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

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.

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Start of an experiment to remove the use of gs for cpu local variables.

Fix unsigned conversion bug.

Since readi() returns -1 for errors, checking with < against an unsigned
value is inadvisable. Checking with != works as intended however.

Delete two left-over print statements

Straight replacement of B_BUSY with a sleeping lock.

add check for wrapping of address + size in exec()

add alignment check of virtual address to exec()

a start at concurrent FS system calls

every iput() and namei() must be inside a transaction

Remove unused argument to setupkvm (thanks to Peter Froehlich)

I can't do math; fix bug introduced in 5a9761

Fit exec on a page. Again

clear_pte_u -> clearpteu

inaccessible page under the user stack page, to help exec deal w/ too-large args

Make elf proghdr fields match what objdump prints

Use static page table for boot, mapping first 4Mbyte; no more segment trick
Allocate proper kernel page table immediately in main using boot allocator
Remove pginit
Simplify address space layout a ti

Use static page table for boot, mapping first 4Mbyte; no more segment trick
Allocate proper kernel page table immediately in main using boot allocator
Remove pginit
Simplify address space layout a tiny bit
More to come (e.g., superpages to simplify static table)

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Map kernel high
Very important to give qemu memory through PHYSTOP :(

xv6: formatting, cleanup, rev5 (take 2)

make new code like old code

Variable declarations at top of function,
separate from initialization.

Use == 0 instead of ! for checking pointers.

Consistent spacing around {, *, casts.

Declare 0-p

make new code like old code

Variable declarations at top of function,
separate from initialization.

Use == 0 instead of ! for checking pointers.

Consistent spacing around {, *, casts.

Declare 0-parameter functions as (void) not ().

Integer valued functions return -1 on failure, 0 on success.

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even more fabulous exec

check exec() arg length
fix double iunlockput

copyout() copies data to a va in a pagetable, for exec() &c
usertest that passes too many arguments, break exec

my comment is wrong, exec handles BSS fine

exec questions

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

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).

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