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| author | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2009-08-27 21:46:35 +0200 |
|---|---|---|
| committer | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2009-09-10 01:37:39 +0200 |
| commit | 577eebeae34d340685d8985dfdb7dfe337c511e8 (patch) | |
| tree | 047aa135d143ed12035ca04433e563b948f9b059 /arch/x86/xen/Makefile | |
| parent | Linux 2.6.31-rc9 (diff) | |
| download | linux-577eebeae34d340685d8985dfdb7dfe337c511e8.tar.xz linux-577eebeae34d340685d8985dfdb7dfe337c511e8.zip | |
xen: make -fstack-protector work under Xen
-fstack-protector uses a special per-cpu "stack canary" value.
gcc generates special code in each function to test the canary to make
sure that the function's stack hasn't been overrun.
On x86-64, this is simply an offset of %gs, which is the usual per-cpu
base segment register, so setting it up simply requires loading %gs's
base as normal.
On i386, the stack protector segment is %gs (rather than the usual kernel
percpu %fs segment register). This requires setting up the full kernel
GDT and then loading %gs accordingly. We also need to make sure %gs is
initialized when bringing up secondary cpus too.
To keep things consistent, we do the full GDT/segment register setup on
both architectures.
Because we need to avoid -fstack-protected code before setting up the GDT
and because there's no way to disable it on a per-function basis, several
files need to have stack-protector inhibited.
[ Impact: allow Xen booting with stack-protector enabled ]
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Diffstat (limited to 'arch/x86/xen/Makefile')
| -rw-r--r-- | arch/x86/xen/Makefile | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile index 7410640db173..3bb4fc21f4f2 100644 --- a/arch/x86/xen/Makefile +++ b/arch/x86/xen/Makefile @@ -8,6 +8,7 @@ endif # Make sure early boot has no stackprotector nostackp := $(call cc-option, -fno-stack-protector) CFLAGS_enlighten.o := $(nostackp) +CFLAGS_mmu.o := $(nostackp) obj-y := enlighten.o setup.o multicalls.o mmu.o irq.o \ time.o xen-asm.o xen-asm_$(BITS).o \ @@ -16,3 +17,4 @@ obj-y := enlighten.o setup.o multicalls.o mmu.o irq.o \ obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinlock.o obj-$(CONFIG_XEN_DEBUG_FS) += debugfs.o + |