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x86/Xen: swap NX determination and GDT setup on BSP

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commit ae897fda4f507e4b239f0bdfd578b3688ca96fb4 upstream.

xen_setup_gdt(), via xen_load_gdt_boot(), wants to adjust page tables.
For this to work when NX is not available, x86_configure_nx() needs to
be called first.

[jgross] Note that this is a revert of 36104cb9012a82e73 ("x86/xen:
Delay get_cpu_cap until stack canary is established"), which is possible
now that we no longer support running as PV guest in 32-bit mode.

Cc: <stable.vger.kernel.org> # 5.9
Fixes: 36104cb9012a82e73 ("x86/xen: Delay get_cpu_cap until stack canary is established")
Reported-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Link: https://lore.kernel.org/r/12a866b0-9e89-59f7-ebeb-a2a6cec0987a@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Jan Beulich 2021-05-20 13:42:42 +02:00 committed by Greg Kroah-Hartman
parent d5c4605e9e
commit e2c26ddd4e
1 changed files with 4 additions and 4 deletions
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8
arch/x86/xen/enlighten_pv.c
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@ -1262,16 +1262,16 @@ asmlinkage __visible void __init xen_start_kernel(void)
/* Get mfn list */
xen_build_dynamic_phys_to_machine();
/* Work out if we support NX */
get_cpu_cap(&boot_cpu_data);
x86_configure_nx();
/*
* Set up kernel GDT and segment registers, mainly so that
* -fstack-protector code can be executed.
*/
xen_setup_gdt(0);
/* Work out if we support NX */
get_cpu_cap(&boot_cpu_data);
x86_configure_nx();
/* Determine virtual and physical address sizes */
get_cpu_address_sizes(&boot_cpu_data);