/* Store hartid-to-scratch function address in scratch space */
la a4, _hartid_to_scratch
REG_S a4, SBI_SCRATCH_HARTID_TO_SCRATCH_OFFSET(tp)
+ /* Store trap-exit function address in scratch space */
+ la a4, _trap_exit
+ REG_S a4, SBI_SCRATCH_TRAP_EXIT_OFFSET(tp)
/* Clear tmp0 in scratch space */
REG_S zero, SBI_SCRATCH_TMP0_OFFSET(tp)
/* Store firmware options in scratch space */
#endif
csrw CSR_MTVEC, a4
+#if __riscv_xlen == 32
+ /* Override trap exit for H-extension */
+ csrr a5, CSR_MISA
+ srli a5, a5, ('H' - 'A')
+ andi a5, a5, 0x1
+ beq a5, zero, _skip_trap_exit_rv32_hyp
+ la a4, _trap_exit_rv32_hyp
+ csrr a5, CSR_MSCRATCH
+ REG_S a4, SBI_SCRATCH_TRAP_EXIT_OFFSET(a5)
+_skip_trap_exit_rv32_hyp:
+#endif
+
/* Initialize SBI runtime */
csrr a0, CSR_MSCRATCH
call sbi_init
mret
+ .section .entry, "ax", %progbits
+ .align 3
+ .globl _trap_exit
+_trap_exit:
+ add sp, a0, zero
+
+ TRAP_RESTORE_GENERAL_REGS_EXCEPT_SP_T0
+
+ TRAP_RESTORE_MEPC_MSTATUS 0
+
+ TRAP_RESTORE_SP_T0
+
+ mret
+
#if __riscv_xlen == 32
.section .entry, "ax", %progbits
.align 3
TRAP_RESTORE_SP_T0
mret
+
+ .section .entry, "ax", %progbits
+ .align 3
+ .globl _trap_exit_rv32_hyp
+_trap_exit_rv32_hyp:
+ add sp, a0, zero
+
+ TRAP_RESTORE_GENERAL_REGS_EXCEPT_SP_T0
+
+ TRAP_RESTORE_MEPC_MSTATUS 1
+
+ TRAP_RESTORE_SP_T0
+
+ mret
#endif
.section .entry, "ax", %progbits
#define SBI_SCRATCH_PLATFORM_ADDR_OFFSET (6 * __SIZEOF_POINTER__)
/** Offset of hartid_to_scratch member in sbi_scratch */
#define SBI_SCRATCH_HARTID_TO_SCRATCH_OFFSET (7 * __SIZEOF_POINTER__)
+/** Offset of trap_exit member in sbi_scratch */
+#define SBI_SCRATCH_TRAP_EXIT_OFFSET (8 * __SIZEOF_POINTER__)
/** Offset of tmp0 member in sbi_scratch */
-#define SBI_SCRATCH_TMP0_OFFSET (8 * __SIZEOF_POINTER__)
+#define SBI_SCRATCH_TMP0_OFFSET (9 * __SIZEOF_POINTER__)
/** Offset of options member in sbi_scratch */
-#define SBI_SCRATCH_OPTIONS_OFFSET (9 * __SIZEOF_POINTER__)
+#define SBI_SCRATCH_OPTIONS_OFFSET (10 * __SIZEOF_POINTER__)
/** Offset of extra space in sbi_scratch */
-#define SBI_SCRATCH_EXTRA_SPACE_OFFSET (10 * __SIZEOF_POINTER__)
+#define SBI_SCRATCH_EXTRA_SPACE_OFFSET (11 * __SIZEOF_POINTER__)
/** Maximum size of sbi_scratch (4KB) */
#define SBI_SCRATCH_SIZE (0x1000)
unsigned long platform_addr;
/** Address of HART ID to sbi_scratch conversion function */
unsigned long hartid_to_scratch;
+ /** Address of trap exit function */
+ unsigned long trap_exit;
/** Temporary storage */
unsigned long tmp0;
/** Options for OpenSBI library */
void sbi_trap_handler(struct sbi_trap_regs *regs);
+void __noreturn sbi_trap_exit(const struct sbi_trap_regs *regs);
+
#endif
#endif
#include <sbi/sbi_illegal_insn.h>
#include <sbi/sbi_ipi.h>
#include <sbi/sbi_misaligned_ldst.h>
+#include <sbi/sbi_scratch.h>
#include <sbi/sbi_timer.h>
#include <sbi/sbi_trap.h>
if (rc)
sbi_trap_error(msg, rc, mcause, mtval, mtval2, mtinst, regs);
}
+
+typedef void (*trap_exit_t)(const struct sbi_trap_regs *regs);
+
+/**
+ * Exit trap/interrupt handling
+ *
+ * This function is called by non-firmware code to abruptly exit
+ * trap/interrupt handling and resume execution at context pointed
+ * by given register state.
+ *
+ * @param regs pointer to register state
+ */
+void __noreturn sbi_trap_exit(const struct sbi_trap_regs *regs)
+{
+ struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
+
+ ((trap_exit_t)scratch->trap_exit)(regs);
+ __builtin_unreachable();
+}