syscall improvements

Author: tombl

arch/wasm/include/asm/thread_info.h

@@ -17,12 +17,13 @@ struct thread_info {
 	int preempt_count;
 	int cpu; // this is for the kernel
 	atomic_t running_cpu; // negative means unscheduled
+	unsigned long tp_value;
 };
 
 #define INIT_THREAD_INFO(tsk)                                              \
 	{                                                                  \
 		.flags = 0, .preempt_count = INIT_PREEMPT_COUNT, .cpu = 0, \
-		.running_cpu = ATOMIC_INIT(0),                             \
+		.running_cpu = ATOMIC_INIT(0), .tp_value = U32_MAX,        \
 	}
 
 #define TIF_SYSCALL_TRACE 0 /* syscall trace active */

arch/wasm/include/asm/unistd.h

@@ -1,9 +1,20 @@
 #define _WASM_UNISTD_H
 #ifdef _WASM_UNISTD_H
 
-#include <uapi/asm/unistd.h>
-
 #define sys_mmap2 sys_mmap_pgoff
+#define __ARCH_WANT_RENAMEAT
+#define __ARCH_WANT_STAT64
+#define __ARCH_WANT_SET_GET_RLIMIT
 #define __ARCH_WANT_SYS_CLONE
+#define __ARCH_WANT_SYS_CLONE3
+#define __ARCH_WANT_SYS_VFORK
+#define __ARCH_WANT_SYS_FORK
+#define __ARCH_WANT_TIME32_SYSCALLS
+#define __ARCH_WANT_SYNC_FILE_RANGE2
+
+#include <asm-generic/unistd.h>
+
+#define __NR_set_thread_area (__NR_arch_specific_syscall + 0)
+__SYSCALL(__NR_set_thread_area, sys_set_thread_area)
 
 #endif

arch/wasm/kernel/syscall.c

@@ -43,4 +43,18 @@ wasm_syscall(long nr, unsigned long arg0, unsigned long arg1,
 	syscall_exit_to_user_mode(regs);
 
 	return ret;
+}
+
+SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
+{
+	struct thread_info *ti = task_thread_info(current);
+	ti->tp_value = addr;
+	return 0;
+}
+
+__attribute__((export_name("get_thread_area"))) unsigned long
+wasm_get_thread_area(void)
+{
+	struct thread_info *ti = task_thread_info(current);
+	return ti->tp_value;
 }

tools/wasm/src/init2.cpio

@@ -12,6 +12,7 @@ export interface Instance extends WebAssembly.Instance {
       arg4: number,
       arg5: number,
     ): number;
+    get_thread_area(): number;
   };
 }
 

tools/wasm/src/wasm.ts

@@ -62,6 +62,7 @@ self.onmessage = (event: MessageEvent<InitMessage>) => {
             },
             linux: {
               syscall: instance.exports.syscall,
+              get_thread_area: instance.exports.get_thread_area,
             },
           });