[PATCH] uml: check for differences in host support

If running on a host not supporting TLS (for instance 2.4) we should report
that cleanly to the user, instead of printing not comprehensible "error 5" for
that.

Additionally, i386 and x86_64 support different ranges for
user_desc->entry_number, and we must account for that; we couldn't pass
ourselves -1 because we need to override previously existing TLS descriptors
which glibc has possibly set, so test at startup the range to use.

x86 and x86_64 existing ranges are hardcoded.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/um/include/sysdep-i386/tls.h b/arch/um/include/sysdep-i386/tls.h
index 938f953b26cc..918fd3c5ff9c 100644
--- a/arch/um/include/sysdep-i386/tls.h
+++ b/arch/um/include/sysdep-i386/tls.h
@@ -25,4 +25,8 @@ typedef struct um_dup_user_desc {
 typedef struct user_desc user_desc_t;
 
 # endif /* __KERNEL__ */
+
+#define GDT_ENTRY_TLS_MIN_I386 6
+#define GDT_ENTRY_TLS_MIN_X86_64 12
+
 #endif /* _SYSDEP_TLS_H */