sysdeps/managarm: add riscv64 sysdeps

abis/linux/signal.h

@@ -361,6 +361,13 @@ typedef struct __ucontext {
 	mcontext_t uc_mcontext;
 } ucontext_t;
 
+struct sigcontext {
+  unsigned long int gregs[32];
+  unsigned long long int fpregs[66] __attribute__ ((__aligned__ (16)));
+};
+
+#warning amnogusd
+
 #elif defined (__aarch64__)
 
 typedef struct sigcontext {

sysdeps/managarm/generic/file.cpp

@@ -2463,6 +2463,8 @@ int sys_uname(struct utsname *buf) {
 	strcpy(buf->machine, "x86_64");
 #elif defined (__aarch64__)
 	strcpy(buf->machine, "aarch64");
+#elif defined (__riscv) && __riscv_xlen == 64
+	strcpy(buf->machine, "riscv64");
 #else
 #	error Unknown architecture
 #endif

sysdeps/managarm/meson.build

@@ -62,6 +62,12 @@ elif host_machine.cpu_family() == 'x86_64'
 		'x86_64/thread_entry.S',
 		'x86_64/thread.cpp'
 	)
+elif host_machine.cpu_family() == 'riscv64'
+        libc_sources += files(
+                'riscv64/signals.S',
+                'riscv64/thread_entry.S',
+                'riscv64/thread.cpp'
+        )
 else
 	error('Unknown architecture')
 endif

sysdeps/managarm/riscv64/crt-src/crt0.S

@@ -0,0 +1,15 @@
+.section .text
+.global _start
+_start:
+	.weak __global_pointer$
+	.hidden __global_pointer$
+	.option push
+	.option norelax
+	lla gp, __global_pointer$
+	.option pop
+
+	mv a0, sp
+	la a1, main
+	call __mlibc_entry
+.section .note.GNU-stack,"",%progbits
+

sysdeps/managarm/riscv64/signals.S

@@ -0,0 +1,8 @@
+.section .text
+	nop // TODO: why is this needed?
+.global __mlibc_signal_restore
+.type __mlibc_signal_restore, @function
+__mlibc_signal_restore:
+	unimp // TODO
+.section .note.GNU-stack,"",%progbits
+

sysdeps/managarm/riscv64/thread.cpp

@@ -0,0 +1,56 @@
+#include <mlibc/thread-entry.hpp>
+#include <mlibc/all-sysdeps.hpp>
+#include <mlibc/tcb.hpp>
+#include <bits/ensure.h>
+#include <sys/mman.h>
+#include <stdint.h>
+#include <stddef.h>
+
+extern "C" void __mlibc_enter_thread(void *entry, void *user_arg, Tcb *tcb) {
+	// Wait until our parent sets up the TID.
+	while(!__atomic_load_n(&tcb->tid, __ATOMIC_RELAXED))
+		mlibc::sys_futex_wait(&tcb->tid, 0, nullptr);
+
+	if(mlibc::sys_tcb_set(tcb))
+		__ensure(!"sys_tcb_set() failed");
+
+	void *(*func)(void *) = reinterpret_cast<void *(*)(void *)>(entry);
+	auto result = func(user_arg);
+
+	auto self = reinterpret_cast<Tcb *>(tcb);
+
+	self->returnValue = result;
+	__atomic_store_n(&self->didExit, 1, __ATOMIC_RELEASE);
+	mlibc::sys_futex_wake(&self->didExit);
+
+	mlibc::sys_thread_exit();
+}
+
+namespace mlibc {
+
+static constexpr size_t default_stacksize = 0x200000;
+
+int sys_prepare_stack(void **stack, void *entry, void *user_arg, void *tcb, size_t *stack_size, size_t *guard_size) {
+	if (!*stack_size)
+		*stack_size = default_stacksize;
+	*guard_size = 0;
+
+	uintptr_t *sp;
+	if (*stack) {
+		sp = reinterpret_cast<uintptr_t *>(*stack);
+	} else {
+		sp = reinterpret_cast<uintptr_t *>(reinterpret_cast<uintptr_t>(
+					mmap(nullptr, *stack_size,
+						PROT_READ | PROT_WRITE,
+						MAP_PRIVATE | MAP_ANONYMOUS, -1, 0)
+					) + *stack_size);
+	}
+
+	*--sp = reinterpret_cast<uintptr_t>(tcb);
+	*--sp = reinterpret_cast<uintptr_t>(user_arg);
+	*--sp = reinterpret_cast<uintptr_t>(entry);
+	*stack = reinterpret_cast<void*>(sp);
+	return 0;
+}
+
+} //namespace mlibc

sysdeps/managarm/riscv64/thread_entry.S

@@ -0,0 +1,17 @@
+.section .text
+.global __mlibc_start_thread
+.type __mlibc_start_thread, "function"
+__mlibc_start_thread:
+	// if this works i am going to eat my dog
+	ld a0, 0(sp)
+	ld a1, 8(sp)
+	ld a2, 16(sp)
+	addi sp, sp, 24
+	andi sp, sp, -16
+	call __mlibc_enter_thread
+	unimp
+
+.parent:
+	ret
+.section .note.GNU-stack,"",%progbits
+