2d72cbec41
. add cpufeature detection of both . use it for both ipc and kernelcall traps, using a register for call number . SYSENTER/SYSCALL does not save any context, therefore userland has to save it . to accomodate multiple kernel entry/exit types, the entry type is recorded in the process struct. hitherto all types were interrupt (soft int, exception, hard int); now SYSENTER/SYSCALL is new, with the difference that context is not fully restored from proc struct when running the process again. this can't be done as some information is missing. . complication: cases in which the kernel has to fully change process context (i.e. sigreturn). in that case the exit type is changed from SYSENTER/SYSEXIT to soft-int (i.e. iret) and context is fully restored from the proc struct. this does mean the PC and SP must change, as the sysenter/sysexit userland code will otherwise try to restore its own context. this is true in the sigreturn case. . override all usage by setting libc_ipc=1
102 lines
2.8 KiB
C
102 lines
2.8 KiB
C
#ifndef __SCONST_H__
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#define __SCONST_H__
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#include "kernel/const.h"
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#include "kernel/procoffsets.h"
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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 $KERN_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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/*
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* restore kernel segments. %cs is aready set and %fs, %gs are not used */
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#define RESTORE_KERNEL_SEGS \
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mov $KERN_DS_SELECTOR, %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, AXREG(pptr) ;\
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mov %ecx, CXREG(pptr) ;\
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mov %edx, DXREG(pptr) ;\
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mov %ebx, BXREG(pptr) ;\
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mov %esi, SIREG(pptr) ;\
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mov %edi, DIREG(pptr) ;
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#define RESTORE_GP_REGS(pptr) \
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movl AXREG(pptr), %eax ;\
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movl CXREG(pptr), %ecx ;\
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movl DXREG(pptr), %edx ;\
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movl BXREG(pptr), %ebx ;\
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movl SIREG(pptr), %esi ;\
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movl 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, trapcode) \
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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_GP_REGS(%ebp) ;\
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movl $trapcode, P_KERN_TRAP_STYLE(%ebp) ;\
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pop %esi /* get the orig %ebp and save it */ ;\
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mov %esi, 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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