cd8b915ed9
- no longer have kernel have its own page table that is loaded
on every kernel entry (trap, interrupt, exception). the primary
purpose is to reduce the number of required reloads.
Result:
- kernel can only access memory of process that was running when
kernel was entered
- kernel must be mapped into every process page table, so traps to
kernel keep working
Problem:
- kernel must often access memory of arbitrary processes (e.g. send
arbitrary processes messages); this can't happen directly any more;
usually because that process' page table isn't loaded at all, sometimes
because that memory isn't mapped in at all, sometimes because it isn't
mapped in read-write.
So:
- kernel must be able to map in memory of any process, in its own
address space.
Implementation:
- VM and kernel share a range of memory in which addresses of
all page tables of all processes are available. This has two purposes:
. Kernel has to know what data to copy in order to map in a range
. Kernel has to know where to write the data in order to map it in
That last point is because kernel has to write in the currently loaded
page table.
- Processes and kernel are separated through segments; kernel segments
haven't changed.
- The kernel keeps the process whose page table is currently loaded
in 'ptproc.'
- If it wants to map in a range of memory, it writes the value of the
page directory entry for that range into the page directory entry
in the currently loaded map. There is a slot reserved for such
purposes. The kernel can then access this memory directly.
- In order to do this, its segment has been increased (and the
segments of processes start where it ends).
- In the pagefault handler, detect if the kernel is doing
'trappable' memory access (i.e. a pagefault isn't a fatal
error) and if so,
- set the saved instruction pointer to phys_copy_fault,
breaking out of phys_copy
- set the saved eax register to the address of the page
fault, both for sanity checking and for checking in
which of the two ranges that phys_copy was called
with the fault occured
- Some boot-time processes do not have their own page table,
and are mapped in with the kernel, and separated with
segments. The kernel detects this using HASPT. If such a
process has to be scheduled, any page table will work and
no page table switch is done.
Major changes in kernel are
- When accessing user processes memory, kernel no longer
explicitly checks before it does so if that memory is OK.
It simply makes the mapping (if necessary), tries to do the
operation, and traps the pagefault if that memory isn't present;
if that happens, the copy function returns EFAULT.
So all of the CHECKRANGE_OR_SUSPEND macros are gone.
- Kernel no longer has to copy/read and parse page tables.
- A message copying optimisation: when messages are copied, and
the recipient isn't mapped in, they are copied into a buffer
in the kernel. This is done in QueueMess. The next time
the recipient is scheduled, this message is copied into
its memory. This happens in schedcheck().
This eliminates the mapping/copying step for messages, and makes
it easier to deliver messages. This eliminates soft_notify.
- Kernel no longer creates a page table at all, so the vm_setbuf
and pagetable writing in memory.c is gone.
Minor changes in kernel are
- ipc_stats thrown out, wasn't used
- misc flags all renamed to MF_*
- NOREC_* macros to enter and leave functions that should not
be called recursively; just sanity checks really
- code to fully decode segment selectors and descriptors
to print on exceptions
- lots of vmassert()s added, only executed if DEBUG_VMASSERT is 1
112 lines
5.2 KiB
C
112 lines
5.2 KiB
C
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#ifndef _I386_PROTO_H
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#define _I386_PROTO_H
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/* Hardware interrupt handlers. */
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_PROTOTYPE( void hwint00, (void) );
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_PROTOTYPE( void hwint01, (void) );
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_PROTOTYPE( void hwint02, (void) );
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_PROTOTYPE( void hwint03, (void) );
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_PROTOTYPE( void hwint04, (void) );
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_PROTOTYPE( void hwint05, (void) );
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_PROTOTYPE( void hwint06, (void) );
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_PROTOTYPE( void hwint07, (void) );
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_PROTOTYPE( void hwint08, (void) );
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_PROTOTYPE( void hwint09, (void) );
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_PROTOTYPE( void hwint10, (void) );
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_PROTOTYPE( void hwint11, (void) );
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_PROTOTYPE( void hwint12, (void) );
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_PROTOTYPE( void hwint13, (void) );
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_PROTOTYPE( void hwint14, (void) );
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_PROTOTYPE( void hwint15, (void) );
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/* Exception handlers (real or protected mode), in numerical order. */
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void _PROTOTYPE( int00, (void) ), _PROTOTYPE( divide_error, (void) );
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void _PROTOTYPE( int01, (void) ), _PROTOTYPE( single_step_exception, (void) );
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void _PROTOTYPE( int02, (void) ), _PROTOTYPE( nmi, (void) );
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void _PROTOTYPE( int03, (void) ), _PROTOTYPE( breakpoint_exception, (void) );
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void _PROTOTYPE( int04, (void) ), _PROTOTYPE( overflow, (void) );
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void _PROTOTYPE( int05, (void) ), _PROTOTYPE( bounds_check, (void) );
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void _PROTOTYPE( int06, (void) ), _PROTOTYPE( inval_opcode, (void) );
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void _PROTOTYPE( int07, (void) ), _PROTOTYPE( copr_not_available, (void) );
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void _PROTOTYPE( double_fault, (void) );
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void _PROTOTYPE( copr_seg_overrun, (void) );
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void _PROTOTYPE( inval_tss, (void) );
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void _PROTOTYPE( segment_not_present, (void) );
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void _PROTOTYPE( stack_exception, (void) );
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void _PROTOTYPE( general_protection, (void) );
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void _PROTOTYPE( page_fault, (void) );
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void _PROTOTYPE( copr_error, (void) );
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/* Software interrupt handlers, in numerical order. */
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_PROTOTYPE( void trp, (void) );
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_PROTOTYPE( void s_call, (void) ), _PROTOTYPE( p_s_call, (void) );
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_PROTOTYPE( void level0_call, (void) );
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/* memory.c */
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_PROTOTYPE( void vir_insb, (u16_t port, struct proc *proc, u32_t vir, size_t count));
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_PROTOTYPE( void vir_outsb, (u16_t port, struct proc *proc, u32_t vir, size_t count));
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_PROTOTYPE( void vir_insw, (u16_t port, struct proc *proc, u32_t vir, size_t count));
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_PROTOTYPE( void vir_outsw, (u16_t port, struct proc *proc, u32_t vir, size_t count));
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_PROTOTYPE( void i386_updatepde, (int pde, u32_t val));
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_PROTOTYPE( void i386_freepde, (int pde));
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_PROTOTYPE( void getcr3val, (void));
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_PROTOTYPE( void switchedcr3, (void));
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_PROTOTYPE( void vm_set_cr3, (struct proc *));
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/* exception.c */
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_PROTOTYPE( void exception, (unsigned vec_nr, u32_t trap_errno,
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u32_t old_eip, U16_t old_cs, u32_t old_eflags,
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u32_t *old_eip_ptr, u32_t *old_eax_ptr, u32_t pagefaultcr2) );
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/* klib386.s */
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_PROTOTYPE( void level0, (void (*func)(void)) );
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_PROTOTYPE( void monitor, (void) );
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_PROTOTYPE( void reset, (void) );
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_PROTOTYPE( void int86, (void) );
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_PROTOTYPE( unsigned long read_cr0, (void) );
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_PROTOTYPE( void write_cr0, (unsigned long value) );
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_PROTOTYPE( unsigned long read_cr4, (void) );
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_PROTOTYPE( void write_cr4, (unsigned long value) );
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_PROTOTYPE( void write_cr3, (unsigned long value) );
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_PROTOTYPE( unsigned long read_cpu_flags, (void) );
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_PROTOTYPE( void phys_insb, (U16_t port, phys_bytes buf, size_t count) );
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_PROTOTYPE( void phys_insw, (U16_t port, phys_bytes buf, size_t count) );
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_PROTOTYPE( void phys_outsb, (U16_t port, phys_bytes buf, size_t count) );
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_PROTOTYPE( void phys_outsw, (U16_t port, phys_bytes buf, size_t count) );
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_PROTOTYPE( void i386_invlpg_level0, (void) );
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_PROTOTYPE( int _memcpy_k, (void *dst, void *src, size_t n) );
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_PROTOTYPE( int _memcpy_k_fault, (void) );
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_PROTOTYPE( u32_t read_cr3, (void) );
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_PROTOTYPE( void reload_cr3, (void) );
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_PROTOTYPE( void phys_memset, (phys_bytes ph, u32_t c, phys_bytes bytes) );
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/* protect.c */
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_PROTOTYPE( void prot_init, (void) );
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_PROTOTYPE( void init_codeseg, (struct segdesc_s *segdp, phys_bytes base,
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vir_bytes size, int privilege) );
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_PROTOTYPE( void init_dataseg, (struct segdesc_s *segdp, phys_bytes base,
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vir_bytes size, int privilege) );
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_PROTOTYPE( void enable_iop, (struct proc *pp) );
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_PROTOTYPE( int prot_set_kern_seg_limit, (vir_bytes limit) );
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_PROTOTYPE( void printseg, (char *banner, int iscs, struct proc *pr, u32_t selector) );
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/* prototype of an interrupt vector table entry */
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struct gate_table_s {
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_PROTOTYPE( 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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EXTERN struct gate_table_s gate_table_pic[];
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/* copies an array of vectors to the IDT. The last vector must be zero filled */
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_PROTOTYPE(void idt_copy_vectors, (struct gate_table_s * first));
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/* functions defined in architecture-independent kernel source. */
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#include "../../proto.h"
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#endif
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