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authorFrans Kaashoek <[email protected]>2018-09-23 08:24:42 -0400
committerFrans Kaashoek <[email protected]>2018-09-23 08:35:30 -0400
commitab0db651af6f1ffa8fe96909ce16ae314d65c3fb (patch)
treec429f8ee36fa7da1e25f564a160b031613ca05e9 /mp.h
parentb818915f793cd20c5d1e24f668534a9d690f3cc8 (diff)
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Checkpoint port of xv6 to x86-64. Passed usertests on 2 processors a few times.
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
Diffstat (limited to 'mp.h')
-rw-r--r--mp.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/mp.h b/mp.h
index 4d17283..5964b63 100644
--- a/mp.h
+++ b/mp.h
@@ -2,7 +2,7 @@
struct mp { // floating pointer
uchar signature[4]; // "_MP_"
- void *physaddr; // phys addr of MP config table
+ uint32 physaddr; // phys addr of MP config table
uchar length; // 1
uchar specrev; // [14]
uchar checksum; // all bytes must add up to 0
@@ -17,10 +17,10 @@ struct mpconf { // configuration table header
uchar version; // [14]
uchar checksum; // all bytes must add up to 0
uchar product[20]; // product id
- uint *oemtable; // OEM table pointer
+ uint32 oemtable; // OEM table pointer
ushort oemlength; // OEM table length
ushort entry; // entry count
- uint *lapicaddr; // address of local APIC
+ uint32 lapicaddr_p; // address of local APIC
ushort xlength; // extended table length
uchar xchecksum; // extended table checksum
uchar reserved;
@@ -42,7 +42,7 @@ struct mpioapic { // I/O APIC table entry
uchar apicno; // I/O APIC id
uchar version; // I/O APIC version
uchar flags; // I/O APIC flags
- uint *addr; // I/O APIC address
+ uint32 addr_p; // I/O APIC address
};
// Table entry types