[compiler-rt] [compiler-rt][RISCV] Implement __riscv_ifunc_select (PR #85790)

Piyou Chen via llvm-commits llvm-commits at lists.llvm.org
Tue Apr 9 00:01:25 PDT 2024


https://github.com/BeMg updated https://github.com/llvm/llvm-project/pull/85790

>From 446b4a9936967b146c612f7489a8b53c38662e70 Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Thu, 14 Mar 2024 05:50:51 -0700
Subject: [PATCH 01/15] [compiler-rt][RISCV] Implement __riscv_ifunc_select

This patch implement the `__riscv_ifunc_select` base on `Hwprobe/cpuinfo`.

```
unsigned __riscv_ifunc_select(char *FeatStrs);
```

The __riscv_ifunc_select function checks if the features specified in FeatStrs are supported.
If all features are available in the current runtime environment, it returns 1. Otherwise, it returns 0.
---
 compiler-rt/lib/builtins/CMakeLists.txt       |   1 +
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 260 ++++++++++++++++++
 2 files changed, 261 insertions(+)
 create mode 100644 compiler-rt/lib/builtins/riscv/ifunc_select.c

diff --git a/compiler-rt/lib/builtins/CMakeLists.txt b/compiler-rt/lib/builtins/CMakeLists.txt
index f9611574a562b4..c9f82f3c38dbf5 100644
--- a/compiler-rt/lib/builtins/CMakeLists.txt
+++ b/compiler-rt/lib/builtins/CMakeLists.txt
@@ -716,6 +716,7 @@ endif()
 set(powerpc64le_SOURCES ${powerpc64_SOURCES})
 
 set(riscv_SOURCES
+  riscv/ifunc_select.c
   riscv/fp_mode.c
   riscv/save.S
   riscv/restore.S
diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
new file mode 100644
index 00000000000000..75639c19011c13
--- /dev/null
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -0,0 +1,260 @@
+//=== ifunc_select.c - Check environment hardware feature -*- C -*-===========//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#define BUFSIZE 1024
+
+static void fillzero(char *s, unsigned size) {
+  for (int i = 0; i < size; i++)
+    s[i] = '\0';
+}
+
+static unsigned strcmp(const char *a, const char *b) {
+  while (*a != '\0' && *b != '\0') {
+    if (*a != *b)
+      return 0;
+    a++;
+    b++;
+  }
+  if (*a == *b)
+    return 1;
+  return 0;
+}
+
+static void memcpy(char *dest, const char *src, unsigned len) {
+  for (unsigned i = 0; i < len; i++)
+    dest[i] = src[i];
+}
+
+static unsigned strlen(char *s) {
+  int len = 0;
+  while (*s != '\0') {
+    len++;
+    s++;
+  }
+  return len;
+}
+
+// TODO: Replace with more efficient algorithm
+static unsigned isPatternInSrc(char *src, char *pattern) {
+  char buf[BUFSIZE];
+  int lenOfSrc = strlen(src);
+  int lenOfPattern = strlen(pattern);
+  for (int i = 0; i + lenOfPattern < lenOfSrc; i++) {
+    fillzero(buf, BUFSIZE);
+    memcpy(buf, src + i, lenOfPattern);
+    if (strcmp(buf, pattern))
+      return 1;
+  }
+  return 0;
+}
+
+static char *tokenize(char *src, char *rst, char delim) {
+  while (*src != '\0' && *src != delim) {
+    *rst = *src;
+    src++;
+    rst++;
+  }
+  if (*src == delim)
+    src++;
+  return src;
+}
+
+static void getBasicExtFromHwFeatStr(char *rst, char *src) {
+  while (*src != 'r') {
+    src++;
+  }
+
+  while (*src != '_' && *src != '\0') {
+    *rst = *src;
+    rst++;
+    src++;
+  }
+}
+
+static unsigned checkFeatStrInHwFeatStr(char *FeatStr, char *HwFeatStr) {
+  // For basic extension like a,m,f,d...
+  if (strlen(FeatStr) == 1) {
+    char BasicExt[BUFSIZE];
+    fillzero(BasicExt, BUFSIZE);
+    getBasicExtFromHwFeatStr(BasicExt, HwFeatStr);
+    return isPatternInSrc(BasicExt, FeatStr);
+  }
+  // For zbb,zihintntl...
+  return isPatternInSrc(HwFeatStr, FeatStr);
+}
+
+#if defined(__linux__)
+
+#define SYS_read 63
+#define SYS_openat 56
+#define SYS_riscv_hwprobe 258
+
+static long syscall_impl_3_args(long number, long arg1, long arg2, long arg3) {
+  register long a7 __asm__("a7") = number;
+  register long a0 __asm__("a0") = arg1;
+  register long a1 __asm__("a1") = arg2;
+  register long a2 __asm__("a2") = arg3;
+  __asm__ __volatile__("ecall\n\t"
+                       : "=r"(a0)
+                       : "r"(a7), "r"(a0), "r"(a1), "r"(a2)
+                       : "memory");
+  return a0;
+}
+
+static long syscall_impl_5_args(long number, long arg1, long arg2, long arg3,
+                                long arg4, long arg5) {
+  register long a7 __asm__("a7") = number;
+  register long a0 __asm__("a0") = arg1;
+  register long a1 __asm__("a1") = arg2;
+  register long a2 __asm__("a2") = arg3;
+  register long a3 __asm__("a3") = arg4;
+  register long a4 __asm__("a4") = arg5;
+  __asm__ __volatile__("ecall\n\t"
+                       : "=r"(a0)
+                       : "r"(a7), "r"(a0), "r"(a1), "r"(a2), "r"(a3), "r"(a4)
+                       : "memory");
+  return a0;
+}
+
+static unsigned read(int fd, const void *buf, unsigned count) {
+  return syscall_impl_3_args(SYS_read, fd, (long)buf, count);
+}
+
+static int openat(int dirfd, const char *pathname, int flags) {
+  return syscall_impl_3_args(SYS_openat, (long)dirfd, (long)pathname, flags);
+}
+
+static void readUntilNextLine(int fd, char *rst, int len) {
+  char buf = '\0';
+  while (buf != '\n' && read(fd, &buf, 1) != 0 && len > 0) {
+    *rst = buf;
+    rst++;
+    len--;
+  }
+}
+
+static void __riscv_cpuinfo(char *FeatStr) {
+  char buf[BUFSIZE];
+  int fd = openat(0, "/proc/cpuinfo", 2);
+  do {
+    fillzero(buf, BUFSIZE);
+    readUntilNextLine(fd, buf, BUFSIZE);
+    if (isPatternInSrc(buf, "isa")) {
+      memcpy(FeatStr, buf, BUFSIZE);
+      return;
+    }
+  } while (strlen(buf) != 0);
+}
+
+struct riscv_hwprobe {
+  long long key;
+  unsigned long long value;
+};
+
+#define RISCV_HWPROBE_MAX_KEY 5
+#define RISCV_HWPROBE_KEY_MVENDORID 0
+#define RISCV_HWPROBE_KEY_MARCHID 1
+#define RISCV_HWPROBE_KEY_MIMPID 2
+#define RISCV_HWPROBE_KEY_BASE_BEHAVIOR 3
+#define RISCV_HWPROBE_BASE_BEHAVIOR_IMA (1 << 0)
+#define RISCV_HWPROBE_KEY_IMA_EXT_0 4
+#define RISCV_HWPROBE_IMA_FD (1 << 0)
+#define RISCV_HWPROBE_IMA_C (1 << 1)
+#define RISCV_HWPROBE_IMA_V (1 << 2)
+#define RISCV_HWPROBE_EXT_ZBA (1 << 3)
+#define RISCV_HWPROBE_EXT_ZBB (1 << 4)
+#define RISCV_HWPROBE_EXT_ZBS (1 << 5)
+#define RISCV_HWPROBE_KEY_CPUPERF_0 5
+#define RISCV_HWPROBE_MISALIGNED_UNKNOWN (0 << 0)
+#define RISCV_HWPROBE_MISALIGNED_EMULATED (1 << 0)
+#define RISCV_HWPROBE_MISALIGNED_SLOW (2 << 0)
+#define RISCV_HWPROBE_MISALIGNED_FAST (3 << 0)
+#define RISCV_HWPROBE_MISALIGNED_UNSUPPORTED (4 << 0)
+#define RISCV_HWPROBE_MISALIGNED_MASK (7 << 0)
+
+/* Size definition for CPU sets.  */
+#define __CPU_SETSIZE 1024
+#define __NCPUBITS (8 * sizeof(unsigned long int))
+
+/* Data structure to describe CPU mask.  */
+typedef struct {
+  unsigned long int __bits[__CPU_SETSIZE / __NCPUBITS];
+} cpu_set_t;
+
+static long sys_riscv_hwprobe(struct riscv_hwprobe *pairs, unsigned pair_count,
+                              unsigned cpu_count, cpu_set_t *cpus,
+                              unsigned int flags) {
+  return syscall_impl_5_args(SYS_riscv_hwprobe, (long)pairs, pair_count,
+                             cpu_count, (long)cpus, flags);
+}
+
+static void initHwProbe(struct riscv_hwprobe *Hwprobes, int len) {
+  sys_riscv_hwprobe(Hwprobes, len, 0, 0, 0);
+}
+
+static unsigned checkFeatStrInHwProbe(char *FeatStr,
+                                      struct riscv_hwprobe Hwprobe) {
+  if (Hwprobe.key == -1)
+    return 0;
+
+  if (strcmp(FeatStr, "i"))
+    return Hwprobe.value & RISCV_HWPROBE_KEY_IMA_EXT_0;
+  if (strcmp(FeatStr, "m"))
+    return Hwprobe.value & RISCV_HWPROBE_KEY_IMA_EXT_0;
+  if (strcmp(FeatStr, "a"))
+    return Hwprobe.value & RISCV_HWPROBE_KEY_IMA_EXT_0;
+  if (strcmp(FeatStr, "f"))
+    return Hwprobe.value & RISCV_HWPROBE_IMA_FD;
+  if (strcmp(FeatStr, "d"))
+    return Hwprobe.value & RISCV_HWPROBE_IMA_FD;
+  if (strcmp(FeatStr, "c"))
+    return Hwprobe.value & RISCV_HWPROBE_IMA_C;
+  if (strcmp(FeatStr, "v"))
+    return Hwprobe.value & RISCV_HWPROBE_IMA_V;
+  if (strcmp(FeatStr, "zba"))
+    return Hwprobe.value & RISCV_HWPROBE_EXT_ZBA;
+  if (strcmp(FeatStr, "zbb"))
+    return Hwprobe.value & RISCV_HWPROBE_EXT_ZBB;
+  if (strcmp(FeatStr, "zbs"))
+    return Hwprobe.value & RISCV_HWPROBE_EXT_ZBS;
+
+  return 0;
+}
+#endif // defined(__linux__)
+
+// FeatStr format is like <Feature1>;<Feature2>...<FeatureN>.
+unsigned __riscv_ifunc_select(char *FeatStrs) {
+#if defined(__linux__)
+  // Init Hwprobe
+  struct riscv_hwprobe pairs[] = {
+      {RISCV_HWPROBE_KEY_IMA_EXT_0, 0},
+  };
+  initHwProbe(pairs, 1);
+  // Init from cpuinfo
+  char HwFeatStr[BUFSIZE];
+  fillzero(HwFeatStr, BUFSIZE);
+  __riscv_cpuinfo(HwFeatStr);
+
+  // Check each extension whether available
+  char FeatStr[BUFSIZE];
+  while (*FeatStrs != '\0') {
+    fillzero(FeatStr, BUFSIZE);
+    FeatStrs = tokenize(FeatStrs, FeatStr, ';');
+    if (checkFeatStrInHwProbe(FeatStr, pairs[0]))
+      continue;
+    if (!checkFeatStrInHwFeatStr(FeatStr, HwFeatStr))
+      return 0;
+  }
+
+  return 1;
+#else
+  // If other platform support IFUNC, need to implement its
+  // __riscv_ifunc_select.
+  return 0;
+#endif
+}

>From 60848d3e4fda19a2ac0c2571d68eb3ee18c7a773 Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Sat, 30 Mar 2024 04:07:35 -0700
Subject: [PATCH 02/15] Use bitset instead of string

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 225 ++++--------------
 1 file changed, 52 insertions(+), 173 deletions(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index 75639c19011c13..93269054835c29 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -6,106 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define BUFSIZE 1024
-
-static void fillzero(char *s, unsigned size) {
-  for (int i = 0; i < size; i++)
-    s[i] = '\0';
-}
-
-static unsigned strcmp(const char *a, const char *b) {
-  while (*a != '\0' && *b != '\0') {
-    if (*a != *b)
-      return 0;
-    a++;
-    b++;
-  }
-  if (*a == *b)
-    return 1;
-  return 0;
-}
-
-static void memcpy(char *dest, const char *src, unsigned len) {
-  for (unsigned i = 0; i < len; i++)
-    dest[i] = src[i];
-}
-
-static unsigned strlen(char *s) {
-  int len = 0;
-  while (*s != '\0') {
-    len++;
-    s++;
-  }
-  return len;
-}
-
-// TODO: Replace with more efficient algorithm
-static unsigned isPatternInSrc(char *src, char *pattern) {
-  char buf[BUFSIZE];
-  int lenOfSrc = strlen(src);
-  int lenOfPattern = strlen(pattern);
-  for (int i = 0; i + lenOfPattern < lenOfSrc; i++) {
-    fillzero(buf, BUFSIZE);
-    memcpy(buf, src + i, lenOfPattern);
-    if (strcmp(buf, pattern))
-      return 1;
-  }
-  return 0;
-}
-
-static char *tokenize(char *src, char *rst, char delim) {
-  while (*src != '\0' && *src != delim) {
-    *rst = *src;
-    src++;
-    rst++;
-  }
-  if (*src == delim)
-    src++;
-  return src;
-}
-
-static void getBasicExtFromHwFeatStr(char *rst, char *src) {
-  while (*src != 'r') {
-    src++;
-  }
-
-  while (*src != '_' && *src != '\0') {
-    *rst = *src;
-    rst++;
-    src++;
-  }
-}
-
-static unsigned checkFeatStrInHwFeatStr(char *FeatStr, char *HwFeatStr) {
-  // For basic extension like a,m,f,d...
-  if (strlen(FeatStr) == 1) {
-    char BasicExt[BUFSIZE];
-    fillzero(BasicExt, BUFSIZE);
-    getBasicExtFromHwFeatStr(BasicExt, HwFeatStr);
-    return isPatternInSrc(BasicExt, FeatStr);
-  }
-  // For zbb,zihintntl...
-  return isPatternInSrc(HwFeatStr, FeatStr);
-}
-
 #if defined(__linux__)
 
-#define SYS_read 63
-#define SYS_openat 56
 #define SYS_riscv_hwprobe 258
-
-static long syscall_impl_3_args(long number, long arg1, long arg2, long arg3) {
-  register long a7 __asm__("a7") = number;
-  register long a0 __asm__("a0") = arg1;
-  register long a1 __asm__("a1") = arg2;
-  register long a2 __asm__("a2") = arg3;
-  __asm__ __volatile__("ecall\n\t"
-                       : "=r"(a0)
-                       : "r"(a7), "r"(a0), "r"(a1), "r"(a2)
-                       : "memory");
-  return a0;
-}
-
 static long syscall_impl_5_args(long number, long arg1, long arg2, long arg3,
                                 long arg4, long arg5) {
   register long a7 __asm__("a7") = number;
@@ -121,42 +24,12 @@ static long syscall_impl_5_args(long number, long arg1, long arg2, long arg3,
   return a0;
 }
 
-static unsigned read(int fd, const void *buf, unsigned count) {
-  return syscall_impl_3_args(SYS_read, fd, (long)buf, count);
-}
-
-static int openat(int dirfd, const char *pathname, int flags) {
-  return syscall_impl_3_args(SYS_openat, (long)dirfd, (long)pathname, flags);
-}
-
-static void readUntilNextLine(int fd, char *rst, int len) {
-  char buf = '\0';
-  while (buf != '\n' && read(fd, &buf, 1) != 0 && len > 0) {
-    *rst = buf;
-    rst++;
-    len--;
-  }
-}
-
-static void __riscv_cpuinfo(char *FeatStr) {
-  char buf[BUFSIZE];
-  int fd = openat(0, "/proc/cpuinfo", 2);
-  do {
-    fillzero(buf, BUFSIZE);
-    readUntilNextLine(fd, buf, BUFSIZE);
-    if (isPatternInSrc(buf, "isa")) {
-      memcpy(FeatStr, buf, BUFSIZE);
-      return;
-    }
-  } while (strlen(buf) != 0);
-}
-
 struct riscv_hwprobe {
   long long key;
   unsigned long long value;
 };
 
-#define RISCV_HWPROBE_MAX_KEY 5
+// Note: sync with linux/arch/riscv/include/uapi/asm/hwprobe.h
 #define RISCV_HWPROBE_KEY_MVENDORID 0
 #define RISCV_HWPROBE_KEY_MARCHID 1
 #define RISCV_HWPROBE_KEY_MIMPID 2
@@ -169,6 +42,36 @@ struct riscv_hwprobe {
 #define RISCV_HWPROBE_EXT_ZBA (1 << 3)
 #define RISCV_HWPROBE_EXT_ZBB (1 << 4)
 #define RISCV_HWPROBE_EXT_ZBS (1 << 5)
+#define RISCV_HWPROBE_EXT_ZICBOZ (1 << 6)
+#define RISCV_HWPROBE_EXT_ZBC (1 << 7)
+#define RISCV_HWPROBE_EXT_ZBKB (1 << 8)
+#define RISCV_HWPROBE_EXT_ZBKC (1 << 9)
+#define RISCV_HWPROBE_EXT_ZBKX (1 << 10)
+#define RISCV_HWPROBE_EXT_ZKND (1 << 11)
+#define RISCV_HWPROBE_EXT_ZKNE (1 << 12)
+#define RISCV_HWPROBE_EXT_ZKNH (1 << 13)
+#define RISCV_HWPROBE_EXT_ZKSED (1 << 14)
+#define RISCV_HWPROBE_EXT_ZKSH (1 << 15)
+#define RISCV_HWPROBE_EXT_ZKT (1 << 16)
+#define RISCV_HWPROBE_EXT_ZVBB (1 << 17)
+#define RISCV_HWPROBE_EXT_ZVBC (1 << 18)
+#define RISCV_HWPROBE_EXT_ZVKB (1 << 19)
+#define RISCV_HWPROBE_EXT_ZVKG (1 << 20)
+#define RISCV_HWPROBE_EXT_ZVKNED (1 << 21)
+#define RISCV_HWPROBE_EXT_ZVKNHA (1 << 22)
+#define RISCV_HWPROBE_EXT_ZVKNHB (1 << 23)
+#define RISCV_HWPROBE_EXT_ZVKSED (1 << 24)
+#define RISCV_HWPROBE_EXT_ZVKSH (1 << 25)
+#define RISCV_HWPROBE_EXT_ZVKT (1 << 26)
+#define RISCV_HWPROBE_EXT_ZFH (1 << 27)
+#define RISCV_HWPROBE_EXT_ZFHMIN (1 << 28)
+#define RISCV_HWPROBE_EXT_ZIHINTNTL (1 << 29)
+#define RISCV_HWPROBE_EXT_ZVFH (1 << 30)
+#define RISCV_HWPROBE_EXT_ZVFHMIN (1 << 31)
+#define RISCV_HWPROBE_EXT_ZFA (1ULL << 32)
+#define RISCV_HWPROBE_EXT_ZTSO (1ULL << 33)
+#define RISCV_HWPROBE_EXT_ZACAS (1ULL << 34)
+#define RISCV_HWPROBE_EXT_ZICOND (1ULL << 35)
 #define RISCV_HWPROBE_KEY_CPUPERF_0 5
 #define RISCV_HWPROBE_MISALIGNED_UNKNOWN (0 << 0)
 #define RISCV_HWPROBE_MISALIGNED_EMULATED (1 << 0)
@@ -176,6 +79,11 @@ struct riscv_hwprobe {
 #define RISCV_HWPROBE_MISALIGNED_FAST (3 << 0)
 #define RISCV_HWPROBE_MISALIGNED_UNSUPPORTED (4 << 0)
 #define RISCV_HWPROBE_MISALIGNED_MASK (7 << 0)
+#define RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE 6
+/* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
+
+/* Flags */
+#define RISCV_HWPROBE_WHICH_CPUS (1 << 0)
 
 /* Size definition for CPU sets.  */
 #define __CPU_SETSIZE 1024
@@ -197,59 +105,30 @@ static void initHwProbe(struct riscv_hwprobe *Hwprobes, int len) {
   sys_riscv_hwprobe(Hwprobes, len, 0, 0, 0);
 }
 
-static unsigned checkFeatStrInHwProbe(char *FeatStr,
-                                      struct riscv_hwprobe Hwprobe) {
-  if (Hwprobe.key == -1)
-    return 0;
-
-  if (strcmp(FeatStr, "i"))
-    return Hwprobe.value & RISCV_HWPROBE_KEY_IMA_EXT_0;
-  if (strcmp(FeatStr, "m"))
-    return Hwprobe.value & RISCV_HWPROBE_KEY_IMA_EXT_0;
-  if (strcmp(FeatStr, "a"))
-    return Hwprobe.value & RISCV_HWPROBE_KEY_IMA_EXT_0;
-  if (strcmp(FeatStr, "f"))
-    return Hwprobe.value & RISCV_HWPROBE_IMA_FD;
-  if (strcmp(FeatStr, "d"))
-    return Hwprobe.value & RISCV_HWPROBE_IMA_FD;
-  if (strcmp(FeatStr, "c"))
-    return Hwprobe.value & RISCV_HWPROBE_IMA_C;
-  if (strcmp(FeatStr, "v"))
-    return Hwprobe.value & RISCV_HWPROBE_IMA_V;
-  if (strcmp(FeatStr, "zba"))
-    return Hwprobe.value & RISCV_HWPROBE_EXT_ZBA;
-  if (strcmp(FeatStr, "zbb"))
-    return Hwprobe.value & RISCV_HWPROBE_EXT_ZBB;
-  if (strcmp(FeatStr, "zbs"))
-    return Hwprobe.value & RISCV_HWPROBE_EXT_ZBS;
-
-  return 0;
-}
 #endif // defined(__linux__)
 
-// FeatStr format is like <Feature1>;<Feature2>...<FeatureN>.
-unsigned __riscv_ifunc_select(char *FeatStrs) {
+unsigned __riscv_ifunc_select(unsigned long long BaseKey,
+                              unsigned long long IMAKey) {
 #if defined(__linux__)
   // Init Hwprobe
   struct riscv_hwprobe pairs[] = {
+      {RISCV_HWPROBE_KEY_BASE_BEHAVIOR, 0},
       {RISCV_HWPROBE_KEY_IMA_EXT_0, 0},
   };
-  initHwProbe(pairs, 1);
-  // Init from cpuinfo
-  char HwFeatStr[BUFSIZE];
-  fillzero(HwFeatStr, BUFSIZE);
-  __riscv_cpuinfo(HwFeatStr);
+  initHwProbe(pairs, 2);
+
+  // sys_riscv_hwprobe key is unknown to the kernel
+  if (pairs[0].key == -1 || pairs[1].key == -1)
+    return 0;
+
+  // Check KEY_BASE_BEHAVIOR
+  if ((BaseKey & pairs[0].value) != BaseKey)
+    return 0;
+
+  if ((IMAKey & pairs[1].value) != IMAKey)
+    return 0;
 
-  // Check each extension whether available
-  char FeatStr[BUFSIZE];
-  while (*FeatStrs != '\0') {
-    fillzero(FeatStr, BUFSIZE);
-    FeatStrs = tokenize(FeatStrs, FeatStr, ';');
-    if (checkFeatStrInHwProbe(FeatStr, pairs[0]))
-      continue;
-    if (!checkFeatStrInHwFeatStr(FeatStr, HwFeatStr))
-      return 0;
-  }
+  // Check KEY_IMA_EXT_0
 
   return 1;
 #else

>From 6022ee358d7a1c493f7ca989ebd658c47c70daff Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Sun, 31 Mar 2024 19:20:56 -0700
Subject: [PATCH 03/15] Fixup comment

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index 93269054835c29..cbfd2df74d7228 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -125,11 +125,10 @@ unsigned __riscv_ifunc_select(unsigned long long BaseKey,
   if ((BaseKey & pairs[0].value) != BaseKey)
     return 0;
 
+  // Check KEY_IMA_EXT_0
   if ((IMAKey & pairs[1].value) != IMAKey)
     return 0;
 
-  // Check KEY_IMA_EXT_0
-
   return 1;
 #else
   // If other platform support IFUNC, need to implement its

>From 368789deb0dfaef0e8bf8e8d27751c0f5b6ec623 Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Sun, 31 Mar 2024 19:22:26 -0700
Subject: [PATCH 04/15] Make SYS_riscv_hwprobe closer to use

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index cbfd2df74d7228..5e98caeada286b 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -8,7 +8,6 @@
 
 #if defined(__linux__)
 
-#define SYS_riscv_hwprobe 258
 static long syscall_impl_5_args(long number, long arg1, long arg2, long arg3,
                                 long arg4, long arg5) {
   register long a7 __asm__("a7") = number;
@@ -94,6 +93,7 @@ typedef struct {
   unsigned long int __bits[__CPU_SETSIZE / __NCPUBITS];
 } cpu_set_t;
 
+#define SYS_riscv_hwprobe 258
 static long sys_riscv_hwprobe(struct riscv_hwprobe *pairs, unsigned pair_count,
                               unsigned cpu_count, cpu_set_t *cpus,
                               unsigned int flags) {

>From 8b2aa7d176143a8ab46d8855111a1ff720a1b2d7 Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Sun, 31 Mar 2024 19:25:33 -0700
Subject: [PATCH 05/15] Update hwprobe relate comment

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index 5e98caeada286b..fac8bea07c3e6a 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -28,7 +28,7 @@ struct riscv_hwprobe {
   unsigned long long value;
 };
 
-// Note: sync with linux/arch/riscv/include/uapi/asm/hwprobe.h
+// Note: sync with https://docs.kernel.org/arch/riscv/hwprobe.html
 #define RISCV_HWPROBE_KEY_MVENDORID 0
 #define RISCV_HWPROBE_KEY_MARCHID 1
 #define RISCV_HWPROBE_KEY_MIMPID 2

>From 7e1dc72d7279f9ccf850ce145d379aad7d8942ad Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Sun, 31 Mar 2024 19:29:52 -0700
Subject: [PATCH 06/15] Pass NULL-like form for cpu_set_t *cpus

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index fac8bea07c3e6a..13a4582fd1add1 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -102,7 +102,7 @@ static long sys_riscv_hwprobe(struct riscv_hwprobe *pairs, unsigned pair_count,
 }
 
 static void initHwProbe(struct riscv_hwprobe *Hwprobes, int len) {
-  sys_riscv_hwprobe(Hwprobes, len, 0, 0, 0);
+  sys_riscv_hwprobe(Hwprobes, len, 0, (cpu_set_t *)((void*) 0), 0);
 }
 
 #endif // defined(__linux__)

>From 822358039cae1d1e9c24289c8063c763098e0c9c Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Sun, 31 Mar 2024 19:36:07 -0700
Subject: [PATCH 07/15] Fix format issue

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index 13a4582fd1add1..f8678473ae0747 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -102,7 +102,7 @@ static long sys_riscv_hwprobe(struct riscv_hwprobe *pairs, unsigned pair_count,
 }
 
 static void initHwProbe(struct riscv_hwprobe *Hwprobes, int len) {
-  sys_riscv_hwprobe(Hwprobes, len, 0, (cpu_set_t *)((void*) 0), 0);
+  sys_riscv_hwprobe(Hwprobes, len, 0, (cpu_set_t *)((void *)0), 0);
 }
 
 #endif // defined(__linux__)

>From 4a3f4b65ebceaf6a15b0e336435eb16925ab0ac3 Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Wed, 3 Apr 2024 02:17:32 -0700
Subject: [PATCH 08/15] [compiler-rt] Update __riscv_ifunc_select prototype

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 37 ++++++++++---------
 1 file changed, 19 insertions(+), 18 deletions(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index f8678473ae0747..580c18ea88bff9 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -101,34 +101,35 @@ static long sys_riscv_hwprobe(struct riscv_hwprobe *pairs, unsigned pair_count,
                              cpu_count, (long)cpus, flags);
 }
 
-static void initHwProbe(struct riscv_hwprobe *Hwprobes, int len) {
-  sys_riscv_hwprobe(Hwprobes, len, 0, (cpu_set_t *)((void *)0), 0);
+static long initHwProbe(struct riscv_hwprobe *Hwprobes, int len) {
+  return sys_riscv_hwprobe(Hwprobes, len, 0, (cpu_set_t *)((void *)0), 0);
 }
 
 #endif // defined(__linux__)
 
-unsigned __riscv_ifunc_select(unsigned long long BaseKey,
-                              unsigned long long IMAKey) {
+unsigned __riscv_ifunc_select(struct riscv_hwprobe *ReqirePreKey,
+                              unsigned Length) {
 #if defined(__linux__)
   // Init Hwprobe
-  struct riscv_hwprobe pairs[] = {
-      {RISCV_HWPROBE_KEY_BASE_BEHAVIOR, 0},
-      {RISCV_HWPROBE_KEY_IMA_EXT_0, 0},
-  };
-  initHwProbe(pairs, 2);
-
-  // sys_riscv_hwprobe key is unknown to the kernel
-  if (pairs[0].key == -1 || pairs[1].key == -1)
-    return 0;
+  struct riscv_hwprobe Pairs[64];
 
-  // Check KEY_BASE_BEHAVIOR
-  if ((BaseKey & pairs[0].value) != BaseKey)
-    return 0;
+  for (unsigned Idx = 0; Idx < Length; Idx++) {
+    Pairs[Idx].key = ReqirePreKey[Idx].key;
+    Pairs[Idx].value = 0;
+  }
 
-  // Check KEY_IMA_EXT_0
-  if ((IMAKey & pairs[1].value) != IMAKey)
+  // hwprobe not success
+  if (initHwProbe(Pairs, 2))
     return 0;
 
+  for (unsigned Idx = 0; Idx < Length; Idx++) {
+    if (Pairs[Idx].key == -1)
+      return 0;
+
+    if ((ReqirePreKey[Idx].value & Pairs[Idx].value) != ReqirePreKey[Idx].value)
+      return 0;
+  }
+
   return 1;
 #else
   // If other platform support IFUNC, need to implement its

>From 305af7dffd2e92f2137d5027e0e888f4922df0f6 Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Sun, 7 Apr 2024 21:26:08 -0700
Subject: [PATCH 09/15] [NFC] Rename ReqirePreKey to ReqireKeys

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index 580c18ea88bff9..0e7eb757f2aa30 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -107,14 +107,14 @@ static long initHwProbe(struct riscv_hwprobe *Hwprobes, int len) {
 
 #endif // defined(__linux__)
 
-unsigned __riscv_ifunc_select(struct riscv_hwprobe *ReqirePreKey,
+unsigned __riscv_ifunc_select(struct riscv_hwprobe *ReqireKeys,
                               unsigned Length) {
 #if defined(__linux__)
   // Init Hwprobe
   struct riscv_hwprobe Pairs[64];
 
   for (unsigned Idx = 0; Idx < Length; Idx++) {
-    Pairs[Idx].key = ReqirePreKey[Idx].key;
+    Pairs[Idx].key = ReqireKeys[Idx].key;
     Pairs[Idx].value = 0;
   }
 
@@ -126,7 +126,7 @@ unsigned __riscv_ifunc_select(struct riscv_hwprobe *ReqirePreKey,
     if (Pairs[Idx].key == -1)
       return 0;
 
-    if ((ReqirePreKey[Idx].value & Pairs[Idx].value) != ReqirePreKey[Idx].value)
+    if ((ReqireKeys[Idx].value & Pairs[Idx].value) != ReqireKeys[Idx].value)
       return 0;
   }
 

>From f39b2cc4ef5d64580bd0f1abbd014ee1a61d9160 Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Sun, 7 Apr 2024 21:32:14 -0700
Subject: [PATCH 10/15] [NFC] Rename Pairs to HwprobePairs

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index 0e7eb757f2aa30..4a93944be8129f 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -111,22 +111,22 @@ unsigned __riscv_ifunc_select(struct riscv_hwprobe *ReqireKeys,
                               unsigned Length) {
 #if defined(__linux__)
   // Init Hwprobe
-  struct riscv_hwprobe Pairs[64];
+  struct riscv_hwprobe HwprobePairs[64];
 
   for (unsigned Idx = 0; Idx < Length; Idx++) {
-    Pairs[Idx].key = ReqireKeys[Idx].key;
-    Pairs[Idx].value = 0;
+    HwprobePairs[Idx].key = ReqireKeys[Idx].key;
+    HwprobePairs[Idx].value = 0;
   }
 
   // hwprobe not success
-  if (initHwProbe(Pairs, 2))
+  if (initHwProbe(HwprobePairs, 2))
     return 0;
 
   for (unsigned Idx = 0; Idx < Length; Idx++) {
-    if (Pairs[Idx].key == -1)
+    if (HwprobePairs[Idx].key == -1)
       return 0;
 
-    if ((ReqireKeys[Idx].value & Pairs[Idx].value) != ReqireKeys[Idx].value)
+    if ((ReqireKeys[Idx].value & HwprobePairs[Idx].value) != ReqireKeys[Idx].value)
       return 0;
   }
 

>From a0ad273c03a9f43dcccee3de8a469a7feedcd601 Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Sun, 7 Apr 2024 21:34:45 -0700
Subject: [PATCH 11/15] Move sys_hwprobe define key into caller site

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 56 -------------------
 1 file changed, 56 deletions(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index 4a93944be8129f..1e235fa8451cd8 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -28,62 +28,6 @@ struct riscv_hwprobe {
   unsigned long long value;
 };
 
-// Note: sync with https://docs.kernel.org/arch/riscv/hwprobe.html
-#define RISCV_HWPROBE_KEY_MVENDORID 0
-#define RISCV_HWPROBE_KEY_MARCHID 1
-#define RISCV_HWPROBE_KEY_MIMPID 2
-#define RISCV_HWPROBE_KEY_BASE_BEHAVIOR 3
-#define RISCV_HWPROBE_BASE_BEHAVIOR_IMA (1 << 0)
-#define RISCV_HWPROBE_KEY_IMA_EXT_0 4
-#define RISCV_HWPROBE_IMA_FD (1 << 0)
-#define RISCV_HWPROBE_IMA_C (1 << 1)
-#define RISCV_HWPROBE_IMA_V (1 << 2)
-#define RISCV_HWPROBE_EXT_ZBA (1 << 3)
-#define RISCV_HWPROBE_EXT_ZBB (1 << 4)
-#define RISCV_HWPROBE_EXT_ZBS (1 << 5)
-#define RISCV_HWPROBE_EXT_ZICBOZ (1 << 6)
-#define RISCV_HWPROBE_EXT_ZBC (1 << 7)
-#define RISCV_HWPROBE_EXT_ZBKB (1 << 8)
-#define RISCV_HWPROBE_EXT_ZBKC (1 << 9)
-#define RISCV_HWPROBE_EXT_ZBKX (1 << 10)
-#define RISCV_HWPROBE_EXT_ZKND (1 << 11)
-#define RISCV_HWPROBE_EXT_ZKNE (1 << 12)
-#define RISCV_HWPROBE_EXT_ZKNH (1 << 13)
-#define RISCV_HWPROBE_EXT_ZKSED (1 << 14)
-#define RISCV_HWPROBE_EXT_ZKSH (1 << 15)
-#define RISCV_HWPROBE_EXT_ZKT (1 << 16)
-#define RISCV_HWPROBE_EXT_ZVBB (1 << 17)
-#define RISCV_HWPROBE_EXT_ZVBC (1 << 18)
-#define RISCV_HWPROBE_EXT_ZVKB (1 << 19)
-#define RISCV_HWPROBE_EXT_ZVKG (1 << 20)
-#define RISCV_HWPROBE_EXT_ZVKNED (1 << 21)
-#define RISCV_HWPROBE_EXT_ZVKNHA (1 << 22)
-#define RISCV_HWPROBE_EXT_ZVKNHB (1 << 23)
-#define RISCV_HWPROBE_EXT_ZVKSED (1 << 24)
-#define RISCV_HWPROBE_EXT_ZVKSH (1 << 25)
-#define RISCV_HWPROBE_EXT_ZVKT (1 << 26)
-#define RISCV_HWPROBE_EXT_ZFH (1 << 27)
-#define RISCV_HWPROBE_EXT_ZFHMIN (1 << 28)
-#define RISCV_HWPROBE_EXT_ZIHINTNTL (1 << 29)
-#define RISCV_HWPROBE_EXT_ZVFH (1 << 30)
-#define RISCV_HWPROBE_EXT_ZVFHMIN (1 << 31)
-#define RISCV_HWPROBE_EXT_ZFA (1ULL << 32)
-#define RISCV_HWPROBE_EXT_ZTSO (1ULL << 33)
-#define RISCV_HWPROBE_EXT_ZACAS (1ULL << 34)
-#define RISCV_HWPROBE_EXT_ZICOND (1ULL << 35)
-#define RISCV_HWPROBE_KEY_CPUPERF_0 5
-#define RISCV_HWPROBE_MISALIGNED_UNKNOWN (0 << 0)
-#define RISCV_HWPROBE_MISALIGNED_EMULATED (1 << 0)
-#define RISCV_HWPROBE_MISALIGNED_SLOW (2 << 0)
-#define RISCV_HWPROBE_MISALIGNED_FAST (3 << 0)
-#define RISCV_HWPROBE_MISALIGNED_UNSUPPORTED (4 << 0)
-#define RISCV_HWPROBE_MISALIGNED_MASK (7 << 0)
-#define RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE 6
-/* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
-
-/* Flags */
-#define RISCV_HWPROBE_WHICH_CPUS (1 << 0)
-
 /* Size definition for CPU sets.  */
 #define __CPU_SETSIZE 1024
 #define __NCPUBITS (8 * sizeof(unsigned long int))

>From b7900935e49ed206f60302139677a1ebc2b0c715 Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Sun, 7 Apr 2024 21:48:15 -0700
Subject: [PATCH 12/15] Fix format issue

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index 1e235fa8451cd8..daaeed4a1db6ba 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -70,7 +70,8 @@ unsigned __riscv_ifunc_select(struct riscv_hwprobe *ReqireKeys,
     if (HwprobePairs[Idx].key == -1)
       return 0;
 
-    if ((ReqireKeys[Idx].value & HwprobePairs[Idx].value) != ReqireKeys[Idx].value)
+    if ((ReqireKeys[Idx].value & HwprobePairs[Idx].value) !=
+        ReqireKeys[Idx].value)
       return 0;
   }
 

>From bf7ca4c8a171d9d7715557d8dc842d5120a5c843 Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Mon, 8 Apr 2024 23:55:07 -0700
Subject: [PATCH 13/15] Use Length as system call argument

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index daaeed4a1db6ba..952d72dd59e12f 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -63,7 +63,7 @@ unsigned __riscv_ifunc_select(struct riscv_hwprobe *ReqireKeys,
   }
 
   // hwprobe not success
-  if (initHwProbe(HwprobePairs, 2))
+  if (initHwProbe(HwprobePairs, Length))
     return 0;
 
   for (unsigned Idx = 0; Idx < Length; Idx++) {

>From e5a2d6cde320cbbed797d4f110cc97f085ea7e3a Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Mon, 8 Apr 2024 23:58:14 -0700
Subject: [PATCH 14/15] Rename ReqireKeys to RequireKeys

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index 952d72dd59e12f..ffc507eecc6df9 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -51,14 +51,14 @@ static long initHwProbe(struct riscv_hwprobe *Hwprobes, int len) {
 
 #endif // defined(__linux__)
 
-unsigned __riscv_ifunc_select(struct riscv_hwprobe *ReqireKeys,
+unsigned __riscv_ifunc_select(struct riscv_hwprobe *RequireKeys,
                               unsigned Length) {
 #if defined(__linux__)
   // Init Hwprobe
   struct riscv_hwprobe HwprobePairs[64];
 
   for (unsigned Idx = 0; Idx < Length; Idx++) {
-    HwprobePairs[Idx].key = ReqireKeys[Idx].key;
+    HwprobePairs[Idx].key = RequireKeys[Idx].key;
     HwprobePairs[Idx].value = 0;
   }
 
@@ -70,8 +70,8 @@ unsigned __riscv_ifunc_select(struct riscv_hwprobe *ReqireKeys,
     if (HwprobePairs[Idx].key == -1)
       return 0;
 
-    if ((ReqireKeys[Idx].value & HwprobePairs[Idx].value) !=
-        ReqireKeys[Idx].value)
+    if ((RequireKeys[Idx].value & HwprobePairs[Idx].value) !=
+        RequireKeys[Idx].value)
       return 0;
   }
 

>From 9b06f1bc429e50c073b35421a300dd803c8dd83e Mon Sep 17 00:00:00 2001
From: Piyou Chen <piyou.chen at sifive.com>
Date: Mon, 8 Apr 2024 23:59:53 -0700
Subject: [PATCH 15/15] Use Length to declare  HwprobePairs

---
 compiler-rt/lib/builtins/riscv/ifunc_select.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler-rt/lib/builtins/riscv/ifunc_select.c b/compiler-rt/lib/builtins/riscv/ifunc_select.c
index ffc507eecc6df9..b341d876378b8c 100644
--- a/compiler-rt/lib/builtins/riscv/ifunc_select.c
+++ b/compiler-rt/lib/builtins/riscv/ifunc_select.c
@@ -55,7 +55,7 @@ unsigned __riscv_ifunc_select(struct riscv_hwprobe *RequireKeys,
                               unsigned Length) {
 #if defined(__linux__)
   // Init Hwprobe
-  struct riscv_hwprobe HwprobePairs[64];
+  struct riscv_hwprobe HwprobePairs[Length];
 
   for (unsigned Idx = 0; Idx < Length; Idx++) {
     HwprobePairs[Idx].key = RequireKeys[Idx].key;



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