Rename lib/ to src/ (better for Tab-completion)

1 files changed, 0 insertions, 264 deletions

diff --git a/lib/thread_create.asm b/lib/thread_create.asm
deleted file mode 100644
index 9a6fe78..0000000
--- a/lib/thread_create.asm
+++ /dev/null
@@ -1,264 +0,0 @@
-; Under MIT license, see /LICENSE.txt
-
-
-; Cheat sheet for Linux' x86_64 calling convention:
-;
-; - free to overwrite (caller should save them):
-;       rax, rcx, rdx, rsi, rdi, r8-r11, xmm0-xmm15
-; - caller expects be kept (callee should save them):
-;       rbx, rbp, r12-r15
-;
-; - for passing paramters to functions:
-;       rdi, rsi, rdx, rcx, r8, r9, xmm0-xmm7
-; - for getting return values from functions:
-;       rax, rdx, xmm0
-;
-; - for passing parameters to syscalls:
-;       rax, rdi, rsi, rdx, r10, r8, r9
-; - for getting return values from syscalls:
-;       rax, rdx
-; - overwritten by syscalls (all others preserved):
-;       rcx, r11
-
-
-section .text
-
-
-; Relevant system call IDs
-%define SYS_MMAP      9
-%define SYS_MPROTECT 10
-%define SYS_CLONE    56
-%define SYS_EXIT     60
-
-; Relevant flags for mmap
-%define MAP_SHARED    0x00001
-%define MAP_PRIVATE   0x00002
-%define MAP_ANONYMOUS 0x00020
-;%define MAP_GROWSDOWN 0x00100 ; Insecure, segfaults anyway
-%define MAP_LOCKED    0x02000
-%define MAP_POPULATE  0x08000
-%define MAP_STACK     0x20000
-
-; Relevant flags for mprotect
-%define PROT_READ  0x1
-%define PROT_WRITE 0x2
-
-; Relevant flags for clone
-%define CLONE_VM             0x00000100
-%define CLONE_FS             0x00000200
-%define CLONE_FILES          0x00000400
-%define CLONE_SIGHAND        0x00000800
-%define CLONE_PARENT         0x00008000
-%define CLONE_THREAD         0x00010000
-%define CLONE_SYSVSEM        0x00040000
-%define CLONE_SETTLS         0x00080000
-%define CLONE_PARENT_SETTID  0x00100000
-%define CLONE_CHILD_CLEARTID 0x00200000
-%define CLONE_CHILD_SETTID   0x01000000
-%define CLONE_IO             0x80000000
-
-
-%define STACK_SIZE 2097152 ; 2 MiB stack
-%define GUARD_PAGE    4096 ; 4 KiB guard page
-
-
-; Create a new thread executing a given function. Arguments:
-;	rdi: struct{u32,u32}** = where to put the thread handle
-;	rsi: void* (*)(void*)  = function to make the child run
-;	rdx: void*             = single argument for function
-; Returns zero on success, or a standard error code.
-global linen_thread_create
-linen_thread_create:
-		; Callee-save registers
-		push rbx
-
-		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-		;;;; Check validity of arguments ;;;;
-		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-		; Return EINVAL if any argument is NULL
-		mov eax, -22 ; (EINVAL = -22)
-		test rdi, rdi
-		jz create_return ; Nowhere to store the thread handle
-		test rsi, rsi
-		jz create_return ; No function for the thread to run
-
-		; Note: we allow rdx to be NULL; in that case the worst that can happen
-		; is a segmentation fault in the user's code (not really our problem).
-
-		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-		;;;; Allocate a stack and guard page ;;;;
-		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-		; Save these registers: we'll clobber them for the mmap call
-		mov rbx, rdi
-		push rdx
-		push rsi
-
-		; The mmap system call does many things, in this case allocate memory.
-		; See: man 2 mmap
-
-		; mmap: rdi = addr: address for mapping; 0 lets kernel choose
-		xor edi, edi
-		; mmap: rsi = length: size of buffer to allocate
-		mov esi, (STACK_SIZE + GUARD_PAGE)
-		; mmap: rdx = prot: mprotect-style access permissions
-		mov edx, (PROT_WRITE | PROT_READ)
-		; mmap: r10 = flags: configuration flags for mapping:
-		; - MAP_ANONYMOUS: there is no file backing this buffer
-		; - MAP_PRIVATE:   only this process can see thread's stack
-		; - MAP_STACK:     no-op; inform kernel that this is a stack
-		mov r10, (MAP_ANONYMOUS | MAP_PRIVATE | MAP_STACK)
-		; mmap: r8 = fd: ignored for MAP_ANONYMOUS, recommended -1
-		mov r8, -1
-		; mmap: r9 = offset: should be 0 when MAP_ANONYMOUS is used
-		xor r9, r9
-		; mmap: rax = system call ID
-		mov eax, SYS_MMAP
-		; mmap: rax = mmap(rdi, rsi, rdx, r10, r8, 9)
-		syscall
-
-		; Pop these now before we start branching. Those registers
-		; won't be used by the next system calls, so they're safe.
-		pop r8 ; function
-		pop r9 ; argument
-
-		; Check result of mmap: negative means failure,
-		; otherwise rax is the address of the new mapping.
-		test rax, rax
-		js create_return
-
-		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-		;;;; Revoke guard page's R/W permissions ;;;;
-		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-		; Keep in mind that stacks grow downward, so the guard page is at
-		; the lowest address of the newly-allocated buffer, i.e. at [rax].
-
-		; The mprotect system call changes the permissions of a memory region.
-		; See: man 2 mprotect
-
-		; mprotect: rdi = addr: lower address of region to control
-		mov rdi, rax
-		; mprotect: rsi = len: size of region, one page in this case
-		mov esi, GUARD_PAGE
-		; mprotect: rdx = prot: access permissions; zero for none
-		xor edx, edx
-		; mprotect: rax = system call ID
-		mov eax, SYS_MPROTECT
-		; mprotect: rax = mprotect(rdi, rsi, rdx)
-		syscall
-
-		; Check result of mprotect: nonzero means failure
-		test rax, rax
-		jnz create_return
-
-		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-		;;;; Spawn a thread with the new stack ;;;;
-		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-		; The clone system call spawns a new thread, cloned from a parent.
-		; Both threads end up running the same code, i.e. it returns "twice",
-		; once in the parent (0 if success) and once in the child (the TID).
-		; See: man 2 clone
-
-		; clone: rsi = stack
-		; Currently rdi points to the lowest byte of the stack area.
-		; Again, stacks grow downward, so we calculate the address of
-		; the top qword to use as the child thread's starting point.
-		lea rsi, [rdi + (STACK_SIZE + GUARD_PAGE - 8)]
-
-		; clone: rdi = flags: settings for cloned thread
-		; These flags make the parent and child share resources:
-		; - CLONE_VM:      memory address space
-		; - CLONE_FS:      filesystem information, e.g. working directory
-		; - CLONE_FILES:   file descriptor table
-		; - CLONE_IO:      I/O scheduler context
-		; - CLONE_SIGHAND: signal handlers
-		; - CLONE_PARENT:  parent process (implied by CLONE_THREAD?)
-		; - CLONE_THREAD:  shared PID, distinguish by TID instead (I think?)
-		; These flags are relevant for a threading API:
-		; - CLONE_CHILD_SETTID:   store child's TID at supplied address (in r10)
-		; - CLONE_CHILD_CLEARTID: set stored TID to zero when child finishes
-		;                         (this will be used for joining threads)
-		mov edi, (CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_IO \
-		        | CLONE_SIGHAND | CLONE_PARENT | CLONE_THREAD \
-		        | CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)
-
-		; clone: rdx = parent_tid: ignored unless CLONE_PARENT_SETTID is used
-
-		; clone: r10 = child_tid: address to store new thread's TID
-		; We use "bottom" of stack (rsi), i.e. where child will start.
-		mov r10, rsi
-
-		; clone: r8 = tls: ignored unless CLONE_SETTLS is used
-
-		; clone: rax = system call ID
-		mov eax, SYS_CLONE
-		; clone: rax = clone(rdi, rsi, (rdx), r10, (r8));
-		syscall
-
-		; Ideally, both parent and new-born child are executing this code now.
-
-		; Check result of clone:
-		test rax, rax
-		js create_return   ; Negative means failure
-		jnz create_success ; Positive means we're in the parent thread
-		; Zero means we're in the child thread
-
-		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-		;;;; Initialization in child thread ;;;;
-		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-		; Best practice is to clear the frame pointer
-		xor ebp, ebp
-
-		; Move argument into place and call supplied function
-		mov rdi, r9
-		call r8
-
-		; Once done, leave function's return value lying around
-		push rax
-
-		; Exit the thread with return value 0
-		xor edi, edi
-		mov rax, SYS_EXIT
-		syscall ; (never returns)
-
-		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-		;;;; Clean up in parent thread ;;;;
-		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-	create_success:
-		; We use the highest dword of the child's stack buffer as a futex
-		; to detect when it has finished (see CLONE_CHILD_CLEARTID above).
-		; That dword's address also acts as a thread handle for our API,
-		; so we store it at the address the caller supplied (now in rbx).
-		mov [rbx], rsi
-
-		; We place a canary value in the unused dword at the top:
-		; checking this value tells us if a thread handle is valid.
-		mov dword [rsi + 4], 0xDEADBEEF
-
-		; "Sketch" of child's stack buffer's layout:
-		;
-		; (bottom of range allocated by mmap)
-		; 4 KiB: guard page, unused
-		; (bottom of usable buffer)
-		; ...
-		; ... Child is currently doing work here ...
-		; ...
-		; qword: return address of function called by child (from r8)
-		; dword: futex to detect when child has returned (address: rsi)
-		; dword: canary value to know if handle is valid (address: rsi + 4)
-		; (top of range allocated by mmap = top of usable buffer)
-
-		; Return 0 for success
-		xor eax, eax
-
-	create_return:
-		; Restore callee-save registers
-		pop rbx
-
-		ret
-