A tiny bit of clean up (e.g., move code searching cpu array from lapic.c into
mycpu() in proc.c.

Eliminate code for gs trick to track per-cpu state. We rely on lapiccpunum()
to find a per-cpu id with which we locate a cpu's cpu struct.

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.

Thanks to Wolfgang Keller <nubok@users.noreply.github.com>

Move retry loop/sleep/wakeup in bio.c into sleeping locks

Straight replacement of B_BUSY with a sleeping lock.

Removed useless function and prototypes.

Pick up where i left off in april:
- move log into metadata part of disk, so that marking
that the log's blocks are in use falls out for free
- superblock describes the whole disk (sizes and offets)

Pick up where i left off in april:
- move log into metadata part of disk, so that marking
that the log's blocks are in use falls out for free
- superblock describes the whole disk (sizes and offets)
- sizes and offsets are computed in one place (mkfs) and
the rest of the code refers to the superblock for these values,
instead of recomputing them.

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cmosgetdate() for system-call homework

the day of reckoning has come for the debug port "Shutdown" hack.

instead of mucking with ACPI or using a new hack, the student will now write
sys_date() usin

cmosgetdate() for system-call homework

the day of reckoning has come for the debug port "Shutdown" hack.

instead of mucking with ACPI or using a new hack, the student will now write
sys_date() using the cmosgetdate() helper.

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a start at concurrent FS system calls

Remove unused argument to setupkvm (thanks to Peter Froehlich)

Remove unused argument from lapicinit (thanks to Peter Froehlich)

Make fetchint and fetchstr use proc instead of taking a struct proc

Previously, these were inconsistent: they used their struct proc
argument for bounds checking, but always copied the argument from

Make fetchint and fetchstr use proc instead of taking a struct proc

Previously, these were inconsistent: they used their struct proc
argument for bounds checking, but always copied the argument from the
current address space (and hence the current process). Drop the
struct proc argument and always use the current proc.

Suggested by Carmi Merimovich.

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eliminate enter_alloc -- use kalloc for everything

clear_pte_u -> clearpteu

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

Revert "Introduce and use sleeplocks instead of BUSY flags"
My changes have a race with re-used bufs and the code doesn't seem to get shorter
Keep the changes that fixed ip->off race

This reverts co

Revert "Introduce and use sleeplocks instead of BUSY flags"
My changes have a race with re-used bufs and the code doesn't seem to get shorter
Keep the changes that fixed ip->off race

This reverts commit 3a5fa7ed9020eaf8ab843a16d26db7393b2ec072.

Conflicts:

defs.h
file.c
file.h

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Style nits; indentation and tabs

Introduce and use sleeplocks instead of BUSY flags
Remove I_BUSY, B_BUSY, and intrans defs and usages
One spinlock per buf to avoid ugly loop in bget
fix race in filewrite (don't update f->off after

Introduce and use sleeplocks instead of BUSY flags
Remove I_BUSY, B_BUSY, and intrans defs and usages
One spinlock per buf to avoid ugly loop in bget
fix race in filewrite (don't update f->off after releasing lock)

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Clean up memlayout.h
Get rid of last instances of linear address and "la"
Get ready for detecting physical memory dynamically

Avoid "boot" in xv6

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 :(

Dirt simple logging
Passes usertests and stressfs
Seems to recover correctly in a number of simple cases