50e2064049
This commit removes all traces of Minix segments (the text/data/stack
memory map abstraction in the kernel) and significance of Intel segments
(hardware segments like CS, DS that add offsets to all addressing before
page table translation). This ultimately simplifies the memory layout
and addressing and makes the same layout possible on non-Intel
architectures.
There are only two types of addresses in the world now: virtual
and physical; even the kernel and processes have the same virtual
address space. Kernel and user processes can be distinguished at a
glance as processes won't use 0xF0000000 and above.
No static pre-allocated memory sizes exist any more.
Changes to booting:
. The pre_init.c leaves the kernel and modules exactly as
they were left by the bootloader in physical memory
. The kernel starts running using physical addressing,
loaded at a fixed location given in its linker script by the
bootloader. All code and data in this phase are linked to
this fixed low location.
. It makes a bootstrap pagetable to map itself to a
fixed high location (also in linker script) and jumps to
the high address. All code and data then use this high addressing.
. All code/data symbols linked at the low addresses is prefixed by
an objcopy step with __k_unpaged_*, so that that code cannot
reference highly-linked symbols (which aren't valid yet) or vice
versa (symbols that aren't valid any more).
. The two addressing modes are separated in the linker script by
collecting the unpaged_*.o objects and linking them with low
addresses, and linking the rest high. Some objects are linked
twice, once low and once high.
. The bootstrap phase passes a lot of information (e.g. free memory
list, physical location of the modules, etc.) using the kinfo
struct.
. After this bootstrap the low-linked part is freed.
. The kernel maps in VM into the bootstrap page table so that VM can
begin executing. Its first job is to make page tables for all other
boot processes. So VM runs before RS, and RS gets a fully dynamic,
VM-managed address space. VM gets its privilege info from RS as usual
but that happens after RS starts running.
. Both the kernel loading VM and VM organizing boot processes happen
using the libexec logic. This removes the last reason for VM to
still know much about exec() and vm/exec.c is gone.
Further Implementation:
. All segments are based at 0 and have a 4 GB limit.
. The kernel is mapped in at the top of the virtual address
space so as not to constrain the user processes.
. Processes do not use segments from the LDT at all; there are
no segments in the LDT any more, so no LLDT is needed.
. The Minix segments T/D/S are gone and so none of the
user-space or in-kernel copy functions use them. The copy
functions use a process endpoint of NONE to realize it's
a physical address, virtual otherwise.
. The umap call only makes sense to translate a virtual address
to a physical address now.
. Segments-related calls like newmap and alloc_segments are gone.
. All segments-related translation in VM is gone (vir2map etc).
. Initialization in VM is simpler as no moving around is necessary.
. VM and all other boot processes can be linked wherever they wish
and will be mapped in at the right location by the kernel and VM
respectively.
Other changes:
. The multiboot code is less special: it does not use mb_print
for its diagnostics any more but uses printf() as normal, saving
the output into the diagnostics buffer, only printing to the
screen using the direct print functions if a panic() occurs.
. The multiboot code uses the flexible 'free memory map list'
style to receive the list of free memory if available.
. The kernel determines the memory layout of the processes to
a degree: it tells VM where the kernel starts and ends and
where the kernel wants the top of the process to be. VM then
uses this entire range, i.e. the stack is right at the top,
and mmap()ped bits of memory are placed below that downwards,
and the break grows upwards.
Other Consequences:
. Every process gets its own page table as address spaces
can't be separated any more by segments.
. As all segments are 0-based, there is no distinction between
virtual and linear addresses, nor between userspace and
kernel addresses.
. Less work is done when context switching, leading to a net
performance increase. (8% faster on my machine for 'make servers'.)
. The layout and configuration of the GDT makes sysenter and syscall
possible.
244 lines
6.4 KiB
C
244 lines
6.4 KiB
C
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#ifndef _I386_PROTO_H
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#define _I386_PROTO_H
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#include <machine/vm.h>
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#define K_STACK_SIZE I386_PAGE_SIZE
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#ifndef __ASSEMBLY__
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/* Hardware interrupt handlers. */
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void hwint00(void);
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void hwint01(void);
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void hwint02(void);
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void hwint03(void);
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void hwint04(void);
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void hwint05(void);
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void hwint06(void);
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void hwint07(void);
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void hwint08(void);
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void hwint09(void);
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void hwint10(void);
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void hwint11(void);
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void hwint12(void);
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void hwint13(void);
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void hwint14(void);
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void hwint15(void);
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/* Exception handlers (real or protected mode), in numerical order. */
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void int00(void), divide_error (void);
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void int01(void), single_step_exception (void);
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void int02(void), nmi (void);
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void int03(void), breakpoint_exception (void);
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void int04(void), overflow (void);
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void int05(void), bounds_check (void);
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void int06(void), inval_opcode (void);
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void int07(void), copr_not_available (void);
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void double_fault(void);
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void copr_seg_overrun(void);
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void inval_tss(void);
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void segment_not_present(void);
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void stack_exception(void);
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void general_protection(void);
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void page_fault(void);
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void copr_error(void);
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void alignment_check(void);
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void machine_check(void);
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void simd_exception(void);
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/* Software interrupt handlers, in numerical order. */
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void trp(void);
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void ipc_entry(void);
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void kernel_call_entry(void);
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void level0_call(void);
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/* exception.c */
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struct exception_frame {
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reg_t vector; /* which interrupt vector was triggered */
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reg_t errcode; /* zero if no exception does not push err code */
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reg_t eip;
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reg_t cs;
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reg_t eflags;
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reg_t esp; /* undefined if trap is nested */
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reg_t ss; /* undefined if trap is nested */
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};
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void exception(struct exception_frame * frame);
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/* klib386.s */
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__dead void monitor(void);
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__dead void reset(void);
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__dead void x86_triplefault(void);
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reg_t read_cr0(void);
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reg_t read_cr2(void);
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void write_cr0(unsigned long value);
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unsigned long read_cr4(void);
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void write_cr4(unsigned long value);
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void write_cr3(unsigned long value);
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unsigned long read_cpu_flags(void);
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phys_bytes vir2phys(void *);
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void phys_insb(u16_t port, phys_bytes buf, size_t count);
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void phys_insw(u16_t port, phys_bytes buf, size_t count);
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void phys_outsb(u16_t port, phys_bytes buf, size_t count);
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void phys_outsw(u16_t port, phys_bytes buf, size_t count);
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u32_t read_cr3(void);
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void reload_cr3(void);
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void i386_invlpg(phys_bytes linaddr);
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vir_bytes phys_memset(phys_bytes ph, u32_t c, phys_bytes bytes);
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void reload_ds(void);
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void ia32_msr_read(u32_t reg, u32_t * hi, u32_t * lo);
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void ia32_msr_write(u32_t reg, u32_t hi, u32_t lo);
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void fninit(void);
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void clts(void);
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void fxsave(void *);
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void fnsave(void *);
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int fxrstor(void *);
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int __fxrstor_end(void *);
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int frstor(void *);
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int __frstor_end(void *);
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int __frstor_failure(void *);
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unsigned short fnstsw(void);
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void fnstcw(unsigned short* cw);
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void x86_lgdt(void *);
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void x86_lldt(u32_t);
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void x86_ltr(u32_t);
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void x86_lidt(void *);
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void x86_load_kerncs(void);
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void x86_load_ds(u32_t);
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void x86_load_ss(u32_t);
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void x86_load_es(u32_t);
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void x86_load_fs(u32_t);
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void x86_load_gs(u32_t);
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void switch_k_stack(void * esp, void (* continuation)(void));
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void __switch_address_space(struct proc * p, struct proc ** __ptproc);
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#define switch_address_space(proc) \
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__switch_address_space(proc, get_cpulocal_var_ptr(ptproc))
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void refresh_tlb(void);
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/* multiboot.c */
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void multiboot_init(void);
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/* protect.c */
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struct tss_s {
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reg_t backlink;
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reg_t sp0; /* stack pointer to use during interrupt */
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reg_t ss0; /* " segment " " " " */
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reg_t sp1;
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reg_t ss1;
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reg_t sp2;
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reg_t ss2;
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reg_t cr3;
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reg_t ip;
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reg_t flags;
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reg_t ax;
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reg_t cx;
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reg_t dx;
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reg_t bx;
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reg_t sp;
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reg_t bp;
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reg_t si;
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reg_t di;
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reg_t es;
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reg_t cs;
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reg_t ss;
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reg_t ds;
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reg_t fs;
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reg_t gs;
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reg_t ldt;
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u16_t trap;
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u16_t iobase;
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/* u8_t iomap[0]; */
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} __attribute__((packed));
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void enable_iop(struct proc *pp);
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u32_t read_cs(void);
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u32_t read_ds(void);
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u32_t read_ss(void);
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void add_memmap(kinfo_t *cbi, u64_t addr, u64_t len);
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void vm_enable_paging(void);
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void cut_memmap(kinfo_t *cbi, phys_bytes start, phys_bytes end);
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phys_bytes pg_roundup(phys_bytes b);
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void pg_info(reg_t *, u32_t **);
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void pg_clear(void);
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void pg_identity(void);
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phys_bytes pg_load(void);
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void pg_map(phys_bytes phys, vir_bytes vaddr, vir_bytes vaddr_end, kinfo_t *cbi);
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int pg_mapkernel(void);
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void pg_mapproc(struct proc *p, struct boot_image *ip, kinfo_t *cbi);
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/* prototype of an interrupt vector table entry */
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struct gate_table_s {
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void(*gate) (void);
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unsigned char vec_nr;
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unsigned char privilege;
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};
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/* copies an array of vectors to the IDT. The last vector must be zero filled */
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void idt_copy_vectors(struct gate_table_s * first);
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void idt_copy_vectors_pic(void);
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void idt_reload(void);
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EXTERN void * k_stacks_start;
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extern void * k_stacks;
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#define get_k_stack_top(cpu) ((void *)(((char*)(k_stacks)) \
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+ 2 * ((cpu) + 1) * K_STACK_SIZE))
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void mfence(void);
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#define barrier() do { mfence(); } while(0)
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#ifndef __GNUC__
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/* call a function to read the stack fram pointer (%ebp) */
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reg_t read_ebp(void);
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#define get_stack_frame(__X) ((reg_t)read_ebp())
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#else
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/* read %ebp directly */
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#define get_stack_frame(__X) ((reg_t)__builtin_frame_address(0))
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#endif
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/*
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* sets up TSS for a cpu and assigns kernel stack and cpu id
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*/
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int tss_init(unsigned cpu, void * kernel_stack);
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void int_gate_idt(unsigned vec_nr, vir_bytes offset, unsigned dpl_type);
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void __copy_msg_from_user_end(void);
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void __copy_msg_to_user_end(void);
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void __user_copy_msg_pointer_failure(void);
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int platform_tbl_checksum_ok(void *ptr, unsigned int length);
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int platform_tbl_ptr(phys_bytes start, phys_bytes end, unsigned
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increment, void * buff, unsigned size, phys_bytes * phys_addr, int ((*
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cmp_f)(void *)));
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/* breakpoints.c */
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int breakpoint_set(phys_bytes linaddr, int bp, const int flags);
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#define BREAKPOINT_COUNT 4
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#define BREAKPOINT_FLAG_RW_MASK (3 << 0)
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#define BREAKPOINT_FLAG_RW_EXEC (0 << 0)
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#define BREAKPOINT_FLAG_RW_WRITE (1 << 0)
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#define BREAKPOINT_FLAG_RW_RW (2 << 0)
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#define BREAKPOINT_FLAG_LEN_MASK (3 << 2)
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#define BREAKPOINT_FLAG_LEN_1 (0 << 2)
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#define BREAKPOINT_FLAG_LEN_2 (1 << 2)
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#define BREAKPOINT_FLAG_LEN_4 (2 << 2)
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#define BREAKPOINT_FLAG_MODE_MASK (3 << 4)
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#define BREAKPOINT_FLAG_MODE_OFF (0 << 4)
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#define BREAKPOINT_FLAG_MODE_LOCAL (1 << 4)
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#define BREAKPOINT_FLAG_MODE_GLOBAL (2 << 4)
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/* functions defined in architecture-independent kernel source. */
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#include "kernel/proto.h"
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#endif /* __ASSEMBLY__ */
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#endif
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