[PATCH v5 11/17] x86/entry/64: Migrate 64-bit and compat syscalls to new exit hooks

Andy Lutomirski
2015-07-03T19:47:23Z

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

Signed-off-by: Andy Lutomirski <luto@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 ccfcba90de6e..4ca5b782ed70 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 efe0b1e499fa..204528cf4359 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -209,10 +209,10 @@ 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
@@ -231,7 +231,7 @@ 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

sysenter_auditsys:
--
2.4.3