From 34525e1f7e8dc47834b52d19b02c94b250df6f1f Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky <schwidefsky@de.ibm.com> Date: Wed, 25 Jan 2017 12:54:17 +0100 Subject: [PATCH] s390: store breaking event address only for program checks The principles of operations specifies that the breaking event address is stored to the address 0x110 in the prefix page only for program checks. The last branch in user space is lost as soon as a branch in kernel space is executed after e.g. an svc. This makes it impossible to accurately maintain the breaking event address for a user space process. Simplify the code, just copy the current breaking event address from 0x110 to the task structure for program checks from user space. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> --- arch/s390/kernel/entry.S | 50 ++++++++++------------------------------ 1 file changed, 12 insertions(+), 38 deletions(-) diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 97298c58b2be..f687f168c94d 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -103,8 +103,7 @@ _PIF_WORK = (_PIF_PER_TRAP) CHECK_STACK 1<<STACK_SHIFT,\savearea aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) j 3f -1: LAST_BREAK %r14 - UPDATE_VTIME %r14,%r15,\timer +1: UPDATE_VTIME %r14,%r15,\timer 2: lg %r15,__LC_ASYNC_STACK # load async stack 3: la %r11,STACK_FRAME_OVERHEAD(%r15) .endm @@ -121,18 +120,6 @@ _PIF_WORK = (_PIF_PER_TRAP) mvc __LC_LAST_UPDATE_TIMER(8),\enter_timer .endm - .macro LAST_BREAK scratch - srag \scratch,%r10,23 -#ifdef CONFIG_HAVE_MARCH_Z990_FEATURES - jz .+10 - stg %r10,__TASK_thread+__THREAD_last_break(%r12) -#else - jz .+14 - lghi \scratch,__TASK_thread - stg %r10,__THREAD_last_break(\scratch,%r12) -#endif - .endm - .macro REENABLE_IRQS stg %r8,__LC_RETURN_PSW ni __LC_RETURN_PSW,0xbf @@ -278,15 +265,14 @@ ENTRY(system_call) stpt __LC_SYNC_ENTER_TIMER .Lsysc_stmg: stmg %r8,%r15,__LC_SAVE_AREA_SYNC - lg %r10,__LC_LAST_BREAK lg %r12,__LC_CURRENT + lghi %r13,__TASK_thread lghi %r14,_PIF_SYSCALL .Lsysc_per: lg %r15,__LC_KERNEL_STACK la %r11,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs - LAST_BREAK %r13 .Lsysc_vtime: - UPDATE_VTIME %r10,%r13,__LC_SYNC_ENTER_TIMER + UPDATE_VTIME %r8,%r9,__LC_SYNC_ENTER_TIMER stmg %r0,%r7,__PT_R0(%r11) mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC mvc __PT_PSW(16,%r11),__LC_SVC_OLD_PSW @@ -294,12 +280,7 @@ ENTRY(system_call) stg %r14,__PT_FLAGS(%r11) .Lsysc_do_svc: # load address of system call table -#ifdef CONFIG_HAVE_MARCH_Z990_FEATURES - lg %r10,__TASK_thread+__THREAD_sysc_table(%r12) -#else - lghi %r13,__TASK_thread lg %r10,__THREAD_sysc_table(%r13,%r12) -#endif llgh %r8,__PT_INT_CODE+2(%r11) slag %r8,%r8,2 # shift and test for svc 0 jnz .Lsysc_nr_ok @@ -508,8 +489,7 @@ ENTRY(pgm_check_handler) 1: CHECK_STACK STACK_SIZE,__LC_SAVE_AREA_SYNC aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) j 3f -2: LAST_BREAK %r14 - UPDATE_VTIME %r14,%r15,__LC_SYNC_ENTER_TIMER +2: UPDATE_VTIME %r14,%r15,__LC_SYNC_ENTER_TIMER lg %r15,__LC_KERNEL_STACK lgr %r14,%r12 aghi %r14,__TASK_thread # pointer to thread_struct @@ -518,6 +498,7 @@ ENTRY(pgm_check_handler) jz 3f mvc __THREAD_trap_tdb(256,%r14),0(%r13) 3: la %r11,STACK_FRAME_OVERHEAD(%r15) + stg %r10,__THREAD_last_break(%r14) stmg %r0,%r7,__PT_R0(%r11) mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC stmg %r8,%r9,__PT_PSW(%r11) @@ -576,7 +557,6 @@ ENTRY(io_int_handler) STCK __LC_INT_CLOCK stpt __LC_ASYNC_ENTER_TIMER stmg %r8,%r15,__LC_SAVE_AREA_ASYNC - lg %r10,__LC_LAST_BREAK lg %r12,__LC_CURRENT larl %r13,cleanup_critical lmg %r8,%r9,__LC_IO_OLD_PSW @@ -750,7 +730,6 @@ ENTRY(ext_int_handler) STCK __LC_INT_CLOCK stpt __LC_ASYNC_ENTER_TIMER stmg %r8,%r15,__LC_SAVE_AREA_ASYNC - lg %r10,__LC_LAST_BREAK lg %r12,__LC_CURRENT larl %r13,cleanup_critical lmg %r8,%r9,__LC_EXT_OLD_PSW @@ -893,7 +872,6 @@ ENTRY(mcck_int_handler) la %r1,4095 # revalidate r1 spt __LC_CPU_TIMER_SAVE_AREA-4095(%r1) # revalidate cpu timer lmg %r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r1)# revalidate gprs - lg %r10,__LC_LAST_BREAK lg %r12,__LC_CURRENT larl %r13,cleanup_critical lmg %r8,%r9,__LC_MCK_OLD_PSW @@ -1088,9 +1066,10 @@ cleanup_critical: 0: # check if base register setup + TIF bit load has been done clg %r9,BASED(.Lcleanup_system_call_insn+16) jhe 0f - # set up saved registers r10 and r12 - stg %r10,16(%r11) # r10 last break - stg %r12,32(%r11) # r12 task struct pointer + # set up saved register r12 task struct pointer + stg %r12,32(%r11) + # set up saved register r13 __TASK_thread offset + mvc 40(8,%r11),BASED(.Lcleanup_system_call_const) 0: # check if the user time update has been done clg %r9,BASED(.Lcleanup_system_call_insn+24) jh 0f @@ -1107,14 +1086,7 @@ cleanup_critical: stg %r15,__LC_SYSTEM_TIMER 0: # update accounting time stamp mvc __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER - # do LAST_BREAK - lg %r9,16(%r11) - srag %r9,%r9,23 - jz 0f - lgr %r9,%r12 - aghi %r9,__TASK_thread - mvc __THREAD_last_break(8,%r9),16(%r11) -0: # set up saved register r11 + # set up saved register r11 lg %r15,__LC_KERNEL_STACK la %r9,STACK_FRAME_OVERHEAD(%r15) stg %r9,24(%r11) # r11 pt_regs pointer @@ -1136,6 +1108,8 @@ cleanup_critical: .quad .Lsysc_per .quad .Lsysc_vtime+36 .quad .Lsysc_vtime+42 +.Lcleanup_system_call_const: + .quad __TASK_thread .Lcleanup_sysc_tif: larl %r9,.Lsysc_tif -- 2.30.9