[S390] Fix irq tracing and lockdep_sys_exit calls.

Current support for TRACE_IRQFLAGS and lockdep_sys_exit is broken.
IRQ flag tracing is broken for program checks. Even worse is that
the newly introduced calls to lockdep_sys_exit are in the critical
section code which is not supposed to call any C functions. In
addition the checks if locks are still held are also done when
returning to kernel code which is broken as well.
Fix all this by disabling interrupts and machine checks at the
exit paths and then do the appropriate checks and calls.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 73 insertions, 33 deletions

diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 05e26d1fdf40..e15c80efdd05 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -67,12 +67,28 @@ _TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK | _TIF_NEED_RESCHED | \
          brasl  %r14,trace_hardirqs_off
         .endm
 
-        .macro  LOCKDEP_SYS_EXIT
-         brasl  %r14,lockdep_sys_exit
+        .macro TRACE_IRQS_CHECK
+        tm      SP_PSW(%r15),0x03       # irqs enabled?
+        jz      0f
+        brasl   %r14,trace_hardirqs_on
+        j       1f
+0:      brasl   %r14,trace_hardirqs_off
+1:
         .endm
 #else
 #define TRACE_IRQS_ON
 #define TRACE_IRQS_OFF
+#define TRACE_IRQS_CHECK
+#endif
+
+#ifdef CONFIG_LOCKDEP
+        .macro  LOCKDEP_SYS_EXIT
+        tm      SP_PSW+1(%r15),0x01     # returning to user ?
+        jz      0f
+        brasl   %r14,lockdep_sys_exit
+0:
+        .endm
+#else
 #define LOCKDEP_SYS_EXIT
 #endif
 
@@ -222,8 +238,6 @@ sysc_saveall:
         llgh    %r7,__LC_SVC_INT_CODE   # get svc number from lowcore
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 sysc_vtime:
-        tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
-        jz      sysc_do_svc
         UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
 sysc_stime:
         UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
@@ -257,19 +271,34 @@ sysc_noemu:
 
 sysc_return:
         tm      SP_PSW+1(%r15),0x01     # returning to user ?
-        jno     sysc_leave
+        jno     sysc_restore
         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
+        .align  8
+        .globl sysc_restore_trace_psw
+sysc_restore_trace_psw:
+        .quad   0, sysc_restore_trace
+#endif
 
 #
 # recheck if there is more work to do
 #
 sysc_work_loop:
         tm      __TI_flags+7(%r9),_TIF_WORK_SVC
-        jz      sysc_leave        # there is no work to do
+        jz      sysc_restore      # there is no work to do
 #
 # One of the work bits is on. Find out which one.
 #
@@ -284,8 +313,8 @@ sysc_work:
         jo      sysc_restart
         tm      __TI_flags+7(%r9),_TIF_SINGLE_STEP
         jo      sysc_singlestep
-        LOCKDEP_SYS_EXIT
-        j       sysc_leave
+        j       sysc_restore
+sysc_work_done:
 
 #
 # _TIF_NEED_RESCHED is set, call schedule
@@ -445,6 +474,7 @@ pgm_check_handler:
 pgm_no_vtime:
 #endif
         lg      %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
+        TRACE_IRQS_OFF
         lgf     %r3,__LC_PGM_ILC        # load program interruption code
         lghi    %r8,0x7f
         ngr     %r8,%r3
@@ -484,6 +514,7 @@ pgm_per_std:
 pgm_no_vtime2:
 #endif
         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
@@ -504,12 +535,9 @@ pgm_svcper:
         SAVE_ALL_SYNC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
         CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
-        tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
-        jz      pgm_no_vtime3
         UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
         UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
-pgm_no_vtime3:
 #endif
         llgh    %r7,__LC_SVC_INT_CODE   # get svc number from lowcore
         lg      %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
@@ -529,7 +557,7 @@ kernel_per:
         lhi     %r0,__LC_PGM_OLD_PSW
         sth     %r0,SP_TRAP(%r15)       # set trap indication to pgm check
         la      %r2,SP_PTREGS(%r15)     # address of register-save area
-        larl    %r14,sysc_leave         # load adr. of system ret, no work
+        larl    %r14,sysc_restore       # load adr. of system ret, no work
         jg      do_single_step          # branch to do_single_step
 
 /*
@@ -554,26 +582,38 @@ io_no_vtime:
         TRACE_IRQS_OFF
         la      %r2,SP_PTREGS(%r15)     # address of register-save area
         brasl   %r14,do_IRQ             # call standard irq handler
-        TRACE_IRQS_ON
-
 io_return:
         tm      SP_PSW+1(%r15),0x01     # returning to user ?
 #ifdef CONFIG_PREEMPT
         jno     io_preempt              # no -> check for preemptive scheduling
 #else
-        jno     io_leave                # no-> skip resched & signal
+        jno     io_restore              # no-> skip resched & signal
 #endif
         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
+        .align  8
+        .globl io_restore_trace_psw
+io_restore_trace_psw:
+        .quad   0, io_restore_trace
+#endif
+
 #ifdef CONFIG_PREEMPT
 io_preempt:
         icm     %r0,15,__TI_precount(%r9)
-        jnz     io_leave
+        jnz     io_restore
         # switch to kernel stack
         lg      %r1,SP_R15(%r15)
         aghi    %r1,-SP_SIZE
@@ -582,12 +622,14 @@ io_preempt:
         lgr     %r15,%r1
 io_resume_loop:
         tm      __TI_flags+7(%r9),_TIF_NEED_RESCHED
-        jno     io_leave
+        jno     io_restore
         larl    %r1,.Lc_pactive
         mvc     __TI_precount(4,%r9),0(%r1)
+        TRACE_IRQS_ON
         stosm   __SF_EMPTY(%r15),0x03   # reenable interrupts
         brasl   %r14,schedule           # call schedule
         stnsm   __SF_EMPTY(%r15),0xfc   # disable I/O and ext. interrupts
+        TRACE_IRQS_OFF
         xc      __TI_precount(4,%r9),__TI_precount(%r9)
         j       io_resume_loop
 #endif
@@ -613,37 +655,39 @@ io_work_loop:
         jo      io_reschedule
         tm      __TI_flags+7(%r9),(_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK)
         jnz     io_sigpending
-        LOCKDEP_SYS_EXIT
-        j       io_leave
+        j       io_restore
+io_work_done:
 
 #
 # _TIF_MCCK_PENDING is set, call handler
 #
 io_mcck_pending:
-        TRACE_IRQS_OFF
         brasl   %r14,s390_handle_mcck   # TIF bit will be cleared by handler
-        TRACE_IRQS_ON
         j       io_work_loop
 
 #
 # _TIF_NEED_RESCHED is set, call schedule
 #
 io_reschedule:
+        TRACE_IRQS_ON
         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
         tm      __TI_flags+7(%r9),_TIF_WORK_INT
-        jz      io_leave                # there is no work to do
+        jz      io_restore              # there is no work to do
         j       io_work_loop
 
 #
 # _TIF_SIGPENDING or _TIF_RESTORE_SIGMASK is set, call do_signal
 #
 io_sigpending:
+        TRACE_IRQS_ON
         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
 
 /*
@@ -669,7 +713,6 @@ ext_no_vtime:
         la      %r2,SP_PTREGS(%r15)     # address of register-save area
         llgh    %r3,__LC_EXT_INT_CODE   # get interruption code
         brasl   %r14,do_extint
-        TRACE_IRQS_ON
         j       io_return
 
 __critical_end:
@@ -824,15 +867,15 @@ cleanup_table_system_call:
 cleanup_table_sysc_return:
         .quad   sysc_return, sysc_leave
 cleanup_table_sysc_leave:
-        .quad   sysc_leave, sysc_work_loop
+        .quad   sysc_leave, sysc_done
 cleanup_table_sysc_work_loop:
-        .quad   sysc_work_loop, sysc_reschedule
+        .quad   sysc_work_loop, sysc_work_done
 cleanup_table_io_return:
         .quad   io_return, io_leave
 cleanup_table_io_leave:
         .quad   io_leave, io_done
 cleanup_table_io_work_loop:
-        .quad   io_work_loop, io_mcck_pending
+        .quad   io_work_loop, io_work_done
 
 cleanup_critical:
         clc     8(8,%r12),BASED(cleanup_table_system_call)
@@ -901,8 +944,6 @@ cleanup_system_call:
 cleanup_vtime:
         clc     __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn+24)
         jhe     cleanup_stime
-        tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
-        jz      cleanup_novtime
         UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
 cleanup_stime:
         clc     __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn+32)
@@ -910,7 +951,6 @@ cleanup_stime:
         UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 cleanup_update:
         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
-cleanup_novtime:
 #endif
         mvc     __LC_RETURN_PSW+8(8),BASED(cleanup_table_system_call+8)
         la      %r12,__LC_RETURN_PSW
@@ -949,10 +989,10 @@ cleanup_sysc_leave:
 2:      la      %r12,__LC_RETURN_PSW
         br      %r14
 cleanup_sysc_leave_insn:
+        .quad   sysc_done - 4
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
-        .quad   sysc_leave + 16
+        .quad   sysc_done - 8
 #endif
-        .quad   sysc_leave + 12
 
 cleanup_io_return:
         mvc     __LC_RETURN_PSW(8),0(%r12)
@@ -979,10 +1019,10 @@ cleanup_io_leave:
 2:      la      %r12,__LC_RETURN_PSW
         br      %r14
 cleanup_io_leave_insn:
+        .quad   io_done - 4
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
-        .quad   io_leave + 20
+        .quad   io_done - 8
 #endif
-        .quad   io_leave + 16
 
 /*
  * Integer constants