diff options
| author | Rusty Russell <rusty@rustcorp.com.au> | 2009-06-03 14:52:24 +0930 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-04 11:50:06 -0700 |
| commit | 2cb7878a3a4341d1faa208de962d66f0817d3e7a (patch) | |
| tree | 6639c4dcce9f213a58144e0c0431a339b69c42b2 | |
| parent | 9fa7eb283c5cdc2b0f4a8cfe6387ed82e5e9a3d3 (diff) | |
lguest: fix 'unhandled trap 13' with CONFIG_CC_STACKPROTECTOR
We don't set up the canary; let's disable stack protector on boot.c so
we can get into lguest_init, then set it up. As a side effect,
switch_to_new_gdt() sets up %fs for us properly too.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | arch/x86/lguest/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/lguest/boot.c | 17 |
2 files changed, 14 insertions, 4 deletions
diff --git a/arch/x86/lguest/Makefile b/arch/x86/lguest/Makefile index 27f0c9ed7f6..94e0e54056a 100644 --- a/arch/x86/lguest/Makefile +++ b/arch/x86/lguest/Makefile @@ -1 +1,2 @@ obj-y := i386_head.o boot.o +CFLAGS_boot.o := $(call cc-option, -fno-stack-protector) diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index ca7ec44bafc..33a93b41739 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -67,6 +67,7 @@ #include <asm/mce.h> #include <asm/io.h> #include <asm/i387.h> +#include <asm/stackprotector.h> #include <asm/reboot.h> /* for struct machine_ops */ /*G:010 Welcome to the Guest! @@ -1088,13 +1089,21 @@ __init void lguest_init(void) * lguest_init() where the rest of the fairly chaotic boot setup * occurs. */ + /* The stack protector is a weird thing where gcc places a canary + * value on the stack and then checks it on return. This file is + * compiled with -fno-stack-protector it, so we got this far without + * problems. The value of the canary is kept at offset 20 from the + * %gs register, so we need to set that up before calling C functions + * in other files. */ + setup_stack_canary_segment(0); + /* We could just call load_stack_canary_segment(), but we might as + * call switch_to_new_gdt() which loads the whole table and sets up + * the per-cpu segment descriptor register %fs as well. */ + switch_to_new_gdt(0); + /* As described in head_32.S, we map the first 128M of memory. */ max_pfn_mapped = (128*1024*1024) >> PAGE_SHIFT; - /* Load the %fs segment register (the per-cpu segment register) with - * the normal data segment to get through booting. */ - asm volatile ("mov %0, %%fs" : : "r" (__KERNEL_DS) : "memory"); - /* The Host<->Guest Switcher lives at the top of our address space, and * the Host told us how big it is when we made LGUEST_INIT hypercall: * it put the answer in lguest_data.reserve_mem */ |