Kernel/LibC: pass environ pointer to process

kernel/arch/x86_64/Thread.S

@@ -25,7 +25,7 @@ continue_thread:
 	movq $0, %rax
 	jmp *%rsi
 
-# void thread_userspace_trampoline(uint64_t rsp, uint64_t rip, int argc, char** argv)
+# void thread_userspace_trampoline(uint64_t rsp, uint64_t rip, int argc, char** argv, char** envp)
 .global thread_userspace_trampoline
 thread_userspace_trampoline:
 	pushq $0x23
@@ -35,4 +35,5 @@ thread_userspace_trampoline:
 	pushq %rsi
 	movq %rdx, %rdi
 	movq %rcx, %rsi
+	movq %r8, %rdx
 	iretq

kernel/arch/x86_64/crt0.S

@@ -9,10 +9,12 @@ _start:
 	movq %rsp, %rbp
 
 	# We need those in a moment when we call main.
+	pushq %rdx
 	pushq %rsi
 	pushq %rdi
 
 	# Prepare signals, memory allocation, stdio and such.
+	movq %rdx, %rdi
 	call _init_libc
 
 	# Run the global constructors.
@@ -21,6 +23,7 @@ _start:
 	# Restore argc and argv.
 	popq %rdi
 	popq %rsi
+	popq %rdx
 
 	# Run main
 	call main