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2018-10-03Switch back bpmain back to mainFrans Kaashoek1-6/+6
2018-09-23Checkpoint port of xv6 to x86-64. Passed usertests on 2 processors a few times.Frans Kaashoek1-41/+28
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
2018-08-30thanks eyalz800Frans Kaashoek1-1/+1
2017-08-29fix runoff complaints about pagination and long linesRobert Morris1-0/+4
2017-08-09Commit to running on an SMP (perhaps with only 1 core). Remove most codeFrans Kaashoek1-3/+1
from picirq.c and remove timer.c completely. Update runoff.list.
2017-02-01Eliminate code for gs trick to track per-cpu state. We rely on lapiccpunum()Frans Kaashoek1-1/+1
to find a per-cpu id with which we locate a cpu's cpu struct.
2017-01-31Start of an experiment to remove the use of gs for cpu local variables.Frans Kaashoek1-5/+4
2016-09-02Make runoff happyFrans Kaashoek1-3/+0
2016-09-02APIC IDs may not be consecutive and start from zero, so we cannot really use itFrans Kaashoek1-3/+3
as a direct index into cpus. Record apicid in struct cpu and have cpunum() look for it. Replace cpu->id with cpunum() everywhere, and replace cpu->id with cpu->apicid. Thanks to Xi Wang.
2016-08-25Remove trailing white space with:Frans Kaashoek1-3/+3
for f in *.{h,c}; do sed -i .sed 's/[[:blank:]]*$//' $f; done (Thanks to Nicolás Wolovick)
2016-08-24p2v -> P2VRobert Morris1-3/+3
2016-08-11main commentsRobert Morris1-7/+6
2016-08-10more comments in entryother.SRobert Morris1-4/+5
2015-06-27Pick up where i left off in april:Frans Kaashoek1-1/+0
- 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.
2014-08-29Nice layout for a printout of the codeFrans Kaashoek1-1/+4
2012-08-22Remove unused argument from lapicinit (thanks to Peter Froehlich)Frans Kaashoek1-2/+2
2011-09-14Use | instead of + for entrypgdir. Linker doesn't get in our way here.Austin Clements1-2/+2
2011-09-13eliminate enter_alloc -- use kalloc for everythingRobert Morris1-9/+6
2011-09-01Fix layout issues for printed versionFrans Kaashoek1-8/+9
2011-08-30enterpgdir -> entrypgdirRobert Morris1-5/+5
2011-08-29Style nits; indentation and tabsAustin Clements1-4/+4
2011-08-22Remove sys_init syscallFrans Kaashoek1-1/+1
Invoke initlog from forkret on first user process
2011-08-15Avoid "boot" in xv6Frans Kaashoek1-29/+21
2011-08-15Use 4Mbyte pages during bootFrans Kaashoek1-1034/+3
2011-08-15Separate more clearly bootloader from xv6 by renaming multiboot.S to entry.S ↵Frans Kaashoek1-11/+11
etc. Maybe the string boot shouldn't appear in xv6 code?
2011-08-12OopsFrans Kaashoek1-2/+2
2011-08-12Some commentsFrans Kaashoek1-1/+7
2011-08-11Make AP processors boot using bootpgdirFrans Kaashoek1-23/+14
Remove device mapping from bootpgdir Remove unnecessary vmenable Set CPUS back to 2 in Makefile Passes all usertests
2011-08-09Remove jmpkstackFrans Kaashoek1-27/+2
2011-08-09Use static page table for boot, mapping first 4Mbyte; no more segment trickFrans Kaashoek1-4/+1058
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)
2011-07-29Map kernel highFrans Kaashoek1-10/+23
Very important to give qemu memory through PHYSTOP :(
2011-07-27Dirt simple loggingFrans Kaashoek1-1/+1
Passes usertests and stressfs Seems to recover correctly in a number of simple cases
2011-02-19xv6: formatting, cleanup, rev5 (take 2)Russ Cox1-1/+6
2011-01-11make new code like old codeRuss Cox1-15/+15
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.
2010-09-13change some comments, maybe more informativeRobert Morris1-8/+16
delete most comments from bootother.S (since copy of bootasm.S) ksegment() -> seginit() move more stuff from main() to mainc()
2010-09-01Space policeAustin Clements1-1/+1
2010-08-31no more pminit, or ELF header at 0x10000Robert Morris1-1/+1
kinit() knows about end and PHYSTOP map all of kernel read/write (rather than r/o instructions) thanks, austin
2010-08-31kalloc/kfree now only a page at a timeRobert Morris1-2/+2
do not keep sorted contiguous free list
2010-08-30xxRobert Morris1-1/+1
2010-08-30set only PG and WP in vminit; the rest don't seem to be needed and are confusingRobert Morris1-1/+1
2010-08-05add some commentsRobert Morris1-10/+12
find out the hard way why user and kernel must have separate segment descriptors
2010-08-05move jkstack to main.cRobert Morris1-6/+16
replace jstack with asm()s
2010-07-23Checkpoint page-table version for SMPFrans Kaashoek1-14/+9
Includes code for TLB shootdown (which actually seems unnecessary for xv6)
2010-07-02Initial version of single-cpu xv6 with page tablesFrans Kaashoek1-6/+20
2009-09-02another attempt at cpu-local variables.Russ Cox1-3/+1
this time do it ourselves instead of piggybacking on TLS. add -fno-pic to Makefile; pic code breaks our fake TLS.
2009-08-30assorted fixes:Russ Cox1-10/+10
* rename c/cp to cpu/proc * rename cpu.context to cpu.scheduler * fix some comments * formatting for printout
2009-05-31Some proc cleanup, moving some of copyproc into allocproc.rsc1-11/+16
Also, an experiment: use "thread-local" storage for c and cp instead of the #define macro for curproc[cpu()].
2009-03-08be consistent: no underscores in function namesrsc1-10/+10
2009-03-08xv6: boot loader adjustmentsrsc1-5/+0
do Bochs breakpoint and spin in bootasm.S. not needed in bootmain too. fix readseg bug (rounding of va). zero segments when memsz > filesz. no need to clear BSS in kernel main. make bootother.S like bootasm.S
2008-08-21fix obvious printf nits after reading through codekolya1-1/+1
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