diff --git a/src/target.cpp b/src/target.cpp
index 05eb3c662f..5a418aa547 100644
--- a/src/target.cpp
+++ b/src/target.cpp
@@ -1320,6 +1320,8 @@ const char *arch_stack_pointer_register_name(ZigLLVM_ArchType arch) {
         case ZigLLVM_aarch64:
         case ZigLLVM_aarch64_be:
         case ZigLLVM_aarch64_32:
+        case ZigLLVM_riscv32:
+        case ZigLLVM_riscv64:
             return "sp";
 
         case ZigLLVM_arm:
@@ -1350,8 +1352,6 @@ const char *arch_stack_pointer_register_name(ZigLLVM_ArchType arch) {
         case ZigLLVM_r600:
         case ZigLLVM_renderscript32:
         case ZigLLVM_renderscript64:
-        case ZigLLVM_riscv32:
-        case ZigLLVM_riscv64:
         case ZigLLVM_shave:
         case ZigLLVM_sparc:
         case ZigLLVM_sparcel:
diff --git a/std/os/bits/linux.zig b/std/os/bits/linux.zig
index 8430a05bf0..d7c23ffadb 100644
--- a/std/os/bits/linux.zig
+++ b/std/os/bits/linux.zig
@@ -7,6 +7,7 @@ pub usingnamespace @import("linux/errno.zig");
 pub usingnamespace switch (builtin.arch) {
     .x86_64 => @import("linux/x86_64.zig"),
     .aarch64 => @import("linux/arm64.zig"),
+    .riscv64 => @import("linux/riscv64.zig"),
     else => struct {},
 };
 
diff --git a/std/os/bits/linux/riscv64.zig b/std/os/bits/linux/riscv64.zig
new file mode 100644
index 0000000000..cb3124792d
--- /dev/null
+++ b/std/os/bits/linux/riscv64.zig
@@ -0,0 +1,279 @@
+// riscv64-specific declarations that are intended to be imported into the POSIX namespace.
+
+pub const SYS_io_setup = 0;
+pub const SYS_io_destroy = 1;
+pub const SYS_io_submit = 2;
+pub const SYS_io_cancel = 3;
+pub const SYS_io_getevents = 4;
+pub const SYS_setxattr = 5;
+pub const SYS_lsetxattr = 6;
+pub const SYS_fsetxattr = 7;
+pub const SYS_getxattr = 8;
+pub const SYS_lgetxattr = 9;
+pub const SYS_fgetxattr = 10;
+pub const SYS_listxattr = 11;
+pub const SYS_llistxattr = 12;
+pub const SYS_flistxattr = 13;
+pub const SYS_removexattr = 14;
+pub const SYS_lremovexattr = 15;
+pub const SYS_fremovexattr = 16;
+pub const SYS_getcwd = 17;
+pub const SYS_lookup_dcookie = 18;
+pub const SYS_eventfd2 = 19;
+pub const SYS_epoll_create1 = 20;
+pub const SYS_epoll_ctl = 21;
+pub const SYS_epoll_pwait = 22;
+pub const SYS_dup = 23;
+pub const SYS_dup3 = 24;
+pub const SYS_fcntl = 25;
+pub const SYS_inotify_init1 = 26;
+pub const SYS_inotify_add_watch = 27;
+pub const SYS_inotify_rm_watch = 28;
+pub const SYS_ioctl = 29;
+pub const SYS_ioprio_set = 30;
+pub const SYS_ioprio_get = 31;
+pub const SYS_flock = 32;
+pub const SYS_mknodat = 33;
+pub const SYS_mkdirat = 34;
+pub const SYS_unlinkat = 35;
+pub const SYS_symlinkat = 36;
+pub const SYS_linkat = 37;
+pub const SYS_umount2 = 39;
+pub const SYS_mount = 40;
+pub const SYS_pivot_root = 41;
+pub const SYS_nfsservctl = 42;
+pub const SYS_statfs = 43;
+pub const SYS_fstatfs = 44;
+pub const SYS_truncate = 45;
+pub const SYS_ftruncate = 46;
+pub const SYS_fallocate = 47;
+pub const SYS_faccessat = 48;
+pub const SYS_chdir = 49;
+pub const SYS_fchdir = 50;
+pub const SYS_chroot = 51;
+pub const SYS_fchmod = 52;
+pub const SYS_fchmodat = 53;
+pub const SYS_fchownat = 54;
+pub const SYS_fchown = 55;
+pub const SYS_openat = 56;
+pub const SYS_close = 57;
+pub const SYS_vhangup = 58;
+pub const SYS_pipe2 = 59;
+pub const SYS_quotactl = 60;
+pub const SYS_getdents64 = 61;
+pub const SYS_lseek = 62;
+pub const SYS_read = 63;
+pub const SYS_write = 64;
+pub const SYS_readv = 65;
+pub const SYS_writev = 66;
+pub const SYS_pread64 = 67;
+pub const SYS_pwrite64 = 68;
+pub const SYS_preadv = 69;
+pub const SYS_pwritev = 70;
+pub const SYS_sendfile = 71;
+pub const SYS_pselect6 = 72;
+pub const SYS_ppoll = 73;
+pub const SYS_signalfd4 = 74;
+pub const SYS_vmsplice = 75;
+pub const SYS_splice = 76;
+pub const SYS_tee = 77;
+pub const SYS_readlinkat = 78;
+pub const SYS_fstatat = 79;
+pub const SYS_fstat = 80;
+pub const SYS_sync = 81;
+pub const SYS_fsync = 82;
+pub const SYS_fdatasync = 83;
+pub const SYS_sync_file_range = 84;
+pub const SYS_timerfd_create = 85;
+pub const SYS_timerfd_settime = 86;
+pub const SYS_timerfd_gettime = 87;
+pub const SYS_utimensat = 88;
+pub const SYS_acct = 89;
+pub const SYS_capget = 90;
+pub const SYS_capset = 91;
+pub const SYS_personality = 92;
+pub const SYS_exit = 93;
+pub const SYS_exit_group = 94;
+pub const SYS_waitid = 95;
+pub const SYS_set_tid_address = 96;
+pub const SYS_unshare = 97;
+pub const SYS_futex = 98;
+pub const SYS_set_robust_list = 99;
+pub const SYS_get_robust_list = 100;
+pub const SYS_nanosleep = 101;
+pub const SYS_getitimer = 102;
+pub const SYS_setitimer = 103;
+pub const SYS_kexec_load = 104;
+pub const SYS_init_module = 105;
+pub const SYS_delete_module = 106;
+pub const SYS_timer_create = 107;
+pub const SYS_timer_gettime = 108;
+pub const SYS_timer_getoverrun = 109;
+pub const SYS_timer_settime = 110;
+pub const SYS_timer_delete = 111;
+pub const SYS_clock_settime = 112;
+pub const SYS_clock_gettime = 113;
+pub const SYS_clock_getres = 114;
+pub const SYS_clock_nanosleep = 115;
+pub const SYS_syslog = 116;
+pub const SYS_ptrace = 117;
+pub const SYS_sched_setparam = 118;
+pub const SYS_sched_setscheduler = 119;
+pub const SYS_sched_getscheduler = 120;
+pub const SYS_sched_getparam = 121;
+pub const SYS_sched_setaffinity = 122;
+pub const SYS_sched_getaffinity = 123;
+pub const SYS_sched_yield = 124;
+pub const SYS_sched_get_priority_max = 125;
+pub const SYS_sched_get_priority_min = 126;
+pub const SYS_sched_rr_get_interval = 127;
+pub const SYS_restart_syscall = 128;
+pub const SYS_kill = 129;
+pub const SYS_tkill = 130;
+pub const SYS_tgkill = 131;
+pub const SYS_sigaltstack = 132;
+pub const SYS_rt_sigsuspend = 133;
+pub const SYS_rt_sigaction = 134;
+pub const SYS_rt_sigprocmask = 135;
+pub const SYS_rt_sigpending = 136;
+pub const SYS_rt_sigtimedwait = 137;
+pub const SYS_rt_sigqueueinfo = 138;
+pub const SYS_rt_sigreturn = 139;
+pub const SYS_setpriority = 140;
+pub const SYS_getpriority = 141;
+pub const SYS_reboot = 142;
+pub const SYS_setregid = 143;
+pub const SYS_setgid = 144;
+pub const SYS_setreuid = 145;
+pub const SYS_setuid = 146;
+pub const SYS_setresuid = 147;
+pub const SYS_getresuid = 148;
+pub const SYS_setresgid = 149;
+pub const SYS_getresgid = 150;
+pub const SYS_setfsuid = 151;
+pub const SYS_setfsgid = 152;
+pub const SYS_times = 153;
+pub const SYS_setpgid = 154;
+pub const SYS_getpgid = 155;
+pub const SYS_getsid = 156;
+pub const SYS_setsid = 157;
+pub const SYS_getgroups = 158;
+pub const SYS_setgroups = 159;
+pub const SYS_uname = 160;
+pub const SYS_sethostname = 161;
+pub const SYS_setdomainname = 162;
+pub const SYS_getrlimit = 163;
+pub const SYS_setrlimit = 164;
+pub const SYS_getrusage = 165;
+pub const SYS_umask = 166;
+pub const SYS_prctl = 167;
+pub const SYS_getcpu = 168;
+pub const SYS_gettimeofday = 169;
+pub const SYS_settimeofday = 170;
+pub const SYS_adjtimex = 171;
+pub const SYS_getpid = 172;
+pub const SYS_getppid = 173;
+pub const SYS_getuid = 174;
+pub const SYS_geteuid = 175;
+pub const SYS_getgid = 176;
+pub const SYS_getegid = 177;
+pub const SYS_gettid = 178;
+pub const SYS_sysinfo = 179;
+pub const SYS_mq_open = 180;
+pub const SYS_mq_unlink = 181;
+pub const SYS_mq_timedsend = 182;
+pub const SYS_mq_timedreceive = 183;
+pub const SYS_mq_notify = 184;
+pub const SYS_mq_getsetattr = 185;
+pub const SYS_msgget = 186;
+pub const SYS_msgctl = 187;
+pub const SYS_msgrcv = 188;
+pub const SYS_msgsnd = 189;
+pub const SYS_semget = 190;
+pub const SYS_semctl = 191;
+pub const SYS_semtimedop = 192;
+pub const SYS_semop = 193;
+pub const SYS_shmget = 194;
+pub const SYS_shmctl = 195;
+pub const SYS_shmat = 196;
+pub const SYS_shmdt = 197;
+pub const SYS_socket = 198;
+pub const SYS_socketpair = 199;
+pub const SYS_bind = 200;
+pub const SYS_listen = 201;
+pub const SYS_accept = 202;
+pub const SYS_connect = 203;
+pub const SYS_getsockname = 204;
+pub const SYS_getpeername = 205;
+pub const SYS_sendto = 206;
+pub const SYS_recvfrom = 207;
+pub const SYS_setsockopt = 208;
+pub const SYS_getsockopt = 209;
+pub const SYS_shutdown = 210;
+pub const SYS_sendmsg = 211;
+pub const SYS_recvmsg = 212;
+pub const SYS_readahead = 213;
+pub const SYS_brk = 214;
+pub const SYS_munmap = 215;
+pub const SYS_mremap = 216;
+pub const SYS_add_key = 217;
+pub const SYS_request_key = 218;
+pub const SYS_keyctl = 219;
+pub const SYS_clone = 220;
+pub const SYS_execve = 221;
+pub const SYS_mmap = 222;
+pub const SYS_fadvise64 = 223;
+pub const SYS_swapon = 224;
+pub const SYS_swapoff = 225;
+pub const SYS_mprotect = 226;
+pub const SYS_msync = 227;
+pub const SYS_mlock = 228;
+pub const SYS_munlock = 229;
+pub const SYS_mlockall = 230;
+pub const SYS_munlockall = 231;
+pub const SYS_mincore = 232;
+pub const SYS_madvise = 233;
+pub const SYS_remap_file_pages = 234;
+pub const SYS_mbind = 235;
+pub const SYS_get_mempolicy = 236;
+pub const SYS_set_mempolicy = 237;
+pub const SYS_migrate_pages = 238;
+pub const SYS_move_pages = 239;
+pub const SYS_rt_tgsigqueueinfo = 240;
+pub const SYS_perf_event_open = 241;
+pub const SYS_accept4 = 242;
+pub const SYS_recvmmsg = 243;
+pub const SYS_arch_specific_syscall = 244;
+pub const SYS_wait4 = 260;
+pub const SYS_prlimit64 = 261;
+pub const SYS_fanotify_init = 262;
+pub const SYS_fanotify_mark = 263;
+pub const SYS_name_to_handle_at = 264;
+pub const SYS_open_by_handle_at = 265;
+pub const SYS_clock_adjtime = 266;
+pub const SYS_syncfs = 267;
+pub const SYS_setns = 268;
+pub const SYS_sendmmsg = 269;
+pub const SYS_process_vm_readv = 270;
+pub const SYS_process_vm_writev = 271;
+pub const SYS_kcmp = 272;
+pub const SYS_finit_module = 273;
+pub const SYS_sched_setattr = 274;
+pub const SYS_sched_getattr = 275;
+pub const SYS_renameat2 = 276;
+pub const SYS_seccomp = 277;
+pub const SYS_getrandom = 278;
+pub const SYS_memfd_create = 279;
+pub const SYS_bpf = 280;
+pub const SYS_execveat = 281;
+pub const SYS_userfaultfd = 282;
+pub const SYS_membarrier = 283;
+pub const SYS_mlock2 = 284;
+pub const SYS_copy_file_range = 285;
+pub const SYS_preadv2 = 286;
+pub const SYS_pwritev2 = 287;
+pub const SYS_pkey_mprotect = 288;
+pub const SYS_pkey_alloc = 289;
+pub const SYS_pkey_free = 290;
+pub const SYS_sysriscv = 244;
+pub const SYS_riscv_flush_icache = SYS_sysriscv + 15;
diff --git a/std/os/linux.zig b/std/os/linux.zig
index 053f30d265..e217430e27 100644
--- a/std/os/linux.zig
+++ b/std/os/linux.zig
@@ -17,6 +17,7 @@ pub const is_the_target = builtin.os == .linux;
 pub usingnamespace switch (builtin.arch) {
     .x86_64 => @import("linux/x86_64.zig"),
     .aarch64 => @import("linux/arm64.zig"),
+    .riscv64 => @import("linux/riscv64.zig"),
     else => struct {},
 };
 pub usingnamespace @import("bits.zig");
diff --git a/std/os/linux/arm64.zig b/std/os/linux/arm64.zig
index 94cf8818de..f50374a503 100644
--- a/std/os/linux/arm64.zig
+++ b/std/os/linux/arm64.zig
@@ -2,6 +2,7 @@ pub fn syscall0(number: usize) usize {
     return asm volatile ("svc #0"
         : [ret] "={x0}" (-> usize)
         : [number] "{x8}" (number)
+        : "memory"
     );
 }
 
@@ -10,6 +11,7 @@ pub fn syscall1(number: usize, arg1: usize) usize {
         : [ret] "={x0}" (-> usize)
         : [number] "{x8}" (number),
           [arg1] "{x0}" (arg1)
+        : "memory"
     );
 }
 
@@ -19,6 +21,7 @@ pub fn syscall2(number: usize, arg1: usize, arg2: usize) usize {
         : [number] "{x8}" (number),
           [arg1] "{x0}" (arg1),
           [arg2] "{x1}" (arg2)
+        : "memory"
     );
 }
 
@@ -29,6 +32,7 @@ pub fn syscall3(number: usize, arg1: usize, arg2: usize, arg3: usize) usize {
           [arg1] "{x0}" (arg1),
           [arg2] "{x1}" (arg2),
           [arg3] "{x2}" (arg3)
+        : "memory"
     );
 }
 
@@ -40,6 +44,7 @@ pub fn syscall4(number: usize, arg1: usize, arg2: usize, arg3: usize, arg4: usiz
           [arg2] "{x1}" (arg2),
           [arg3] "{x2}" (arg3),
           [arg4] "{x3}" (arg4)
+        : "memory"
     );
 }
 
@@ -52,6 +57,7 @@ pub fn syscall5(number: usize, arg1: usize, arg2: usize, arg3: usize, arg4: usiz
           [arg3] "{x2}" (arg3),
           [arg4] "{x3}" (arg4),
           [arg5] "{x4}" (arg5)
+        : "memory"
     );
 }
 
@@ -73,6 +79,7 @@ pub fn syscall6(
           [arg4] "{x3}" (arg4),
           [arg5] "{x4}" (arg5),
           [arg6] "{x5}" (arg6)
+        : "memory"
     );
 }
 
diff --git a/std/os/linux/riscv64.zig b/std/os/linux/riscv64.zig
new file mode 100644
index 0000000000..b9264aa3db
--- /dev/null
+++ b/std/os/linux/riscv64.zig
@@ -0,0 +1,78 @@
+pub fn syscall0(number: usize) usize {
+    return asm volatile ("ecall"
+        : [ret] "={a0}" (-> usize)
+        : [number] "{a7}" (number)
+        : "memory"
+    );
+}
+
+pub fn syscall1(number: usize, arg1: usize) usize {
+    return asm volatile ("ecall"
+        : [ret] "={a0}" (-> usize)
+        : [number] "{a7}" (number),
+          [arg1] "{a0}" (arg1)
+    );
+}
+
+pub fn syscall2(number: usize, arg1: usize, arg2: usize) usize {
+    return asm volatile ("ecall"
+        : [ret] "={a0}" (-> usize)
+        : [number] "{a7}" (number),
+          [arg1] "{a0}" (arg1),
+          [arg2] "{a1}" (arg2)
+    );
+}
+
+pub fn syscall3(number: usize, arg1: usize, arg2: usize, arg3: usize) usize {
+    return asm volatile ("ecall"
+        : [ret] "={a0}" (-> usize)
+        : [number] "{a7}" (number),
+          [arg1] "{a0}" (arg1),
+          [arg2] "{a1}" (arg2),
+          [arg3] "{a2}" (arg3)
+    );
+}
+
+pub fn syscall4(number: usize, arg1: usize, arg2: usize, arg3: usize, arg4: usize) usize {
+    return asm volatile ("ecall"
+        : [ret] "={a0}" (-> usize)
+        : [number] "{a7}" (number),
+          [arg1] "{a0}" (arg1),
+          [arg2] "{a1}" (arg2),
+          [arg3] "{a2}" (arg3),
+          [arg4] "{a3}" (arg4)
+    );
+}
+
+pub fn syscall5(number: usize, arg1: usize, arg2: usize, arg3: usize, arg4: usize, arg5: usize) usize {
+    return asm volatile ("ecall"
+        : [ret] "={a0}" (-> usize)
+        : [number] "{a7}" (number),
+          [arg1] "{a0}" (arg1),
+          [arg2] "{a1}" (arg2),
+          [arg3] "{a2}" (arg3),
+          [arg4] "{a3}" (arg4),
+          [arg5] "{a4}" (arg5)
+    );
+}
+
+pub fn syscall6(
+    number: usize,
+    arg1: usize,
+    arg2: usize,
+    arg3: usize,
+    arg4: usize,
+    arg5: usize,
+    arg6: usize,
+) usize {
+    return asm volatile ("ecall"
+        : [ret] "={a0}" (-> usize)
+        : [number] "{a7}" (number),
+          [arg1] "{a0}" (arg1),
+          [arg2] "{a1}" (arg2),
+          [arg3] "{a2}" (arg3),
+          [arg4] "{a3}" (arg4),
+          [arg5] "{a4}" (arg5),
+          [arg6] "{a5}" (arg6)
+    );
+}
diff --git a/std/os/linux/tls.zig b/std/os/linux/tls.zig
index a10d68663b..4996065121 100644
--- a/std/os/linux/tls.zig
+++ b/std/os/linux/tls.zig
@@ -47,7 +47,7 @@ const TLSVariant = enum {
 };
 
 const tls_variant = switch (builtin.arch) {
-    .arm, .armeb, .aarch64, .aarch64_be => TLSVariant.VariantI,
+    .arm, .armeb, .aarch64, .aarch64_be, .riscv32, .riscv64 => TLSVariant.VariantI,
     .x86_64, .i386 => TLSVariant.VariantII,
     else => @compileError("undefined tls_variant for this architecture"),
 };
@@ -118,6 +118,13 @@ pub fn setThreadPointer(addr: usize) void {
                 : [addr] "r" (addr)
             );
         },
+        .riscv64 => {
+            asm volatile (
+                \\ mv tp, %[addr]
+                :
+                : [addr] "r" (addr)
+            );
+        },
         else => @compileError("Unsupported architecture"),
     }
 }
diff --git a/std/os/linux/x86_64.zig b/std/os/linux/x86_64.zig
index 82eed0256b..0f3a36636a 100644
--- a/std/os/linux/x86_64.zig
+++ b/std/os/linux/x86_64.zig
@@ -4,7 +4,7 @@ pub fn syscall0(number: usize) usize {
     return asm volatile ("syscall"
         : [ret] "={rax}" (-> usize)
         : [number] "{rax}" (number)
-        : "rcx", "r11"
+        : "rcx", "r11", "memory"
     );
 }
 
@@ -13,7 +13,7 @@ pub fn syscall1(number: usize, arg1: usize) usize {
         : [ret] "={rax}" (-> usize)
         : [number] "{rax}" (number),
           [arg1] "{rdi}" (arg1)
-        : "rcx", "r11"
+        : "rcx", "r11", "memory"
     );
 }
 
@@ -23,7 +23,7 @@ pub fn syscall2(number: usize, arg1: usize, arg2: usize) usize {
         : [number] "{rax}" (number),
           [arg1] "{rdi}" (arg1),
           [arg2] "{rsi}" (arg2)
-        : "rcx", "r11"
+        : "rcx", "r11", "memory"
     );
 }
 
@@ -34,7 +34,7 @@ pub fn syscall3(number: usize, arg1: usize, arg2: usize, arg3: usize) usize {
           [arg1] "{rdi}" (arg1),
           [arg2] "{rsi}" (arg2),
           [arg3] "{rdx}" (arg3)
-        : "rcx", "r11"
+        : "rcx", "r11", "memory"
     );
 }
 
@@ -46,7 +46,7 @@ pub fn syscall4(number: usize, arg1: usize, arg2: usize, arg3: usize, arg4: usiz
           [arg2] "{rsi}" (arg2),
           [arg3] "{rdx}" (arg3),
           [arg4] "{r10}" (arg4)
-        : "rcx", "r11"
+        : "rcx", "r11", "memory"
     );
 }
 
@@ -59,7 +59,7 @@ pub fn syscall5(number: usize, arg1: usize, arg2: usize, arg3: usize, arg4: usiz
           [arg3] "{rdx}" (arg3),
           [arg4] "{r10}" (arg4),
           [arg5] "{r8}" (arg5)
-        : "rcx", "r11"
+        : "rcx", "r11", "memory"
     );
 }
 
@@ -81,7 +81,7 @@ pub fn syscall6(
           [arg4] "{r10}" (arg4),
           [arg5] "{r8}" (arg5),
           [arg6] "{r9}" (arg6)
-        : "rcx", "r11"
+        : "rcx", "r11", "memory"
     );
 }
 
diff --git a/std/special/start.zig b/std/special/start.zig
index 30298669e3..42dda53121 100644
--- a/std/special/start.zig
+++ b/std/special/start.zig
@@ -59,6 +59,11 @@ nakedcc fn _start() noreturn {
                 : [argc] "=r" (-> [*]usize)
             );
         },
+        .riscv64 => {
+            argc_ptr = asm ("mov %[argc], sp"
+                : [argc] "=r" (-> [*]usize)
+            );
+        },
         else => @compileError("unsupported arch"),
     }
     // If LLVM inlines stack variables into _start, they will overwrite