[tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

tip-bot for Andy Lutomirski
2015-07-07T10:54:42Z

Commit-ID: 02bc7768fe447ae305e924b931fa629073a4a1b9
Gitweb: http://git.kernel.org/tip/02bc7768fe447ae305e924b931fa629073a4a1b9
Author: Andy Lutomirski <luto@kernel.org>
AuthorDate: Fri, 3 Jul 2015 12:44:31 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 7 Jul 2015 10:59:08 +0200

x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/60e90901eee611e59e958bfdbbe39969b4f88fe5.1435952415.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@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 83eb63d..168ee26 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 d9bbd31..25aca51 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -458,6 +458,11 @@ 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