[PATCH v8 05/29] riscv: zicfiss / zicfilp extension csr and bit definitions

Deepak Gupta
2024-11-11T21:06:11Z

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>
Reviewed-by: Charlie Jenkins <charlie@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 fe5d4eb9adea..e07b55028cc0 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)
@@ -205,6 +214,8 @@
#define ENVCFG_PMM_PMLEN_16 (_AC(0x3, ULL) << 32)
#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)
@@ -223,6 +234,11 @@
#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

/* mseccfg bits */
#define MSECCFG_PMM ENVCFG_PMM