[tip:x86/asm] x86/entry/64: Migrate 64-bit and compat syscalls to the new exit handlers and remove old assembly code

tip-bot for Andy Lutomirski
2015-07-07T10:53:40Z

Commit-ID: 29ea1b258b98a862e59d72556714b75051ae93fb
Gitweb: http://git.kernel.org/tip/29ea1b258b98a862e59d72556714b75051ae93fb
Author: Andy Lutomirski <luto@kernel.org>
AuthorDate: Fri, 3 Jul 2015 12:44:28 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 7 Jul 2015 10:59:07 +0200

x86/entry/64: Migrate 64-bit and compat syscalls to the new exit handlers and remove old assembly code

These need to be migrated together, as the compat case used to
jump into the middle of the 64-bit exit code.

Remove the 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/d4d1d70de08ac3640badf50048a9e8f18fe2497f.1435952415.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/entry_64.S | 69 +++++-----------------------------------
arch/x86/entry/entry_64_compat.S | 6 ++--
2 files changed, 11 insertions(+), 64 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index ccfcba9..4ca5b78 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -229,6 +229,11 @@ entry_SYSCALL_64_fastpath:
*/
USERGS_SYSRET64

+GLOBAL(int_ret_from_sys_call_irqs_off)
+ TRACE_IRQS_ON
+ ENABLE_INTERRUPTS(CLBR_NONE)
+ jmp int_ret_from_sys_call
+
/* Do syscall entry tracing */
tracesys:
movq %rsp, %rdi
@@ -272,69 +277,11 @@ tracesys_phase2:
* Has correct iret frame.
*/
GLOBAL(int_ret_from_sys_call)
- DISABLE_INTERRUPTS(CLBR_NONE)
-int_ret_from_sys_call_irqs_off: /* jumps come here from the irqs-off SYSRET path */
- TRACE_IRQS_OFF
- movl $_TIF_ALLWORK_MASK, %edi
- /* edi: mask to check */
-GLOBAL(int_with_check)
- LOCKDEP_SYS_EXIT_IRQ
- GET_THREAD_INFO(%rcx)
- movl TI_flags(%rcx), %edx
- andl %edi, %edx
- jnz int_careful
- andl $~TS_COMPAT, TI_status(%rcx)
- jmp syscall_return
-
- /*
- * Either reschedule or signal or syscall exit tracking needed.
- * First do a reschedule test.
- * edx: work, edi: workmask
- */
-int_careful:
- bt $TIF_NEED_RESCHED, %edx
- jnc int_very_careful
- TRACE_IRQS_ON
- ENABLE_INTERRUPTS(CLBR_NONE)
- pushq %rdi
- SCHEDULE_USER
- popq %rdi
- DISABLE_INTERRUPTS(CLBR_NONE)
- TRACE_IRQS_OFF
- jmp int_with_check
-
- /* handle signals and tracing -- both require a full pt_regs */
-int_very_careful:
- TRACE_IRQS_ON
- ENABLE_INTERRUPTS(CLBR_NONE)
SAVE_EXTRA_REGS
- /* Check for syscall exit trace */
- testl $_TIF_WORK_SYSCALL_EXIT, %edx
- jz int_signal
- pushq %rdi
- leaq 8(%rsp), %rdi /* &ptregs -> arg1 */
- call syscall_trace_leave
- popq %rdi
- andl $~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU), %edi
- jmp int_restore_rest
-
-int_signal:
- testl $_TIF_DO_NOTIFY_MASK, %edx
- jz 1f
- movq %rsp, %rdi /* &ptregs -> arg1 */
- xorl %esi, %esi /* oldset -> arg2 */
- call do_notify_resume
-1: movl $_TIF_WORK_MASK, %edi
-int_restore_rest:
+ movq %rsp, %rdi
+ call syscall_return_slowpath /* returns with IRQs disabled */
RESTORE_EXTRA_REGS
- DISABLE_INTERRUPTS(CLBR_NONE)
- TRACE_IRQS_OFF
- jmp int_with_check
-
-syscall_return:
- /* The IRETQ could re-enable interrupts: */
- DISABLE_INTERRUPTS(CLBR_ANY)
- TRACE_IRQS_IRETQ
+ TRACE_IRQS_IRETQ /* we're about to change IF */

/*
* Try to use SYSRET instead of IRET if we're returning to
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index e5ebdd9..d9bbd31 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -210,10 +210,10 @@ sysexit_from_sys_call:
.endm

.macro auditsys_exit exit
- testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
- jnz ia32_ret_from_sys_call
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_NONE)
+ testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+ jnz ia32_ret_from_sys_call
movl %eax, %esi /* second arg, syscall return value */
cmpl $-MAX_ERRNO, %eax /* is it an error ? */
jbe 1f
@@ -232,7 +232,7 @@ sysexit_from_sys_call:
movq %rax, R10(%rsp)
movq %rax, R9(%rsp)
movq %rax, R8(%rsp)
- jmp int_with_check
+ jmp int_ret_from_sys_call_irqs_off
.endm