Re: [PATCH v3 06/29] riscv: zicfiss / zicfilp extension csr and bit definitions

Charlie Jenkins
2024-05-10T22:37:46Z

On Wed, Apr 03, 2024 at 04:34:54PM -0700, Deepak Gupta wrote:
> zicfiss and zicfilp extension gets enabled via b3 and b2 in *envcfg CSR.
> menvcfg controls enabling for S/HS mode. henvcfg control enabling for VS
> while senvcfg controls enabling for U/VU mode.
>
> zicfilp extension extends *status CSR to hold `expected landing pad` bit.
> A trap or interrupt can occur between an indirect jmp/call and target
> instr. `expected landing pad` bit from CPU is recorded into xstatus CSR so
> that when supervisor performs xret, `expected landing pad` state of CPU can
> be restored.
>
> zicfiss adds one new CSR
> - CSR_SSP: CSR_SSP contains current shadow stack pointer.
>
> Signed-off-by: Deepak Gupta <debug@rivosinc.com>
> ---
> arch/riscv/include/asm/csr.h | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
> index bbd2207adb39..3bb126d1c5ff 100644
> --- a/arch/riscv/include/asm/csr.h
> +++ b/arch/riscv/include/asm/csr.h
> @@ -18,6 +18,15 @@
> #define SR_MPP _AC(0x00001800, UL) /* Previously Machine */
> #define SR_SUM _AC(0x00040000, UL) /* Supervisor User Memory Access */
>
> +/* zicfilp landing pad status bit */
> +#define SR_SPELP _AC(0x00800000, UL)
> +#define SR_MPELP _AC(0x020000000000, UL)
> +#ifdef CONFIG_RISCV_M_MODE
> +#define SR_ELP SR_MPELP
> +#else
> +#define SR_ELP SR_SPELP
> +#endif
> +
> #define SR_FS _AC(0x00006000, UL) /* Floating-point Status */
> #define SR_FS_OFF _AC(0x00000000, UL)
> #define SR_FS_INITIAL _AC(0x00002000, UL)
> @@ -196,6 +205,8 @@
> #define ENVCFG_PBMTE (_AC(1, ULL) << 62)
> #define ENVCFG_CBZE (_AC(1, UL) << 7)
> #define ENVCFG_CBCFE (_AC(1, UL) << 6)
> +#define ENVCFG_LPE (_AC(1, UL) << 2)
> +#define ENVCFG_SSE (_AC(1, UL) << 3)
> #define ENVCFG_CBIE_SHIFT 4
> #define ENVCFG_CBIE (_AC(0x3, UL) << ENVCFG_CBIE_SHIFT)
> #define ENVCFG_CBIE_ILL _AC(0x0, UL)
> @@ -216,6 +227,11 @@
> #define SMSTATEEN0_HSENVCFG (_ULL(1) << SMSTATEEN0_HSENVCFG_SHIFT)
> #define SMSTATEEN0_SSTATEEN0_SHIFT 63
> #define SMSTATEEN0_SSTATEEN0 (_ULL(1) << SMSTATEEN0_SSTATEEN0_SHIFT)
> +/*
> + * zicfiss user mode csr
> + * CSR_SSP holds current shadow stack pointer.
> + */
> +#define CSR_SSP 0x011
>
> /* symbolic CSR names: */
> #define CSR_CYCLE 0xc00
> --
> 2.43.2
>

Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>