Commit c89191ce authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Borislav Petkov
Browse files

x86/entry: Convert SWAPGS to swapgs and remove the definition of SWAPGS 



XENPV doesn't use swapgs_restore_regs_and_return_to_usermode(),
error_entry() and the code between entry_SYSENTER_compat() and
entry_SYSENTER_compat_after_hwframe.

Change the PV-compatible SWAPGS to the ASM instruction swapgs in these
places.

Also remove the definition of SWAPGS since no more users.

Signed-off-by: default avatarLai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220503032107.680190-7-jiangshanlai@gmail.com
parent 64cbd0ac

arch/x86/entry/entry_64.S

+3 −3
Original line number Diff line number Diff line
@@ -1019,7 +1019,7 @@ SYM_CODE_START_LOCAL(error_entry) 
	 * We entered from user mode or we're pretending to have entered

	 * from user mode due to an IRET fault.

	 */

	SWAPGS

	swapgs

	FENCE_SWAPGS_USER_ENTRY

	/* We have user CR3.  Change to kernel CR3. */

	SWITCH_TO_KERNEL_CR3 scratch_reg=%rax
@@ -1051,7 +1051,7 @@ SYM_CODE_START_LOCAL(error_entry) 
	 * gsbase and proceed.  We'll fix up the exception and land in

	 * .Lgs_change's error handler with kernel gsbase.

	 */

	SWAPGS

	swapgs



	/*

	 * Issue an LFENCE to prevent GS speculation, regardless of whether it is a
@@ -1072,7 +1072,7 @@ SYM_CODE_START_LOCAL(error_entry) 
	 * We came from an IRET to user mode, so we have user

	 * gsbase and CR3.  Switch to kernel gsbase and CR3:

	 */

	SWAPGS

	swapgs

	FENCE_SWAPGS_USER_ENTRY

	SWITCH_TO_KERNEL_CR3 scratch_reg=%rax

arch/x86/entry/entry_64_compat.S

+1 −1
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ SYM_CODE_START(entry_SYSENTER_compat) 
	UNWIND_HINT_EMPTY

	ENDBR

	/* Interrupts are off on entry. */

	SWAPGS

	swapgs



	pushq	%rax

	SWITCH_TO_KERNEL_CR3 scratch_reg=%rax

arch/x86/include/asm/irqflags.h

+0 −8
Original line number Diff line number Diff line
@@ -137,14 +137,6 @@ static __always_inline void arch_local_irq_restore(unsigned long flags) 
	if (!arch_irqs_disabled_flags(flags))

		arch_local_irq_enable();

}

#else

#ifdef CONFIG_X86_64

#ifdef CONFIG_XEN_PV

#define SWAPGS	ALTERNATIVE "swapgs", "", X86_FEATURE_XENPV

#else

#define SWAPGS	swapgs

#endif

#endif

#endif /* !__ASSEMBLY__ */



#endif