提交 b75fe4e5 编写于 作者: J Jeremy Fitzhardinge

xen: check EFER for NX before setting up GDT mapping

x86-64 assumes NX is available by default, so we need to
explicitly check for it before using NX.  Some first-generation
Intel x86-64 processors didn't support NX, and even recent systems
allow it to be disabled in BIOS.

[ Impact: prevent Xen crash on NX-less 64-bit machines ]
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
上级 79b520e8
......@@ -4,6 +4,7 @@ obj-y := init.o init_$(BITS).o fault.o ioremap.o extable.o pageattr.o mmap.o \
# Make sure __phys_addr has no stackprotector
nostackp := $(call cc-option, -fno-stack-protector)
CFLAGS_physaddr.o := $(nostackp)
CFLAGS_init.o := $(nostackp)
obj-$(CONFIG_SMP) += tlb.o
......
......@@ -1083,6 +1083,11 @@ asmlinkage void __init xen_start_kernel(void)
__supported_pte_mask |= _PAGE_IOMAP;
#ifdef CONFIG_X86_64
/* Work out if we support NX */
check_efer();
#endif
xen_setup_features();
/* Get mfn list */
......@@ -1123,11 +1128,6 @@ asmlinkage void __init xen_start_kernel(void)
pgd = (pgd_t *)xen_start_info->pt_base;
#ifdef CONFIG_X86_64
/* Work out if we support NX */
check_efer();
#endif
/* Don't do the full vcpu_info placement stuff until we have a
possible map and a non-dummy shared_info. */
per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
......
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