xv6-riscv - MIT xv6-RISCV kernel modified to RV64I base integer extension

Age	Commit message (Collapse)	Author
2019-06-11	separate source into kernel/ user/ mkfs/	Robert Morris

2019-06-06	gdb backtraces: -ggdb, -fno-omit-frame-pointer, BSIZE=1024	Robert Morris

2019-06-05	push_off() and pop_off() in myproc()	Robert Morris

2019-06-04	fix exec argc	Robert Morris

2019-06-04	support read() and write() bigger than one page	Robert Morris

2019-06-03	console input and sbrk	Robert Morris

2019-06-01	first shell prints $ prompt, though no console input yet	Robert Morris

2019-05-31	fork/wait/exit work	Robert Morris

2018-09-23	Checkpoint port of xv6 to x86-64. Passed usertests on 2 processors a few times.	Frans Kaashoek
	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
2017-08-09	Commit to running on an SMP (perhaps with only 1 core). Remove most code	Frans Kaashoek
	from picirq.c and remove timer.c completely. Update runoff.list.
2017-02-01	A tiny bit of clean up (e.g., move code searching cpu array from lapic.c into	Frans Kaashoek
	mycpu() in proc.c.
2017-02-01	use panic	Frans Kaashoek

2017-01-31	Start of an experiment to remove the use of gs for cpu local variables.	Frans Kaashoek

2016-09-11	Replace I_BUSY with sleep locks	Frans Kaashoek

2016-09-02	Fix a few lines that runoff is complaining about that they are too long	Frans Kaashoek

2016-09-02	APIC IDs may not be consecutive and start from zero, so we cannot really use it	Frans Kaashoek
	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.
2016-08-25	Remove trailing white space with:	Frans Kaashoek
	for f in .{h,c}; do sed -i .sed 's/[[:blank:]]$//' $f; done (Thanks to Nicolás Wolovick)
2015-11-15	nits	Frans Kaashoek

2015-11-15	Remove console input.lock	Nathaniel Wesley Filardo
	Use cons.lock for everything. This eliminates the possibility that two CPUS independently, simultaneously manipulate the CRTC in cgaputc.
2015-11-15	Add sanity check panic for CRTC interactions	Nathaniel Wesley Filardo

2011-09-07	Remove unused 'state' variable that broke the build in recent gcc's	Austin Clements

2011-09-02	Fix same wonky pagebreak bug in console.c	Austin Clements

2011-07-29	Map kernel high	Frans Kaashoek
	Very important to give qemu memory through PHYSTOP :(
2011-02-28	fixes from Peter Froehlich	Russ Cox

2011-01-11	make new code like old code	Russ Cox
	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.
2010-09-02	Get consoleintr back on one page	Austin Clements

2010-09-02	Get cgaputc and consputc back on the same page	Austin Clements

2010-09-01	Space police	Austin Clements

2010-09-01	Tab police	Austin Clements

2009-09-30	Handle backspace on serial input and output better. Better solutions are ↵	Austin Clements
	welcome.
2009-09-20	Hack to make newlines on the serial port work	Austin Clements

2009-08-30	assorted fixes:	Russ Cox
	* rename c/cp to cpu/proc * rename cpu.context to cpu.scheduler * fix some comments * formatting for printout
2009-08-08	shuffle and tweak for formatting.	Russ Cox
	pdf has very good page breaks now. would be a good copy for fall 2009.
2009-05-31	group locks into structs they protect.	rsc
	few naming nits.
2009-05-31	Add serial port input/output.	rsc
	Delete parallel port output. Works well with qemu -nographic mode.
2009-03-08	be consistent: no underscores in function names	rsc

2008-10-12	minor cleanup	kolya

2008-08-22	clean up circular buffers, so pipe can queue 512 bytes rather than 511	kolya

2008-08-21	fix obvious printf nits after reading through code	kolya

2007-09-27	nit	rsc

2007-09-27	use console lock	rsc

2007-08-30	make new Homework 8 work	rtm

2007-08-30	oops - broke circular buffer	rsc

2007-08-28	comments; rename irq_ to pic_	rsc

2007-08-28	spaces around else for rtm	rsc

2007-08-28	more consistent spacing	rsc

2007-08-28	nits	rsc

2007-08-28	Change dev read/write functions	rsc
	to take inode* instead of minor number. Unlock console inode during console_read and console_write. Otherwise background processes cannot write to console while the shell is reading it waiting for input.
2007-08-28	avoid double echo	rsc

2007-08-28	oops	rsc