpu_bits.h | 6 ++++++ > target/riscv/csr.c | 31 +++++++++++++++++++++++++++++++ > target/riscv/pmp.c | 5 +++++ > target/riscv/pmp.h | 3 ++- > 6 files changed, 49 insertions(+), 1 deletion(-) Reviewed-by: Richard Henderson r~