[libc] Add riscv64 syscall implementation.

[sivachandra]

Summary

All syscall wrapper functions which have unit tests have been enabled.

[sivachandra]

@mikhail.ramalho - Feel free to submit this if you like it.

[kito-cheng]

Per my experience from RISC-V newlib port, LGTM.

[jrtc27]

libc/src/__support/OSUtil/linux/riscv64/syscall.h

44

What condition codes?

[sivachandra]

• Remove a copy paste remnant from the syscall implementation.
• Enable more string functions.

libc/src/__support/OSUtil/linux/riscv64/syscall.h

44

Thanks for catching - it was a copy-paste remnant which I have now removed.

[arichardson]

libc/src/__support/OSUtil/linux/riscv64/syscall.h

11

Copy paste error in the include guard

[sivachandra]

Fix more typos.

[mikhail.ramalho]

Hey @sivachandra, we seem to need the signal-macros.h and the fenv stuff to get this patch compiling:

/home/mgadelha/llvm-project/build/projects/libc/include/llvm-libc-macros/linux/signal-macros.h:86:2: error: "Signal stack sizes not defined for your platform."
#error "Signal stack sizes not defined for your platform."
 ^
1 error generated.

/home/mgadelha/llvm-project/libc/src/__support/FPUtil/FEnvImpl.h:51:25: error: unknown type name 'fenv_t'
LIBC_INLINE int get_env(fenv_t *) { return 0; }
                        ^
/home/mgadelha/llvm-project/libc/src/__support/FPUtil/FEnvImpl.h:53:31: error: unknown type name 'fenv_t'
LIBC_INLINE int set_env(const fenv_t *) { return 0; }
                              ^
2 errors generated.

[mikhail.ramalho]

This was enough to fix compilation, and all tests are passing:

diff --git a/libc/include/llvm-libc-macros/linux/signal-macros.h b/libc/include/llvm-libc-macros/linux/signal-macros.h
index 069a23347797..4dc39dec47de 100644
--- a/libc/include/llvm-libc-macros/linux/signal-macros.h
+++ b/libc/include/llvm-libc-macros/linux/signal-macros.h
@@ -82,6 +82,9 @@
 #elif defined(__aarch64__)
 #define MINSIGSTKSZ 5120
 #define SIGSTKSZ 16384
+#elif defined(__riscv)
+#define MINSIGSTKSZ 2048
+#define SIGSTKSZ 8192
 #else
 #error "Signal stack sizes not defined for your platform."
 #endif
diff --git a/libc/src/__support/FPUtil/FEnvImpl.h b/libc/src/__support/FPUtil/FEnvImpl.h
index ec21555071c8..179140ae6b9b 100644
--- a/libc/src/__support/FPUtil/FEnvImpl.h
+++ b/libc/src/__support/FPUtil/FEnvImpl.h
@@ -48,9 +48,9 @@ LIBC_INLINE int get_round() { return FE_TONEAREST; }
 
 LIBC_INLINE int set_round(int) { return 0; }
 
-LIBC_INLINE int get_env(fenv_t *) { return 0; }
+LIBC_INLINE int get_env(void *) { return 0; }
 
-LIBC_INLINE int set_env(const fenv_t *) { return 0; }
+LIBC_INLINE int set_env(const void *) { return 0; }
 
 } // namespace __llvm_libc::fputil
 #endif

[sivachandra]

@mikhail.ramalho - there are two modes for building the libc, the overlay mode and the full build mode. With this patch, I am only bringing up the overlay mode. The signal macros and fenv pieces become relevant in the full build mode. Can we do them as follow ups?

[mikhail.ramalho]

Oh, I see, my mistake! I was always building with -DLLVM_LIBC_FULL_BUILD=ON

I agree, let's disable it for now.

Em ter., 7 de mar. de 2023 às 16:55, Siva Chandra via Phabricator <
[e-mail]> escreveu:

sivachandra added a comment.

@mikhail.ramalho - there are two modes for building the libc, the overlay
mode and the full build mode. With this patch, I am only bringing up the
overlay mode. The signal macros and fenv pieces become relevant in the full
build mode. Can we do them as follow ups?

Repository:

rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION

https://reviews.llvm.org/D145452/new/

https://reviews.llvm.org/D145452

libc/config/linux/riscv64/entrypoints.txt

set(TARGET_LIBC_ENTRYPOINTS
     libc.src.ctype.isxdigit
     libc.src.ctype.toascii
     libc.src.ctype.tolower
     libc.src.ctype.toupper
 
     # errno.h entrypoints
     libc.src.errno.errno
 
+    # fcntl.h entrypoints
+    libc.src.fcntl.creat
+    libc.src.fcntl.open
+    libc.src.fcntl.openat
+
+    # sched.h entrypoints
+    libc.src.sched.sched_getaffinity
+    libc.src.sched.sched_setaffinity
+
     # string.h entrypoints
     libc.src.string.bcmp
     libc.src.string.bcopy
     libc.src.string.bzero
     libc.src.string.memccpy
     libc.src.string.memchr
     libc.src.string.memcmp
     libc.src.string.memcpy
     libc.src.string.memmove
     libc.src.string.mempcpy
     libc.src.string.memrchr
     libc.src.string.memset
     libc.src.string.stpcpy
     libc.src.string.stpncpy
     libc.src.string.strcasecmp
     libc.src.string.strcasestr
     libc.src.string.strcat
     libc.src.string.strchr
     libc.src.string.strcmp
     libc.src.string.strcpy
     libc.src.string.strcspn
+    libc.src.string.strdup
+    libc.src.string.strerror
+    libc.src.string.strerror_r
     libc.src.string.strlcat
     libc.src.string.strlcpy
     libc.src.string.strlen
     libc.src.string.strncasecmp
     libc.src.string.strncat
     libc.src.string.strncmp
     libc.src.string.strncpy
+    libc.src.string.strndup
     libc.src.string.strnlen
     libc.src.string.strpbrk
     libc.src.string.strrchr
+    libc.src.string.strsignal
     libc.src.string.strspn
     libc.src.string.strstr
     libc.src.string.strtok
     libc.src.string.strtok_r
 
     # inttypes.h entrypoints
     libc.src.inttypes.imaxabs
     libc.src.inttypes.imaxdiv
set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdlib.qsort
     libc.src.stdlib.strtod
     libc.src.stdlib.strtof
     libc.src.stdlib.strtol
     libc.src.stdlib.strtold
     libc.src.stdlib.strtoll
     libc.src.stdlib.strtoul
     libc.src.stdlib.strtoull
+
+    # stdlib.h external entrypoints
+    libc.src.stdlib.malloc
+    libc.src.stdlib.calloc
+    libc.src.stdlib.realloc
+    libc.src.stdlib.aligned_alloc
+    libc.src.stdlib.free
+
+    # stdio.h entrypoints
+    libc.src.stdio.remove
+
+    # sys/mman.h entrypoints
+    libc.src.sys.mman.madvise
+    libc.src.sys.mman.mmap
+    libc.src.sys.mman.mprotect
+    libc.src.sys.mman.munmap
+    libc.src.sys.mman.posix_madvise
+
+    # sys/random.h entrypoints
+    libc.src.sys.random.getrandom
+
+    # sys/resource.h entrypoints
+    libc.src.sys.resource.getrlimit
+    libc.src.sys.resource.setrlimit
+
+    # sys/sendfile entrypoints
+    libc.src.sys.sendfile.sendfile
+
+    # sys/stat.h entrypoints
+    libc.src.sys.stat.chmod
+    libc.src.sys.stat.fchmod
+    libc.src.sys.stat.fchmodat
+    libc.src.sys.stat.fstat
+    libc.src.sys.stat.lstat
+    libc.src.sys.stat.mkdir
+    libc.src.sys.stat.mkdirat
+    libc.src.sys.stat.stat
+
+    # sys/utsname.h entrypoints
+    libc.src.sys.utsname.uname
+
+    # sys/wait.h entrypoints
+    libc.src.sys.wait.wait
+    libc.src.sys.wait.wait4
+    libc.src.sys.wait.waitpid
+
+    # termios.h entrypoints
+    libc.src.termios.cfgetispeed
+    libc.src.termios.cfgetospeed
+    libc.src.termios.cfsetispeed
+    libc.src.termios.cfsetospeed
+    libc.src.termios.tcgetattr
+    libc.src.termios.tcgetsid
+    libc.src.termios.tcdrain
+    libc.src.termios.tcflow
+    libc.src.termios.tcflush
+    libc.src.termios.tcsendbreak
+    libc.src.termios.tcsetattr
+
+    # unistd.h entrypoints
+    libc.src.unistd.access
+    libc.src.unistd.chdir
+    libc.src.unistd.close
+    libc.src.unistd.dup
+    libc.src.unistd.dup2
+    libc.src.unistd.dup3
+    libc.src.unistd.fchdir
+    libc.src.unistd.fsync
+    libc.src.unistd.ftruncate
+    libc.src.unistd.getcwd
+    libc.src.unistd.geteuid
+    libc.src.unistd.getpid
+    libc.src.unistd.getppid
+    libc.src.unistd.getuid
+    libc.src.unistd.link
+    libc.src.unistd.linkat
+    libc.src.unistd.lseek
+    libc.src.unistd.pread
+    libc.src.unistd.pwrite
+    libc.src.unistd.read
+    libc.src.unistd.readlink
+    libc.src.unistd.readlinkat
+    libc.src.unistd.rmdir
+    libc.src.unistd.symlink
+    libc.src.unistd.symlinkat
+    libc.src.unistd.sysconf
+    libc.src.unistd.truncate
+    libc.src.unistd.unlink
+    libc.src.unistd.unlinkat
+    libc.src.unistd.write
 )
 
 set(TARGET_LIBM_ENTRYPOINTS
     # math.h entrypoints
     libc.src.math.fabs
     libc.src.math.fabsf
     libc.src.math.fabsl
     libc.src.math.fdim

libc/src/__support/OSUtil/linux/riscv64/CMakeLists.txt

+add_header_library(
+  linux_riscv64_util
+  HDRS
+    syscall.h
+  DEPENDS
+    libc.src.__support.common
+)

libc/src/__support/OSUtil/linux/riscv64/syscall.h

+//===--------- inline implementation of riscv64 syscalls ----------* 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_RISCV64_SYSCALL_H
+#define LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_RISCV64_SYSCALL_H
+
+#include "src/__support/common.h"
+
+#define REGISTER_DECL_0                                                        \
+  register long a7 __asm__("a7") = number;                                     \
+  register long a0 __asm__("a0");
+#define REGISTER_DECL_1                                                        \
+  register long a7 __asm__("a7") = number;                                     \
+  register long a0 __asm__("a0") = arg1;
+#define REGISTER_DECL_2 REGISTER_DECL_1 register long a1 __asm__("a1") = arg2;
+#define REGISTER_DECL_3                                                        \
+  REGISTER_DECL_2                                                              \
+  register long a2 __asm__("a2") = arg3;
+#define REGISTER_DECL_4                                                        \
+  REGISTER_DECL_3                                                              \
+  register long a3 __asm__("a3") = arg4;
+#define REGISTER_DECL_5                                                        \
+  REGISTER_DECL_4                                                              \
+  register long a4 __asm__("a4") = arg5;
+#define REGISTER_DECL_6                                                        \
+  REGISTER_DECL_5                                                              \
+  register long a5 __asm__("a5") = arg6;
+
+#define REGISTER_CONSTRAINT_0 "r"(a7)
+#define REGISTER_CONSTRAINT_1 REGISTER_CONSTRAINT_0, "r"(a0)
+#define REGISTER_CONSTRAINT_2 REGISTER_CONSTRAINT_1, "r"(a1)
+#define REGISTER_CONSTRAINT_3 REGISTER_CONSTRAINT_2, "r"(a2)
+#define REGISTER_CONSTRAINT_4 REGISTER_CONSTRAINT_3, "r"(a3)
+#define REGISTER_CONSTRAINT_5 REGISTER_CONSTRAINT_4, "r"(a4)
+#define REGISTER_CONSTRAINT_6 REGISTER_CONSTRAINT_5, "r"(a5)
+
+#define SYSCALL_INSTR(input_constraint)                                        \
+  LIBC_INLINE_ASM("ecall\n\t" : "=r"(a0) : input_constraint : "memory")
+
+namespace __llvm_libc {
+
+LIBC_INLINE long syscall_impl(long number) {
+  REGISTER_DECL_0;
+  SYSCALL_INSTR(REGISTER_CONSTRAINT_0);
+  return a0;
+}
+
+LIBC_INLINE long syscall_impl(long number, long arg1) {
+  REGISTER_DECL_1;
+  SYSCALL_INSTR(REGISTER_CONSTRAINT_1);
+  return a0;
+}
+
+LIBC_INLINE long syscall_impl(long number, long arg1, long arg2) {
+  REGISTER_DECL_2;
+  SYSCALL_INSTR(REGISTER_CONSTRAINT_2);
+  return a0;
+}
+
+LIBC_INLINE long syscall_impl(long number, long arg1, long arg2, long arg3) {
+  REGISTER_DECL_3;
+  SYSCALL_INSTR(REGISTER_CONSTRAINT_3);
+  return a0;
+}
+
+LIBC_INLINE long syscall_impl(long number, long arg1, long arg2, long arg3,
+                              long arg4) {
+  REGISTER_DECL_4;
+  SYSCALL_INSTR(REGISTER_CONSTRAINT_4);
+  return a0;
+}
+
+LIBC_INLINE long syscall_impl(long number, long arg1, long arg2, long arg3,
+                              long arg4, long arg5) {
+  REGISTER_DECL_5;
+  SYSCALL_INSTR(REGISTER_CONSTRAINT_5);
+  return a0;
+}
+
+LIBC_INLINE long syscall_impl(long number, long arg1, long arg2, long arg3,
+                              long arg4, long arg5, long arg6) {
+  REGISTER_DECL_6;
+  SYSCALL_INSTR(REGISTER_CONSTRAINT_6);
+  return a0;
+}
+
+} // namespace __llvm_libc
+
+#undef REGISTER_DECL_0
+#undef REGISTER_DECL_1
+#undef REGISTER_DECL_2
+#undef REGISTER_DECL_3
+#undef REGISTER_DECL_4
+#undef REGISTER_DECL_5
+#undef REGISTER_DECL_6
+
+#undef REGISTER_CONSTRAINT_0
+#undef REGISTER_CONSTRAINT_1
+#undef REGISTER_CONSTRAINT_2
+#undef REGISTER_CONSTRAINT_3
+#undef REGISTER_CONSTRAINT_4
+#undef REGISTER_CONSTRAINT_5
+#undef REGISTER_CONSTRAINT_6
+
+#endif // LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_RISCV64_SYSCALL_H

libc/src/__support/OSUtil/linux/syscall.h

 #include "src/__support/macros/properties/architectures.h"
 
 #ifdef LIBC_TARGET_ARCH_IS_X86_64
 #include "x86_64/syscall.h"
 #elif defined(LIBC_TARGET_ARCH_IS_AARCH64)
 #include "aarch64/syscall.h"
 #elif defined(LIBC_TARGET_ARCH_IS_ARM)
 #include "arm/syscall.h"
+#elif defined(LIBC_TARGET_ARCH_IS_RISCV64)
+#include "riscv64/syscall.h"
 #endif
 
 namespace __llvm_libc {
 
 template <typename... Ts>
 LIBC_INLINE long syscall_impl(long __number, Ts... ts) {
   static_assert(sizeof...(Ts) <= 6, "Too many arguments for syscall");
   return syscall_impl(__number, (long)ts...);
 }
 
 } // namespace __llvm_libc
 
 #endif // LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_SYSCALL_H

libc/src/__support/macros/properties/architectures.h

 #if (defined(__arm__) || defined(_M_ARM))
 #define LIBC_TARGET_ARCH_IS_ARM
 #endif
 
 #if defined(__aarch64__) || defined(__arm64__) || defined(_M_ARM64)
 #define LIBC_TARGET_ARCH_IS_AARCH64
 #endif
 
+#if defined(__riscv) && (__riscv_xlen == 64)
+#define LIBC_TARGET_ARCH_IS_RISCV64
+#endif
+
 #if (defined(LIBC_TARGET_ARCH_IS_AARCH64) || defined(LIBC_TARGET_ARCH_IS_ARM))
 #define LIBC_TARGET_ARCH_IS_ANY_ARM
 #endif
 
 #endif // LLVM_LIBC_SUPPORT_MACROS_PROPERTIES_ARCHITECTURES_H