diff options
Diffstat (limited to 'arch/s390/kernel/entry.S')
| -rw-r--r-- | arch/s390/kernel/entry.S | 67 |
1 files changed, 40 insertions, 27 deletions
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 3f4d272577d3..de7918a6830c 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -115,26 +115,29 @@ _LPP_OFFSET = __LC_LPP .macro SWITCH_ASYNC savearea,timer tmhh %r8,0x0001 # interrupting from user ? - jnz 1f + jnz 2f lgr %r14,%r9 + cghi %r14,__LC_RETURN_LPSWE + je 0f slg %r14,BASED(.Lcritical_start) clg %r14,BASED(.Lcritical_length) - jhe 0f + jhe 1f +0: lghi %r11,\savearea # inside critical section, do cleanup brasl %r14,cleanup_critical tmhh %r8,0x0001 # retest problem state after cleanup - jnz 1f -0: lg %r14,__LC_ASYNC_STACK # are we already on the target stack? + jnz 2f +1: lg %r14,__LC_ASYNC_STACK # are we already on the target stack? slgr %r14,%r15 srag %r14,%r14,STACK_SHIFT - jnz 2f + jnz 3f CHECK_STACK \savearea aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) - j 3f -1: UPDATE_VTIME %r14,%r15,\timer + j 4f +2: UPDATE_VTIME %r14,%r15,\timer BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP -2: lg %r15,__LC_ASYNC_STACK # load async stack -3: la %r11,STACK_FRAME_OVERHEAD(%r15) +3: lg %r15,__LC_ASYNC_STACK # load async stack +4: la %r11,STACK_FRAME_OVERHEAD(%r15) .endm .macro UPDATE_VTIME w1,w2,enter_timer @@ -365,9 +368,9 @@ ENTRY(system_call) jnz .Lsysc_nr_ok # svc 0: system call number in %r1 llgfr %r1,%r1 # clear high word in r1 + sth %r1,__PT_INT_CODE+2(%r11) cghi %r1,NR_syscalls jnl .Lsysc_nr_ok - sth %r1,__PT_INT_CODE+2(%r11) slag %r8,%r1,3 .Lsysc_nr_ok: xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) @@ -401,7 +404,7 @@ ENTRY(system_call) stpt __LC_EXIT_TIMER mvc __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER lmg %r11,%r15,__PT_R11(%r11) - lpswe __LC_RETURN_PSW + b __LC_RETURN_LPSWE(%r0) .Lsysc_done: # @@ -608,43 +611,50 @@ ENTRY(pgm_check_handler) BPOFF stmg %r8,%r15,__LC_SAVE_AREA_SYNC lg %r10,__LC_LAST_BREAK - lg %r12,__LC_CURRENT + srag %r11,%r10,12 + jnz 0f + /* if __LC_LAST_BREAK is < 4096, it contains one of + * the lpswe addresses in lowcore. Set it to 1 (initial state) + * to prevent leaking that address to userspace. + */ + lghi %r10,1 +0: lg %r12,__LC_CURRENT lghi %r11,0 larl %r13,cleanup_critical lmg %r8,%r9,__LC_PGM_OLD_PSW tmhh %r8,0x0001 # test problem state bit - jnz 2f # -> fault in user space + jnz 3f # -> fault in user space #if IS_ENABLED(CONFIG_KVM) # cleanup critical section for program checks in sie64a lgr %r14,%r9 slg %r14,BASED(.Lsie_critical_start) clg %r14,BASED(.Lsie_critical_length) - jhe 0f + jhe 1f lg %r14,__SF_SIE_CONTROL(%r15) # get control block pointer ni __SIE_PROG0C+3(%r14),0xfe # no longer in SIE lctlg %c1,%c1,__LC_USER_ASCE # load primary asce larl %r9,sie_exit # skip forward to sie_exit lghi %r11,_PIF_GUEST_FAULT #endif -0: tmhh %r8,0x4000 # PER bit set in old PSW ? - jnz 1f # -> enabled, can't be a double fault +1: tmhh %r8,0x4000 # PER bit set in old PSW ? + jnz 2f # -> enabled, can't be a double fault tm __LC_PGM_ILC+3,0x80 # check for per exception jnz .Lpgm_svcper # -> single stepped svc -1: CHECK_STACK __LC_SAVE_AREA_SYNC +2: CHECK_STACK __LC_SAVE_AREA_SYNC aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) - # CHECK_VMAP_STACK branches to stack_overflow or 4f - CHECK_VMAP_STACK __LC_SAVE_AREA_SYNC,4f -2: UPDATE_VTIME %r14,%r15,__LC_SYNC_ENTER_TIMER + # CHECK_VMAP_STACK branches to stack_overflow or 5f + CHECK_VMAP_STACK __LC_SAVE_AREA_SYNC,5f +3: UPDATE_VTIME %r14,%r15,__LC_SYNC_ENTER_TIMER BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP lg %r15,__LC_KERNEL_STACK lgr %r14,%r12 aghi %r14,__TASK_thread # pointer to thread_struct lghi %r13,__LC_PGM_TDB tm __LC_PGM_ILC+2,0x02 # check for transaction abort - jz 3f + jz 4f mvc __THREAD_trap_tdb(256,%r14),0(%r13) -3: stg %r10,__THREAD_last_break(%r14) -4: lgr %r13,%r11 +4: stg %r10,__THREAD_last_break(%r14) +5: lgr %r13,%r11 la %r11,STACK_FRAME_OVERHEAD(%r15) stmg %r0,%r7,__PT_R0(%r11) # clear user controlled registers to prevent speculative use @@ -663,14 +673,14 @@ ENTRY(pgm_check_handler) stg %r13,__PT_FLAGS(%r11) stg %r10,__PT_ARGS(%r11) tm __LC_PGM_ILC+3,0x80 # check for per exception - jz 5f + jz 6f tmhh %r8,0x0001 # kernel per event ? jz .Lpgm_kprobe oi __PT_FLAGS+7(%r11),_PIF_PER_TRAP mvc __THREAD_per_address(8,%r14),__LC_PER_ADDRESS mvc __THREAD_per_cause(2,%r14),__LC_PER_CODE mvc __THREAD_per_paid(1,%r14),__LC_PER_ACCESS_ID -5: REENABLE_IRQS +6: REENABLE_IRQS xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) larl %r1,pgm_check_table llgh %r10,__PT_INT_CODE+2(%r11) @@ -775,7 +785,7 @@ ENTRY(io_int_handler) mvc __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER .Lio_exit_kernel: lmg %r11,%r15,__PT_R11(%r11) - lpswe __LC_RETURN_PSW + b __LC_RETURN_LPSWE(%r0) .Lio_done: # @@ -1216,7 +1226,7 @@ ENTRY(mcck_int_handler) stpt __LC_EXIT_TIMER mvc __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER 0: lmg %r11,%r15,__PT_R11(%r11) - lpswe __LC_RETURN_MCCK_PSW + b __LC_RETURN_MCCK_LPSWE .Lmcck_panic: lg %r15,__LC_NODAT_STACK @@ -1273,6 +1283,8 @@ ENDPROC(stack_overflow) #endif ENTRY(cleanup_critical) + cghi %r9,__LC_RETURN_LPSWE + je .Lcleanup_lpswe #if IS_ENABLED(CONFIG_KVM) clg %r9,BASED(.Lcleanup_table_sie) # .Lsie_gmap jl 0f @@ -1426,6 +1438,7 @@ ENDPROC(cleanup_critical) mvc __LC_RETURN_PSW(16),__PT_PSW(%r9) mvc 0(64,%r11),__PT_R8(%r9) lmg %r0,%r7,__PT_R0(%r9) +.Lcleanup_lpswe: 1: lmg %r8,%r9,__LC_RETURN_PSW BR_EX %r14,%r11 .Lcleanup_sysc_restore_insn: |