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Be more careful about cleaning up the stack after function calls early

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in the boot.  The cleanup must be done in one of the few ways that
db_numargs() understands, so that early backtraces in ddb don't underrun
the stack.  The underruns caused reboots a few years ago when there
was an unmapped page above the stack (trapping to abort the command
doesn't work early).

Cleaned up some nearby code.
This commit is contained in:
bde 2000-09-13 14:08:50 +00:00
parent d113e79649
commit 1f9f76e138
3 changed files with 48 additions and 33 deletions
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27
sys/amd64/amd64/locore.S
View File

@ -348,22 +348,27 @@ NON_GPROF_ENTRY(btext)
/* now running relocated at KERNBASE where the system is linked to run */
begin:
/* set up bootstrap stack */
movl _proc0paddr,%esp /* location of in-kernel pages */
addl $UPAGES*PAGE_SIZE,%esp /* bootstrap stack end location */
xorl %eax,%eax /* mark end of frames */
movl %eax,%ebp
movl _proc0paddr,%eax
movl _IdlePTD, %esi
movl _proc0paddr,%eax /* location of in-kernel pages */
leal UPAGES*PAGE_SIZE(%eax),%esp /* bootstrap stack end location */
xorl %ebp,%ebp /* mark end of frames */
movl _IdlePTD,%esi
movl %esi,PCB_CR3(%eax)
movl physfree, %esi
pushl %esi /* value of first for init386(first) */
pushl physfree /* value of first for init386(first) */
call _init386 /* wire 386 chip for unix operation */
popl %esi
/*
* Clean up the stack in a way that db_numargs() understands, so
* that backtraces in ddb don't underrun the stack. Traps for
* inaccessible memory are more fatal than usual this early.
*/
addl $4,%esp
call _mi_startup /* autoconfiguration, mountroot etc */
hlt /* never returns to here */
/* NOTREACHED */
addl $0,%esp /* for db_numargs() again */
/*
* Signal trampoline, copied to top of user stack

27
sys/amd64/amd64/locore.s
View File

@ -348,22 +348,27 @@ NON_GPROF_ENTRY(btext)
/* now running relocated at KERNBASE where the system is linked to run */
begin:
/* set up bootstrap stack */
movl _proc0paddr,%esp /* location of in-kernel pages */
addl $UPAGES*PAGE_SIZE,%esp /* bootstrap stack end location */
xorl %eax,%eax /* mark end of frames */
movl %eax,%ebp
movl _proc0paddr,%eax
movl _IdlePTD, %esi
movl _proc0paddr,%eax /* location of in-kernel pages */
leal UPAGES*PAGE_SIZE(%eax),%esp /* bootstrap stack end location */
xorl %ebp,%ebp /* mark end of frames */
movl _IdlePTD,%esi
movl %esi,PCB_CR3(%eax)
movl physfree, %esi
pushl %esi /* value of first for init386(first) */
pushl physfree /* value of first for init386(first) */
call _init386 /* wire 386 chip for unix operation */
popl %esi
/*
* Clean up the stack in a way that db_numargs() understands, so
* that backtraces in ddb don't underrun the stack. Traps for
* inaccessible memory are more fatal than usual this early.
*/
addl $4,%esp
call _mi_startup /* autoconfiguration, mountroot etc */
hlt /* never returns to here */
/* NOTREACHED */
addl $0,%esp /* for db_numargs() again */
/*
* Signal trampoline, copied to top of user stack

27
sys/i386/i386/locore.s
View File

@ -348,22 +348,27 @@ NON_GPROF_ENTRY(btext)
/* now running relocated at KERNBASE where the system is linked to run */
begin:
/* set up bootstrap stack */
movl _proc0paddr,%esp /* location of in-kernel pages */
addl $UPAGES*PAGE_SIZE,%esp /* bootstrap stack end location */
xorl %eax,%eax /* mark end of frames */
movl %eax,%ebp
movl _proc0paddr,%eax
movl _IdlePTD, %esi
movl _proc0paddr,%eax /* location of in-kernel pages */
leal UPAGES*PAGE_SIZE(%eax),%esp /* bootstrap stack end location */
xorl %ebp,%ebp /* mark end of frames */
movl _IdlePTD,%esi
movl %esi,PCB_CR3(%eax)
movl physfree, %esi
pushl %esi /* value of first for init386(first) */
pushl physfree /* value of first for init386(first) */
call _init386 /* wire 386 chip for unix operation */
popl %esi
/*
* Clean up the stack in a way that db_numargs() understands, so
* that backtraces in ddb don't underrun the stack. Traps for
* inaccessible memory are more fatal than usual this early.
*/
addl $4,%esp
call _mi_startup /* autoconfiguration, mountroot etc */
hlt /* never returns to here */
/* NOTREACHED */
addl $0,%esp /* for db_numargs() again */
/*
* Signal trampoline, copied to top of user stack