[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, 76 insertions, 33 deletions

diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 139ca153d5cc..764d56177cb5 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -69,13 +69,31 @@ STACK_SIZE  = 1 << STACK_SHIFT
         basr    %r14,%r1
         .endm
 
-        .macro  LOCKDEP_SYS_EXIT
-        l       %r1,BASED(.Llockdep_sys_exit)
+        .macro  TRACE_IRQS_CHECK
+        tm      SP_PSW(%r15),0x03       # irqs enabled?
+        jz      0f
+        l       %r1,BASED(.Ltrace_irq_on)
         basr    %r14,%r1
+        j       1f
+0:      l       %r1,BASED(.Ltrace_irq_off)
+        basr    %r14,%r1
+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
+        l       %r1,BASED(.Llockdep_sys_exit)
+        basr    %r14,%r1
+0:
+        .endm
+#else
 #define LOCKDEP_SYS_EXIT
 #endif
 
@@ -234,8 +252,6 @@ sysc_saveall:
         lh      %r7,0x8a          # get svc number from lowcore
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 sysc_vtime:
-        tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
-        bz      BASED(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
@@ -263,19 +279,34 @@ sysc_do_restart:
 
 sysc_return:
         tm      SP_PSW+1(%r15),0x01     # returning to user ?
-        bno     BASED(sysc_leave)
+        bno     BASED(sysc_restore)
         tm      __TI_flags+3(%r9),_TIF_WORK_SVC
         bnz     BASED(sysc_work)  # there is work to do (signals etc.)
+sysc_restore:
+#ifdef CONFIG_TRACE_IRQFLAGS
+        la      %r1,BASED(sysc_restore_trace_psw)
+        lpsw    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:
+        .long   0, sysc_restore_trace + 0x80000000
+#endif
 
 #
 # recheck if there is more work to do
 #
 sysc_work_loop:
         tm      __TI_flags+3(%r9),_TIF_WORK_SVC
-        bz      BASED(sysc_leave)       # there is no work to do
+        bz      BASED(sysc_restore)     # there is no work to do
 #
 # One of the work bits is on. Find out which one.
 #
@@ -290,8 +321,8 @@ sysc_work:
         bo      BASED(sysc_restart)
         tm      __TI_flags+3(%r9),_TIF_SINGLE_STEP
         bo      BASED(sysc_singlestep)
-        LOCKDEP_SYS_EXIT
-        b       BASED(sysc_leave)
+        b       BASED(sysc_restore)
+sysc_work_done:
 
 #
 # _TIF_NEED_RESCHED is set, call schedule
@@ -458,6 +489,7 @@ pgm_check_handler:
 pgm_no_vtime:
 #endif
         l       %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
+        TRACE_IRQS_OFF
         l       %r3,__LC_PGM_ILC        # load program interruption code
         la      %r8,0x7f
         nr      %r8,%r3
@@ -497,6 +529,7 @@ pgm_per_std:
 pgm_no_vtime2:
 #endif
         l       %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
+        TRACE_IRQS_OFF
         l       %r1,__TI_task(%r9)
         mvc     __THREAD_per+__PER_atmid(2,%r1),__LC_PER_ATMID
         mvc     __THREAD_per+__PER_address(4,%r1),__LC_PER_ADDRESS
@@ -517,15 +550,13 @@ 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 ?
-        bz      BASED(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
         lh      %r7,0x8a                # get svc number from lowcore
         l       %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
+        TRACE_IRQS_OFF
         l       %r1,__TI_task(%r9)
         mvc     __THREAD_per+__PER_atmid(2,%r1),__LC_PER_ATMID
         mvc     __THREAD_per+__PER_address(4,%r1),__LC_PER_ADDRESS
@@ -542,7 +573,7 @@ kernel_per:
         mvi     SP_TRAP+1(%r15),0x28    # set trap indication to pgm check
         la      %r2,SP_PTREGS(%r15)     # address of register-save area
         l       %r1,BASED(.Lhandle_per) # load adr. of per handler
-        la      %r14,BASED(sysc_leave)  # load adr. of system return
+        la      %r14,BASED(sysc_restore)# load adr. of system return
         br      %r1                     # branch to do_single_step
 
 /*
@@ -569,26 +600,38 @@ io_no_vtime:
         l       %r1,BASED(.Ldo_IRQ)     # load address of do_IRQ
         la      %r2,SP_PTREGS(%r15)     # address of register-save area
         basr    %r14,%r1                # branch to standard irq handler
-        TRACE_IRQS_ON
-
 io_return:
         tm      SP_PSW+1(%r15),0x01     # returning to user ?
 #ifdef CONFIG_PREEMPT
         bno     BASED(io_preempt)       # no -> check for preemptive scheduling
 #else
-        bno     BASED(io_leave)         # no-> skip resched & signal
+        bno     BASED(io_restore)       # no-> skip resched & signal
 #endif
         tm      __TI_flags+3(%r9),_TIF_WORK_INT
         bnz     BASED(io_work)          # there is work to do (signals etc.)
+io_restore:
+#ifdef CONFIG_TRACE_IRQFLAGS
+        la      %r1,BASED(io_restore_trace_psw)
+        lpsw    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:
+        .long   0, io_restore_trace + 0x80000000
+#endif
+
 #ifdef CONFIG_PREEMPT
 io_preempt:
         icm     %r0,15,__TI_precount(%r9)
-        bnz     BASED(io_leave)
+        bnz     BASED(io_restore)
         l       %r1,SP_R15(%r15)
         s       %r1,BASED(.Lc_spsize)
         mvc     SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)
@@ -596,12 +639,14 @@ io_preempt:
         lr      %r15,%r1
 io_resume_loop:
         tm      __TI_flags+3(%r9),_TIF_NEED_RESCHED
-        bno     BASED(io_leave)
+        bno     BASED(io_restore)
         mvc     __TI_precount(4,%r9),BASED(.Lc_pactive)
+        TRACE_IRQS_ON
         stosm   __SF_EMPTY(%r15),0x03  # reenable interrupts
         l       %r1,BASED(.Lschedule)
         basr    %r14,%r1               # call schedule
         stnsm   __SF_EMPTY(%r15),0xfc  # disable I/O and ext. interrupts
+        TRACE_IRQS_OFF
         xc      __TI_precount(4,%r9),__TI_precount(%r9)
         b       BASED(io_resume_loop)
 #endif
@@ -627,40 +672,42 @@ io_work_loop:
         bo      BASED(io_reschedule)
         tm      __TI_flags+3(%r9),(_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK)
         bnz     BASED(io_sigpending)
-        LOCKDEP_SYS_EXIT
-        b       BASED(io_leave)
+        b       BASED(io_restore)
+io_work_done:
 
 #
 # _TIF_MCCK_PENDING is set, call handler
 #
 io_mcck_pending:
-        TRACE_IRQS_OFF
         l       %r1,BASED(.Ls390_handle_mcck)
         basr    %r14,%r1                # TIF bit will be cleared by handler
-        TRACE_IRQS_ON
         b       BASED(io_work_loop)
 
 #
 # _TIF_NEED_RESCHED is set, call schedule
 #
 io_reschedule:
+        TRACE_IRQS_ON
         l       %r1,BASED(.Lschedule)
         stosm   __SF_EMPTY(%r15),0x03   # reenable interrupts
         basr    %r14,%r1                # call scheduler
         stnsm   __SF_EMPTY(%r15),0xfc   # disable I/O and ext. interrupts
+        TRACE_IRQS_OFF
         tm      __TI_flags+3(%r9),_TIF_WORK_INT
-        bz      BASED(io_leave)         # there is no work to do
+        bz      BASED(io_restore)       # there is no work to do
         b       BASED(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
         l       %r1,BASED(.Ldo_signal)
         basr    %r14,%r1                # call do_signal
         stnsm   __SF_EMPTY(%r15),0xfc   # disable I/O and ext. interrupts
+        TRACE_IRQS_OFF
         b       BASED(io_work_loop)
 
 /*
@@ -688,7 +735,6 @@ ext_no_vtime:
         lh      %r3,__LC_EXT_INT_CODE   # get interruption code
         l       %r1,BASED(.Ldo_extint)
         basr    %r14,%r1
-        TRACE_IRQS_ON
         b       BASED(io_return)
 
 __critical_end:
@@ -853,15 +899,15 @@ cleanup_table_system_call:
 cleanup_table_sysc_return:
         .long   sysc_return + 0x80000000, sysc_leave + 0x80000000
 cleanup_table_sysc_leave:
-        .long   sysc_leave + 0x80000000, sysc_work_loop + 0x80000000
+        .long   sysc_leave + 0x80000000, sysc_done + 0x80000000
 cleanup_table_sysc_work_loop:
-        .long   sysc_work_loop + 0x80000000, sysc_reschedule + 0x80000000
+        .long   sysc_work_loop + 0x80000000, sysc_work_done + 0x80000000
 cleanup_table_io_return:
         .long   io_return + 0x80000000, io_leave + 0x80000000
 cleanup_table_io_leave:
         .long   io_leave + 0x80000000, io_done + 0x80000000
 cleanup_table_io_work_loop:
-        .long   io_work_loop + 0x80000000, io_mcck_pending + 0x80000000
+        .long   io_work_loop + 0x80000000, io_work_done + 0x80000000
 
 cleanup_critical:
         clc     4(4,%r12),BASED(cleanup_table_system_call)
@@ -930,8 +976,6 @@ cleanup_system_call:
 cleanup_vtime:
         clc     __LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn+12)
         bhe     BASED(cleanup_stime)
-        tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
-        bz      BASED(cleanup_novtime)
         UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
 cleanup_stime:
         clc     __LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn+16)
@@ -939,7 +983,6 @@ 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+4(4),BASED(cleanup_table_system_call+4)
         la      %r12,__LC_RETURN_PSW
@@ -978,10 +1021,10 @@ cleanup_sysc_leave:
 2:      la      %r12,__LC_RETURN_PSW
         br      %r14
 cleanup_sysc_leave_insn:
+        .long   sysc_done - 4 + 0x80000000
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
-        .long   sysc_leave + 14 + 0x80000000
+        .long   sysc_done - 8 + 0x80000000
 #endif
-        .long   sysc_leave + 10 + 0x80000000
 
 cleanup_io_return:
         mvc     __LC_RETURN_PSW(4),0(%r12)
@@ -1008,10 +1051,10 @@ cleanup_io_leave:
 2:      la      %r12,__LC_RETURN_PSW
         br      %r14
 cleanup_io_leave_insn:
+        .long   io_done - 4 + 0x80000000
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
-        .long   io_leave + 18 + 0x80000000
+        .long   io_done - 8 + 0x80000000
 #endif
-        .long   io_leave + 14 + 0x80000000
 
 /*
  * Integer constants