Module Name: src
Committed By: martin
Date: Thu Feb 25 09:36:27 UTC 2021
Modified Files:
src/sys/arch/m68k/m68k [netbsd-9]: reenter_syscall.s
Log Message:
Pull up following revision(s) (requested by tsutsui in ticket #1214):
sys/arch/m68k/m68k/reenter_syscall.s: revision 1.5
sys/arch/m68k/m68k/reenter_syscall.s: revision 1.6
sys/arch/m68k/m68k/reenter_syscall.s: revision 1.7
Replace magic numbers with proper macros prepared in assym.h.
No binary changes.
Note this is a preparation for a possible fix of PR port-m68k/55990.
Consistently use motorola style. No binary changes.
Seems missed in rev 1.3:
https://mail-index.netbsd.org/source-changes/2013/08/01/msg046378.html
Plug kernel stack leaks in reenter_syscall() for setcontext(2).
This fixes long standing kernel crashes (MMU fault, address error,
and silent freeze by a double bus fault etc. seen for ~10 years)
caused by kernel stack overflow, especially on x68k and sun3 running
Xorg based servers. See PR/55990 for more details.
"This change seems perfectly reasonable" from thorpej@ and
jklos@ also reported this also solved freeze of his mac68k system
with 10 megabyes of memory.
Should be pulled up to netbsd-9 and netbsd-8.
To generate a diff of this commit:
cvs rdiff -u -r1.4 -r1.4.34.1 src/sys/arch/m68k/m68k/reenter_syscall.s
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/m68k/m68k/reenter_syscall.s
diff -u src/sys/arch/m68k/m68k/reenter_syscall.s:1.4 src/sys/arch/m68k/m68k/reenter_syscall.s:1.4.34.1
--- src/sys/arch/m68k/m68k/reenter_syscall.s:1.4 Sat Sep 7 19:06:29 2013
+++ src/sys/arch/m68k/m68k/reenter_syscall.s Thu Feb 25 09:36:27 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: reenter_syscall.s,v 1.4 2013/09/07 19:06:29 chs Exp $ */
+/* $NetBSD: reenter_syscall.s,v 1.4.34.1 2021/02/25 09:36:27 martin Exp $ */
/*
* Written by ITOH Yasufumi.
@@ -6,6 +6,7 @@
*/
#include <m68k/asm.h>
+#include "assym.h"
/*
* void reenter_syscall(struct frame *fp, int stkadj)
@@ -38,18 +39,31 @@ ENTRY_NOPROFILE(reenter_syscall)
.Lcpfr: movel (%a0)+,(%a1)+
dbra %d0,.Lcpfr
- movew %d1,%sp@(16*4+2) | set stack adjust count
+ movew %d1,FR_ADJ(%sp) | set stack adjust count
movel (%sp),-(%sp) | push syscall no (original d0 value)
jbsr _C_LABEL(syscall) | re-enter syscall()
addql #4,%sp | pop syscall no
#ifdef DEBUG
- tstw %sp@(16*4+2) | stack adjust must be zero
+ tstw FR_ADJ(%sp) | stack adjust must be zero
jeq .Ladjzero
PANIC("reenter_syscall")
.Ladjzero:
#endif
- moveal %sp@(15*4),%a0 | grab and restore
+ moveal FR_SP(%sp),%a0 | grab and restore
movel %a0,%usp | user SP
+ movw FR_ADJ(%sp),%d0 | need to adjust stack?
+ jne .Ladjstk | yes, go to it
moveml (%sp)+,#0x7FFF | restore user registers
addql #8,%sp | pop SP and stack adjust
jra _ASM_LABEL(rei) | rte
+.Ladjstk:
+ lea FR_HW(%sp),%a1 | pointer to HW frame
+ addql #8,%a1 | source pointer
+ movl %a1,%a0 | source
+ addw %d0,%a0 | + hole size = dest pointer
+ movl -(%a1),-(%a0) | copy
+ movl -(%a1),-(%a0) | 8 bytes
+ movl %a0,FR_SP(%sp) | new SSP
+ moveml (%sp)+,#0x7FFF | restore user register
+ movl (%sp),%sp | and do real RTE
+ jra _ASM_LABEL(rei) | rte
