diff options
Diffstat (limited to 'exec.c')
| -rw-r--r-- | exec.c | 28 |
1 files changed, 14 insertions, 14 deletions
@@ -13,7 +13,7 @@ exec(char *path, char **argv) { char *s, *last; int i, off; - uint64 argc, sz, sp, ustack[3+MAXARG+1]; + uint64 argc, sz, sp, ustack[MAXARG+1]; struct elfhdr elf; struct inode *ip; struct proghdr ph; @@ -71,24 +71,24 @@ exec(char *path, char **argv) for(argc = 0; argv[argc]; argc++) { if(argc >= MAXARG) goto bad; - sp = (sp - (strlen(argv[argc]) + 1)) & ~(sizeof(uint64)-1); + sp -= strlen(argv[argc]) + 1; + sp -= sp % 16; // riscv sp must be 16-byte aligned if(copyout(pagetable, sp, argv[argc], strlen(argv[argc]) + 1) < 0) goto bad; - ustack[3+argc] = sp; + ustack[argc] = sp; } - ustack[3+argc] = 0; + ustack[argc] = 0; - ustack[0] = 0xffffffff; // fake return PC - ustack[1] = argc; - ustack[2] = sp - (argc+1)*sizeof(uint64); // argv pointer + // push the array of argv[] pointers. + sp -= (argc+1) * sizeof(uint64); + sp -= sp % 16; + if(copyout(pagetable, sp, (char *)ustack, (argc+1)*sizeof(uint64)) < 0) + goto bad; // arguments to user main(argc, argv) - p->tf->a0 = argc; - p->tf->a1 = sp - (argc+1)*sizeof(uint64); - - sp -= (3+argc+1) * sizeof(uint64); - if(copyout(pagetable, sp, (char *)ustack, (3+argc+1)*sizeof(uint64)) < 0) - goto bad; + // argc is returned via the system call return + // value, which goes in a0. + p->tf->a1 = sp; // Save program name for debugging. for(last=s=path; *s; s++) @@ -103,7 +103,7 @@ exec(char *path, char **argv) p->tf->epc = elf.entry; // initial program counter = main p->tf->sp = sp; // initial stack pointer proc_freepagetable(oldpagetable, oldsz); - return 0; + return argc; // this ends up in a0, the first argument to main(argc, argv) bad: if(pagetable) |