Re-arrange the page layout used by vm86_bioscall so that we can
potentially re-use the stack page. Cosmetic cleanup of the code to de-obfuscate it and make it easier to follow. There should be no functional changes in this commit.
This commit is contained in:
jlemon
parent
3f4090e1b7
commit
d757cde4ed
@ -34,7 +34,7 @@
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* SUCH DAMAGE.
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*
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* from: @(#)locore.s 7.3 (Berkeley) 5/13/91
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* $Id: locore.s,v 1.109 1998/06/21 18:02:34 bde Exp $
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* $Id: locore.s,v 1.110 1998/06/30 03:01:35 jmg Exp $
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*
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* originally from: locore.s, by William F. Jolitz
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*
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@ -134,6 +134,8 @@ _proc0paddr: .long 0 /* address of proc 0 address space */
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p0upa: .long 0 /* phys addr of proc0's UPAGES */
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#ifdef VM86
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vm86phystk: .long 0 /* PA of vm86/bios stack */
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.globl _vm86paddr, _vm86pa
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_vm86paddr: .long 0 /* address of vm86 region */
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_vm86pa: .long 0 /* phys addr of vm86 region */
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@ -786,7 +788,10 @@ over_symalloc:
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movl %esi, R(_proc0paddr)
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#ifdef VM86
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ALLOCPAGES(4) /* IOPAGES + ext + stack */
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ALLOCPAGES(1) /* vm86/bios stack */
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movl %esi,R(vm86phystk)
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ALLOCPAGES(3) /* pgtable + ext + IOPAGES */
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movl %esi,R(_vm86pa)
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addl $KERNBASE, %esi
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movl %esi, R(_vm86paddr)
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@ -860,7 +865,7 @@ map_read_write:
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#ifdef VM86
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/* Map space for the vm86 region */
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movl R(_vm86pa), %eax
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movl R(vm86phystk), %eax
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movl $4, %ecx
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fillkptphys($PG_RW)
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@ -34,7 +34,7 @@
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* SUCH DAMAGE.
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*
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* from: @(#)locore.s 7.3 (Berkeley) 5/13/91
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* $Id: locore.s,v 1.109 1998/06/21 18:02:34 bde Exp $
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* $Id: locore.s,v 1.110 1998/06/30 03:01:35 jmg Exp $
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*
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* originally from: locore.s, by William F. Jolitz
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*
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@ -134,6 +134,8 @@ _proc0paddr: .long 0 /* address of proc 0 address space */
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p0upa: .long 0 /* phys addr of proc0's UPAGES */
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#ifdef VM86
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vm86phystk: .long 0 /* PA of vm86/bios stack */
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.globl _vm86paddr, _vm86pa
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_vm86paddr: .long 0 /* address of vm86 region */
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_vm86pa: .long 0 /* phys addr of vm86 region */
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@ -786,7 +788,10 @@ over_symalloc:
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movl %esi, R(_proc0paddr)
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#ifdef VM86
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ALLOCPAGES(4) /* IOPAGES + ext + stack */
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ALLOCPAGES(1) /* vm86/bios stack */
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movl %esi,R(vm86phystk)
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ALLOCPAGES(3) /* pgtable + ext + IOPAGES */
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movl %esi,R(_vm86pa)
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addl $KERNBASE, %esi
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movl %esi, R(_vm86paddr)
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@ -860,7 +865,7 @@ map_read_write:
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#ifdef VM86
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/* Map space for the vm86 region */
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movl R(_vm86pa), %eax
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movl R(vm86phystk), %eax
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movl $4, %ecx
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fillkptphys($PG_RW)
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@ -34,7 +34,7 @@
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* SUCH DAMAGE.
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*
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* from: @(#)locore.s 7.3 (Berkeley) 5/13/91
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* $Id: locore.s,v 1.109 1998/06/21 18:02:34 bde Exp $
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* $Id: locore.s,v 1.110 1998/06/30 03:01:35 jmg Exp $
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*
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* originally from: locore.s, by William F. Jolitz
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*
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@ -134,6 +134,8 @@ _proc0paddr: .long 0 /* address of proc 0 address space */
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p0upa: .long 0 /* phys addr of proc0's UPAGES */
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#ifdef VM86
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vm86phystk: .long 0 /* PA of vm86/bios stack */
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.globl _vm86paddr, _vm86pa
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_vm86paddr: .long 0 /* address of vm86 region */
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_vm86pa: .long 0 /* phys addr of vm86 region */
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@ -786,7 +788,10 @@ over_symalloc:
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movl %esi, R(_proc0paddr)
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#ifdef VM86
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ALLOCPAGES(4) /* IOPAGES + ext + stack */
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ALLOCPAGES(1) /* vm86/bios stack */
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movl %esi,R(vm86phystk)
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ALLOCPAGES(3) /* pgtable + ext + IOPAGES */
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movl %esi,R(_vm86pa)
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addl $KERNBASE, %esi
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movl %esi, R(_vm86paddr)
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@ -860,7 +865,7 @@ map_read_write:
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#ifdef VM86
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/* Map space for the vm86 region */
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movl R(_vm86pa), %eax
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movl R(vm86phystk), %eax
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movl $4, %ecx
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fillkptphys($PG_RW)
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@ -23,7 +23,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: vm86.c,v 1.11 1998/03/24 16:47:12 jlemon Exp $
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* $Id: vm86.c,v 1.12 1998/04/15 17:45:08 bde Exp $
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*/
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#include "opt_vm86.h"
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@ -334,55 +334,71 @@ vm86_emulate(vmf)
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return (SIGBUS);
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}
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#define PGTABLE_SIZE ((1024 + 64) * 1024 / PAGE_SIZE)
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#define INTMAP_SIZE 32
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#define IOMAP_SIZE ctob(IOPAGES)
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#define TSS_SIZE \
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(sizeof(struct pcb_ext) - sizeof(struct segment_descriptor) + \
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INTMAP_SIZE + IOMAP_SIZE + 1)
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struct vm86_layout {
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pt_entry_t vml_pgtbl[PGTABLE_SIZE];
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struct pcb vml_pcb;
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struct pcb_ext vml_ext;
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char vml_intmap[INTMAP_SIZE];
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char vml_iomap[IOMAP_SIZE];
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char vml_iomap_trailer;
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};
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static void
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vm86_initialize(void)
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{
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int i, offset;
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int i;
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u_long *addr;
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struct vm86_layout *vml = (struct vm86_layout *)vm86paddr;
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struct pcb *pcb;
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struct pcb_ext *ext;
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struct segment_descriptor sd;
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struct soft_segment_descriptor ssd = {
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0, /* segment base address (overwritten) */
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ctob(IOPAGES + 1) - 1, /* length */
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0, /* length (overwritten) */
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SDT_SYS386TSS, /* segment type */
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0, /* priority level */
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1, /* descriptor present */
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0, 0,
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0, /* default 32 size */
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0, /* default 16 size */
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0 /* granularity */
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};
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/*
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* this should be a compile time error, but cpp doesn't grok sizeof().
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*/
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if (sizeof(struct vm86_layout) > ctob(3))
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panic("struct vm86_layout exceeds space allocated in locore.s");
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/*
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* Below is the memory layout that we use for the vm86 region.
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*
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* The last byte of the i/o map must be followed by an 0xff byte.
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* We arbitrarily allocate 16 bytes here, to keep the starting
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* address on a doubleword boundary.
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*
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* If a ~2K stack is enough for interrupt handling, then
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* it may be possible to get the page count down to 3 pages.
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*
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* +--------+ +--------+
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* | | |Page Tbl| 1M + 64K = 272 entries = 1088 bytes
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* | | +--------+
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* | page 0 |
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* +--------+
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* | |
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* | |
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* | page 0 |
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* | | +--------+
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* | | | stack |
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* +--------+ +--------+
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* +--------+ +--------+
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* | | | PCB | size: ~240 bytes
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* | | |PCB Ext | size: ~140 bytes (includes TSS)
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* +--------+ +--------+ <--------- vm86paddr
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* | | |Page Tbl| 1M + 64K = 272 entries = 1088 bytes
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* | | +--------+
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* | page 1 |
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* | | | PCB | size: ~240 bytes
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* | page 1 | |PCB Ext | size: ~140 bytes (includes TSS)
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* | | +--------+
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* | | |int map |
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* | | +--------+ <-- &(PAGE 1) - 16
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* | | +--------+
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* +--------+ | |
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* | page 2 | | I/O |
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* +--------+ | bitmap |
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* | page 3 | | |
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* +--------+ +--------+
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* | | +--------+
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* +--------+
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*/
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/*
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@ -398,35 +414,37 @@ vm86_initialize(void)
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* pcb_fs = saved TSS descriptor, word 0
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* pcb_gs = saved TSS descriptor, word 1
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*/
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#define new_ptd pcb_esi
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#define vm86_frame pcb_ebp
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#define pgtable_va pcb_ebx
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pcb = (struct pcb *)(vm86paddr + PAGE_SIZE);
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bzero(pcb, sizeof(struct pcb));
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pcb->pcb_esi = vm86pa | PG_V | PG_RW | PG_U;
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pcb->pcb_ebp = vm86paddr + PAGE_SIZE - sizeof(struct vm86frame);
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pcb->pcb_ebx = vm86paddr;
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pcb = &vml->vml_pcb;
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ext = &vml->vml_ext;
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ext = (struct pcb_ext *)((u_int)pcb + sizeof(struct pcb));
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bzero(pcb, sizeof(struct pcb));
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pcb->new_ptd = vm86pa | PG_V | PG_RW | PG_U;
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pcb->vm86_frame = vm86paddr - sizeof(struct vm86frame);
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pcb->pgtable_va = vm86paddr;
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pcb->pcb_ext = ext;
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bzero(ext, sizeof(struct pcb_ext));
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ext->ext_tss.tss_esp0 = vm86paddr + PAGE_SIZE;
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ext->ext_tss.tss_esp0 = vm86paddr;
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ext->ext_tss.tss_ss0 = GSEL(GDATA_SEL, SEL_KPL);
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offset = PAGE_SIZE - 16;
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ext->ext_tss.tss_ioopt =
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(offset - ((u_int)&ext->ext_tss & PAGE_MASK)) << 16;
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ext->ext_iomap = (caddr_t)(offset + ((u_int)&ext->ext_tss & PG_FRAME));
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((u_int)vml->vml_iomap - (u_int)&ext->ext_tss) << 16;
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ext->ext_iomap = vml->vml_iomap;
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ext->ext_vm86.vm86_intmap = vml->vml_intmap;
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ext->ext_vm86.vm86_intmap = ext->ext_iomap - 32;
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if (cpu_feature & CPUID_VME)
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ext->ext_vm86.vm86_has_vme = (rcr4() & CR4_VME ? 1 : 0);
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addr = (u_long *)ext->ext_vm86.vm86_intmap;
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for (i = 0; i < (ctob(IOPAGES) + 32 + 16) / sizeof(u_long); i++)
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for (i = 0; i < (INTMAP_SIZE + IOMAP_SIZE) / sizeof(u_long); i++)
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*addr++ = 0;
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vml->vml_iomap_trailer = 0xff;
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ssd.ssd_base = (u_int)&ext->ext_tss;
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ssd.ssd_limit -= ((u_int)&ext->ext_tss & PAGE_MASK);
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ssd.ssd_limit = TSS_SIZE - 1;
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ssdtosd(&ssd, &ext->ext_tssd);
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vm86pcb = pcb;
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@ -23,7 +23,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: vm86bios.s,v 1.1 1998/03/23 19:52:39 jlemon Exp $
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* $Id: vm86bios.s,v 1.2 1998/03/24 16:51:36 jlemon Exp $
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*/
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#include "opt_vm86.h"
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@ -33,6 +33,14 @@
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#include "assym.s"
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#define SCR_NEWPTD PCB_ESI /* readability macros */
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#define SCR_VMFRAME PCB_EBP /* see vm86.c for explanation */
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#define SCR_STACK PCB_ESP
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#define SCR_PGTABLE PCB_EBX
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#define SCR_ARGFRAME PCB_EIP
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#define SCR_TSS0 PCB_FS
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#define SCR_TSS1 PCB_GS
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.data
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ALIGN_DATA
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@ -47,9 +55,9 @@ _vm86pcb: .long 0
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* vm86_bioscall(struct trapframe_vm86 *vm86)
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*/
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ENTRY(vm86_bioscall)
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movl _vm86pcb,%edx /* data area, see vm86.c for layout */
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movl _vm86pcb,%edx /* scratch data area */
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movl 4(%esp),%eax
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movl %eax,PCB_EIP(%edx) /* save argument pointer */
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movl %eax,SCR_ARGFRAME(%edx) /* save argument pointer */
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pushl %ebx
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pushl %ebp
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pushl %esi
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@ -78,9 +86,9 @@ ENTRY(vm86_bioscall)
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#endif
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1:
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movl PCB_EBP(%edx),%ebx /* target frame location */
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movl SCR_VMFRAME(%edx),%ebx /* target frame location */
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movl %ebx,%edi /* destination */
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movl PCB_EIP(%edx),%esi /* source (set on entry) */
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movl SCR_ARGFRAME(%edx),%esi /* source (set on entry) */
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movl $21,%ecx /* sizeof(struct vm86frame)/4 */
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cld
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rep
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@ -95,7 +103,7 @@ ENTRY(vm86_bioscall)
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orl $PG_V|PG_RW|PG_U,%ebx /* XXX assembler error?? */
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#endif
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orl $0x7,%ebx
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movl PCB_EBX(%edx),%eax /* va of vm86 page table */
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movl SCR_PGTABLE(%edx),%eax /* va of vm86 page table */
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movl %ebx,4(%eax) /* set vm86 PTE entry 1 */
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1:
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movl _curpcb,%eax
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@ -106,10 +114,10 @@ ENTRY(vm86_bioscall)
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movl _my_tr,%esi
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leal _gdt(,%esi,8),%ebx /* entry in GDT */
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movl 0(%ebx),%eax
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movl %eax,PCB_FS(%edx) /* save first word */
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movl %eax,SCR_TSS0(%edx) /* save first word */
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movl 4(%ebx),%eax
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andl $~0x200, %eax /* flip 386BSY -> 386TSS */
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movl %eax,PCB_GS(%edx) /* save second word */
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movl %eax,SCR_TSS1(%edx) /* save second word */
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movl PCB_EXT(%edx),%edi /* vm86 tssd entry */
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movl 0(%edi),%eax
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@ -132,13 +140,13 @@ ENTRY(vm86_bioscall)
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pushl %eax /* old ptde != 0 when booting */
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pushl %ebx /* keep for reuse */
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movl %esp,PCB_ESP(%edx) /* save current stack location */
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movl %esp,SCR_STACK(%edx) /* save current stack location */
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movl PCB_ESI(%edx),%eax /* mapping for vm86 page table */
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movl SCR_NEWPTD(%edx),%eax /* mapping for vm86 page table */
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movl %eax,0(%ebx) /* ... install as PTD entry 0 */
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movl %ecx,%cr3 /* new page tables */
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movl PCB_EBP(%edx),%esp /* switch to new stack */
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movl SCR_VMFRAME(%edx),%esp /* switch to new stack */
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call _vm86_prepcall /* finish setup */
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@ -170,13 +178,13 @@ ENTRY(vm86_biosret)
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movl _vm86pcb,%edx /* data area */
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movl 4(%esp),%esi /* source */
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movl PCB_EIP(%edx),%edi /* destination */
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movl SCR_ARGFRAME(%edx),%edi /* destination */
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movl $21,%ecx /* size */
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cld
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rep
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movsl /* copy frame to original frame */
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movl PCB_ESP(%edx),%esp /* back to old stack */
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movl SCR_STACK(%edx),%esp /* back to old stack */
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popl %ebx /* saved va of Idle PTD */
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popl %eax
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movl %eax,0(%ebx) /* restore old pte */
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@ -184,21 +192,21 @@ ENTRY(vm86_biosret)
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movl %eax,%cr3 /* install old page table */
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movl $0,_in_vm86call /* reset trapflag */
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movl PCB_EBX(%edx),%ebx /* va of vm86 page table */
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movl SCR_PGTABLE(%edx),%ebx /* va of vm86 page table */
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movl $0,4(%ebx) /* ...clear entry 1 */
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movl _my_tr,%esi
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leal _gdt(,%esi,8),%ebx /* entry in GDT */
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movl PCB_FS(%edx),%eax
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movl SCR_TSS0(%edx),%eax
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movl %eax,0(%ebx) /* restore first word */
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movl PCB_GS(%edx),%eax
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movl SCR_TSS1(%edx),%eax
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movl %eax,4(%ebx) /* restore second word */
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shll $3,%esi /* GSEL(entry, SEL_KPL) */
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ltr %si
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popl _curpcb /* restore curpcb/curproc */
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popl _curproc
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movl PCB_EIP(%edx),%edx /* original stack frame */
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movl SCR_ARGFRAME(%edx),%edx /* original stack frame */
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movl TF_TRAPNO(%edx),%eax /* return (trapno) */
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popl %gs
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