[PATCH v4 4/7] tcg/riscv: Support raising sigbus for user-only

[Richard Henderson <richard.henderson@linaro.org>]

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/riscv/tcg-target.h     |  2 --
 tcg/riscv/tcg-target.c.inc | 63 ++++++++++++++++++++++++++++++++++++--
 2 files changed, 61 insertions(+), 4 deletions(-)

diff --git a/tcg/riscv/tcg-target.h b/tcg/riscv/tcg-target.h
index ef78b99e98..11c9b3e4f4 100644
--- a/tcg/riscv/tcg-target.h
+++ b/tcg/riscv/tcg-target.h
@@ -165,9 +165,7 @@ void tb_target_set_jmp_target(uintptr_t, uintptr_t, uintptr_t, uintptr_t);
 
 #define TCG_TARGET_DEFAULT_MO (0)
 
-#ifdef CONFIG_SOFTMMU
 #define TCG_TARGET_NEED_LDST_LABELS
-#endif
 #define TCG_TARGET_NEED_POOL_LABELS
 
 #define TCG_TARGET_HAS_MEMORY_BSWAP 0
diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc
index 9b13a46fb4..49e84cbe13 100644
--- a/tcg/riscv/tcg-target.c.inc
+++ b/tcg/riscv/tcg-target.c.inc
@@ -27,6 +27,7 @@
  * THE SOFTWARE.
  */
 
+#include "../tcg-ldst.c.inc"
 #include "../tcg-pool.c.inc"
 
 #ifdef CONFIG_DEBUG_TCG
@@ -847,8 +848,6 @@ static void tcg_out_mb(TCGContext *s, TCGArg a0)
  */
 
 #if defined(CONFIG_SOFTMMU)
-#include "../tcg-ldst.c.inc"
-
 /* helper signature: helper_ret_ld_mmu(CPUState *env, target_ulong addr,
  *                                     MemOpIdx oi, uintptr_t ra)
  */
@@ -1053,6 +1052,54 @@ static bool tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
     tcg_out_goto(s, l->raddr);
     return true;
 }
+#else
+
+static void tcg_out_test_alignment(TCGContext *s, bool is_ld, TCGReg addr_reg,
+                                   unsigned a_bits)
+{
+    unsigned a_mask = (1 << a_bits) - 1;
+    TCGLabelQemuLdst *l = new_ldst_label(s);
+
+    l->is_ld = is_ld;
+    l->addrlo_reg = addr_reg;
+
+    /* We are expecting a_bits to max out at 7, so we can always use andi. */
+    tcg_debug_assert(a_bits < 12);
+    tcg_out_opc_imm(s, OPC_ANDI, TCG_REG_TMP1, addr_reg, a_mask);
+
+    l->label_ptr[0] = s->code_ptr;
+    tcg_out_opc_branch(s, OPC_BNE, TCG_REG_TMP1, TCG_REG_ZERO, 0);
+
+    l->raddr = tcg_splitwx_to_rx(s->code_ptr);
+}
+
+static bool tcg_out_fail_alignment(TCGContext *s, TCGLabelQemuLdst *l)
+{
+    /* resolve label address */
+    if (!reloc_sbimm12(l->label_ptr[0], tcg_splitwx_to_rx(s->code_ptr))) {
+        return false;
+    }
+
+    tcg_out_mov(s, TCG_TYPE_TL, TCG_REG_A1, l->addrlo_reg);
+    tcg_out_mov(s, TCG_TYPE_PTR, TCG_REG_A0, TCG_AREG0);
+
+    /* tail call, with the return address back inline. */
+    tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_RA, (uintptr_t)l->raddr);
+    tcg_out_call_int(s, (const void *)(l->is_ld ? helper_unaligned_ld
+                                       : helper_unaligned_st), true);
+    return true;
+}
+
+static bool tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
+{
+    return tcg_out_fail_alignment(s, l);
+}
+
+static bool tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
+{
+    return tcg_out_fail_alignment(s, l);
+}
+
 #endif /* CONFIG_SOFTMMU */
 
 static void tcg_out_qemu_ld_direct(TCGContext *s, TCGReg lo, TCGReg hi,
@@ -1108,6 +1155,8 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args, bool is_64)
     MemOp opc;
 #if defined(CONFIG_SOFTMMU)
     tcg_insn_unit *label_ptr[1];
+#else
+    unsigned a_bits;
 #endif
     TCGReg base = TCG_REG_TMP0;
 
@@ -1130,6 +1179,10 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args, bool is_64)
         tcg_out_ext32u(s, base, addr_regl);
         addr_regl = base;
     }
+    a_bits = get_alignment_bits(opc);
+    if (a_bits) {
+        tcg_out_test_alignment(s, true, addr_regl, a_bits);
+    }
     if (guest_base != 0) {
         tcg_out_opc_reg(s, OPC_ADD, base, TCG_GUEST_BASE_REG, addr_regl);
     }
@@ -1174,6 +1227,8 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args, bool is_64)
     MemOp opc;
 #if defined(CONFIG_SOFTMMU)
     tcg_insn_unit *label_ptr[1];
+#else
+    unsigned a_bits;
 #endif
     TCGReg base = TCG_REG_TMP0;
 
@@ -1196,6 +1251,10 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args, bool is_64)
         tcg_out_ext32u(s, base, addr_regl);
         addr_regl = base;
     }
+    a_bits = get_alignment_bits(opc);
+    if (a_bits) {
+        tcg_out_test_alignment(s, false, addr_regl, a_bits);
+    }
     if (guest_base != 0) {
         tcg_out_opc_reg(s, OPC_ADD, base, TCG_GUEST_BASE_REG, addr_regl);
     }
-- 
2.25.1