[tip: x86/cpu] x86/cpu: Drop 32-bit Xen PV guest code in update_task_stack()

[tip-bot2 for Juergen Gross]

The following commit has been merged into the x86/cpu branch of tip:

Commit-ID:     dfbd9e4059c4edad4d92ef7f3deb4954f76e4ba0
Gitweb:        https://git.kernel.org/tip/dfbd9e4059c4edad4d92ef7f3deb4954f76e4ba0
Author:        Juergen Gross <jgross@xxxxxxxx>
AuthorDate:    Fri, 04 Nov 2022 08:26:59 +01:00
Committer:     Borislav Petkov <bp@xxxxxxx>
CommitterDate: Tue, 22 Nov 2022 16:14:15 +01:00

x86/cpu: Drop 32-bit Xen PV guest code in update_task_stack()

Testing for Xen PV guest mode in a 32-bit only code section can be
dropped, as Xen PV guests are supported in 64-bit mode only.

While at it, switch from boot_cpu_has() to cpu_feature_enabled() in the
64-bit part of the code.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221104072701.20283-4-jgross@xxxxxxxx
---
 arch/x86/include/asm/switch_to.h | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h
index c08eb0f..5c91305 100644
--- a/arch/x86/include/asm/switch_to.h
+++ b/arch/x86/include/asm/switch_to.h
@@ -66,13 +66,10 @@ static inline void update_task_stack(struct task_struct *task)
 {
 	/* sp0 always points to the entry trampoline stack, which is constant: */
 #ifdef CONFIG_X86_32
-	if (static_cpu_has(X86_FEATURE_XENPV))
-		load_sp0(task->thread.sp0);
-	else
-		this_cpu_write(cpu_tss_rw.x86_tss.sp1, task->thread.sp0);
+	this_cpu_write(cpu_tss_rw.x86_tss.sp1, task->thread.sp0);
 #else
 	/* Xen PV enters the kernel on the thread stack. */
-	if (static_cpu_has(X86_FEATURE_XENPV))
+	if (cpu_feature_enabled(X86_FEATURE_XENPV))
 		load_sp0(task_top_of_stack(task));
 #endif
 }