[PATCH V6 6/8] x86/entry: Convert SWAPGS to swapgs and remove the definition of SWAPGS

From: Lai Jiangshan <jiangshanlai@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Borislav Petkov <bp@alien8.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Juergen Gross <jgross@suse.com>,
	x86@kernel.org, Lai Jiangshan <jiangshan.ljs@antgroup.com>,
	Ingo Molnar <mingo@redhat.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Kirill A. Shutemov" <kirill@shutemov.name>
Subject: [PATCH V6 6/8] x86/entry: Convert SWAPGS to swapgs and remove the definition of SWAPGS
Date: Thu, 21 Apr 2022 22:10:53 +0800	[thread overview]
Message-ID: <20220421141055.316239-7-jiangshanlai@gmail.com> (raw)
In-Reply-To: <20220421141055.316239-1-jiangshanlai@gmail.com>

From: Lai Jiangshan <jiangshan.ljs@antgroup.com>

XENPV doesn't use swapgs_restore_regs_and_return_to_usermode(),
error_entry() and entry_SYSENTER_compat().

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

Also remove the definition of SWAPGS since there is no user of the
SWAPGS anymore.

Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
---
 arch/x86/entry/entry_64.S        | 6 +++---
 arch/x86/entry/entry_64_compat.S | 2 +-
 arch/x86/include/asm/irqflags.h  | 8 --------
 3 files changed, 4 insertions(+), 12 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 062aa9d95961..312186612f4e 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -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
 
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 4fdb007cddbd..c5aeb0819707 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -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
diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index 111104d1c2cd..7793e52d6237 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -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
-- 
2.19.1.6.gb485710b

