diff options
| author |   Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> | 2006-05-01 12:16:04 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@g5.osdl.org> | 2006-05-01 18:17:45 -0700 |
| commit | 275e6e1ee2bafde77e9390b27e876fa83f24cb60 (patch) | |
| tree | fca0c0a7e3bdabe82bc75a0dad5c765f3b6edaf0 /arch/um/kernel | |
| parent | [PATCH] uml: use Kbuild tracking for all files and fix compilation output (diff) | |
| download | linux-dev-275e6e1ee2bafde77e9390b27e876fa83f24cb60.tar.xz linux-dev-275e6e1ee2bafde77e9390b27e876fa83f24cb60.zip | |
[PATCH] uml: fix compilation and execution with hardened GCC
To make some half-assembly stubs compile, disable various "hardened" GCC
features:
*) we can't make it build PIC code as we need %ebx to do syscalls and GCC
wants it free for PIC
*) we can't leave stack protection as the stub is moved (not relocated!) in
memory so the RIP-relative access to the canary tries reading from an
unmapped address and causes a segfault, since we move the stub of various
megabytes (the exact amount will be decided at runtime) away from the
link-time address.
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>
Diffstat (limited to 'arch/um/kernel')
| -rw-r--r-- | arch/um/kernel/skas/Makefile | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/um/kernel/skas/Makefile b/arch/um/kernel/skas/Makefile index 57181a920d48..ad842964707a 100644 --- a/arch/um/kernel/skas/Makefile +++ b/arch/um/kernel/skas/Makefile @@ -11,4 +11,11 @@ USER_OBJS := clone.o include arch/um/scripts/Makefile.rules # clone.o is in the stub, so it can't be built with profiling -$(obj)/clone.o : c_flags = -Wp,-MD,$(depfile) $(call unprofile,$(USER_CFLAGS)) +# GCC hardened also auto-enables -fpic, but we need %ebx so it can't work -> +# disable it + +CFLAGS_clone.o := $(CFLAGS_NO_HARDENING) + +# since we're setting c_flags we _must_ add $(CFLAGS_$(*F).o). + +$(obj)/clone.o : c_flags = -Wp,-MD,$(depfile) $(call unprofile,$(USER_CFLAGS)) $(CFLAGS_$(*F).o) |