From 7231a21b00028a52d7938131bfeca4d663d09071 Mon Sep 17 00:00:00 2001
From: Prefetch
Date: Sat, 22 Jul 2023 19:22:06 +0200
Subject: Add locks, with some minor improvements to threads

---
 lib/thread_create.asm | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

(limited to 'lib/thread_create.asm')

diff --git a/lib/thread_create.asm b/lib/thread_create.asm
index 2ccd1fa..9a6fe78 100644
--- a/lib/thread_create.asm
+++ b/lib/thread_create.asm
@@ -3,9 +3,9 @@
 
 ; Cheat sheet for Linux' x86_64 calling convention:
 ;
-; - free to overwrite; the caller should save them:
+; - free to overwrite (caller should save them):
 ;       rax, rcx, rdx, rsi, rdi, r8-r11, xmm0-xmm15
-; - caller expects no change; callee should save them:
+; - caller expects be kept (callee should save them):
 ;       rbx, rbp, r12-r15
 ;
 ; - for passing paramters to functions:
@@ -63,9 +63,9 @@ section .text
 
 
 ; Create a new thread executing a given function. Arguments:
-;	rdi: u32**            = where to put the thread handle
-;	rsi: void* (*)(void*) = function to make the child run
-;	rdx: void*            = single argument for function
+;	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:
@@ -79,9 +79,9 @@ linen_thread_create:
 		; Return EINVAL if any argument is NULL
 		mov eax, -22 ; (EINVAL = -22)
 		test rdi, rdi
-		jz create_end ; Nowhere to store the thread handle
+		jz create_return ; Nowhere to store the thread handle
 		test rsi, rsi
-		jz create_end ; No function for the thread to run
+		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).
@@ -104,7 +104,7 @@ linen_thread_create:
 		mov esi, (STACK_SIZE + GUARD_PAGE)
 		; mmap: rdx = prot: mprotect-style access permissions
 		mov edx, (PROT_WRITE | PROT_READ)
-		; mmap: r10 = flags: settings for mapping
+		; 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
@@ -126,7 +126,7 @@ linen_thread_create:
 		; Check result of mmap: negative means failure,
 		; otherwise rax is the address of the new mapping.
 		test rax, rax
-		js create_end
+		js create_return
 
 		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 		;;;; Revoke guard page's R/W permissions ;;;;
@@ -151,7 +151,7 @@ linen_thread_create:
 
 		; Check result of mprotect: nonzero means failure
 		test rax, rax
-		jnz create_end
+		jnz create_return
 
 		;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 		;;;; Spawn a thread with the new stack ;;;;
@@ -202,7 +202,7 @@ linen_thread_create:
 
 		; Check result of clone:
 		test rax, rax
-		js create_end      ; Negative means failure
+		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
 
@@ -256,7 +256,7 @@ linen_thread_create:
 		; Return 0 for success
 		xor eax, eax
 
-	create_end:
+	create_return:
 		; Restore callee-save registers
 		pop rbx
 
-- 
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