lib: Emulate AMO instructions when Zaamo is not available

The AMO instructions are very critical for Linux so allow low-end
RISC-V implementations without Zaamo to boot Linux by emulating AMO
instructions using Zalrsc when OpenSBI is compiled without Zaamo.

Signed-off-by: Chao-ying Fu <cfu@mips.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Link: https://lore.kernel.org/r/20250519121207.976949-1-apatel@ventanamicro.com
Signed-off-by: Anup Patel <anup@brainfault.org>

3 files changed, 668 insertions, 4 deletions

diff --git a/lib/sbi/objects.mk b/lib/sbi/objects.mk
index 9cb2842..8abe1e8 100644
--- a/lib/sbi/objects.mk
+++ b/lib/sbi/objects.mk
@@ -79,6 +79,7 @@ libsbi-objs-y += sbi_heap.o
 libsbi-objs-y += sbi_math.o
 libsbi-objs-y += sbi_hfence.o
 libsbi-objs-y += sbi_hsm.o
+libsbi-objs-y += sbi_illegal_atomic.o
 libsbi-objs-y += sbi_illegal_insn.o
 libsbi-objs-y += sbi_init.o
 libsbi-objs-y += sbi_ipi.o
diff --git a/lib/sbi/sbi_illegal_atomic.c b/lib/sbi/sbi_illegal_atomic.c
new file mode 100644
index 0000000..2161b23
--- /dev/null
+++ b/lib/sbi/sbi_illegal_atomic.c
@@ -0,0 +1,664 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2025 MIPS
+ *
+ */
+
+#include <sbi/riscv_asm.h>
+#include <sbi/sbi_hart.h>
+#include <sbi/sbi_trap.h>
+#include <sbi/sbi_illegal_atomic.h>
+#include <sbi/sbi_illegal_insn.h>
+
+#if !defined(__riscv_atomic) && !defined(__riscv_zalrsc)
+#error "opensbi strongly relies on the A extension of RISC-V"
+#endif
+
+#ifdef __riscv_atomic
+
+int sbi_illegal_atomic(ulong insn, struct sbi_trap_regs *regs)
+{
+	return truly_illegal_insn(insn, regs);
+}
+
+#elif __riscv_zalrsc
+
+#define DEFINE_UNPRIVILEGED_LR_FUNCTION(type, aqrl, insn)			\
+	static type lr_##type##aqrl(const type *addr,				\
+				struct sbi_trap_info *trap)			\
+	{									\
+		register ulong tinfo asm("a3");					\
+		register ulong mstatus = 0;					\
+		register ulong mtvec = sbi_hart_expected_trap_addr();		\
+		type ret = 0;							\
+		trap->cause = 0;						\
+		asm volatile(							\
+			"add %[tinfo], %[taddr], zero\n"			\
+			"csrrw %[mtvec], " STR(CSR_MTVEC) ", %[mtvec]\n"	\
+			"csrrs %[mstatus], " STR(CSR_MSTATUS) ", %[mprv]\n"	\
+			".option push\n"					\
+			".option norvc\n"					\
+			#insn " %[ret], %[addr]\n"				\
+			".option pop\n"						\
+			"csrw " STR(CSR_MSTATUS) ", %[mstatus]\n"		\
+			"csrw " STR(CSR_MTVEC) ", %[mtvec]"			\
+		    : [mstatus] "+&r"(mstatus), [mtvec] "+&r"(mtvec),		\
+		      [tinfo] "+&r"(tinfo), [ret] "=&r"(ret)			\
+		    : [addr] "m"(*addr), [mprv] "r"(MSTATUS_MPRV),		\
+		      [taddr] "r"((ulong)trap)					\
+		    : "a4", "memory");						\
+		return ret;							\
+	}
+
+#define DEFINE_UNPRIVILEGED_SC_FUNCTION(type, aqrl, insn)			\
+	static type sc_##type##aqrl(type *addr, type val,			\
+				struct sbi_trap_info *trap)			\
+	{									\
+		register ulong tinfo asm("a3");					\
+		register ulong mstatus = 0;					\
+		register ulong mtvec = sbi_hart_expected_trap_addr();		\
+		type ret = 0;							\
+		trap->cause = 0;						\
+		asm volatile(							\
+			"add %[tinfo], %[taddr], zero\n"			\
+			"csrrw %[mtvec], " STR(CSR_MTVEC) ", %[mtvec]\n"	\
+			"csrrs %[mstatus], " STR(CSR_MSTATUS) ", %[mprv]\n"	\
+			".option push\n"					\
+			".option norvc\n"					\
+			#insn " %[ret], %[val], %[addr]\n"			\
+			".option pop\n"						\
+			"csrw " STR(CSR_MSTATUS) ", %[mstatus]\n"		\
+			"csrw " STR(CSR_MTVEC) ", %[mtvec]"			\
+		    : [mstatus] "+&r"(mstatus), [mtvec] "+&r"(mtvec),		\
+		      [tinfo] "+&r"(tinfo), [ret] "=&r"(ret)			\
+		    : [addr] "m"(*addr), [mprv] "r"(MSTATUS_MPRV),		\
+		      [val] "r"(val), [taddr] "r"((ulong)trap)			\
+		    : "a4", "memory");						\
+		return ret;							\
+	}
+
+DEFINE_UNPRIVILEGED_LR_FUNCTION(s32, , lr.w);
+DEFINE_UNPRIVILEGED_LR_FUNCTION(s32, _aq, lr.w.aq);
+DEFINE_UNPRIVILEGED_LR_FUNCTION(s32, _rl, lr.w.rl);
+DEFINE_UNPRIVILEGED_LR_FUNCTION(s32, _aqrl, lr.w.aqrl);
+DEFINE_UNPRIVILEGED_SC_FUNCTION(s32, , sc.w);
+DEFINE_UNPRIVILEGED_SC_FUNCTION(s32, _aq, sc.w.aq);
+DEFINE_UNPRIVILEGED_SC_FUNCTION(s32, _rl, sc.w.rl);
+DEFINE_UNPRIVILEGED_SC_FUNCTION(s32, _aqrl, sc.w.aqrl);
+#if __riscv_xlen == 64
+DEFINE_UNPRIVILEGED_LR_FUNCTION(s64, , lr.d);
+DEFINE_UNPRIVILEGED_LR_FUNCTION(s64, _aq, lr.d.aq);
+DEFINE_UNPRIVILEGED_LR_FUNCTION(s64, _rl, lr.d.rl);
+DEFINE_UNPRIVILEGED_LR_FUNCTION(s64, _aqrl, lr.d.aqrl);
+DEFINE_UNPRIVILEGED_SC_FUNCTION(s64, , sc.d);
+DEFINE_UNPRIVILEGED_SC_FUNCTION(s64, _aq, sc.d.aq);
+DEFINE_UNPRIVILEGED_SC_FUNCTION(s64, _rl, sc.d.rl);
+DEFINE_UNPRIVILEGED_SC_FUNCTION(s64, _aqrl, sc.d.aqrl);
+#endif
+
+#define DEFINE_ATOMIC_FUNCTION(name, type, func)				\
+	static int atomic_##name(ulong insn, struct sbi_trap_regs *regs)	\
+	{									\
+		struct sbi_trap_info uptrap;					\
+		ulong addr = GET_RS1(insn, regs);				\
+		ulong val = GET_RS2(insn, regs);				\
+		ulong rd_val = 0;						\
+		ulong fail = 1;							\
+		while (fail) {							\
+			rd_val = lr_##type((void *)addr, &uptrap);		\
+			if (uptrap.cause) {					\
+				return sbi_trap_redirect(regs, &uptrap);	\
+			}							\
+			fail = sc_##type((void *)addr, func, &uptrap);	\
+			if (uptrap.cause) {					\
+				return sbi_trap_redirect(regs, &uptrap);	\
+			}							\
+		}								\
+		SET_RD(insn, regs, rd_val);					\
+		regs->mepc += 4;						\
+		return 0;							\
+	}
+
+DEFINE_ATOMIC_FUNCTION(add_w, s32, rd_val + val);
+DEFINE_ATOMIC_FUNCTION(add_w_aq, s32_aq, rd_val + val);
+DEFINE_ATOMIC_FUNCTION(add_w_rl, s32_rl, rd_val + val);
+DEFINE_ATOMIC_FUNCTION(add_w_aqrl, s32_aqrl, rd_val + val);
+DEFINE_ATOMIC_FUNCTION(and_w, s32, rd_val & val);
+DEFINE_ATOMIC_FUNCTION(and_w_aq, s32_aq, rd_val & val);
+DEFINE_ATOMIC_FUNCTION(and_w_rl, s32_rl, rd_val & val);
+DEFINE_ATOMIC_FUNCTION(and_w_aqrl, s32_aqrl, rd_val & val);
+DEFINE_ATOMIC_FUNCTION(or_w, s32, rd_val | val);
+DEFINE_ATOMIC_FUNCTION(or_w_aq, s32_aq, rd_val | val);
+DEFINE_ATOMIC_FUNCTION(or_w_rl, s32_rl, rd_val | val);
+DEFINE_ATOMIC_FUNCTION(or_w_aqrl, s32_aqrl, rd_val | val);
+DEFINE_ATOMIC_FUNCTION(xor_w, s32, rd_val ^ val);
+DEFINE_ATOMIC_FUNCTION(xor_w_aq, s32_aq, rd_val ^ val);
+DEFINE_ATOMIC_FUNCTION(xor_w_rl, s32_rl, rd_val ^ val);
+DEFINE_ATOMIC_FUNCTION(xor_w_aqrl, s32_aqrl, rd_val ^ val);
+DEFINE_ATOMIC_FUNCTION(swap_w, s32, val);
+DEFINE_ATOMIC_FUNCTION(swap_w_aq, s32_aq, val);
+DEFINE_ATOMIC_FUNCTION(swap_w_rl, s32_rl, val);
+DEFINE_ATOMIC_FUNCTION(swap_w_aqrl, s32_aqrl, val);
+DEFINE_ATOMIC_FUNCTION(max_w, s32, (s32)rd_val > (s32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(max_w_aq, s32_aq, (s32)rd_val > (s32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(max_w_rl, s32_rl, (s32)rd_val > (s32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(max_w_aqrl, s32_aqrl, (s32)rd_val > (s32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(maxu_w, s32, (u32)rd_val > (u32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(maxu_w_aq, s32_aq, (u32)rd_val > (u32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(maxu_w_rl, s32_rl, (u32)rd_val > (u32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(maxu_w_aqrl, s32_aqrl, (u32)rd_val > (u32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(min_w, s32, (s32)rd_val < (s32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(min_w_aq, s32_aq, (s32)rd_val < (s32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(min_w_rl, s32_rl, (s32)rd_val < (s32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(min_w_aqrl, s32_aqrl, (s32)rd_val < (s32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(minu_w, s32, (u32)rd_val < (u32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(minu_w_aq, s32_aq, (u32)rd_val < (u32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(minu_w_rl, s32_rl, (u32)rd_val < (u32)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(minu_w_aqrl, s32_aqrl, (u32)rd_val < (u32)val ? rd_val : val);
+
+#if __riscv_xlen == 64
+DEFINE_ATOMIC_FUNCTION(add_d, s64, rd_val + val);
+DEFINE_ATOMIC_FUNCTION(add_d_aq, s64_aq, rd_val + val);
+DEFINE_ATOMIC_FUNCTION(add_d_rl, s64_rl, rd_val + val);
+DEFINE_ATOMIC_FUNCTION(add_d_aqrl, s64_aqrl, rd_val + val);
+DEFINE_ATOMIC_FUNCTION(and_d, s64, rd_val & val);
+DEFINE_ATOMIC_FUNCTION(and_d_aq, s64_aq, rd_val & val);
+DEFINE_ATOMIC_FUNCTION(and_d_rl, s64_rl, rd_val & val);
+DEFINE_ATOMIC_FUNCTION(and_d_aqrl, s64_aqrl, rd_val & val);
+DEFINE_ATOMIC_FUNCTION(or_d, s64, rd_val | val);
+DEFINE_ATOMIC_FUNCTION(or_d_aq, s64_aq, rd_val | val);
+DEFINE_ATOMIC_FUNCTION(or_d_rl, s64_rl, rd_val | val);
+DEFINE_ATOMIC_FUNCTION(or_d_aqrl, s64_aqrl, rd_val | val);
+DEFINE_ATOMIC_FUNCTION(xor_d, s64, rd_val ^ val);
+DEFINE_ATOMIC_FUNCTION(xor_d_aq, s64_aq, rd_val ^ val);
+DEFINE_ATOMIC_FUNCTION(xor_d_rl, s64_rl, rd_val ^ val);
+DEFINE_ATOMIC_FUNCTION(xor_d_aqrl, s64_aqrl, rd_val ^ val);
+DEFINE_ATOMIC_FUNCTION(swap_d, s64, val);
+DEFINE_ATOMIC_FUNCTION(swap_d_aq, s64_aq, val);
+DEFINE_ATOMIC_FUNCTION(swap_d_rl, s64_rl, val);
+DEFINE_ATOMIC_FUNCTION(swap_d_aqrl, s64_aqrl, val);
+DEFINE_ATOMIC_FUNCTION(max_d, s64, (s64)rd_val > (s64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(max_d_aq, s64_aq, (s64)rd_val > (s64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(max_d_rl, s64_rl, (s64)rd_val > (s64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(max_d_aqrl, s64_aqrl, (s64)rd_val > (s64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(maxu_d, s64, (u64)rd_val > (u64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(maxu_d_aq, s64_aq, (u64)rd_val > (u64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(maxu_d_rl, s64_rl, (u64)rd_val > (u64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(maxu_d_aqrl, s64_aqrl, (u64)rd_val > (u64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(min_d, s64, (s64)rd_val < (s64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(min_d_aq, s64_aq, (s64)rd_val < (s64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(min_d_rl, s64_rl, (s64)rd_val < (s64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(min_d_aqrl, s64_aqrl, (s64)rd_val < (s64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(minu_d, s64, (u64)rd_val < (u64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(minu_d_aq, s64_aq, (u64)rd_val < (u64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(minu_d_rl, s64_rl, (u64)rd_val < (u64)val ? rd_val : val);
+DEFINE_ATOMIC_FUNCTION(minu_d_aqrl, s64_aqrl, (u64)rd_val < (u64)val ? rd_val : val);
+#endif
+
+static const illegal_insn_func amoadd_table[32] = {
+	truly_illegal_insn, /* 0 */
+	truly_illegal_insn, /* 1 */
+	truly_illegal_insn, /* 2 */
+	truly_illegal_insn, /* 3 */
+	truly_illegal_insn, /* 4 */
+	truly_illegal_insn, /* 5 */
+	truly_illegal_insn, /* 6 */
+	truly_illegal_insn, /* 7 */
+	atomic_add_w, /* 8 */
+	atomic_add_w_rl, /* 9 */
+	atomic_add_w_aq, /* 10 */
+	atomic_add_w_aqrl, /* 11 */
+#if __riscv_xlen == 64
+	atomic_add_d, /* 12 */
+	atomic_add_d_rl, /* 13 */
+	atomic_add_d_aq, /* 14 */
+	atomic_add_d_aqrl, /* 15 */
+#else
+	truly_illegal_insn, /* 12 */
+	truly_illegal_insn, /* 13 */
+	truly_illegal_insn, /* 14 */
+	truly_illegal_insn, /* 15 */
+#endif
+	truly_illegal_insn, /* 16 */
+	truly_illegal_insn, /* 17 */
+	truly_illegal_insn, /* 18 */
+	truly_illegal_insn, /* 19 */
+	truly_illegal_insn, /* 20 */
+	truly_illegal_insn, /* 21 */
+	truly_illegal_insn, /* 22 */
+	truly_illegal_insn, /* 23 */
+	truly_illegal_insn, /* 24 */
+	truly_illegal_insn, /* 25 */
+	truly_illegal_insn, /* 26 */
+	truly_illegal_insn, /* 27 */
+	truly_illegal_insn, /* 28 */
+	truly_illegal_insn, /* 29 */
+	truly_illegal_insn, /* 30 */
+	truly_illegal_insn, /* 31 */
+};
+
+static const illegal_insn_func amoswap_table[32] = {
+	truly_illegal_insn, /* 0 */
+	truly_illegal_insn, /* 1 */
+	truly_illegal_insn, /* 2 */
+	truly_illegal_insn, /* 3 */
+	truly_illegal_insn, /* 4 */
+	truly_illegal_insn, /* 5 */
+	truly_illegal_insn, /* 6 */
+	truly_illegal_insn, /* 7 */
+	atomic_swap_w, /* 8 */
+	atomic_swap_w_rl, /* 9 */
+	atomic_swap_w_aq, /* 10 */
+	atomic_swap_w_aqrl, /* 11 */
+#if __riscv_xlen == 64
+	atomic_swap_d, /* 12 */
+	atomic_swap_d_rl, /* 13 */
+	atomic_swap_d_aq, /* 14 */
+	atomic_swap_d_aqrl, /* 15 */
+#else
+	truly_illegal_insn, /* 12 */
+	truly_illegal_insn, /* 13 */
+	truly_illegal_insn, /* 14 */
+	truly_illegal_insn, /* 15 */
+#endif
+	truly_illegal_insn, /* 16 */
+	truly_illegal_insn, /* 17 */
+	truly_illegal_insn, /* 18 */
+	truly_illegal_insn, /* 19 */
+	truly_illegal_insn, /* 20 */
+	truly_illegal_insn, /* 21 */
+	truly_illegal_insn, /* 22 */
+	truly_illegal_insn, /* 23 */
+	truly_illegal_insn, /* 24 */
+	truly_illegal_insn, /* 25 */
+	truly_illegal_insn, /* 26 */
+	truly_illegal_insn, /* 27 */
+	truly_illegal_insn, /* 28 */
+	truly_illegal_insn, /* 29 */
+	truly_illegal_insn, /* 30 */
+	truly_illegal_insn, /* 31 */
+};
+
+static const illegal_insn_func amoxor_table[32] = {
+	truly_illegal_insn, /* 0 */
+	truly_illegal_insn, /* 1 */
+	truly_illegal_insn, /* 2 */
+	truly_illegal_insn, /* 3 */
+	truly_illegal_insn, /* 4 */
+	truly_illegal_insn, /* 5 */
+	truly_illegal_insn, /* 6 */
+	truly_illegal_insn, /* 7 */
+	atomic_xor_w, /* 8 */
+	atomic_xor_w_rl, /* 9 */
+	atomic_xor_w_aq, /* 10 */
+	atomic_xor_w_aqrl, /* 11 */
+#if __riscv_xlen == 64
+	atomic_xor_d, /* 12 */
+	atomic_xor_d_rl, /* 13 */
+	atomic_xor_d_aq, /* 14 */
+	atomic_xor_d_aqrl, /* 15 */
+#else
+	truly_illegal_insn, /* 12 */
+	truly_illegal_insn, /* 13 */
+	truly_illegal_insn, /* 14 */
+	truly_illegal_insn, /* 15 */
+#endif
+	truly_illegal_insn, /* 16 */
+	truly_illegal_insn, /* 17 */
+	truly_illegal_insn, /* 18 */
+	truly_illegal_insn, /* 19 */
+	truly_illegal_insn, /* 20 */
+	truly_illegal_insn, /* 21 */
+	truly_illegal_insn, /* 22 */
+	truly_illegal_insn, /* 23 */
+	truly_illegal_insn, /* 24 */
+	truly_illegal_insn, /* 25 */
+	truly_illegal_insn, /* 26 */
+	truly_illegal_insn, /* 27 */
+	truly_illegal_insn, /* 28 */
+	truly_illegal_insn, /* 29 */
+	truly_illegal_insn, /* 30 */
+	truly_illegal_insn, /* 31 */
+};
+
+static const illegal_insn_func amoor_table[32] = {
+	truly_illegal_insn, /* 0 */
+	truly_illegal_insn, /* 1 */
+	truly_illegal_insn, /* 2 */
+	truly_illegal_insn, /* 3 */
+	truly_illegal_insn, /* 4 */
+	truly_illegal_insn, /* 5 */
+	truly_illegal_insn, /* 6 */
+	truly_illegal_insn, /* 7 */
+	atomic_or_w, /* 8 */
+	atomic_or_w_rl, /* 9 */
+	atomic_or_w_aq, /* 10 */
+	atomic_or_w_aqrl, /* 11 */
+#if __riscv_xlen == 64
+	atomic_or_d, /* 12 */
+	atomic_or_d_rl, /* 13 */
+	atomic_or_d_aq, /* 14 */
+	atomic_or_d_aqrl, /* 15 */
+#else
+	truly_illegal_insn, /* 12 */
+	truly_illegal_insn, /* 13 */
+	truly_illegal_insn, /* 14 */
+	truly_illegal_insn, /* 15 */
+#endif
+	truly_illegal_insn, /* 16 */
+	truly_illegal_insn, /* 17 */
+	truly_illegal_insn, /* 18 */
+	truly_illegal_insn, /* 19 */
+	truly_illegal_insn, /* 20 */
+	truly_illegal_insn, /* 21 */
+	truly_illegal_insn, /* 22 */
+	truly_illegal_insn, /* 23 */
+	truly_illegal_insn, /* 24 */
+	truly_illegal_insn, /* 25 */
+	truly_illegal_insn, /* 26 */
+	truly_illegal_insn, /* 27 */
+	truly_illegal_insn, /* 28 */
+	truly_illegal_insn, /* 29 */
+	truly_illegal_insn, /* 30 */
+	truly_illegal_insn, /* 31 */
+};
+
+static const illegal_insn_func amoand_table[32] = {
+	truly_illegal_insn, /* 0 */
+	truly_illegal_insn, /* 1 */
+	truly_illegal_insn, /* 2 */
+	truly_illegal_insn, /* 3 */
+	truly_illegal_insn, /* 4 */
+	truly_illegal_insn, /* 5 */
+	truly_illegal_insn, /* 6 */
+	truly_illegal_insn, /* 7 */
+	atomic_and_w, /* 8 */
+	atomic_and_w_rl, /* 9 */
+	atomic_and_w_aq, /* 10 */
+	atomic_and_w_aqrl, /* 11 */
+#if __riscv_xlen == 64
+	atomic_and_d, /* 12 */
+	atomic_and_d_rl, /* 13 */
+	atomic_and_d_aq, /* 14 */
+	atomic_and_d_aqrl, /* 15 */
+#else
+	truly_illegal_insn, /* 12 */
+	truly_illegal_insn, /* 13 */
+	truly_illegal_insn, /* 14 */
+	truly_illegal_insn, /* 15 */
+#endif
+	truly_illegal_insn, /* 16 */
+	truly_illegal_insn, /* 17 */
+	truly_illegal_insn, /* 18 */
+	truly_illegal_insn, /* 19 */
+	truly_illegal_insn, /* 20 */
+	truly_illegal_insn, /* 21 */
+	truly_illegal_insn, /* 22 */
+	truly_illegal_insn, /* 23 */
+	truly_illegal_insn, /* 24 */
+	truly_illegal_insn, /* 25 */
+	truly_illegal_insn, /* 26 */
+	truly_illegal_insn, /* 27 */
+	truly_illegal_insn, /* 28 */
+	truly_illegal_insn, /* 29 */
+	truly_illegal_insn, /* 30 */
+	truly_illegal_insn, /* 31 */
+};
+
+static const illegal_insn_func amomin_table[32] = {
+	truly_illegal_insn, /* 0 */
+	truly_illegal_insn, /* 1 */
+	truly_illegal_insn, /* 2 */
+	truly_illegal_insn, /* 3 */
+	truly_illegal_insn, /* 4 */
+	truly_illegal_insn, /* 5 */
+	truly_illegal_insn, /* 6 */
+	truly_illegal_insn, /* 7 */
+	atomic_min_w, /* 8 */
+	atomic_min_w_rl, /* 9 */
+	atomic_min_w_aq, /* 10 */
+	atomic_min_w_aqrl, /* 11 */
+#if __riscv_xlen == 64
+	atomic_min_d, /* 12 */
+	atomic_min_d_rl, /* 13 */
+	atomic_min_d_aq, /* 14 */
+	atomic_min_d_aqrl, /* 15 */
+#else
+	truly_illegal_insn, /* 12 */
+	truly_illegal_insn, /* 13 */
+	truly_illegal_insn, /* 14 */
+	truly_illegal_insn, /* 15 */
+#endif
+	truly_illegal_insn, /* 16 */
+	truly_illegal_insn, /* 17 */
+	truly_illegal_insn, /* 18 */
+	truly_illegal_insn, /* 19 */
+	truly_illegal_insn, /* 20 */
+	truly_illegal_insn, /* 21 */
+	truly_illegal_insn, /* 22 */
+	truly_illegal_insn, /* 23 */
+	truly_illegal_insn, /* 24 */
+	truly_illegal_insn, /* 25 */
+	truly_illegal_insn, /* 26 */
+	truly_illegal_insn, /* 27 */
+	truly_illegal_insn, /* 28 */
+	truly_illegal_insn, /* 29 */
+	truly_illegal_insn, /* 30 */
+	truly_illegal_insn, /* 31 */
+};
+
+static const illegal_insn_func amomax_table[32] = {
+	truly_illegal_insn, /* 0 */
+	truly_illegal_insn, /* 1 */
+	truly_illegal_insn, /* 2 */
+	truly_illegal_insn, /* 3 */
+	truly_illegal_insn, /* 4 */
+	truly_illegal_insn, /* 5 */
+	truly_illegal_insn, /* 6 */
+	truly_illegal_insn, /* 7 */
+	atomic_max_w, /* 8 */
+	atomic_max_w_rl, /* 9 */
+	atomic_max_w_aq, /* 10 */
+	atomic_max_w_aqrl, /* 11 */
+#if __riscv_xlen == 64
+	atomic_max_d, /* 12 */
+	atomic_max_d_rl, /* 13 */
+	atomic_max_d_aq, /* 14 */
+	atomic_max_d_aqrl, /* 15 */
+#else
+	truly_illegal_insn, /* 12 */
+	truly_illegal_insn, /* 13 */
+	truly_illegal_insn, /* 14 */
+	truly_illegal_insn, /* 15 */
+#endif
+	truly_illegal_insn, /* 16 */
+	truly_illegal_insn, /* 17 */
+	truly_illegal_insn, /* 18 */
+	truly_illegal_insn, /* 19 */
+	truly_illegal_insn, /* 20 */
+	truly_illegal_insn, /* 21 */
+	truly_illegal_insn, /* 22 */
+	truly_illegal_insn, /* 23 */
+	truly_illegal_insn, /* 24 */
+	truly_illegal_insn, /* 25 */
+	truly_illegal_insn, /* 26 */
+	truly_illegal_insn, /* 27 */
+	truly_illegal_insn, /* 28 */
+	truly_illegal_insn, /* 29 */
+	truly_illegal_insn, /* 30 */
+	truly_illegal_insn, /* 31 */
+};
+
+static const illegal_insn_func amominu_table[32] = {
+	truly_illegal_insn, /* 0 */
+	truly_illegal_insn, /* 1 */
+	truly_illegal_insn, /* 2 */
+	truly_illegal_insn, /* 3 */
+	truly_illegal_insn, /* 4 */
+	truly_illegal_insn, /* 5 */
+	truly_illegal_insn, /* 6 */
+	truly_illegal_insn, /* 7 */
+	atomic_minu_w, /* 8 */
+	atomic_minu_w_rl, /* 9 */
+	atomic_minu_w_aq, /* 10 */
+	atomic_minu_w_aqrl, /* 11 */
+#if __riscv_xlen == 64
+	atomic_minu_d, /* 12 */
+	atomic_minu_d_rl, /* 13 */
+	atomic_minu_d_aq, /* 14 */
+	atomic_minu_d_aqrl, /* 15 */
+#else
+	truly_illegal_insn, /* 12 */
+	truly_illegal_insn, /* 13 */
+	truly_illegal_insn, /* 14 */
+	truly_illegal_insn, /* 15 */
+#endif
+	truly_illegal_insn, /* 16 */
+	truly_illegal_insn, /* 17 */
+	truly_illegal_insn, /* 18 */
+	truly_illegal_insn, /* 19 */
+	truly_illegal_insn, /* 20 */
+	truly_illegal_insn, /* 21 */
+	truly_illegal_insn, /* 22 */
+	truly_illegal_insn, /* 23 */
+	truly_illegal_insn, /* 24 */
+	truly_illegal_insn, /* 25 */
+	truly_illegal_insn, /* 26 */
+	truly_illegal_insn, /* 27 */
+	truly_illegal_insn, /* 28 */
+	truly_illegal_insn, /* 29 */
+	truly_illegal_insn, /* 30 */
+	truly_illegal_insn, /* 31 */
+};
+
+static const illegal_insn_func amomaxu_table[32] = {
+	truly_illegal_insn, /* 0 */
+	truly_illegal_insn, /* 1 */
+	truly_illegal_insn, /* 2 */
+	truly_illegal_insn, /* 3 */
+	truly_illegal_insn, /* 4 */
+	truly_illegal_insn, /* 5 */
+	truly_illegal_insn, /* 6 */
+	truly_illegal_insn, /* 7 */
+	atomic_maxu_w, /* 8 */
+	atomic_maxu_w_rl, /* 9 */
+	atomic_maxu_w_aq, /* 10 */
+	atomic_maxu_w_aqrl, /* 11 */
+#if __riscv_xlen == 64
+	atomic_maxu_d, /* 12 */
+	atomic_maxu_d_rl, /* 13 */
+	atomic_maxu_d_aq, /* 14 */
+	atomic_maxu_d_aqrl, /* 15 */
+#else
+	truly_illegal_insn, /* 12 */
+	truly_illegal_insn, /* 13 */
+	truly_illegal_insn, /* 14 */
+	truly_illegal_insn, /* 15 */
+#endif
+	truly_illegal_insn, /* 16 */
+	truly_illegal_insn, /* 17 */
+	truly_illegal_insn, /* 18 */
+	truly_illegal_insn, /* 19 */
+	truly_illegal_insn, /* 20 */
+	truly_illegal_insn, /* 21 */
+	truly_illegal_insn, /* 22 */
+	truly_illegal_insn, /* 23 */
+	truly_illegal_insn, /* 24 */
+	truly_illegal_insn, /* 25 */
+	truly_illegal_insn, /* 26 */
+	truly_illegal_insn, /* 27 */
+	truly_illegal_insn, /* 28 */
+	truly_illegal_insn, /* 29 */
+	truly_illegal_insn, /* 30 */
+	truly_illegal_insn, /* 31 */
+};
+
+static int amoadd_insn(ulong insn, struct sbi_trap_regs *regs)
+{
+	return amoadd_table[(GET_FUNC3(insn) << 2) + GET_AQRL(insn)](insn, regs);
+}
+
+static int amoswap_insn(ulong insn, struct sbi_trap_regs *regs)
+{
+	return amoswap_table[(GET_FUNC3(insn) << 2) + GET_AQRL(insn)](insn, regs);
+}
+
+static int amoxor_insn(ulong insn, struct sbi_trap_regs *regs)
+{
+	return amoxor_table[(GET_FUNC3(insn) << 2) + GET_AQRL(insn)](insn, regs);
+}
+
+static int amoor_insn(ulong insn, struct sbi_trap_regs *regs)
+{
+	return amoor_table[(GET_FUNC3(insn) << 2) + GET_AQRL(insn)](insn, regs);
+}
+
+static int amoand_insn(ulong insn, struct sbi_trap_regs *regs)
+{
+	return amoand_table[(GET_FUNC3(insn) << 2) + GET_AQRL(insn)](insn, regs);
+}
+
+static int amomin_insn(ulong insn, struct sbi_trap_regs *regs)
+{
+	return amomin_table[(GET_FUNC3(insn) << 2) + GET_AQRL(insn)](insn, regs);
+}
+
+static int amomax_insn(ulong insn, struct sbi_trap_regs *regs)
+{
+	return amomax_table[(GET_FUNC3(insn) << 2) + GET_AQRL(insn)](insn, regs);
+}
+
+static int amominu_insn(ulong insn, struct sbi_trap_regs *regs)
+{
+	return amominu_table[(GET_FUNC3(insn) << 2) + GET_AQRL(insn)](insn, regs);
+}
+
+static int amomaxu_insn(ulong insn, struct sbi_trap_regs *regs)
+{
+	return amomaxu_table[(GET_FUNC3(insn) << 2) + GET_AQRL(insn)](insn, regs);
+}
+
+static const illegal_insn_func amo_insn_table[32] = {
+	amoadd_insn, /* 0 */
+	amoswap_insn, /* 1 */
+	truly_illegal_insn, /* 2 */
+	truly_illegal_insn, /* 3 */
+	amoxor_insn, /* 4 */
+	truly_illegal_insn, /* 5 */
+	truly_illegal_insn, /* 6 */
+	truly_illegal_insn, /* 7 */
+	amoor_insn, /* 8 */
+	truly_illegal_insn, /* 9 */
+	truly_illegal_insn, /* 10 */
+	truly_illegal_insn, /* 11 */
+	amoand_insn, /* 12 */
+	truly_illegal_insn, /* 13 */
+	truly_illegal_insn, /* 14 */
+	truly_illegal_insn, /* 15 */
+	amomin_insn, /* 16 */
+	truly_illegal_insn, /* 17 */
+	truly_illegal_insn, /* 18 */
+	truly_illegal_insn, /* 19 */
+	amomax_insn, /* 20 */
+	truly_illegal_insn, /* 21 */
+	truly_illegal_insn, /* 22 */
+	truly_illegal_insn, /* 23 */
+	amominu_insn, /* 24 */
+	truly_illegal_insn, /* 25 */
+	truly_illegal_insn, /* 26 */
+	truly_illegal_insn, /* 27 */
+	amomaxu_insn, /* 28 */
+	truly_illegal_insn, /* 29 */
+	truly_illegal_insn, /* 30 */
+	truly_illegal_insn  /* 31 */
+};
+
+int sbi_illegal_atomic(ulong insn, struct sbi_trap_regs *regs)
+{
+	return amo_insn_table[(insn >> 27) & 0x1f](insn, regs);
+}
+
+#else
+#error "need a or zalrsc"
+#endif
diff --git a/lib/sbi/sbi_illegal_insn.c b/lib/sbi/sbi_illegal_insn.c
index 784bc4c..fa82264 100644
--- a/lib/sbi/sbi_illegal_insn.c
+++ b/lib/sbi/sbi_illegal_insn.c
@@ -13,15 +13,14 @@
 #include <sbi/sbi_bitops.h>
 #include <sbi/sbi_emulate_csr.h>
 #include <sbi/sbi_error.h>
+#include <sbi/sbi_illegal_atomic.h>
 #include <sbi/sbi_illegal_insn.h>
 #include <sbi/sbi_pmu.h>
 #include <sbi/sbi_trap.h>
 #include <sbi/sbi_unpriv.h>
 #include <sbi/sbi_console.h>
 
-typedef int (*illegal_insn_func)(ulong insn, struct sbi_trap_regs *regs);
-
-static int truly_illegal_insn(ulong insn, struct sbi_trap_regs *regs)
+int truly_illegal_insn(ulong insn, struct sbi_trap_regs *regs)
 {
 	struct sbi_trap_info trap;
 
@@ -123,7 +122,7 @@ static const illegal_insn_func illegal_insn_table[32] = {
 	truly_illegal_insn, /* 8 */
 	truly_illegal_insn, /* 9 */
 	truly_illegal_insn, /* 10 */
-	truly_illegal_insn, /* 11 */
+	sbi_illegal_atomic, /* 11 */
 	truly_illegal_insn, /* 12 */
 	truly_illegal_insn, /* 13 */
 	truly_illegal_insn, /* 14 */