94 lines
2.7 KiB
ArmAsm
94 lines
2.7 KiB
ArmAsm
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/* sections */
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#include <minix/config.h>
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#include <minix/const.h>
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#include <machine/asm.h>
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#include <machine/interrupt.h>
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#include <machine/vm.h>
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#include "archconst.h"
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#include "kernel/const.h"
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#include "sconst.h"
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#include <machine/multiboot.h>
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/*===========================================================================*/
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/* copy_msg_from_user */
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/*===========================================================================*/
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/*
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* int copy_msg_from_user(message * user_mbuf, message * dst);
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*
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* Copies a message of 36 bytes from user process space to a kernel buffer. This
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* function assumes that the process address space is installed (cr3 loaded).
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*
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* This function from the callers point of view either succeeds or returns an
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* error which gives the caller a chance to respond accordingly. In fact it
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* either succeeds or if it generates a pagefault, general protection or other
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* exception, the trap handler has to redirect the execution to
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* __user_copy_msg_pointer_failure where the error is reported to the caller
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* without resolving the pagefault. It is not kernel's problem to deal with
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* wrong pointers from userspace and the caller should return an error to
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* userspace as if wrong values or request were passed to the kernel
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*/
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ENTRY(copy_msg_from_user)
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push {r4-r10, lr}
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/* load the source pointer */
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mov r9, r0
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/* load the destination pointer */
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mov r10, r1
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/* do the copy */
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ldm r9, {r0-r8}
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stm r10, {r0-r8}
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LABEL(__copy_msg_from_user_end)
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pop {r4-r10, lr}
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mov r0, #0
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bx lr
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/*===========================================================================*/
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/* copy_msg_to_user */
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/*===========================================================================*/
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/*
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* void copy_msg_to_user(message * src, message * user_mbuf);
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*
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* Copies a message of 36 bytes to user process space from a kernel buffer.
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*
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* All the other copy_msg_from_user() comments apply here as well!
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*/
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ENTRY(copy_msg_to_user)
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push {r4-r10, lr}
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/* load the source pointer */
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mov r9, r0
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/* load the destination pointer */
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mov r10, r1
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/* do the copy */
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ldm r9, {r0-r8}
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stm r10, {r0-r8}
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LABEL(__copy_msg_to_user_end)
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pop {r4-r10, lr}
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mov r0, #0
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bx lr
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/*
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* if a function from a selected set of copies from or to userspace fails, it is
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* because of a wrong pointer supplied by the userspace. We have to clean up and
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* and return -1 to indicated that something wrong has happend. The place it was
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* called from has to handle this situation. The exception handler redirect us
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* here to continue, clean up and report the error
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*/
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ENTRY(__user_copy_msg_pointer_failure)
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pop {r4-r10, lr}
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mov r0, #-1
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bx lr
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ENTRY(interrupts_enable)
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dsb
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cpsie i
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bx lr
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ENTRY(interrupts_disable)
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dsb
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cpsid i
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bx lr
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