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authorAustin Clements <[email protected]>2010-09-02 18:28:36 -0400
committerAustin Clements <[email protected]>2010-09-02 18:28:36 -0400
commit79cd8b3eedeb1f85d3b19fb6119bd5224c4c532a (patch)
treef9afe121e2b9298b35d3ccd61a329f03421c97fa /exec.c
parentd49d31381df93b40c1c4bc18c97ca42c3256e414 (diff)
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Simplify allocuvm/deallocuvm to operate in a contiguous memory model. This makes their interface match up better with proc->sz and also simplifies the callers (it even gets the main body of exec on one page).
Diffstat (limited to 'exec.c')
-rw-r--r--exec.c26
1 files changed, 11 insertions, 15 deletions
diff --git a/exec.c b/exec.c
index c518c04..222f64c 100644
--- a/exec.c
+++ b/exec.c
@@ -11,7 +11,7 @@ exec(char *path, char **argv)
{
char *mem, *s, *last;
int i, argc, arglen, len, off;
- uint sz, sp, spoffset, argp;
+ uint sz, sp, spbottom, argp;
struct elfhdr elf;
struct inode *ip;
struct proghdr ph;
@@ -41,22 +41,18 @@ exec(char *path, char **argv)
continue;
if(ph.memsz < ph.filesz)
goto bad;
- if(!allocuvm(pgdir, (char *)ph.va, ph.memsz))
+ if(!(sz = allocuvm(pgdir, sz, ph.va + ph.memsz)))
goto bad;
- if(ph.va + ph.memsz > sz)
- sz = ph.va + ph.memsz;
if(!loaduvm(pgdir, (char *)ph.va, ip, ph.offset, ph.filesz))
goto bad;
}
iunlockput(ip);
// Allocate and initialize stack at sz
- sz = PGROUNDUP(sz);
- if(!allocuvm(pgdir, (char *)sz, PGSIZE))
+ sz = spbottom = PGROUNDUP(sz);
+ if(!(sz = allocuvm(pgdir, sz, sz + PGSIZE)))
goto bad;
- mem = uva2ka(pgdir, (char *)sz);
- spoffset = sz;
- sz += PGSIZE;
+ mem = uva2ka(pgdir, (char *)spbottom);
arglen = 0;
for(argc=0; argv[argc]; argc++)
@@ -67,22 +63,22 @@ exec(char *path, char **argv)
argp = sz - arglen - 4*(argc+1);
// Copy argv strings and pointers to stack.
- *(uint*)(mem+argp-spoffset + 4*argc) = 0; // argv[argc]
+ *(uint*)(mem+argp-spbottom + 4*argc) = 0; // argv[argc]
for(i=argc-1; i>=0; i--){
len = strlen(argv[i]) + 1;
sp -= len;
- memmove(mem+sp-spoffset, argv[i], len);
- *(uint*)(mem+argp-spoffset + 4*i) = sp; // argv[i]
+ memmove(mem+sp-spbottom, argv[i], len);
+ *(uint*)(mem+argp-spbottom + 4*i) = sp; // argv[i]
}
// Stack frame for main(argc, argv), below arguments.
sp = argp;
sp -= 4;
- *(uint*)(mem+sp-spoffset) = argp;
+ *(uint*)(mem+sp-spbottom) = argp;
sp -= 4;
- *(uint*)(mem+sp-spoffset) = argc;
+ *(uint*)(mem+sp-spbottom) = argc;
sp -= 4;
- *(uint*)(mem+sp-spoffset) = 0xffffffff; // fake return pc
+ *(uint*)(mem+sp-spbottom) = 0xffffffff; // fake return pc
// Save program name for debugging.
for(last=s=path; *s; s++)