135e2/xv6-labs.git - xv6-labs-2024-winter

Age	Commit message (Collapse)	Author	Files	Lines
2019-06-11	separate source into kernel/ user/ mkfs/	Robert Morris	1	-80/+0

2019-06-04	fix a problem with end. make uartputc() wait until h/w is ready.	Robert Morris	1	-4/+2

2019-05-31	-initrd fs.img, ramdisk.c, file system	Robert Morris	1	-0/+2

2019-05-31	fork/wait/exit work	Robert Morris	1	-38/+20

2018-09-23	Checkpoint port of xv6 to x86-64. Passed usertests on 2 processors a few times.	Frans Kaashoek	1	-2/+4
	The x86-64 doesn't just add two levels to page tables to support 64 bit addresses, but is a different processor. For example, calling conventions, system calls, and segmentation are different from 32-bit x86. Segmentation is basically gone, but gs/fs in combination with MSRs can be used to hold a per-core pointer. In general, x86-64 is more straightforward than 32-bit x86. The port uses code from sv6 and the xv6 "rsc-amd64" branch. A summary of the changes is as follows: - Booting: switch to grub instead of xv6's bootloader (pass -kernel to qemu), because xv6's boot loader doesn't understand 64bit ELF files. And, we don't care anymore about booting. - Makefile: use -m64 instead of -m32 flag for gcc, delete boot loader, xv6.img, bochs, and memfs. For now dont' use -O2, since usertests with -O2 is bigger than MAXFILE! - Update gdb.tmpl to be for i386 or x86-64 - Console/printf: use stdarg.h and treat 64-bit addresses different from ints (32-bit) - Update elfhdr to be 64 bit - entry.S/entryother.S: add code to switch to 64-bit mode: build a simple page table in 32-bit mode before switching to 64-bit mode, share code for entering boot processor and APs, and tweak boot gdt. The boot gdt is the gdt that the kernel proper also uses. (In 64-bit mode, the gdt/segmentation and task state mostly disappear.) - exec.c: fix passing argv (64-bit now instead of 32-bit). - initcode.c: use syscall instead of int. - kernel.ld: load kernel very high, in top terabyte. 64 bits is a lot of address space! - proc.c: initial return is through new syscall path instead of trapret. - proc.h: update struct cpu to have some scratch space since syscall saves less state than int, update struct context to reflect x86-64 calling conventions. - swtch: simplify for x86-64 calling conventions. - syscall: add fetcharg to handle x86-64 calling convetions (6 arguments are passed through registers), and fetchaddr to read a 64-bit value from user space. - sysfile: update to handle pointers from user space (e.g., sys_exec), which are 64 bits. - trap.c: no special trap vector for sys calls, because x86-64 has a different plan for system calls. - trapasm: one plan for syscalls and one plan for traps (interrupt and exceptions). On x86-64, the kernel is responsible for switching user/kernel stacks. To do, xv6 keeps some scratch space in the cpu structure, and uses MSR GS_KERN_BASE to point to the core's cpu structure (using swapgs). - types.h: add uint64, and change pde_t to uint64 - usertests: exit() when fork fails, which helped in tracking down one of the bugs in the switch from 32-bit to 64-bit - vectors: update to make them 64 bits - vm.c: use bootgdt in kernel too, program MSRs for syscalls and core-local state (for swapgs), walk 4 levels in walkpgdir, add DEVSPACETOP, use task segment to set kernel stack for interrupts (but simpler than in 32-bit mode), add an extra argument to freevm (size of user part of address space) to avoid checking all entries till KERNBASE (there are MANY TB before the top 1TB). - x86: update trapframe to have 64-bit entries, which is what the processor pushes on syscalls and traps. simplify lgdt and lidt, using struct desctr, which needs the gcc directives packed and aligned. TODO: - use int32 instead of int? - simplify curproc(). xv6 has per-cpu state again, but this time it must have it. - avoid repetition in walkpgdir - fix validateint() in usertests.c - fix bugs (e.g., observed one a case of entering kernel with invalid gs or proc
2017-08-29	fix runoff complaints about pagination and long lines	Robert Morris	1	-1/+0

2017-08-08	Thanks Anton Burtsev <[email protected]>	Frans Kaashoek	1	-0/+1

2016-08-24	p2v -> P2V	Robert Morris	1	-1/+1

2011-09-13	eliminate enter_alloc -- use kalloc for everything	Robert Morris	1	-24/+31

2011-08-21	delete dead code	Frans Kaashoek	1	-7/+1

2011-08-16	Switch back to #define for PHYSTOP. Using the E820 to retrieve the memory ↵	Frans Kaashoek	1	-3/+2
	map is too complicated (must be done in 16-bit real-mode, probably enlarged bootblock beyond 512 bytes, and a #define requires less explanation).
2011-08-16	Clean up memlayout.h	Frans Kaashoek	1	-3/+10
	Get rid of last instances of linear address and "la" Get ready for detecting physical memory dynamically
2011-08-15	Avoid "boot" in xv6	Frans Kaashoek	1	-3/+3

2011-08-09	Use static page table for boot, mapping first 4Mbyte; no more segment trick	Frans Kaashoek	1	-1/+3
	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)
2011-07-31	Don't map IO space in the user part of the address space	Frans Kaashoek	1	-2/+1
	Passes all tests now (but need to update usertests to allow for more than 640k)
2011-07-29	Map kernel high	Frans Kaashoek	1	-3/+19
	Very important to give qemu memory through PHYSTOP :(
2011-01-11	more trivial cleanup	Russ Cox	1	-1/+1

2011-01-11	make new code like old code	Russ Cox	1	-6/+8
	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.
2010-09-19	exec questions	Robert Morris	1	-3/+3

2010-08-31	Merge branch 'master' of git+ssh://amsterdam.csail.mit.edu/home/am0/6.828/xv6	Robert Morris	1	-0/+1

2010-08-31	oops. last minute simplicifaction to kalloc().	Robert Morris	1	-4/+3

2010-08-31	Page break kalloc.c	Austin Clements	1	-0/+1

2010-08-31	no more pminit, or ELF header at 0x10000	Robert Morris	1	-3/+5
	kinit() knows about end and PHYSTOP map all of kernel read/write (rather than r/o instructions) thanks, austin
2010-08-31	kalloc/kfree now only a page at a time	Robert Morris	1	-66/+23
	do not keep sorted contiguous free list
2010-08-11	uptime() sys call for benchmarking	Robert Morris	1	-4/+0
	increase PHYSTOP
2010-08-06	fix corner cases in exec of ELF	Robert Morris	1	-3/+2
	put an invalid page below the stack have fork() handle invalid pages
2010-07-23	a few nits	Frans Kaashoek	1	-2/+0
	passes all tests on two-processor smp
2010-07-02	nits	Frans Kaashoek	1	-10/+0

2010-07-02	Initial version of single-cpu xv6 with page tables	Frans Kaashoek	1	-11/+25

2009-07-11	rearrangements and cleanup for text	Russ Cox	1	-22/+18

2009-05-31	group locks into structs they protect.	rsc	1	-12/+14
	few naming nits.
2007-08-27	delete unnecessary #include lines	rsc	1	-3/+0

2007-08-27	make kfree loop same as kalloc	rsc	1	-8/+5

2007-08-24	simplify ide queuing	rtm	1	-1/+1
	nits in comments
2007-08-14	formatting, simplify	rsc	1	-24/+17

2007-08-10	tweak kalloc	rsc	1	-7/+7

2007-08-10	Make cp a magic symbol.	rsc	1	-8/+6

2006-09-08	some comment changes	kaashoek	1	-1/+1

2006-09-07	more comments	rsc	1	-0/+4

2006-09-06	writeable => writable	rsc	1	-1/+1

2006-09-06	no /* */ comments	rsc	1	-18/+13

2006-09-06	standardize various * conventions	rsc	1	-8/+8

2006-09-04	nits	rtm	1	-1/+1

2006-08-30	complain if no disk 1	rtm	1	-44/+1
	lots of cleanup
2006-08-10	interrupts could be recursive since lapic_eoi() called before rti	rtm	1	-1/+2
	so fast interrupts overflow the kernel stack fix: cli() before lapic_eoi()
2006-07-29	open()	rtm	1	-1/+1

2006-07-17	add uint and standardize on typedefs instead of unsigned	rsc	1	-2/+2

2006-07-17	nitpicks	rsc	1	-1/+1

2006-07-16	more idiomatic c	rsc	1	-8/+5

2006-07-12	i think my cmpxchg use was wrong in acquire	rtm	1	-0/+3
	nesting cli/sti: release shouldn't always enable interrupts separate setup of lapic from starting of other cpus, so cpu() works earlier flag to disable locking in console output make locks work even when curproc==0 (still crashes in clock interrupt)