[PATCH v5 14/17] x86/asm/entry/64: Migrate error and interrupt exit work to C

From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org, linux-kernel@vger.kernel.org
Cc: "Frédéric Weisbecker" <fweisbec@gmail.com>,
	"Rik van Riel" <riel@redhat.com>,
	"Oleg Nesterov" <oleg@redhat.com>,
	"Denys Vlasenko" <vda.linux@googlemail.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Kees Cook" <keescook@chromium.org>,
	"Brian Gerst" <brgerst@gmail.com>,
	paulmck@linux.vnet.ibm.com, "Andy Lutomirski" <luto@kernel.org>
Subject: [PATCH v5 14/17] x86/asm/entry/64: Migrate error and interrupt exit work to C
Date: Fri,  3 Jul 2015 12:44:31 -0700	[thread overview]
Message-ID: <60e90901eee611e59e958bfdbbe39969b4f88fe5.1435952415.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1435952415.git.luto@kernel.org>
In-Reply-To: <cover.1435952415.git.luto@kernel.org>

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 arch/x86/entry/entry_64.S        | 64 +++++++++++-----------------------------
 arch/x86/entry/entry_64_compat.S |  5 ++++
 2 files changed, 23 insertions(+), 46 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 83eb63d31da4..168ee264c345 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -508,7 +508,16 @@ END(irq_entries_start)
 
 	testb	$3, CS(%rsp)
 	jz	1f
+
+	/*
+	 * IRQ from user mode.  Switch to kernel gsbase and inform context
+	 * tracking that we're in kernel mode.
+	 */
 	SWAPGS
+#ifdef CONFIG_CONTEXT_TRACKING
+	call enter_from_user_mode
+#endif
+
 1:
 	/*
 	 * Save previous stack pointer, optionally switch to interrupt stack.
@@ -547,26 +556,13 @@ ret_from_intr:
 
 	testb	$3, CS(%rsp)
 	jz	retint_kernel
-	/* Interrupt came from user space */
-GLOBAL(retint_user)
-	GET_THREAD_INFO(%rcx)
 
-	/* %rcx: thread info. Interrupts are off. */
-retint_with_reschedule:
-	movl	$_TIF_WORK_MASK, %edi
-retint_check:
+	/* Interrupt came from user space */
 	LOCKDEP_SYS_EXIT_IRQ
-	movl	TI_flags(%rcx), %edx
-	andl	%edi, %edx
-	jnz	retint_careful
-
-retint_swapgs:					/* return to user-space */
-	/*
-	 * The iretq could re-enable interrupts:
-	 */
-	DISABLE_INTERRUPTS(CLBR_ANY)
+GLOBAL(retint_user)
+	mov	%rsp,%rdi
+	call	prepare_exit_to_usermode
 	TRACE_IRQS_IRETQ
-
 	SWAPGS
 	jmp	restore_regs_and_iret
 
@@ -644,35 +640,6 @@ native_irq_return_ldt:
 	popq	%rax
 	jmp	native_irq_return_iret
 #endif
-
-	/* edi: workmask, edx: work */
-retint_careful:
-	bt	$TIF_NEED_RESCHED, %edx
-	jnc	retint_signal
-	TRACE_IRQS_ON
-	ENABLE_INTERRUPTS(CLBR_NONE)
-	pushq	%rdi
-	SCHEDULE_USER
-	popq	%rdi
-	GET_THREAD_INFO(%rcx)
-	DISABLE_INTERRUPTS(CLBR_NONE)
-	TRACE_IRQS_OFF
-	jmp	retint_check
-
-retint_signal:
-	testl	$_TIF_DO_NOTIFY_MASK, %edx
-	jz	retint_swapgs
-	TRACE_IRQS_ON
-	ENABLE_INTERRUPTS(CLBR_NONE)
-	movq	$-1, ORIG_RAX(%rsp)
-	xorl	%esi, %esi			/* oldset */
-	movq	%rsp, %rdi			/* &pt_regs */
-	call	do_notify_resume
-	DISABLE_INTERRUPTS(CLBR_NONE)
-	TRACE_IRQS_OFF
-	GET_THREAD_INFO(%rcx)
-	jmp	retint_with_reschedule
-
 END(common_interrupt)
 
 /*
@@ -1088,7 +1055,12 @@ ENTRY(error_entry)
 	SWAPGS
 
 .Lerror_entry_from_usermode_after_swapgs:
+#ifdef CONFIG_CONTEXT_TRACKING
+	call enter_from_user_mode
+#endif
+
 .Lerror_entry_done:
+
 	TRACE_IRQS_OFF
 	ret
 
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 204528cf4359..55fa85837da2 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -455,6 +455,11 @@ ia32_badarg:
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
 
+	/* Now finish entering normal kernel mode. */
+#ifdef CONFIG_CONTEXT_TRACKING
+	call enter_from_user_mode
+#endif
+
 	/* And exit again. */
 	jmp retint_user
 
-- 
2.4.3

