opensbi/lib/riscv_unpriv.c

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/*
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2019 Western Digital Corporation or its affiliates.
*
* Authors:
* Anup Patel <anup.patel@wdc.com>
*/
#include <sbi/riscv_encoding.h>
#include <sbi/riscv_unpriv.h>
#include <sbi/sbi_bits.h>
#define DEFINE_UNPRIVILEGED_LOAD_FUNCTION(type, insn) \
type load_##type(const type *addr) \
{ \
register ulong __mstatus asm("a2"); \
type val; \
asm volatile( \
"csrrs %0, " STR(CSR_MSTATUS) ", %3\n" \
#insn " %1, %2\n" \
"csrw " STR(CSR_MSTATUS) ", %0" \
: "+&r"(__mstatus), "=&r"(val) \
: "m"(*addr), "r"(MSTATUS_MPRV)); \
return val; \
}
#define DEFINE_UNPRIVILEGED_STORE_FUNCTION(type, insn) \
void store_##type(type *addr, type val) \
{ \
register ulong __mstatus asm("a3"); \
asm volatile( \
"csrrs %0, " STR(CSR_MSTATUS) ", %3\n" \
#insn " %1, %2\n" \
"csrw " STR(CSR_MSTATUS) ", %0" \
: "+&r"(__mstatus) \
: "r"(val), "m"(*addr), "r"(MSTATUS_MPRV)); \
}
DEFINE_UNPRIVILEGED_LOAD_FUNCTION(u8, lbu)
DEFINE_UNPRIVILEGED_LOAD_FUNCTION(u16, lhu)
DEFINE_UNPRIVILEGED_LOAD_FUNCTION(s8, lb)
DEFINE_UNPRIVILEGED_LOAD_FUNCTION(s16, lh)
DEFINE_UNPRIVILEGED_LOAD_FUNCTION(s32, lw)
DEFINE_UNPRIVILEGED_STORE_FUNCTION(u8, sb)
DEFINE_UNPRIVILEGED_STORE_FUNCTION(u16, sh)
DEFINE_UNPRIVILEGED_STORE_FUNCTION(u32, sw)
#if __riscv_xlen == 64
DEFINE_UNPRIVILEGED_LOAD_FUNCTION(u32, lwu)
DEFINE_UNPRIVILEGED_LOAD_FUNCTION(u64, ld)
DEFINE_UNPRIVILEGED_STORE_FUNCTION(u64, sd)
DEFINE_UNPRIVILEGED_LOAD_FUNCTION(ulong, ld)
#else
DEFINE_UNPRIVILEGED_LOAD_FUNCTION(u32, lw)
DEFINE_UNPRIVILEGED_LOAD_FUNCTION(ulong, lw)
u64 load_u64(const u64 *addr)
{
return load_u32((u32 *)addr) + ((u64)load_u32((u32 *)addr + 1) << 32);
}
void store_u64(u64 *addr, u64 val)
{
store_u32((u32 *)addr, val);
store_u32((u32 *)addr + 1, val >> 32);
}
#endif
ulong get_insn(ulong mepc, ulong *mstatus)
{
register ulong __mepc asm("a2") = mepc;
register ulong __mstatus asm("a3");
ulong val;
#ifndef __riscv_compressed
asm("csrrs %[mstatus], " STR(CSR_MSTATUS) ", %[mprv]\n"
#if __riscv_xlen == 64
STR(LWU) " %[insn], (%[addr])\n"
#else
STR(LW) " %[insn], (%[addr])\n"
#endif
"csrw " STR(CSR_MSTATUS) ", %[mstatus]"
: [mstatus] "+&r"(__mstatus), [insn] "=&r"(val)
: [mprv] "r"(MSTATUS_MPRV | MSTATUS_MXR), [addr] "r"(__mepc));
#else
ulong rvc_mask = 3, tmp;
asm("csrrs %[mstatus], " STR(CSR_MSTATUS) ", %[mprv]\n"
"and %[tmp], %[addr], 2\n"
"bnez %[tmp], 1f\n"
#if __riscv_xlen == 64
STR(LWU) " %[insn], (%[addr])\n"
#else
STR(LW) " %[insn], (%[addr])\n"
#endif
"and %[tmp], %[insn], %[rvc_mask]\n"
"beq %[tmp], %[rvc_mask], 2f\n"
"sll %[insn], %[insn], %[xlen_minus_16]\n"
"srl %[insn], %[insn], %[xlen_minus_16]\n"
"j 2f\n"
"1:\n"
"lhu %[insn], (%[addr])\n"
"and %[tmp], %[insn], %[rvc_mask]\n"
"bne %[tmp], %[rvc_mask], 2f\n"
"lhu %[tmp], 2(%[addr])\n"
"sll %[tmp], %[tmp], 16\n"
"add %[insn], %[insn], %[tmp]\n"
"2: csrw " STR(CSR_MSTATUS) ", %[mstatus]"
: [mstatus] "+&r"(__mstatus), [insn] "=&r"(val), [tmp] "=&r"(tmp)
: [mprv] "r"(MSTATUS_MPRV | MSTATUS_MXR), [addr] "r"(__mepc),
[rvc_mask] "r"(rvc_mask), [xlen_minus_16] "i"(__riscv_xlen - 16));
#endif
if (mstatus)
*mstatus = __mstatus;
return val;
}