util/cpuinfo-riscv: Support host/cpuinfo.h for riscv

Move detection code out of tcg, similar to other hosts.

Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

host/include/riscv/host/cpuinfo.h

@@ -0,0 +1,23 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ * Host specific cpu identification for RISC-V.
+ */
+
+#ifndef HOST_CPUINFO_H
+#define HOST_CPUINFO_H
+
+#define CPUINFO_ALWAYS          (1u << 0)  /* so cpuinfo is nonzero */
+#define CPUINFO_ZBA             (1u << 1)
+#define CPUINFO_ZBB             (1u << 2)
+#define CPUINFO_ZICOND          (1u << 3)
+
+/* Initialized with a constructor. */
+extern unsigned cpuinfo;
+
+/*
+ * We cannot rely on constructor ordering, so other constructors must
+ * use the function interface rather than the variable above.
+ */
+unsigned cpuinfo_init(void);
+
+#endif /* HOST_CPUINFO_H */

tcg/riscv/tcg-target.c.inc

@@ -113,20 +113,6 @@ static const int tcg_target_call_iarg_regs[] = {
     TCG_REG_A7,
 };
 
-#ifndef have_zbb
-bool have_zbb;
-#endif
-#if defined(__riscv_arch_test) && defined(__riscv_zba)
-# define have_zba true
-#else
-static bool have_zba;
-#endif
-#if defined(__riscv_arch_test) && defined(__riscv_zicond)
-# define have_zicond true
-#else
-static bool have_zicond;
-#endif
-
 static TCGReg tcg_target_call_oarg_reg(TCGCallReturnKind kind, int slot)
 {
     tcg_debug_assert(kind == TCG_CALL_RET_NORMAL);
@@ -594,7 +580,7 @@ static void tcg_out_ext8u(TCGContext *s, TCGReg ret, TCGReg arg)
 
 static void tcg_out_ext16u(TCGContext *s, TCGReg ret, TCGReg arg)
 {
-    if (have_zbb) {
+    if (cpuinfo & CPUINFO_ZBB) {
         tcg_out_opc_reg(s, OPC_ZEXT_H, ret, arg, TCG_REG_ZERO);
     } else {
         tcg_out_opc_imm(s, OPC_SLLIW, ret, arg, 16);
@@ -604,7 +590,7 @@ static void tcg_out_ext16u(TCGContext *s, TCGReg ret, TCGReg arg)
 
 static void tcg_out_ext32u(TCGContext *s, TCGReg ret, TCGReg arg)
 {
-    if (have_zba) {
+    if (cpuinfo & CPUINFO_ZBA) {
         tcg_out_opc_reg(s, OPC_ADD_UW, ret, arg, TCG_REG_ZERO);
     } else {
         tcg_out_opc_imm(s, OPC_SLLI, ret, arg, 32);
@@ -614,7 +600,7 @@ static void tcg_out_ext32u(TCGContext *s, TCGReg ret, TCGReg arg)
 
 static void tcg_out_ext8s(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg)
 {
-    if (have_zbb) {
+    if (cpuinfo & CPUINFO_ZBB) {
         tcg_out_opc_imm(s, OPC_SEXT_B, ret, arg, 0);
     } else {
         tcg_out_opc_imm(s, OPC_SLLIW, ret, arg, 24);
@@ -624,7 +610,7 @@ static void tcg_out_ext8s(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg)
 
 static void tcg_out_ext16s(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg)
 {
-    if (have_zbb) {
+    if (cpuinfo & CPUINFO_ZBB) {
         tcg_out_opc_imm(s, OPC_SEXT_H, ret, arg, 0);
     } else {
         tcg_out_opc_imm(s, OPC_SLLIW, ret, arg, 16);
@@ -1080,7 +1066,7 @@ static void tcg_out_movcond(TCGContext *s, TCGCond cond, TCGReg ret,
     int tmpflags;
     TCGReg t;
 
-    if (!have_zicond && (!c_cmp2 || cmp2 == 0)) {
+    if (!(cpuinfo & CPUINFO_ZICOND) && (!c_cmp2 || cmp2 == 0)) {
         tcg_out_movcond_br2(s, cond, ret, cmp1, cmp2,
                             val1, c_val1, val2, c_val2);
         return;
@@ -1089,7 +1075,7 @@ static void tcg_out_movcond(TCGContext *s, TCGCond cond, TCGReg ret,
     tmpflags = tcg_out_setcond_int(s, cond, TCG_REG_TMP0, cmp1, cmp2, c_cmp2);
     t = tmpflags & ~SETCOND_FLAGS;
 
-    if (have_zicond) {
+    if (cpuinfo & CPUINFO_ZICOND) {
         if (tmpflags & SETCOND_INV) {
             tcg_out_movcond_zicond(s, ret, t, val2, c_val2, val1, c_val1);
         } else {
@@ -1304,7 +1290,7 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, TCGReg *pbase,
         /* TLB Hit - translate address using addend.  */
         if (addr_type != TCG_TYPE_I32) {
             tcg_out_opc_reg(s, OPC_ADD, TCG_REG_TMP0, addr_reg, TCG_REG_TMP2);
-        } else if (have_zba) {
+        } else if (cpuinfo & CPUINFO_ZBA) {
             tcg_out_opc_reg(s, OPC_ADD_UW, TCG_REG_TMP0,
                             addr_reg, TCG_REG_TMP2);
         } else {
@@ -1335,7 +1321,7 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, TCGReg *pbase,
             if (addr_type != TCG_TYPE_I32) {
                 tcg_out_opc_reg(s, OPC_ADD, base, addr_reg,
                                 TCG_GUEST_BASE_REG);
-            } else if (have_zba) {
+            } else if (cpuinfo & CPUINFO_ZBA) {
                 tcg_out_opc_reg(s, OPC_ADD_UW, base, addr_reg,
                                 TCG_GUEST_BASE_REG);
             } else {
@@ -2110,62 +2096,8 @@ static void tcg_out_tb_start(TCGContext *s)
     /* nothing to do */
 }
 
-static volatile sig_atomic_t got_sigill;
-
-static void sigill_handler(int signo, siginfo_t *si, void *data)
-{
-    /* Skip the faulty instruction */
-    ucontext_t *uc = (ucontext_t *)data;
-    uc->uc_mcontext.__gregs[REG_PC] += 4;
-
-    got_sigill = 1;
-}
-
-static void tcg_target_detect_isa(void)
-{
-#if !defined(have_zba) || !defined(have_zbb) || !defined(have_zicond)
-    /*
-     * TODO: It is expected that this will be determinable via
-     * linux riscv_hwprobe syscall, not yet merged.
-     * In the meantime, test via sigill.
-     */
-
-    struct sigaction sa_old, sa_new;
-
-    memset(&sa_new, 0, sizeof(sa_new));
-    sa_new.sa_flags = SA_SIGINFO;
-    sa_new.sa_sigaction = sigill_handler;
-    sigaction(SIGILL, &sa_new, &sa_old);
-
-#ifndef have_zba
-    /* Probe for Zba: add.uw zero,zero,zero. */
-    got_sigill = 0;
-    asm volatile(".insn r 0x3b, 0, 0x04, zero, zero, zero" : : : "memory");
-    have_zba = !got_sigill;
-#endif
-
-#ifndef have_zbb
-    /* Probe for Zba: andn zero,zero,zero. */
-    got_sigill = 0;
-    asm volatile(".insn r 0x33, 7, 0x20, zero, zero, zero" : : : "memory");
-    have_zbb = !got_sigill;
-#endif
-
-#ifndef have_zicond
-    /* Probe for Zicond: czero.eqz zero,zero,zero. */
-    got_sigill = 0;
-    asm volatile(".insn r 0x33, 5, 0x07, zero, zero, zero" : : : "memory");
-    have_zicond = !got_sigill;
-#endif
-
-    sigaction(SIGILL, &sa_old, NULL);
-#endif
-}
-
 static void tcg_target_init(TCGContext *s)
 {
-    tcg_target_detect_isa();
-
     tcg_target_available_regs[TCG_TYPE_I32] = 0xffffffff;
     tcg_target_available_regs[TCG_TYPE_I64] = 0xffffffff;
 

tcg/riscv/tcg-target.h

@@ -25,6 +25,8 @@
 #ifndef RISCV_TCG_TARGET_H
 #define RISCV_TCG_TARGET_H
 
+#include "host/cpuinfo.h"
+
 #define TCG_TARGET_INSN_UNIT_SIZE 4
 #define TCG_TARGET_NB_REGS 32
 #define MAX_CODE_GEN_BUFFER_SIZE  ((size_t)-1)
@@ -80,18 +82,12 @@ typedef enum {
 #define TCG_TARGET_CALL_ARG_I128        TCG_CALL_ARG_NORMAL
 #define TCG_TARGET_CALL_RET_I128        TCG_CALL_RET_NORMAL
 
-#if defined(__riscv_arch_test) && defined(__riscv_zbb)
-# define have_zbb true
-#else
-extern bool have_zbb;
-#endif
-
 /* optional instructions */
 #define TCG_TARGET_HAS_negsetcond_i32   1
 #define TCG_TARGET_HAS_div_i32          1
 #define TCG_TARGET_HAS_rem_i32          1
 #define TCG_TARGET_HAS_div2_i32         0
-#define TCG_TARGET_HAS_rot_i32          have_zbb
+#define TCG_TARGET_HAS_rot_i32          (cpuinfo & CPUINFO_ZBB)
 #define TCG_TARGET_HAS_deposit_i32      0
 #define TCG_TARGET_HAS_extract_i32      0
 #define TCG_TARGET_HAS_sextract_i32     0
@@ -106,17 +102,17 @@ extern bool have_zbb;
 #define TCG_TARGET_HAS_ext16s_i32       1
 #define TCG_TARGET_HAS_ext8u_i32        1
 #define TCG_TARGET_HAS_ext16u_i32       1
-#define TCG_TARGET_HAS_bswap16_i32      have_zbb
-#define TCG_TARGET_HAS_bswap32_i32      have_zbb
+#define TCG_TARGET_HAS_bswap16_i32      (cpuinfo & CPUINFO_ZBB)
+#define TCG_TARGET_HAS_bswap32_i32      (cpuinfo & CPUINFO_ZBB)
 #define TCG_TARGET_HAS_not_i32          1
-#define TCG_TARGET_HAS_andc_i32         have_zbb
-#define TCG_TARGET_HAS_orc_i32          have_zbb
-#define TCG_TARGET_HAS_eqv_i32          have_zbb
+#define TCG_TARGET_HAS_andc_i32         (cpuinfo & CPUINFO_ZBB)
+#define TCG_TARGET_HAS_orc_i32          (cpuinfo & CPUINFO_ZBB)
+#define TCG_TARGET_HAS_eqv_i32          (cpuinfo & CPUINFO_ZBB)
 #define TCG_TARGET_HAS_nand_i32         0
 #define TCG_TARGET_HAS_nor_i32          0
-#define TCG_TARGET_HAS_clz_i32          have_zbb
-#define TCG_TARGET_HAS_ctz_i32          have_zbb
-#define TCG_TARGET_HAS_ctpop_i32        have_zbb
+#define TCG_TARGET_HAS_clz_i32          (cpuinfo & CPUINFO_ZBB)
+#define TCG_TARGET_HAS_ctz_i32          (cpuinfo & CPUINFO_ZBB)
+#define TCG_TARGET_HAS_ctpop_i32        (cpuinfo & CPUINFO_ZBB)
 #define TCG_TARGET_HAS_brcond2          1
 #define TCG_TARGET_HAS_setcond2         1
 #define TCG_TARGET_HAS_qemu_st8_i32     0
@@ -125,7 +121,7 @@ extern bool have_zbb;
 #define TCG_TARGET_HAS_div_i64          1
 #define TCG_TARGET_HAS_rem_i64          1
 #define TCG_TARGET_HAS_div2_i64         0
-#define TCG_TARGET_HAS_rot_i64          have_zbb
+#define TCG_TARGET_HAS_rot_i64          (cpuinfo & CPUINFO_ZBB)
 #define TCG_TARGET_HAS_deposit_i64      0
 #define TCG_TARGET_HAS_extract_i64      0
 #define TCG_TARGET_HAS_sextract_i64     0
@@ -137,18 +133,18 @@ extern bool have_zbb;
 #define TCG_TARGET_HAS_ext8u_i64        1
 #define TCG_TARGET_HAS_ext16u_i64       1
 #define TCG_TARGET_HAS_ext32u_i64       1
-#define TCG_TARGET_HAS_bswap16_i64      have_zbb
-#define TCG_TARGET_HAS_bswap32_i64      have_zbb
-#define TCG_TARGET_HAS_bswap64_i64      have_zbb
+#define TCG_TARGET_HAS_bswap16_i64      (cpuinfo & CPUINFO_ZBB)
+#define TCG_TARGET_HAS_bswap32_i64      (cpuinfo & CPUINFO_ZBB)
+#define TCG_TARGET_HAS_bswap64_i64      (cpuinfo & CPUINFO_ZBB)
 #define TCG_TARGET_HAS_not_i64          1
-#define TCG_TARGET_HAS_andc_i64         have_zbb
-#define TCG_TARGET_HAS_orc_i64          have_zbb
-#define TCG_TARGET_HAS_eqv_i64          have_zbb
+#define TCG_TARGET_HAS_andc_i64         (cpuinfo & CPUINFO_ZBB)
+#define TCG_TARGET_HAS_orc_i64          (cpuinfo & CPUINFO_ZBB)
+#define TCG_TARGET_HAS_eqv_i64          (cpuinfo & CPUINFO_ZBB)
 #define TCG_TARGET_HAS_nand_i64         0
 #define TCG_TARGET_HAS_nor_i64          0
-#define TCG_TARGET_HAS_clz_i64          have_zbb
-#define TCG_TARGET_HAS_ctz_i64          have_zbb
-#define TCG_TARGET_HAS_ctpop_i64        have_zbb
+#define TCG_TARGET_HAS_clz_i64          (cpuinfo & CPUINFO_ZBB)
+#define TCG_TARGET_HAS_ctz_i64          (cpuinfo & CPUINFO_ZBB)
+#define TCG_TARGET_HAS_ctpop_i64        (cpuinfo & CPUINFO_ZBB)
 #define TCG_TARGET_HAS_add2_i64         1
 #define TCG_TARGET_HAS_sub2_i64         1
 #define TCG_TARGET_HAS_mulu2_i64        0

util/cpuinfo-riscv.c

@@ -0,0 +1,85 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ * Host specific cpu identification for RISC-V.
+ */
+
+#include "qemu/osdep.h"
+#include "host/cpuinfo.h"
+
+unsigned cpuinfo;
+static volatile sig_atomic_t got_sigill;
+
+static void sigill_handler(int signo, siginfo_t *si, void *data)
+{
+    /* Skip the faulty instruction */
+    ucontext_t *uc = (ucontext_t *)data;
+    uc->uc_mcontext.__gregs[REG_PC] += 4;
+
+    got_sigill = 1;
+}
+
+/* Called both as constructor and (possibly) via other constructors. */
+unsigned __attribute__((constructor)) cpuinfo_init(void)
+{
+    unsigned left = CPUINFO_ZBA | CPUINFO_ZBB | CPUINFO_ZICOND;
+    unsigned info = cpuinfo;
+
+    if (info) {
+        return info;
+    }
+
+    /* Test for compile-time settings. */
+#if defined(__riscv_arch_test) && defined(__riscv_zba)
+    info |= CPUINFO_ZBA;
+#endif
+#if defined(__riscv_arch_test) && defined(__riscv_zbb)
+    info |= CPUINFO_ZBB;
+#endif
+#if defined(__riscv_arch_test) && defined(__riscv_zicond)
+    info |= CPUINFO_ZICOND;
+#endif
+    left &= ~info;
+
+    if (left) {
+        struct sigaction sa_old, sa_new;
+
+        memset(&sa_new, 0, sizeof(sa_new));
+        sa_new.sa_flags = SA_SIGINFO;
+        sa_new.sa_sigaction = sigill_handler;
+        sigaction(SIGILL, &sa_new, &sa_old);
+
+        if (left & CPUINFO_ZBA) {
+            /* Probe for Zba: add.uw zero,zero,zero. */
+            got_sigill = 0;
+            asm volatile(".insn r 0x3b, 0, 0x04, zero, zero, zero"
+                         : : : "memory");
+            info |= got_sigill ? 0 : CPUINFO_ZBA;
+            left &= ~CPUINFO_ZBA;
+        }
+
+        if (left & CPUINFO_ZBB) {
+            /* Probe for Zbb: andn zero,zero,zero. */
+            got_sigill = 0;
+            asm volatile(".insn r 0x33, 7, 0x20, zero, zero, zero"
+                         : : : "memory");
+            info |= got_sigill ? 0 : CPUINFO_ZBB;
+            left &= ~CPUINFO_ZBB;
+        }
+
+        if (left & CPUINFO_ZICOND) {
+            /* Probe for Zicond: czero.eqz zero,zero,zero. */
+            got_sigill = 0;
+            asm volatile(".insn r 0x33, 5, 0x07, zero, zero, zero"
+                         : : : "memory");
+            info |= got_sigill ? 0 : CPUINFO_ZICOND;
+            left &= ~CPUINFO_ZICOND;
+        }
+
+        sigaction(SIGILL, &sa_old, NULL);
+        assert(left == 0);
+    }
+
+    info |= CPUINFO_ALWAYS;
+    cpuinfo = info;
+    return info;
+}

util/meson.build

@@ -127,4 +127,6 @@ elif cpu == 'loongarch64'
   util_ss.add(files('cpuinfo-loongarch.c'))
 elif cpu in ['ppc', 'ppc64']
   util_ss.add(files('cpuinfo-ppc.c'))
+elif cpu in ['riscv32', 'riscv64']
+  util_ss.add(files('cpuinfo-riscv.c'))
 endif