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authorJan Beulich <jbeulich@suse.com>2021-09-30 14:16:15 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-10-27 09:59:31 +0200
commit7d8cdaffc518c942ef7c941c091e0b4f782285cb (patch)
tree49fbe17db1fe9e0300ec1d3561bdbbdf64f951b1 /arch
parent28d084adc22d342ae25cff720d43e1c941812b7e (diff)
xen/x86: prevent PVH type from getting clobbered
[ Upstream commit 9172b5c4a778da1f855b2e3780b1afabb3cfd523 ] Like xen_start_flags, xen_domain_type gets set before .bss gets cleared. Hence this variable also needs to be prevented from getting put in .bss, which is possible because XEN_NATIVE is an enumerator evaluating to zero. Any use prior to init_hvm_pv_info() setting the variable again would lead to wrong decisions; one such case is xenboot_console_setup() when called as a result of "earlyprintk=xen". Use __ro_after_init as more applicable than either __section(".data") or __read_mostly. Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/d301677b-6f22-5ae6-bd36-458e1f323d0b@suse.com Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/xen/enlighten.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index c79bd0af2e8c..f252faf5028f 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -52,9 +52,6 @@ DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);
DEFINE_PER_CPU(uint32_t, xen_vcpu_id);
EXPORT_PER_CPU_SYMBOL(xen_vcpu_id);
-enum xen_domain_type xen_domain_type = XEN_NATIVE;
-EXPORT_SYMBOL_GPL(xen_domain_type);
-
unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START;
EXPORT_SYMBOL(machine_to_phys_mapping);
unsigned long machine_to_phys_nr;
@@ -69,9 +66,11 @@ __read_mostly int xen_have_vector_callback;
EXPORT_SYMBOL_GPL(xen_have_vector_callback);
/*
- * NB: needs to live in .data because it's used by xen_prepare_pvh which runs
- * before clearing the bss.
+ * NB: These need to live in .data or alike because they're used by
+ * xen_prepare_pvh() which runs before clearing the bss.
*/
+enum xen_domain_type __ro_after_init xen_domain_type = XEN_NATIVE;
+EXPORT_SYMBOL_GPL(xen_domain_type);
uint32_t xen_start_flags __section(".data") = 0;
EXPORT_SYMBOL(xen_start_flags);