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From: Atish Patra To: opensbi@lists.infradead.org, Anup Patel References: <20250307124451.122828-1-rkanwal@rivosinc.com> Content-Language: en-US In-Reply-To: X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250331_155734_215875_E7E98CEA X-CRM114-Status: GOOD ( 13.77 ) X-BeenThere: opensbi@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "opensbi" Errors-To: opensbi-bounces+opensbi=archiver.kernel.org@lists.infradead.org On 3/7/25 10:00 AM, Atish Kumar Patra wrote: > On Fri, Mar 7, 2025 at 4:44?AM Rajnesh Kanwal wrote: >> >> The Control Transfer Records (CTR) extension provides a method to >> record a limited branch history in register-accessible internal chip >> storage. >> >> This extension is similar to Arch LBR in x86 and BRBE in ARM. >> The Extension has been stable and the latest release can be found here >> https://github.com/riscv/riscv-control-transfer-records/release >> >> Signed-off-by: Rajnesh Kanwal >> >> --- >> Changes in V3: >> Removed FWFT bit. It was discussed in tech-prs group to >> use trap and enable approach rather than FWFT bit. Trap >> and enable approach leads to letter number of traps than >> enabling and disabling FWFT bit on each CTR usage. >> https://lists.riscv.org/g/tech-prs/message/1339 >> >> Changes in V2: >> Added FWFT bit for CTR. >> --- >> include/sbi/riscv_encoding.h | 13 +++++++++++++ >> include/sbi/sbi_hart.h | 4 ++++ >> lib/sbi/sbi_hart.c | 7 +++++++ >> 3 files changed, 24 insertions(+) >> >> diff --git a/include/sbi/riscv_encoding.h b/include/sbi/riscv_encoding.h >> index 03c68a57..f3e2afd5 100644 >> --- a/include/sbi/riscv_encoding.h >> +++ b/include/sbi/riscv_encoding.h >> @@ -375,6 +375,17 @@ >> #define CSR_SSTATEEN2 0x10E >> #define CSR_SSTATEEN3 0x10F >> >> +/* Machine-Level Control transfer records CSRs */ >> +#define CSR_MCTRCTL 0x34e >> + >> +/* Supervisor-Level Control transfer records CSRs */ >> +#define CSR_SCTRCTL 0x14e >> +#define CSR_SCTRSTATUS 0x14f >> +#define CSR_SCTRDEPTH 0x15f >> + >> +/* VS-Level Control transfer records CSRs */ >> +#define CSR_VSCTRCTL 0x24e >> + >> /* ===== Hypervisor-level CSRs ===== */ >> >> /* Hypervisor Trap Setup (H-extension) */ >> @@ -799,6 +810,8 @@ >> #define SMSTATEEN0_CS (_ULL(1) << SMSTATEEN0_CS_SHIFT) >> #define SMSTATEEN0_FCSR_SHIFT 1 >> #define SMSTATEEN0_FCSR (_ULL(1) << SMSTATEEN0_FCSR_SHIFT) >> +#define SMSTATEEN0_CTR_SHIFT 54 >> +#define SMSTATEEN0_CTR (_ULL(1) << SMSTATEEN0_CTR_SHIFT) >> #define SMSTATEEN0_CONTEXT_SHIFT 57 >> #define SMSTATEEN0_CONTEXT (_ULL(1) << SMSTATEEN0_CONTEXT_SHIFT) >> #define SMSTATEEN0_IMSIC_SHIFT 58 >> diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h >> index 4c36c778..c3a7feb7 100644 >> --- a/include/sbi/sbi_hart.h >> +++ b/include/sbi/sbi_hart.h >> @@ -75,6 +75,10 @@ enum sbi_hart_extensions { >> SBI_HART_EXT_ZICFISS, >> /** Hart has Ssdbltrp extension */ >> SBI_HART_EXT_SSDBLTRP, >> + /** HART has CTR M-mode CSRs */ >> + SBI_HART_EXT_SMCTR, >> + /** HART has CTR S-mode CSRs */ >> + SBI_HART_EXT_SSCTR, >> >> /** Maximum index of Hart extension */ >> SBI_HART_EXT_MAX, >> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c >> index 8e2979b5..c343805c 100644 >> --- a/lib/sbi/sbi_hart.c >> +++ b/lib/sbi/sbi_hart.c >> @@ -105,6 +105,11 @@ static void mstatus_init(struct sbi_scratch *scratch) >> else >> mstateen_val &= ~(SMSTATEEN0_SVSLCT); >> >> + if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SSCTR)) >> + mstateen_val |= SMSTATEEN0_CTR; >> + else >> + mstateen_val &= ~SMSTATEEN0_CTR; >> + >> csr_write(CSR_MSTATEEN0, mstateen_val); >> #if __riscv_xlen == 32 >> csr_write(CSR_MSTATEEN0H, mstateen_val >> 32); >> @@ -688,6 +693,8 @@ const struct sbi_hart_ext_data sbi_hart_ext[] = { >> __SBI_HART_EXT_DATA(zicfilp, SBI_HART_EXT_ZICFILP), >> __SBI_HART_EXT_DATA(zicfiss, SBI_HART_EXT_ZICFISS), >> __SBI_HART_EXT_DATA(ssdbltrp, SBI_HART_EXT_SSDBLTRP), >> + __SBI_HART_EXT_DATA(smctr, SBI_HART_EXT_SMCTR), >> + __SBI_HART_EXT_DATA(ssctr, SBI_HART_EXT_SSCTR), >> }; >> > > LGTM. > Reviewed-by: Atish Patra > Hi Anup, Can we pick this patch if no other concerns are there ? >> _Static_assert(SBI_HART_EXT_MAX == array_size(sbi_hart_ext), >> -- >> 2.43.0 >> > -- opensbi mailing list opensbi@lists.infradead.org http://lists.infradead.org/mailman/listinfo/opensbi