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2019-06-11separate source into kernel/ user/ mkfs/Robert Morris1-465/+0
2019-06-04support read() and write() bigger than one pageRobert Morris1-2/+2
2019-06-01first shell prints $ prompt, though no console input yetRobert Morris1-32/+42
2019-05-31exec compiles but argstr() doesn't work yetRobert Morris1-4/+14
2019-05-31fork/wait/exit workRobert Morris1-6/+6
2018-09-23Checkpoint port of xv6 to x86-64. Passed usertests on 2 processors a few times.Frans Kaashoek1-3/+3
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
2017-01-31Read curproc from cpu structure, but be careful because after a schedule eventFrans Kaashoek1-5/+7
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.
2017-01-31Start of an experiment to remove the use of gs for cpu local variables.Frans Kaashoek1-7/+7
2016-09-11Replace I_BUSY with sleep locksFrans Kaashoek1-0/+2
2016-08-18Remove unused variable, nits.Peter H. Froehlich1-6/+5
2014-08-27a start at concurrent FS system callsRobert Morris1-25/+25
2014-08-04every iput() and namei() must be inside a transactionRobert Morris1-9/+26
2012-02-17Make fetchint and fetchstr use proc instead of taking a struct procAustin Clements1-2/+2
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.
2011-10-14don't let dirty blocks be evicted from cache!Robert Morris1-0/+6
2011-09-02Shorten sys_unlink a little; create now fits in columnAustin Clements1-13/+10
2011-08-29Revert "Introduce and use sleeplocks instead of BUSY flags"Frans Kaashoek1-1/+0
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
2011-08-26Introduce and use sleeplocks instead of BUSY flagsFrans Kaashoek1-0/+1
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)
2011-08-15avoid deadlock by calling begin_trans() before locking any inodesRobert Morris1-4/+10
2011-08-12log write() dataRobert Morris1-3/+27
usertest for big write()s push begin_trans/commit_trans down into syscalls
2011-01-11make new code like old codeRuss Cox1-1/+1
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.
2010-09-27copyout() copies data to a va in a pagetable, for exec() &cRobert Morris1-1/+1
usertest that passes too many arguments, break exec
2010-07-02Initial version of single-cpu xv6 with page tablesFrans Kaashoek1-3/+2
2009-08-30assorted fixes:Russ Cox1-9/+9
* rename c/cp to cpu/proc * rename cpu.context to cpu.scheduler * fix some comments * formatting for printout
2009-08-08shuffle and tweak for formatting.Russ Cox1-1/+0
pdf has very good page breaks now. would be a good copy for fall 2009.
2009-07-11rearrangements and cleanup for textRuss Cox1-35/+33
2009-05-31simplifyrsc1-22/+13
2008-10-17try harder to get directory refcounts rightkolya1-2/+8
2008-10-16make mkdir crash-safer, as noticed by many students on midtermkolya1-7/+11
2007-09-27believe it or not, this was workingrsc1-6/+6
the macro expansion of "char *cp;" turned into char *(curproc[cpu()]); which declares a dynamically sized array of char* called curproc. so then &cp == &(curproc[cpu()]) was actually a stack variable as "expected". it was one past the end of the array, but the implicit alloca allocated more than was necessary. do not tell me that making cp a #define was a bad idea. there are worse problems to fix. more on that later.
2007-08-28spaces around else for rtmrsc1-1/+1
2007-08-28more consistent spacingrsc1-1/+1
2007-08-28remove _ from pipe; be like filersc1-1/+1
2007-08-27make code match commentrsc1-1/+1
2007-08-27make code match commentrsc1-1/+1
2007-08-27delete unnecessary #include linesrsc1-7/+2
2007-08-27oopsrsc1-0/+1
2007-08-27nitsrsc1-17/+7
2007-08-27fileincref -> filedup (consistent with idup)rsc1-1/+1
2007-08-24shuffle for formattingrsc1-18/+19
2007-08-24remove unused variablersc1-1/+1
2007-08-24Remove struct uinode.rsc1-52/+61
Remove type arg to mknod (assume T_DEV).
2007-08-22PDF at http://am.lcs.mit.edu/~rsc/xv6.pdfrsc1-103/+211
Various changes made while offline. + bwrite sector argument is redundant; use b->sector. + reformatting of files for nicer PDF page breaks + distinguish between locked, unlocked inodes in type signatures + change FD_FILE to FD_INODE + move userinit (nee proc0init) to proc.c + move ROOTDEV to param.h + always parenthesize sizeof argument
2007-08-21ARGMAX -> MAXARGSrsc1-3/+3
2007-08-21Various cleanup:rsc1-187/+32
- Got rid of dummy proc[0]. Now proc[0] is init. - Added initcode.S to exec /init, so that /init is just a regular binary. - Moved exec out of sysfile to exec.c - Moved code dealing with fs guts (like struct inode) from sysfile.c to fs.c. Code dealing with system call arguments stays in sysfile.c - Refactored directory routines in fs.c; should be simpler. - Changed iget to return *unlocked* inode structure. This solves the lookup-then-use race in namei without introducing deadlocks. It also enabled getting rid of the dummy proc[0].
2007-08-20checkpoint - simpler namei interfacersc1-31/+36
2007-08-10avoid assignments in declarationsrsc1-1/+1
2007-08-10Make cp a magic symbol.rsc1-6/+1
2007-08-09oopsrsc1-1/+1
2007-08-09try to use cp only for curproc[cpu()]rsc1-11/+12
2007-08-08save process name for debuggingrsc1-2/+8