diff options
| -rw-r--r-- | firmware/fw_base.S | 121 | ||||
| -rw-r--r-- | include/sbi/sbi_platform.h | 4 | ||||
| -rw-r--r-- | include/sbi/sbi_trap.h | 2 | ||||
| -rw-r--r-- | lib/sbi/sbi_trap.c | 39 |
4 files changed, 166 insertions, 0 deletions
diff --git a/firmware/fw_base.S b/firmware/fw_base.S index cdb15429..043de7d7 100644 --- a/firmware/fw_base.S +++ b/firmware/fw_base.S @@ -529,6 +529,45 @@ memcmp: csrrw tp, CSR_MSCRATCH, tp .endm +.macro TRAP_SAVE_AND_SETUP_SP_T0_NMI + /* Swap TP and MNSCRATCH (for RNMI) */ + csrrw tp, CSR_MNSCRATCH, tp + + /* Save T0 in scratch space */ + REG_S t0, SBI_SCRATCH_TMP1_OFFSET(tp) + + /* + * Set T0 to appropriate exception stack + * + * Came_From_M_Mode = ((MNSTATUS.MNPP < PRV_M) ? 1 : 0) - 1; + * Exception_Stack = TP ^ (Came_From_M_Mode & (SP ^ TP)) + */ + csrr t0, CSR_MNSTATUS + srl t0, t0, 11 /* MNPP is at bits 11-12 */ + and t0, t0, PRV_M + slti t0, t0, PRV_M + add t0, t0, -1 + xor sp, sp, tp + and t0, t0, sp + xor sp, sp, tp + xor t0, tp, t0 + + /* Save original SP on exception stack */ + REG_S sp, (SBI_TRAP_REGS_OFFSET(sp) - SBI_TRAP_CONTEXT_SIZE)(t0) + + /* Set SP to exception stack and make room for trap context */ + add sp, t0, -(SBI_TRAP_CONTEXT_SIZE) + + /* Restore T0 from scratch space */ + REG_L t0, SBI_SCRATCH_TMP1_OFFSET(tp) + + /* Save T0 on stack */ + REG_S t0, SBI_TRAP_REGS_OFFSET(t0)(sp) + + /* Swap TP and MNSCRATCH */ + csrrw tp, CSR_MNSCRATCH, tp +.endm + .macro TRAP_SAVE_MEPC_MSTATUS have_mstatush /* Save MEPC and MSTATUS CSRs */ csrr t0, CSR_MEPC @@ -543,6 +582,20 @@ memcmp: .endif .endm +.macro TRAP_SAVE_MNEPC_MNSTATUS have_mstatush + /* + * Save MNEPC and MNSTATUS CSRs (for RNMI) + * Note: Trap context structure has generic field names (mepc, mstatus), + * we store MN* CSR values into these same structure fields. + */ + csrr t0, CSR_MNEPC + REG_S t0, SBI_TRAP_REGS_OFFSET(mepc)(sp) + csrr t0, CSR_MNSTATUS + REG_S t0, SBI_TRAP_REGS_OFFSET(mstatus)(sp) + /* MNSTATUSH doesn't exist in SMRNMI spec */ + REG_S zero, SBI_TRAP_REGS_OFFSET(mstatusH)(sp) +.endm + .macro TRAP_SAVE_GENERAL_REGS_EXCEPT_SP_T0 /* Save all general regisers except SP and T0 */ REG_S zero, SBI_TRAP_REGS_OFFSET(zero)(sp) @@ -606,12 +659,36 @@ memcmp: CLEAR_MDT t0 .endm +.macro TRAP_SAVE_NMI_INFO + /* + * Save NMI trap info (MNCAUSE, no MNTVAL in spec) + * Note: Trap info structure has generic field names (cause, tval, etc.), + * we store MN* CSR values into these same structure fields. + */ + csrr t0, CSR_MNCAUSE + REG_S t0, (SBI_TRAP_REGS_SIZE + SBI_TRAP_INFO_OFFSET(cause))(sp) + /* MNTVAL doesn't exist in SMRNMI spec */ + REG_S zero, (SBI_TRAP_REGS_SIZE + SBI_TRAP_INFO_OFFSET(tval))(sp) + REG_S zero, (SBI_TRAP_REGS_SIZE + SBI_TRAP_INFO_OFFSET(tval2))(sp) + REG_S zero, (SBI_TRAP_REGS_SIZE + SBI_TRAP_INFO_OFFSET(tinst))(sp) + REG_S zero, (SBI_TRAP_REGS_SIZE + SBI_TRAP_INFO_OFFSET(gva))(sp) + + /* We are ready to take another trap, clear MDT */ + CLEAR_MDT t0 +.endm + .macro TRAP_CALL_C_ROUTINE /* Call C routine */ add a0, sp, zero call sbi_trap_handler .endm +.macro TRAP_CALL_C_RNMI_ROUTINE + /* Call C routine */ + add a0, sp, zero + call sbi_trap_rnmi_handler +.endm + .macro TRAP_RESTORE_GENERAL_REGS_EXCEPT_A0_T0 /* Restore all general regisers except A0 and T0 */ REG_L ra, SBI_TRAP_REGS_OFFSET(ra)(a0) @@ -660,6 +737,19 @@ memcmp: csrw CSR_MEPC, t0 .endm +.macro TRAP_RESTORE_MNEPC_MNSTATUS + /* + * Restore MNSTATUS and MNEPC CSRs (for RNMI) + * Note: Load from generic structure fields (mstatus, mepc) and + * restore to NMI-specific CSRs (MNSTATUS, MNEPC). + * No MNSTATUSH in SMRNMI spec. + */ + REG_L t0, SBI_TRAP_REGS_OFFSET(mstatus)(a0) + csrw CSR_MNSTATUS, t0 + REG_L t0, SBI_TRAP_REGS_OFFSET(mepc)(a0) + csrw CSR_MNEPC, t0 +.endm + .macro TRAP_RESTORE_A0_T0 /* Restore T0 */ REG_L t0, SBI_TRAP_REGS_OFFSET(t0)(a0) @@ -726,6 +816,37 @@ _trap_handler_hyp: .section .entry, "ax", %progbits .align 3 + .globl _trap_rnmi_handler +_trap_rnmi_handler: + /* + * NMI interrupt handler using MN* CSRs + * + * Context detection via MNPP (previous privilege mode): + * - If MNPP < M-mode: use exception stack (TP) + * - If MNPP == M-mode: use current stack (SP) + * This handles nested interrupt cases. + */ + TRAP_SAVE_AND_SETUP_SP_T0_NMI + + TRAP_SAVE_MNEPC_MNSTATUS 0 + + TRAP_SAVE_GENERAL_REGS_EXCEPT_SP_T0 + + TRAP_SAVE_NMI_INFO + + TRAP_CALL_C_RNMI_ROUTINE + + TRAP_RESTORE_GENERAL_REGS_EXCEPT_A0_T0 + + TRAP_RESTORE_MNEPC_MNSTATUS + + TRAP_RESTORE_A0_T0 + + /* mnret - return from NMI (SMRNMI extension) */ + .word 0x70200073 + + .section .entry, "ax", %progbits + .align 3 .globl _reset_regs _reset_regs: diff --git a/include/sbi/sbi_platform.h b/include/sbi/sbi_platform.h index e65d9877..715df499 100644 --- a/include/sbi/sbi_platform.h +++ b/include/sbi/sbi_platform.h @@ -149,6 +149,10 @@ struct sbi_platform_operations { unsigned long log2len); /** platform specific pmp disable on current HART */ void (*pmp_disable)(unsigned int n); + + /** platform specific Smrnmi NMI handler. + * Returns SBI_SUCCESS on success, error code if NMI cannot be handled. */ + int (*rnmi_handler)(struct sbi_trap_context *tcntx); }; /** Platform default per-HART stack size for exception/interrupt handling */ diff --git a/include/sbi/sbi_trap.h b/include/sbi/sbi_trap.h index 731a0c98..091a2446 100644 --- a/include/sbi/sbi_trap.h +++ b/include/sbi/sbi_trap.h @@ -289,6 +289,8 @@ static inline void sbi_trap_set_context(struct sbi_scratch *scratch, struct sbi_trap_context *sbi_trap_handler(struct sbi_trap_context *tcntx); +struct sbi_trap_context *sbi_trap_rnmi_handler(struct sbi_trap_context *tcntx); + #endif #endif diff --git a/lib/sbi/sbi_trap.c b/lib/sbi/sbi_trap.c index f41db4d1..1e55b885 100644 --- a/lib/sbi/sbi_trap.c +++ b/lib/sbi/sbi_trap.c @@ -20,6 +20,7 @@ #include <sbi/sbi_irqchip.h> #include <sbi/sbi_trap_ldst.h> #include <sbi/sbi_pmu.h> +#include <sbi/sbi_platform.h> #include <sbi/sbi_scratch.h> #include <sbi/sbi_sse.h> #include <sbi/sbi_timer.h> @@ -375,3 +376,41 @@ trap_done: sbi_trap_set_context(scratch, tcntx->prev_context); return tcntx; } + +/** + * Default Resumable NMI (RNMI) handler + * + * This function is called from the _trap_rnmi_handler assembly code. + * It provides a simple wrapper that calls the platform-specific + * NMI handler if registered. If no handler is registered, it prints + * diagnostic information and hangs, similar to unhandled traps. + * + * Note: The trap context stores NMI CSR values (MNCAUSE, MNEPC, MNSTATUS) + * in the generic trap context fields (cause, mepc, mstatus). + * + * @param tcntx Pointer to trap context (saved on stack) + * @return Same trap context pointer (needed for restore macros) + */ +struct sbi_trap_context *sbi_trap_rnmi_handler(struct sbi_trap_context *tcntx) +{ + int rc; + const struct sbi_platform *plat = sbi_platform_thishart_ptr(); + const struct sbi_platform_operations *ops = sbi_platform_ops(plat); + + /* Call platform-specific NMI handler if registered */ + if (ops && ops->rnmi_handler) { + rc = ops->rnmi_handler(tcntx); + if (rc) { + /* Platform handler failed to handle NMI */ + sbi_trap_error("platform NMI handler failed", rc, tcntx); + } + return tcntx; + } + + /* No platform handler - treat as unhandled NMI */ + sbi_trap_error("unhandled NMI (no platform rnmi_handler)", + SBI_ENOTSUPP, tcntx); + + /* Never returns */ + return tcntx; +} |