[S390] improve irq tracing code in entry[64].S

The system call path in entry[64].S is run with interrupts enabled.
Remove the irq tracing check from the system call exit code. If a
program check interrupted a context enabled for interrupts do a
call to trace_irq_off_caller in the program check handler before
branching to the system call exit code.
Restructure the system call and io interrupt return code to avoid
avoid the lpsw[e] to disable machine checks.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 92 insertions, 105 deletions

diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index ca02b10a2c32..860cea1d1c8a 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -61,28 +61,33 @@ _TIF_SYSCALL = (_TIF_SYSCALL_TRACE>>8 | _TIF_SYSCALL_AUDIT>>8 | \
 
 #ifdef CONFIG_TRACE_IRQFLAGS
         .macro  TRACE_IRQS_ON
-         basr   %r2,%r0
-         brasl  %r14,trace_hardirqs_on_caller
+        basr    %r2,%r0
+        brasl   %r14,trace_hardirqs_on_caller
         .endm
 
         .macro  TRACE_IRQS_OFF
-         basr   %r2,%r0
-         brasl  %r14,trace_hardirqs_off_caller
+        basr    %r2,%r0
+        brasl   %r14,trace_hardirqs_off_caller
         .endm
 
-        .macro TRACE_IRQS_CHECK
-        basr    %r2,%r0
+        .macro TRACE_IRQS_CHECK_ON
         tm      SP_PSW(%r15),0x03       # irqs enabled?
         jz      0f
-        brasl   %r14,trace_hardirqs_on_caller
-        j       1f
-0:      brasl   %r14,trace_hardirqs_off_caller
-1:
+        TRACE_IRQS_ON
+0:
+        .endm
+
+        .macro TRACE_IRQS_CHECK_OFF
+        tm      SP_PSW(%r15),0x03       # irqs enabled?
+        jz      0f
+        TRACE_IRQS_OFF
+0:
         .endm
 #else
 #define TRACE_IRQS_ON
 #define TRACE_IRQS_OFF
-#define TRACE_IRQS_CHECK
+#define TRACE_IRQS_CHECK_ON
+#define TRACE_IRQS_CHECK_OFF
 #endif
 
 #ifdef CONFIG_LOCKDEP
@@ -267,29 +272,14 @@ sysc_noemu:
         stg     %r2,SP_R2(%r15) # store return value (change R2 on stack)
 
 sysc_return:
+        LOCKDEP_SYS_EXIT
+sysc_tif:
         tm      __TI_flags+7(%r9),_TIF_WORK_SVC
         jnz     sysc_work       # there is work to do (signals etc.)
 sysc_restore:
-#ifdef CONFIG_TRACE_IRQFLAGS
-        larl    %r1,sysc_restore_trace_psw
-        lpswe   0(%r1)
-sysc_restore_trace:
-        TRACE_IRQS_CHECK
-        LOCKDEP_SYS_EXIT
-#endif
-sysc_leave:
         RESTORE_ALL __LC_RETURN_PSW,1
 sysc_done:
 
-#ifdef CONFIG_TRACE_IRQFLAGS
-        .section .data,"aw",@progbits
-        .align  8
-        .globl sysc_restore_trace_psw
-sysc_restore_trace_psw:
-        .quad   0, sysc_restore_trace
-        .previous
-#endif
-
 #
 # There is work to do, but first we need to check if we return to userspace.
 #
@@ -300,7 +290,7 @@ sysc_work:
 #
 # One of the work bits is on. Find out which one.
 #
-sysc_work_loop:
+sysc_work_tif:
         tm      __TI_flags+7(%r9),_TIF_MCCK_PENDING
         jo      sysc_mcck_pending
         tm      __TI_flags+7(%r9),_TIF_NEED_RESCHED
@@ -319,14 +309,14 @@ sysc_work_loop:
 # _TIF_NEED_RESCHED is set, call schedule
 #
 sysc_reschedule:
-        larl    %r14,sysc_work_loop
-        jg      schedule                # return point is sysc_work_loop
+        larl    %r14,sysc_return
+        jg      schedule                # return point is sysc_return
 
 #
 # _TIF_MCCK_PENDING is set, call handler
 #
 sysc_mcck_pending:
-        larl    %r14,sysc_work_loop
+        larl    %r14,sysc_return
         jg      s390_handle_mcck        # TIF bit will be cleared by handler
 
 #
@@ -340,14 +330,14 @@ sysc_sigpending:
         jo      sysc_restart
         tm      __TI_flags+7(%r9),_TIF_SINGLE_STEP
         jo      sysc_singlestep
-        j       sysc_work_loop
+        j       sysc_return
 
 #
 # _TIF_NOTIFY_RESUME is set, call do_notify_resume
 #
 sysc_notify_resume:
         la      %r2,SP_PTREGS(%r15)     # load pt_regs
-        larl    %r14,sysc_work_loop
+        larl    %r14,sysc_return
         jg      do_notify_resume        # call do_notify_resume
 
 #
@@ -367,7 +357,7 @@ sysc_singlestep:
         ni      __TI_flags+7(%r9),255-_TIF_SINGLE_STEP  # clear TIF_SINGLE_STEP
         xc      SP_SVCNR(2,%r15),SP_SVCNR(%r15)         # clear svc number
         la      %r2,SP_PTREGS(%r15)     # address of register-save area
-        larl    %r14,sysc_work_loop     # load adr. of system return
+        larl    %r14,sysc_return        # load adr. of system return
         jg      do_single_step          # branch to do_sigtrap
 
 #
@@ -433,12 +423,14 @@ kernel_execve:
         br      %r14
         # execve succeeded.
 0:      stnsm   __SF_EMPTY(%r15),0xfc   # disable interrupts
+#       TRACE_IRQS_OFF
         lg      %r15,__LC_KERNEL_STACK  # load ksp
         aghi    %r15,-SP_SIZE           # make room for registers & psw
         lg      %r13,__LC_SVC_NEW_PSW+8
         lg      %r9,__LC_THREAD_INFO
         mvc     SP_PTREGS(__PT_SIZE,%r15),0(%r12)       # copy pt_regs
         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
+#       TRACE_IRQS_ON
         stosm   __SF_EMPTY(%r15),0x03   # reenable interrupts
         brasl   %r14,execve_tail
         j       sysc_return
@@ -474,9 +466,9 @@ pgm_check_handler:
         UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 pgm_no_vtime:
+        TRACE_IRQS_CHECK_OFF
         lg      %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
         mvc     SP_ARGS(8,%r15),__LC_LAST_BREAK
-        TRACE_IRQS_OFF
         lgf     %r3,__LC_PGM_ILC        # load program interruption code
         lghi    %r8,0x7f
         ngr     %r8,%r3
@@ -485,8 +477,10 @@ pgm_do_call:
         larl    %r1,pgm_check_table
         lg      %r1,0(%r8,%r1)          # load address of handler routine
         la      %r2,SP_PTREGS(%r15)     # address of register-save area
-        larl    %r14,sysc_return
-        br      %r1                     # branch to interrupt-handler
+        basr    %r14,%r1                # branch to interrupt-handler
+pgm_exit:
+        TRACE_IRQS_CHECK_ON
+        j       sysc_return
 
 #
 # handle per exception
@@ -513,8 +507,8 @@ pgm_per_std:
         UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 pgm_no_vtime2:
+        TRACE_IRQS_CHECK_OFF
         lg      %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
-        TRACE_IRQS_OFF
         lg      %r1,__TI_task(%r9)
         tm      SP_PSW+1(%r15),0x01     # kernel per event ?
         jz      kernel_per
@@ -525,7 +519,7 @@ pgm_no_vtime2:
         lgf     %r3,__LC_PGM_ILC        # load program interruption code
         lghi    %r8,0x7f
         ngr     %r8,%r3                 # clear per-event-bit and ilc
-        je      sysc_return
+        je      pgm_exit
         j       pgm_do_call
 
 #
@@ -539,14 +533,15 @@ pgm_svcper:
         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
         llgh    %r7,__LC_SVC_INT_CODE   # get svc number from lowcore
         lg      %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
+        TRACE_IRQS_OFF
         lg      %r8,__TI_task(%r9)
         mvc     __THREAD_per+__PER_atmid(2,%r8),__LC_PER_ATMID
         mvc     __THREAD_per+__PER_address(8,%r8),__LC_PER_ADDRESS
         mvc     __THREAD_per+__PER_access_id(1,%r8),__LC_PER_ACCESS_ID
         oi      __TI_flags+7(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP
         TRACE_IRQS_ON
-        lmg     %r2,%r6,SP_R2(%r15)     # load svc arguments
         stosm   __SF_EMPTY(%r15),0x03   # reenable interrupts
+        lmg     %r2,%r6,SP_R2(%r15)     # load svc arguments
         j       sysc_do_svc
 
 #
@@ -555,8 +550,8 @@ pgm_svcper:
 kernel_per:
         xc      SP_SVCNR(2,%r15),SP_SVCNR(%r15) # clear svc number
         la      %r2,SP_PTREGS(%r15)     # address of register-save area
-        larl    %r14,sysc_restore       # load adr. of system ret, no work
-        jg      do_single_step          # branch to do_single_step
+        brasl   %r14,do_single_step
+        j       pgm_exit
 
 /*
  * IO interrupt handler routine
@@ -579,29 +574,15 @@ io_no_vtime:
         la      %r2,SP_PTREGS(%r15)     # address of register-save area
         brasl   %r14,do_IRQ             # call standard irq handler
 io_return:
+        LOCKDEP_SYS_EXIT
+        TRACE_IRQS_ON
+io_tif:
         tm      __TI_flags+7(%r9),_TIF_WORK_INT
         jnz     io_work                 # there is work to do (signals etc.)
 io_restore:
-#ifdef CONFIG_TRACE_IRQFLAGS
-        larl    %r1,io_restore_trace_psw
-        lpswe   0(%r1)
-io_restore_trace:
-        TRACE_IRQS_CHECK
-        LOCKDEP_SYS_EXIT
-#endif
-io_leave:
         RESTORE_ALL __LC_RETURN_PSW,0
 io_done:
 
-#ifdef CONFIG_TRACE_IRQFLAGS
-        .section .data,"aw",@progbits
-        .align  8
-        .globl io_restore_trace_psw
-io_restore_trace_psw:
-        .quad   0, io_restore_trace
-        .previous
-#endif
-
 #
 # There is work todo, find out in which context we have been interrupted:
 # 1) if we return to user space we can do all _TIF_WORK_INT work
@@ -627,18 +608,22 @@ io_work:
         # check for preemptive scheduling
         icm     %r0,15,__TI_precount(%r9)
         jnz     io_restore              # preemption is disabled
+        tm      __TI_flags+7(%r12),_TIF_NEED_RESCHED
+        jno     io_restore
         # switch to kernel stack
         lg      %r1,SP_R15(%r15)
         aghi    %r1,-SP_SIZE
         mvc     SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)
         xc      __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1) # clear back chain
         lgr     %r15,%r1
-io_resume_loop:
-        larl    %r14,io_resume_loop
-        tm      __TI_flags+7(%r12),_TIF_NEED_RESCHED
-        jgo     preempt_schedule_irq
-#endif
+        # TRACE_IRQS_ON already done at io_return, call
+        # TRACE_IRQS_OFF to keep things symmetrical
+        TRACE_IRQS_OFF
+        brasl   %r14,preempt_schedule_irq
+        j       io_return
+#else
         j       io_restore
+#endif
 
 #
 # Need to do work before returning to userspace, switch to kernel stack
@@ -655,7 +640,7 @@ io_work_user:
 # Checked are: _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_NEED_RESCHED
 #              and _TIF_MCCK_PENDING
 #
-io_work_loop:
+io_work_tif:
         tm      __TI_flags+7(%r9),_TIF_MCCK_PENDING
         jo      io_mcck_pending
         tm      __TI_flags+7(%r9),_TIF_NEED_RESCHED
@@ -670,43 +655,45 @@ io_work_loop:
 # _TIF_MCCK_PENDING is set, call handler
 #
 io_mcck_pending:
+        # TRACE_IRQS_ON already done at io_return
         brasl   %r14,s390_handle_mcck   # TIF bit will be cleared by handler
-        j       io_work_loop
+        TRACE_IRQS_OFF
+        j       io_return
 
 #
 # _TIF_NEED_RESCHED is set, call schedule
 #
 io_reschedule:
-        TRACE_IRQS_ON
+        # TRACE_IRQS_ON already done at io_return
         stosm   __SF_EMPTY(%r15),0x03   # reenable interrupts
         brasl   %r14,schedule           # call scheduler
         stnsm   __SF_EMPTY(%r15),0xfc   # disable I/O and ext. interrupts
         TRACE_IRQS_OFF
-        j       io_work_loop
+        j       io_return
 
 #
 # _TIF_SIGPENDING or is set, call do_signal
 #
 io_sigpending:
-        TRACE_IRQS_ON
+        # TRACE_IRQS_ON already done at io_return
         stosm   __SF_EMPTY(%r15),0x03   # reenable interrupts
         la      %r2,SP_PTREGS(%r15)     # load pt_regs
         brasl   %r14,do_signal          # call do_signal
         stnsm   __SF_EMPTY(%r15),0xfc   # disable I/O and ext. interrupts
         TRACE_IRQS_OFF
-        j       io_work_loop
+        j       io_return
 
 #
 # _TIF_NOTIFY_RESUME or is set, call do_notify_resume
 #
 io_notify_resume:
-        TRACE_IRQS_ON
+        # TRACE_IRQS_ON already done at io_return
         stosm   __SF_EMPTY(%r15),0x03   # reenable interrupts
         la      %r2,SP_PTREGS(%r15)     # load pt_regs
         brasl   %r14,do_notify_resume   # call do_notify_resume
         stnsm   __SF_EMPTY(%r15),0xfc   # disable I/O and ext. interrupts
         TRACE_IRQS_OFF
-        j       io_work_loop
+        j       io_return
 
 /*
  * External interrupt handler routine
@@ -883,14 +870,14 @@ stack_overflow:
 
 cleanup_table_system_call:
         .quad   system_call, sysc_do_svc
-cleanup_table_sysc_return:
-        .quad   sysc_return, sysc_leave
-cleanup_table_sysc_leave:
-        .quad   sysc_leave, sysc_done
-cleanup_table_io_return:
-        .quad   io_return, io_leave
-cleanup_table_io_leave:
-        .quad   io_leave, io_done
+cleanup_table_sysc_tif:
+        .quad   sysc_tif, sysc_restore
+cleanup_table_sysc_restore:
+        .quad   sysc_restore, sysc_done
+cleanup_table_io_tif:
+        .quad   io_tif, io_restore
+cleanup_table_io_restore:
+        .quad   io_restore, io_done
 
 cleanup_critical:
         clc     8(8,%r12),BASED(cleanup_table_system_call)
@@ -898,25 +885,25 @@ cleanup_critical:
         clc     8(8,%r12),BASED(cleanup_table_system_call+8)
         jl      cleanup_system_call
 0:
-        clc     8(8,%r12),BASED(cleanup_table_sysc_return)
+        clc     8(8,%r12),BASED(cleanup_table_sysc_tif)
         jl      0f
-        clc     8(8,%r12),BASED(cleanup_table_sysc_return+8)
-        jl      cleanup_sysc_return
+        clc     8(8,%r12),BASED(cleanup_table_sysc_tif+8)
+        jl      cleanup_sysc_tif
 0:
-        clc     8(8,%r12),BASED(cleanup_table_sysc_leave)
+        clc     8(8,%r12),BASED(cleanup_table_sysc_restore)
         jl      0f
-        clc     8(8,%r12),BASED(cleanup_table_sysc_leave+8)
-        jl      cleanup_sysc_leave
+        clc     8(8,%r12),BASED(cleanup_table_sysc_restore+8)
+        jl      cleanup_sysc_restore
 0:
-        clc     8(8,%r12),BASED(cleanup_table_io_return)
+        clc     8(8,%r12),BASED(cleanup_table_io_tif)
         jl      0f
-        clc     8(8,%r12),BASED(cleanup_table_io_return+8)
-        jl      cleanup_io_return
+        clc     8(8,%r12),BASED(cleanup_table_io_tif+8)
+        jl      cleanup_io_tif
 0:
-        clc     8(8,%r12),BASED(cleanup_table_io_leave)
+        clc     8(8,%r12),BASED(cleanup_table_io_restore)
         jl      0f
-        clc     8(8,%r12),BASED(cleanup_table_io_leave+8)
-        jl      cleanup_io_leave
+        clc     8(8,%r12),BASED(cleanup_table_io_restore+8)
+        jl      cleanup_io_restore
 0:
         br      %r14
 
@@ -963,16 +950,16 @@ cleanup_system_call_insn:
         .quad   sysc_stime
         .quad   sysc_update
 
-cleanup_sysc_return:
+cleanup_sysc_tif:
         mvc     __LC_RETURN_PSW(8),0(%r12)
-        mvc     __LC_RETURN_PSW+8(8),BASED(cleanup_table_sysc_return)
+        mvc     __LC_RETURN_PSW+8(8),BASED(cleanup_table_sysc_tif)
         la      %r12,__LC_RETURN_PSW
         br      %r14
 
-cleanup_sysc_leave:
-        clc     8(8,%r12),BASED(cleanup_sysc_leave_insn)
+cleanup_sysc_restore:
+        clc     8(8,%r12),BASED(cleanup_sysc_restore_insn)
         je      3f
-        clc     8(8,%r12),BASED(cleanup_sysc_leave_insn+8)
+        clc     8(8,%r12),BASED(cleanup_sysc_restore_insn+8)
         jhe     0f
         mvc     __LC_EXIT_TIMER(8),__LC_ASYNC_ENTER_TIMER
 0:      mvc     __LC_RETURN_PSW(16),SP_PSW(%r15)
@@ -985,20 +972,20 @@ cleanup_sysc_leave:
         lg      %r15,SP_R15(%r15)
 3:      la      %r12,__LC_RETURN_PSW
         br      %r14
-cleanup_sysc_leave_insn:
+cleanup_sysc_restore_insn:
         .quad   sysc_done - 4
         .quad   sysc_done - 16
 
-cleanup_io_return:
+cleanup_io_tif:
         mvc     __LC_RETURN_PSW(8),0(%r12)
-        mvc     __LC_RETURN_PSW+8(8),BASED(cleanup_table_io_return)
+        mvc     __LC_RETURN_PSW+8(8),BASED(cleanup_table_io_tif)
         la      %r12,__LC_RETURN_PSW
         br      %r14
 
-cleanup_io_leave:
-        clc     8(8,%r12),BASED(cleanup_io_leave_insn)
+cleanup_io_restore:
+        clc     8(8,%r12),BASED(cleanup_io_restore_insn)
         je      3f
-        clc     8(8,%r12),BASED(cleanup_io_leave_insn+8)
+        clc     8(8,%r12),BASED(cleanup_io_restore_insn+8)
         jhe     0f
         mvc     __LC_EXIT_TIMER(8),__LC_ASYNC_ENTER_TIMER
 0:      mvc     __LC_RETURN_PSW(16),SP_PSW(%r15)
@@ -1011,7 +998,7 @@ cleanup_io_leave:
         lg      %r15,SP_R15(%r15)
 3:      la      %r12,__LC_RETURN_PSW
         br      %r14
-cleanup_io_leave_insn:
+cleanup_io_restore_insn:
         .quad   io_done - 4
         .quad   io_done - 16