tree 73d7dbb979a107859fb40730555cb10ca6b4cbbb
parent bcb01b8a67476e6f748086e626df8424cc27036d
author Paolo 'Blaisorblade' Giarrusso <[EMAIL PROTECTED]> Thu, 14 Jul 2005
14:33:36 -0700
committer Linus Torvalds <[EMAIL PROTECTED]> Thu, 14 Jul 2005 23:00:24 -0700
[PATCH] uml: workaround host bug in "TT mode vs. NPTL link fix"
A big bug has been diagnosed on hosts running the SKAS patch and built with
CONFIG_REGPARM, due to some missing prevent_tail_call().
On these hosts, this workaround is needed to avoid triggering that bug,
because "to" is kept by GCC only in EBX, which is corrupted at the return of
mmap2().
Since to trigger this bug int 0x80 must be used when doing the call, it rarely
manifests itself, so I'd prefer to get this merged to workaround that host
bug, since it should cause no functional change. Still, you might prefer to
drop it, I'll leave this to you.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <[EMAIL PROTECTED]>
Cc: Jeff Dike <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
arch/um/sys-i386/unmap.c | 2 +-
arch/um/sys-x86_64/unmap.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/um/sys-i386/unmap.c b/arch/um/sys-i386/unmap.c
--- a/arch/um/sys-i386/unmap.c
+++ b/arch/um/sys-i386/unmap.c
@@ -15,7 +15,7 @@ int switcheroo(int fd, int prot, void *f
if(munmap(to, size) < 0){
return(-1);
}
- if(mmap2(to, size, prot, MAP_SHARED | MAP_FIXED, fd, 0) != to){
+ if(mmap2(to, size, prot, MAP_SHARED | MAP_FIXED, fd, 0) == (void*) -1 ){
return(-1);
}
if(munmap(from, size) < 0){
diff --git a/arch/um/sys-x86_64/unmap.c b/arch/um/sys-x86_64/unmap.c
--- a/arch/um/sys-x86_64/unmap.c
+++ b/arch/um/sys-x86_64/unmap.c
@@ -15,7 +15,7 @@ int switcheroo(int fd, int prot, void *f
if(munmap(to, size) < 0){
return(-1);
}
- if(mmap(to, size, prot, MAP_SHARED | MAP_FIXED, fd, 0) != to){
+ if(mmap(to, size, prot, MAP_SHARED | MAP_FIXED, fd, 0) == (void*) -1){
return(-1);
}
if(munmap(from, size) < 0){
-
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