b984fa41df
This reverts commit eff1369cab.
This was in a working branch and I only intended to commit
exception.c. But I committed the exact inverse. Sorry.
152 lines
4 KiB
C
152 lines
4 KiB
C
#ifndef __SCONST_H__
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#define __SCONST_H__
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#include "kernel/const.h"
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/* Miscellaneous constants used in assembler code. */
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W = _WORD_SIZE /* Machine word size. */
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/* Offsets in struct proc. They MUST match proc.h. */
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P_STACKBASE = 0
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GSREG = P_STACKBASE
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FSREG = GSREG+2 /* 386 introduces FS and GS segments*/
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ESREG = FSREG+2
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DSREG = ESREG+2
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DIREG = DSREG+2
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SIREG = DIREG+W
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BPREG = SIREG+W
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STREG = BPREG+W /* hole for another SP*/
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BXREG = STREG+W
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DXREG = BXREG+W
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CXREG = DXREG+W
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AXREG = CXREG+W
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RETADR = AXREG+W /* return address for save() call*/
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PCREG = RETADR+W
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CSREG = PCREG+W
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PSWREG = CSREG+W
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SPREG = PSWREG+W
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SSREG = SPREG+W
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P_STACKTOP = SSREG+W
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FP_SAVE_AREA_P = P_STACKTOP
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P_LDT_SEL = FP_SAVE_AREA_P + 532
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P_CR3 = P_LDT_SEL+W
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P_CR3_V = P_CR3+4
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P_LDT = P_CR3_V+W
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P_MISC_FLAGS = P_LDT + 50
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Msize = 9 /* size of a message in 32-bit words*/
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/*
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* offset to current process pointer right after trap, we assume we always have
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* error code on the stack
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*/
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#define CURR_PROC_PTR 20
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/*
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* tests whether the interrupt was triggered in kernel. If so, jump to the
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* label. Displacement tell the macro ha far is the CS value saved by the trap
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* from the current %esp. The kernel code segment selector has the lower 3 bits
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* zeroed
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*/
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#define TEST_INT_IN_KERNEL(displ, label) \
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cmpl $CS_SELECTOR, displ(%esp) ;\
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je label ;
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/*
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* saves the basic interrupt context (no error code) to the process structure
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*
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* displ is the displacement of %esp from the original stack after trap
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* pptr is the process structure pointer
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* tmp is an available temporary register
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*/
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#define SAVE_TRAP_CTX(displ, pptr, tmp) \
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movl (0 + displ)(%esp), tmp ;\
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movl tmp, PCREG(pptr) ;\
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movl (4 + displ)(%esp), tmp ;\
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movl tmp, CSREG(pptr) ;\
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movl (8 + displ)(%esp), tmp ;\
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movl tmp, PSWREG(pptr) ;\
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movl (12 + displ)(%esp), tmp ;\
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movl tmp, SPREG(pptr) ;\
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movl tmp, STREG(pptr) ;\
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movl (16 + displ)(%esp), tmp ;\
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movl tmp, SSREG(pptr) ;
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#define SAVE_SEGS(pptr) \
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mov %ds, %ss:DSREG(pptr) ;\
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mov %es, %ss:ESREG(pptr) ;\
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mov %fs, %ss:FSREG(pptr) ;\
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mov %gs, %ss:GSREG(pptr) ;
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#define RESTORE_SEGS(pptr) \
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movw %ss:DSREG(pptr), %ds ;\
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movw %ss:ESREG(pptr), %es ;\
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movw %ss:FSREG(pptr), %fs ;\
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movw %ss:GSREG(pptr), %gs ;
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/*
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* restore kernel segments, %ss is kernnel data segment, %cs is aready set and
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* %fs, %gs are not used
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*/
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#define RESTORE_KERNEL_SEGS \
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mov %ss, %si ;\
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mov %si, %ds ;\
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mov %si, %es ;\
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movw $0, %si ;\
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mov %si, %gs ;\
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mov %si, %fs ;
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#define SAVE_GP_REGS(pptr) \
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mov %eax, %ss:AXREG(pptr) ;\
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mov %ecx, %ss:CXREG(pptr) ;\
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mov %edx, %ss:DXREG(pptr) ;\
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mov %ebx, %ss:BXREG(pptr) ;\
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mov %esi, %ss:SIREG(pptr) ;\
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mov %edi, %ss:DIREG(pptr) ;
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#define RESTORE_GP_REGS(pptr) \
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movl %ss:AXREG(pptr), %eax ;\
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movl %ss:CXREG(pptr), %ecx ;\
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movl %ss:DXREG(pptr), %edx ;\
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movl %ss:BXREG(pptr), %ebx ;\
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movl %ss:SIREG(pptr), %esi ;\
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movl %ss:DIREG(pptr), %edi ;
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/*
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* save the context of the interrupted process to the structure in the process
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* table. It pushses the %ebp to stack to get a scratch register. After %esi is
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* saved, we can use it to get the saved %ebp from stack and save it to the
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* final location
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*
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* displ is the stack displacement. In case of an exception, there are two extra
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* value on the stack - error code and the exception number
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*/
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#define SAVE_PROCESS_CTX(displ) \
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\
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cld /* set the direction flag to a known state */ ;\
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\
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push %ebp ;\
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;\
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movl (CURR_PROC_PTR + 4 + displ)(%esp), %ebp ;\
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\
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/* save the segment registers */ \
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SAVE_SEGS(%ebp) ;\
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\
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SAVE_GP_REGS(%ebp) ;\
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pop %esi /* get the orig %ebp and save it */ ;\
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mov %esi, %ss:BPREG(%ebp) ;\
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\
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RESTORE_KERNEL_SEGS ;\
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SAVE_TRAP_CTX(displ, %ebp, %esi) ;
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/*
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* clear the IF flag in eflags which are stored somewhere in memory, e.g. on
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* stack. iret or popf will load the new value later
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*/
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#define CLEAR_IF(where) \
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mov where, %eax ;\
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andl $0xfffffdff, %eax ;\
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mov %eax, where ;
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#endif /* __SCONST_H__ */
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