From abf847a083888bbed4260ecacf849ea19f23e810 Mon Sep 17 00:00:00 2001
From: Frans Kaashoek <kaashoek@mit.edu>
Date: Tue, 31 Jan 2017 17:47:16 -0500
Subject: Start of an experiment to remove the use of gs for cpu local
 variables.

---
 exec.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

(limited to 'exec.c')

diff --git a/exec.c b/exec.c
index 4d7d97c..14d673f 100644
--- a/exec.c
+++ b/exec.c
@@ -22,6 +22,7 @@ exec(char *path, char **argv)
 
   if((ip = namei(path)) == 0){
     end_op();
+    cprintf("exec: fail\n");
     return -1;
   }
   ilock(ip);
@@ -89,15 +90,15 @@ exec(char *path, char **argv)
   for(last=s=path; *s; s++)
     if(*s == '/')
       last = s+1;
-  safestrcpy(proc->name, last, sizeof(proc->name));
+  safestrcpy(myproc()->name, last, sizeof(myproc()->name));
 
   // Commit to the user image.
-  oldpgdir = proc->pgdir;
-  proc->pgdir = pgdir;
-  proc->sz = sz;
-  proc->tf->eip = elf.entry;  // main
-  proc->tf->esp = sp;
-  switchuvm(proc);
+  oldpgdir = myproc()->pgdir;
+  myproc()->pgdir = pgdir;
+  myproc()->sz = sz;
+  myproc()->tf->eip = elf.entry;  // main
+  myproc()->tf->esp = sp;
+  switchuvm(myproc());
   freevm(oldpgdir);
   return 0;
 
-- 
cgit v1.2.3


From fbb4c0944422f860484142010bb9f366f3e87bf8 Mon Sep 17 00:00:00 2001
From: Frans Kaashoek <kaashoek@mit.edu>
Date: Tue, 31 Jan 2017 20:21:14 -0500
Subject: Read curproc from cpu structure, but be careful because after a
 schedule event myproc() points to a different thread.

   myproc();
   sched();
   myproc();  // this proc maybe different than the one before sched

Thus, in a function that operates on one thread better to retrieve the
current process once at the start of the function.
---
 exec.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

(limited to 'exec.c')

diff --git a/exec.c b/exec.c
index 14d673f..b40134f 100644
--- a/exec.c
+++ b/exec.c
@@ -17,6 +17,7 @@ exec(char *path, char **argv)
   struct inode *ip;
   struct proghdr ph;
   pde_t *pgdir, *oldpgdir;
+  struct proc *curproc = myproc();
 
   begin_op();
 
@@ -90,15 +91,15 @@ exec(char *path, char **argv)
   for(last=s=path; *s; s++)
     if(*s == '/')
       last = s+1;
-  safestrcpy(myproc()->name, last, sizeof(myproc()->name));
+  safestrcpy(curproc->name, last, sizeof(curproc->name));
 
   // Commit to the user image.
-  oldpgdir = myproc()->pgdir;
-  myproc()->pgdir = pgdir;
-  myproc()->sz = sz;
-  myproc()->tf->eip = elf.entry;  // main
-  myproc()->tf->esp = sp;
-  switchuvm(myproc());
+  oldpgdir = curproc->pgdir;
+  curproc->pgdir = pgdir;
+  curproc->sz = sz;
+  curproc->tf->eip = elf.entry;  // main
+  curproc->tf->esp = sp;
+  switchuvm(curproc);
   freevm(oldpgdir);
   return 0;
 
-- 
cgit v1.2.3