From b5ae8e8a650d8cb0134f03f53472fb026d2ee6e6 Mon Sep 17 00:00:00 2001 From: Anup Patel Date: Mon, 24 Dec 2018 16:49:01 +0530 Subject: lib: Add misaligned load/store trap handling We generally don't get misaligned load/store traps from Linux/U-Boot compiled using GCC 8.2 or higher but this is not true with older GCC toolchains. To tackle this we add misaligned load/store trap handling adopted from BBL sources but much more simpler. (Note: BBL sources can be found at https://github.com/riscv/riscv-pk.git) Signed-off-by: Anup Patel --- include/sbi/sbi_misaligned_ldst.h | 26 ++++++++ lib/objects.mk | 1 + lib/sbi_misaligned_ldst.c | 129 ++++++++++++++++++++++++++++++++++++++ lib/sbi_trap.c | 11 +++- 4 files changed, 166 insertions(+), 1 deletion(-) create mode 100644 include/sbi/sbi_misaligned_ldst.h create mode 100644 lib/sbi_misaligned_ldst.c diff --git a/include/sbi/sbi_misaligned_ldst.h b/include/sbi/sbi_misaligned_ldst.h new file mode 100644 index 0000000..1641958 --- /dev/null +++ b/include/sbi/sbi_misaligned_ldst.h @@ -0,0 +1,26 @@ +/* + * Copyright (c) 2018 Western Digital Corporation or its affiliates. + * + * Authors: + * Anup Patel + * + * SPDX-License-Identifier: BSD-2-Clause + */ + +#ifndef __SBI_MISALIGNED_LDST_H__ +#define __SBI_MISALIGNED_LDST_H__ + +#include + +struct sbi_trap_regs; +struct sbi_scratch; + +int sbi_misaligned_load_handler(u32 hartid, ulong mcause, + struct sbi_trap_regs *regs, + struct sbi_scratch *scratch); + +int sbi_misaligned_store_handler(u32 hartid, ulong mcause, + struct sbi_trap_regs *regs, + struct sbi_scratch *scratch); + +#endif diff --git a/lib/objects.mk b/lib/objects.mk index ed14677..b70557d 100644 --- a/lib/objects.mk +++ b/lib/objects.mk @@ -18,6 +18,7 @@ lib-objs-y += sbi_hart.o lib-objs-y += sbi_illegal_insn.o lib-objs-y += sbi_init.o lib-objs-y += sbi_ipi.o +lib-objs-y += sbi_misaligned_ldst.o lib-objs-y += sbi_system.o lib-objs-y += sbi_timer.o lib-objs-y += sbi_trap.o diff --git a/lib/sbi_misaligned_ldst.c b/lib/sbi_misaligned_ldst.c new file mode 100644 index 0000000..b35e919 --- /dev/null +++ b/lib/sbi_misaligned_ldst.c @@ -0,0 +1,129 @@ +/* + * Copyright (c) 2018 Western Digital Corporation or its affiliates. + * + * Authors: + * Anup Patel + * + * SPDX-License-Identifier: BSD-2-Clause + */ + +#include +#include +#include +#include +#include +#include + +union reg_data { + u8 data_bytes[8]; + ulong data_ulong; + u64 data_u64; +}; + +int sbi_misaligned_load_handler(u32 hartid, ulong mcause, + struct sbi_trap_regs *regs, + struct sbi_scratch *scratch) +{ + union reg_data val; + ulong mstatus = csr_read(mstatus); + ulong insn = get_insn(regs->mepc, &mstatus); + ulong addr = csr_read(mtval); + int i, shift = 0, len = 0; + + if ((insn & INSN_MASK_LW) == INSN_MATCH_LW) { + len = 4; + shift = 8 * (sizeof(ulong) - len); +#if __riscv_xlen == 64 + } else if ((insn & INSN_MASK_LD) == INSN_MATCH_LD) { + len = 8; + shift = 8 * (sizeof(ulong) - len); + } else if ((insn & INSN_MASK_LWU) == INSN_MATCH_LWU) { + len = 4; +#endif + } else if ((insn & INSN_MASK_LH) == INSN_MATCH_LH) { + len = 2; + shift = 8 * (sizeof(ulong) - len); + } else if ((insn & INSN_MASK_LHU) == INSN_MATCH_LHU) { + len = 2; +#ifdef __riscv_compressed +# if __riscv_xlen >= 64 + } else if ((insn & INSN_MASK_C_LD) == INSN_MATCH_C_LD) { + len = 8; + shift = 8 * (sizeof(ulong) - len); + insn = RVC_RS2S(insn) << SH_RD; + } else if ((insn & INSN_MASK_C_LDSP) == INSN_MATCH_C_LDSP && + ((insn >> SH_RD) & 0x1f)) { + len = 8; + shift = 8 * (sizeof(ulong) - len); +# endif + } else if ((insn & INSN_MASK_C_LW) ==INSN_MATCH_C_LW) { + len = 4; + shift = 8 * (sizeof(ulong) - len); + insn = RVC_RS2S(insn) << SH_RD; + } else if ((insn & INSN_MASK_C_LWSP) == INSN_MATCH_C_LWSP && + ((insn >> SH_RD) & 0x1f)) { + len = 4; + shift = 8 * (sizeof(ulong) - len); +#endif + } else + return SBI_EILL; + + val.data_u64 = 0; + for (i = 0; i < len; i++) + val.data_bytes[i] = load_u8((void *)(addr + i), regs->mepc); + + SET_RD(insn, regs, val.data_ulong << shift >> shift); + + regs->mepc += INSN_LEN(insn); + + return 0; +} + +int sbi_misaligned_store_handler(u32 hartid, ulong mcause, + struct sbi_trap_regs *regs, + struct sbi_scratch *scratch) +{ + union reg_data val; + ulong mstatus = csr_read(mstatus); + ulong insn = get_insn(regs->mepc, &mstatus); + ulong addr = csr_read(mtval); + int i, len = 0; + + val.data_ulong = GET_RS2(insn, regs); + + if ((insn & INSN_MASK_SW) == INSN_MATCH_SW) { + len = 4; +#if __riscv_xlen == 64 + } else if ((insn & INSN_MASK_SD) == INSN_MATCH_SD) { + len = 8; +#endif + } else if ((insn & INSN_MASK_SH) == INSN_MATCH_SH) { + len = 2; +#ifdef __riscv_compressed +# if __riscv_xlen >= 64 + } else if ((insn & INSN_MASK_C_SD) == INSN_MATCH_C_SD) { + len = 8; + val.data_ulong = GET_RS2S(insn, regs); + } else if ((insn & INSN_MASK_C_SDSP) == INSN_MATCH_C_SDSP && + ((insn >> SH_RD) & 0x1f)) { + len = 8; + val.data_ulong = GET_RS2C(insn, regs); +# endif + } else if ((insn & INSN_MASK_C_SW) == INSN_MATCH_C_SW) { + len = 4; + val.data_ulong = GET_RS2S(insn, regs); + } else if ((insn & INSN_MASK_C_SWSP) == INSN_MATCH_C_SWSP && + ((insn >> SH_RD) & 0x1f)) { + len = 4; + val.data_ulong = GET_RS2C(insn, regs); +#endif + } else + return SBI_EILL; + + for (i = 0; i < len; i++) + store_u8((void *)(addr + i), val.data_bytes[i], regs->mepc); + + regs->mepc += INSN_LEN(insn); + + return 0; +} diff --git a/lib/sbi_trap.c b/lib/sbi_trap.c index 284bb74..012a9a0 100644 --- a/lib/sbi_trap.c +++ b/lib/sbi_trap.c @@ -12,9 +12,10 @@ #include #include #include -#include #include +#include #include +#include #include #include @@ -95,6 +96,14 @@ void sbi_trap_handler(struct sbi_trap_regs *regs, rc = sbi_illegal_insn_handler(hartid, mcause, regs, scratch); msg = "illegal instruction handler failed"; break; + case CAUSE_MISALIGNED_LOAD: + rc = sbi_misaligned_load_handler(hartid, mcause, regs, scratch); + msg = "misaligned load handler failed"; + break; + case CAUSE_MISALIGNED_STORE: + rc = sbi_misaligned_store_handler(hartid, mcause, regs, scratch); + msg = "misaligned store handler failed"; + break; case CAUSE_SUPERVISOR_ECALL: case CAUSE_HYPERVISOR_ECALL: rc = sbi_ecall_handler(hartid, mcause, regs, scratch); -- cgit v1.2.3