Don't rely on the C library

Makefile.in

@@ -91,7 +91,7 @@ COMPILE       := $(CC) -MMD -MP $(CFLAGS) \
 #  - LIBS    : Library flags (eg. -l)
 
 LD            := $(CC)
-LDFLAGS       := @LDFLAGS@ -nostartfiles -nostdlib $(LDFLAGS)
+LDFLAGS       := @LDFLAGS@ -nostartfiles -nostdlib -static $(LDFLAGS)
 LIBS          := @LIBS@
 LINK          := $(LD) $(LDFLAGS) -T $(src_dir)/pk/pk.ld
 

configure

@@ -3953,8 +3953,6 @@ fi
 
 CFLAGS="-Wall -Os -std=gnu99 -Wno-unused -Wno-attributes -fno-delete-null-pointer-checks"
 
-LIBS="-lc -lgcc"
-
 
 
   { $as_echo "$as_me:${as_lineno-$LINENO}: adding default configure arg: --host=riscv" >&5

configure.ac

@@ -72,7 +72,6 @@ AC_HEADER_STDC
 #-------------------------------------------------------------------------
 
 AC_SUBST([CFLAGS],  ["-Wall -Os -std=gnu99 -Wno-unused -Wno-attributes -fno-delete-null-pointer-checks"])
-AC_SUBST([LIBS],  ["-lc -lgcc"])
 
 AX_DEFAULT_CONFIGURE_ARG([--host=riscv])
 

pk/file.h

@@ -4,6 +4,7 @@
 #define _FILE_H
 
 #include <sys/stat.h>
+#include <unistd.h>
 #include "atomic.h"
 
 typedef struct file

pk/handlers.c

@@ -112,8 +112,8 @@ void handle_fault_store(trapframe_t* tf)
 
 static void handle_syscall(trapframe_t* tf)
 {
-  tf->gpr[16] = syscall(tf->gpr[18], tf->gpr[19], tf->gpr[20], tf->gpr[21],
-                        tf->gpr[22], tf->gpr[23], tf->gpr[16]);
+  tf->gpr[16] = do_syscall(tf->gpr[18], tf->gpr[19], tf->gpr[20], tf->gpr[21],
+                           tf->gpr[22], tf->gpr[23], tf->gpr[16]);
   tf->epc += 4;
 }
 

pk/pk.mk.in

@@ -24,6 +24,7 @@ pk_c_srcs = \
 	elf.c \
 	console.c \
 	vm.c \
+	string.c \
 
 pk_asm_srcs = \
 	entry.S \

pk/string.c

@@ -0,0 +1,53 @@
+#include <string.h>
+#include <stdint.h>
+
+void* memcpy(void* dest, const void* src, size_t len)
+{
+  if ((((uintptr_t)dest | (uintptr_t)src | len) & (sizeof(uintptr_t)-1)) == 0) {
+    const uintptr_t* s = src;
+    uintptr_t *d = dest;
+    while (d < (uintptr_t*)(dest + len))
+      *d++ = *s++;
+  } else {
+    const char* s = src;
+    char *d = dest;
+    while (d < (char*)(dest + len))
+      *d++ = *s++;
+  }
+  return dest;
+}
+
+void* memset(void* dest, int byte, size_t len)
+{
+  if ((((uintptr_t)dest | len) & (sizeof(uintptr_t)-1)) == 0) {
+    uintptr_t word = byte & 0xFF;
+    word |= word << 8;
+    word |= word << 16;
+    word |= word << 16 << 16;
+
+    uintptr_t *d = dest;
+    while (d < (uintptr_t*)(dest + len))
+      *d++ = word;
+  } else {
+    char *d = dest;
+    while (d < (char*)(dest + len))
+      *d++ = byte;
+  }
+  return dest;
+}
+
+size_t strlen(const char *s)
+{
+  const char *p = s;
+  while (*p)
+    p++;
+  return p - s;
+}
+
+char* strcpy(char* dest, const char* src)
+{
+  char* d = dest;
+  while ((*d++ = *src++))
+    ;
+  return dest;
+}

pk/syscall.c

@@ -384,12 +384,17 @@ int sys_getdents(int fd, void* dirbuf, int count)
   return 0; //stub
 }
 
-int sys_nosys()
+static int sys_stub_success()
+{
+  return 0;
+}
+
+static int sys_stub_nosys()
 {
   return -ENOSYS;
 }
 
-long syscall(long a0, long a1, long a2, long a3, long a4, long a5, long n)
+long do_syscall(long a0, long a1, long a2, long a3, long a4, long a5, long n)
 {
   const static void* syscall_table[] = {
     [SYS_exit] = sys_exit,
@@ -430,7 +435,8 @@ long syscall(long a0, long a1, long a2, long a3, long a4, long a5, long n)
     [SYS_fcntl] = sys_fcntl,
     [SYS_getdents] = sys_getdents,
     [SYS_dup] = sys_dup,
-    [SYS_readlinkat] = sys_nosys,
+    [SYS_readlinkat] = sys_stub_nosys,
+    [SYS_rt_sigprocmask] = sys_stub_success,
   };
 
   if(n >= ARRAY_SIZE(syscall_table) || !syscall_table[n])

pk/syscall.h

@@ -46,12 +46,13 @@
 #define SYS_getdents 61
 #define SYS_dup 23
 #define SYS_readlinkat 78
+#define SYS_rt_sigprocmask 135
 
 #define IS_ERR_VALUE(x) ((unsigned long)(x) >= (unsigned long)-4096)
 #define ERR_PTR(x) ((void*)(long)(x))
 #define PTR_ERR(x) ((long)(x))
 
 void sys_exit(int code) __attribute__((noreturn));
-long syscall(long a0, long a1, long a2, long a3, long a4, long a5, long n);
+long do_syscall(long a0, long a1, long a2, long a3, long a4, long a5, long n);
 
 #endif