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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * S390 low-level entry points.
4 *
5 * Copyright IBM Corp. 1999, 2012
6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
7 * Hartmut Penner (hp@de.ibm.com),
8 * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
9 */
10
11#include <linux/export.h>
12#include <linux/init.h>
13#include <linux/linkage.h>
14#include <asm/asm-extable.h>
15#include <asm/alternative-asm.h>
16#include <asm/processor.h>
17#include <asm/cache.h>
18#include <asm/dwarf.h>
19#include <asm/errno.h>
20#include <asm/ptrace.h>
21#include <asm/thread_info.h>
22#include <asm/asm-offsets.h>
23#include <asm/unistd.h>
24#include <asm/page.h>
25#include <asm/sigp.h>
26#include <asm/irq.h>
27#include <asm/vx-insn.h>
28#include <asm/setup.h>
29#include <asm/nmi.h>
30#include <asm/nospec-insn.h>
31
32_LPP_OFFSET = __LC_LPP
33
34 .macro STBEAR address
35 ALTERNATIVE "nop", ".insn s,0xb2010000,\address", 193
36 .endm
37
38 .macro LBEAR address
39 ALTERNATIVE "nop", ".insn s,0xb2000000,\address", 193
40 .endm
41
42 .macro LPSWEY address,lpswe
43 ALTERNATIVE "b \lpswe; nopr", ".insn siy,0xeb0000000071,\address,0", 193
44 .endm
45
46 .macro MBEAR reg
47 ALTERNATIVE "brcl 0,0", __stringify(mvc __PT_LAST_BREAK(8,\reg),__LC_LAST_BREAK), 193
48 .endm
49
50 .macro CHECK_STACK savearea
51#ifdef CONFIG_CHECK_STACK
52 tml %r15,THREAD_SIZE - CONFIG_STACK_GUARD
53 lghi %r14,\savearea
54 jz stack_overflow
55#endif
56 .endm
57
58 .macro CHECK_VMAP_STACK savearea,oklabel
59#ifdef CONFIG_VMAP_STACK
60 lgr %r14,%r15
61 nill %r14,0x10000 - THREAD_SIZE
62 oill %r14,STACK_INIT_OFFSET
63 clg %r14,__LC_KERNEL_STACK
64 je \oklabel
65 clg %r14,__LC_ASYNC_STACK
66 je \oklabel
67 clg %r14,__LC_MCCK_STACK
68 je \oklabel
69 clg %r14,__LC_NODAT_STACK
70 je \oklabel
71 clg %r14,__LC_RESTART_STACK
72 je \oklabel
73 lghi %r14,\savearea
74 j stack_overflow
75#else
76 j \oklabel
77#endif
78 .endm
79
80 /*
81 * The TSTMSK macro generates a test-under-mask instruction by
82 * calculating the memory offset for the specified mask value.
83 * Mask value can be any constant. The macro shifts the mask
84 * value to calculate the memory offset for the test-under-mask
85 * instruction.
86 */
87 .macro TSTMSK addr, mask, size=8, bytepos=0
88 .if (\bytepos < \size) && (\mask >> 8)
89 .if (\mask & 0xff)
90 .error "Mask exceeds byte boundary"
91 .endif
92 TSTMSK \addr, "(\mask >> 8)", \size, "(\bytepos + 1)"
93 .exitm
94 .endif
95 .ifeq \mask
96 .error "Mask must not be zero"
97 .endif
98 off = \size - \bytepos - 1
99 tm off+\addr, \mask
100 .endm
101
102 .macro BPOFF
103 ALTERNATIVE "nop", ".insn rrf,0xb2e80000,0,0,12,0", 82
104 .endm
105
106 .macro BPON
107 ALTERNATIVE "nop", ".insn rrf,0xb2e80000,0,0,13,0", 82
108 .endm
109
110 .macro BPENTER tif_ptr,tif_mask
111 ALTERNATIVE "TSTMSK \tif_ptr,\tif_mask; jz .+8; .insn rrf,0xb2e80000,0,0,13,0", \
112 "j .+12; nop; nop", 82
113 .endm
114
115 .macro BPEXIT tif_ptr,tif_mask
116 TSTMSK \tif_ptr,\tif_mask
117 ALTERNATIVE "jz .+8; .insn rrf,0xb2e80000,0,0,12,0", \
118 "jnz .+8; .insn rrf,0xb2e80000,0,0,13,0", 82
119 .endm
120
121#if IS_ENABLED(CONFIG_KVM)
122 /*
123 * The OUTSIDE macro jumps to the provided label in case the value
124 * in the provided register is outside of the provided range. The
125 * macro is useful for checking whether a PSW stored in a register
126 * pair points inside or outside of a block of instructions.
127 * @reg: register to check
128 * @start: start of the range
129 * @end: end of the range
130 * @outside_label: jump here if @reg is outside of [@start..@end)
131 */
132 .macro OUTSIDE reg,start,end,outside_label
133 lgr %r14,\reg
134 larl %r13,\start
135 slgr %r14,%r13
136 clgfrl %r14,.Lrange_size\@
137 jhe \outside_label
138 .section .rodata, "a"
139 .balign 4
140.Lrange_size\@:
141 .long \end - \start
142 .previous
143 .endm
144
145 .macro SIEEXIT
146 lg %r9,__SF_SIE_CONTROL(%r15) # get control block pointer
147 ni __SIE_PROG0C+3(%r9),0xfe # no longer in SIE
148 lctlg %c1,%c1,__LC_KERNEL_ASCE # load primary asce
149 larl %r9,sie_exit # skip forward to sie_exit
150 .endm
151#endif
152
153 .macro STACKLEAK_ERASE
154#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
155 brasl %r14,stackleak_erase_on_task_stack
156#endif
157 .endm
158
159 GEN_BR_THUNK %r14
160
161 .section .kprobes.text, "ax"
162.Ldummy:
163 /*
164 * The following nop exists only in order to avoid that the next
165 * symbol starts at the beginning of the kprobes text section.
166 * In that case there would be several symbols at the same address.
167 * E.g. objdump would take an arbitrary symbol when disassembling
168 * the code.
169 * With the added nop in between this cannot happen.
170 */
171 nop 0
172
173/*
174 * Scheduler resume function, called by switch_to
175 * gpr2 = (task_struct *) prev
176 * gpr3 = (task_struct *) next
177 * Returns:
178 * gpr2 = prev
179 */
180SYM_FUNC_START(__switch_to)
181 stmg %r6,%r15,__SF_GPRS(%r15) # store gprs of prev task
182 lghi %r4,__TASK_stack
183 lghi %r1,__TASK_thread
184 llill %r5,STACK_INIT_OFFSET
185 stg %r15,__THREAD_ksp(%r1,%r2) # store kernel stack of prev
186 lg %r15,0(%r4,%r3) # start of kernel stack of next
187 agr %r15,%r5 # end of kernel stack of next
188 stg %r3,__LC_CURRENT # store task struct of next
189 stg %r15,__LC_KERNEL_STACK # store end of kernel stack
190 lg %r15,__THREAD_ksp(%r1,%r3) # load kernel stack of next
191 aghi %r3,__TASK_pid
192 mvc __LC_CURRENT_PID(4,%r0),0(%r3) # store pid of next
193 lmg %r6,%r15,__SF_GPRS(%r15) # load gprs of next task
194 ALTERNATIVE "nop", "lpp _LPP_OFFSET", 40
195 BR_EX %r14
196SYM_FUNC_END(__switch_to)
197
198#if IS_ENABLED(CONFIG_KVM)
199/*
200 * __sie64a calling convention:
201 * %r2 pointer to sie control block phys
202 * %r3 pointer to sie control block virt
203 * %r4 guest register save area
204 */
205SYM_FUNC_START(__sie64a)
206 stmg %r6,%r14,__SF_GPRS(%r15) # save kernel registers
207 lg %r12,__LC_CURRENT
208 stg %r2,__SF_SIE_CONTROL_PHYS(%r15) # save sie block physical..
209 stg %r3,__SF_SIE_CONTROL(%r15) # ...and virtual addresses
210 stg %r4,__SF_SIE_SAVEAREA(%r15) # save guest register save area
211 xc __SF_SIE_REASON(8,%r15),__SF_SIE_REASON(%r15) # reason code = 0
212 mvc __SF_SIE_FLAGS(8,%r15),__TI_flags(%r12) # copy thread flags
213 lmg %r0,%r13,0(%r4) # load guest gprs 0-13
214 lg %r14,__LC_GMAP # get gmap pointer
215 ltgr %r14,%r14
216 jz .Lsie_gmap
217 lctlg %c1,%c1,__GMAP_ASCE(%r14) # load primary asce
218.Lsie_gmap:
219 lg %r14,__SF_SIE_CONTROL(%r15) # get control block pointer
220 oi __SIE_PROG0C+3(%r14),1 # we are going into SIE now
221 tm __SIE_PROG20+3(%r14),3 # last exit...
222 jnz .Lsie_skip
223 TSTMSK __LC_CPU_FLAGS,_CIF_FPU
224 jo .Lsie_skip # exit if fp/vx regs changed
225 lg %r14,__SF_SIE_CONTROL_PHYS(%r15) # get sie block phys addr
226 BPEXIT __SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
227.Lsie_entry:
228 sie 0(%r14)
229# Let the next instruction be NOP to avoid triggering a machine check
230# and handling it in a guest as result of the instruction execution.
231 nopr 7
232.Lsie_leave:
233 BPOFF
234 BPENTER __SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
235.Lsie_skip:
236 lg %r14,__SF_SIE_CONTROL(%r15) # get control block pointer
237 ni __SIE_PROG0C+3(%r14),0xfe # no longer in SIE
238 lctlg %c1,%c1,__LC_KERNEL_ASCE # load primary asce
239.Lsie_done:
240# some program checks are suppressing. C code (e.g. do_protection_exception)
241# will rewind the PSW by the ILC, which is often 4 bytes in case of SIE. There
242# are some corner cases (e.g. runtime instrumentation) where ILC is unpredictable.
243# Other instructions between __sie64a and .Lsie_done should not cause program
244# interrupts. So lets use 3 nops as a landing pad for all possible rewinds.
245.Lrewind_pad6:
246 nopr 7
247.Lrewind_pad4:
248 nopr 7
249.Lrewind_pad2:
250 nopr 7
251SYM_INNER_LABEL(sie_exit, SYM_L_GLOBAL)
252 lg %r14,__SF_SIE_SAVEAREA(%r15) # load guest register save area
253 stmg %r0,%r13,0(%r14) # save guest gprs 0-13
254 xgr %r0,%r0 # clear guest registers to
255 xgr %r1,%r1 # prevent speculative use
256 xgr %r3,%r3
257 xgr %r4,%r4
258 xgr %r5,%r5
259 lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers
260 lg %r2,__SF_SIE_REASON(%r15) # return exit reason code
261 BR_EX %r14
262.Lsie_fault:
263 lghi %r14,-EFAULT
264 stg %r14,__SF_SIE_REASON(%r15) # set exit reason code
265 j sie_exit
266
267 EX_TABLE(.Lrewind_pad6,.Lsie_fault)
268 EX_TABLE(.Lrewind_pad4,.Lsie_fault)
269 EX_TABLE(.Lrewind_pad2,.Lsie_fault)
270 EX_TABLE(sie_exit,.Lsie_fault)
271SYM_FUNC_END(__sie64a)
272EXPORT_SYMBOL(__sie64a)
273EXPORT_SYMBOL(sie_exit)
274#endif
275
276/*
277 * SVC interrupt handler routine. System calls are synchronous events and
278 * are entered with interrupts disabled.
279 */
280
281SYM_CODE_START(system_call)
282 stpt __LC_SYS_ENTER_TIMER
283 stmg %r8,%r15,__LC_SAVE_AREA_SYNC
284 BPOFF
285 lghi %r14,0
286.Lsysc_per:
287 STBEAR __LC_LAST_BREAK
288 lctlg %c1,%c1,__LC_KERNEL_ASCE
289 lg %r15,__LC_KERNEL_STACK
290 xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
291 stmg %r0,%r7,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
292 # clear user controlled register to prevent speculative use
293 xgr %r0,%r0
294 xgr %r1,%r1
295 xgr %r4,%r4
296 xgr %r5,%r5
297 xgr %r6,%r6
298 xgr %r7,%r7
299 xgr %r8,%r8
300 xgr %r9,%r9
301 xgr %r10,%r10
302 xgr %r11,%r11
303 la %r2,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs
304 mvc __PT_R8(64,%r2),__LC_SAVE_AREA_SYNC
305 MBEAR %r2
306 lgr %r3,%r14
307 brasl %r14,__do_syscall
308 STACKLEAK_ERASE
309 lctlg %c1,%c1,__LC_USER_ASCE
310 mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
311 BPON
312 LBEAR STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
313 lmg %r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
314 stpt __LC_EXIT_TIMER
315 LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE
316SYM_CODE_END(system_call)
317
318#
319# a new process exits the kernel with ret_from_fork
320#
321SYM_CODE_START(ret_from_fork)
322 lgr %r3,%r11
323 brasl %r14,__ret_from_fork
324 STACKLEAK_ERASE
325 lctlg %c1,%c1,__LC_USER_ASCE
326 mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
327 BPON
328 LBEAR STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
329 lmg %r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
330 stpt __LC_EXIT_TIMER
331 LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE
332SYM_CODE_END(ret_from_fork)
333
334/*
335 * Program check handler routine
336 */
337
338SYM_CODE_START(pgm_check_handler)
339 stpt __LC_SYS_ENTER_TIMER
340 BPOFF
341 stmg %r8,%r15,__LC_SAVE_AREA_SYNC
342 lghi %r10,0
343 lmg %r8,%r9,__LC_PGM_OLD_PSW
344 tmhh %r8,0x0001 # coming from user space?
345 jno .Lpgm_skip_asce
346 lctlg %c1,%c1,__LC_KERNEL_ASCE
347 j 3f # -> fault in user space
348.Lpgm_skip_asce:
349#if IS_ENABLED(CONFIG_KVM)
350 # cleanup critical section for program checks in __sie64a
351 OUTSIDE %r9,.Lsie_gmap,.Lsie_done,1f
352 BPENTER __SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
353 SIEEXIT
354 lghi %r10,_PIF_GUEST_FAULT
355#endif
3561: tmhh %r8,0x4000 # PER bit set in old PSW ?
357 jnz 2f # -> enabled, can't be a double fault
358 tm __LC_PGM_ILC+3,0x80 # check for per exception
359 jnz .Lpgm_svcper # -> single stepped svc
3602: CHECK_STACK __LC_SAVE_AREA_SYNC
361 aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
362 # CHECK_VMAP_STACK branches to stack_overflow or 4f
363 CHECK_VMAP_STACK __LC_SAVE_AREA_SYNC,4f
3643: lg %r15,__LC_KERNEL_STACK
3654: la %r11,STACK_FRAME_OVERHEAD(%r15)
366 stg %r10,__PT_FLAGS(%r11)
367 xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
368 stmg %r0,%r7,__PT_R0(%r11)
369 mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC
370 mvc __PT_LAST_BREAK(8,%r11),__LC_PGM_LAST_BREAK
371 stmg %r8,%r9,__PT_PSW(%r11)
372
373 # clear user controlled registers to prevent speculative use
374 xgr %r0,%r0
375 xgr %r1,%r1
376 xgr %r3,%r3
377 xgr %r4,%r4
378 xgr %r5,%r5
379 xgr %r6,%r6
380 xgr %r7,%r7
381 lgr %r2,%r11
382 brasl %r14,__do_pgm_check
383 tmhh %r8,0x0001 # returning to user space?
384 jno .Lpgm_exit_kernel
385 STACKLEAK_ERASE
386 lctlg %c1,%c1,__LC_USER_ASCE
387 BPON
388 stpt __LC_EXIT_TIMER
389.Lpgm_exit_kernel:
390 mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
391 LBEAR STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
392 lmg %r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
393 LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE
394
395#
396# single stepped system call
397#
398.Lpgm_svcper:
399 mvc __LC_RETURN_PSW(8),__LC_SVC_NEW_PSW
400 larl %r14,.Lsysc_per
401 stg %r14,__LC_RETURN_PSW+8
402 lghi %r14,1
403 LBEAR __LC_PGM_LAST_BREAK
404 LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE # branch to .Lsysc_per
405SYM_CODE_END(pgm_check_handler)
406
407/*
408 * Interrupt handler macro used for external and IO interrupts.
409 */
410.macro INT_HANDLER name,lc_old_psw,handler
411SYM_CODE_START(\name)
412 stckf __LC_INT_CLOCK
413 stpt __LC_SYS_ENTER_TIMER
414 STBEAR __LC_LAST_BREAK
415 BPOFF
416 stmg %r8,%r15,__LC_SAVE_AREA_ASYNC
417 lmg %r8,%r9,\lc_old_psw
418 tmhh %r8,0x0001 # interrupting from user ?
419 jnz 1f
420#if IS_ENABLED(CONFIG_KVM)
421 OUTSIDE %r9,.Lsie_gmap,.Lsie_done,0f
422 BPENTER __SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
423 SIEEXIT
424#endif
4250: CHECK_STACK __LC_SAVE_AREA_ASYNC
426 aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
427 j 2f
4281: lctlg %c1,%c1,__LC_KERNEL_ASCE
429 lg %r15,__LC_KERNEL_STACK
4302: xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
431 la %r11,STACK_FRAME_OVERHEAD(%r15)
432 stmg %r0,%r7,__PT_R0(%r11)
433 # clear user controlled registers to prevent speculative use
434 xgr %r0,%r0
435 xgr %r1,%r1
436 xgr %r3,%r3
437 xgr %r4,%r4
438 xgr %r5,%r5
439 xgr %r6,%r6
440 xgr %r7,%r7
441 xgr %r10,%r10
442 xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
443 mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
444 MBEAR %r11
445 stmg %r8,%r9,__PT_PSW(%r11)
446 lgr %r2,%r11 # pass pointer to pt_regs
447 brasl %r14,\handler
448 mvc __LC_RETURN_PSW(16),__PT_PSW(%r11)
449 tmhh %r8,0x0001 # returning to user ?
450 jno 2f
451 STACKLEAK_ERASE
452 lctlg %c1,%c1,__LC_USER_ASCE
453 BPON
454 stpt __LC_EXIT_TIMER
4552: LBEAR __PT_LAST_BREAK(%r11)
456 lmg %r0,%r15,__PT_R0(%r11)
457 LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE
458SYM_CODE_END(\name)
459.endm
460
461INT_HANDLER ext_int_handler,__LC_EXT_OLD_PSW,do_ext_irq
462INT_HANDLER io_int_handler,__LC_IO_OLD_PSW,do_io_irq
463
464/*
465 * Load idle PSW.
466 */
467SYM_FUNC_START(psw_idle)
468 stg %r14,(__SF_GPRS+8*8)(%r15)
469 stg %r3,__SF_EMPTY(%r15)
470 larl %r1,psw_idle_exit
471 stg %r1,__SF_EMPTY+8(%r15)
472 larl %r1,smp_cpu_mtid
473 llgf %r1,0(%r1)
474 ltgr %r1,%r1
475 jz .Lpsw_idle_stcctm
476 .insn rsy,0xeb0000000017,%r1,5,__MT_CYCLES_ENTER(%r2)
477.Lpsw_idle_stcctm:
478 oi __LC_CPU_FLAGS+7,_CIF_ENABLED_WAIT
479 BPON
480 stckf __CLOCK_IDLE_ENTER(%r2)
481 stpt __TIMER_IDLE_ENTER(%r2)
482 lpswe __SF_EMPTY(%r15)
483SYM_INNER_LABEL(psw_idle_exit, SYM_L_GLOBAL)
484 BR_EX %r14
485SYM_FUNC_END(psw_idle)
486
487/*
488 * Machine check handler routines
489 */
490SYM_CODE_START(mcck_int_handler)
491 BPOFF
492 la %r1,4095 # validate r1
493 spt __LC_CPU_TIMER_SAVE_AREA-4095(%r1) # validate cpu timer
494 LBEAR __LC_LAST_BREAK_SAVE_AREA-4095(%r1) # validate bear
495 lmg %r0,%r15,__LC_GPREGS_SAVE_AREA # validate gprs
496 lmg %r8,%r9,__LC_MCK_OLD_PSW
497 TSTMSK __LC_MCCK_CODE,MCCK_CODE_SYSTEM_DAMAGE
498 jo .Lmcck_panic # yes -> rest of mcck code invalid
499 TSTMSK __LC_MCCK_CODE,MCCK_CODE_CR_VALID
500 jno .Lmcck_panic # control registers invalid -> panic
501 lctlg %c0,%c15,__LC_CREGS_SAVE_AREA # validate ctl regs
502 ptlb
503 lghi %r14,__LC_CPU_TIMER_SAVE_AREA
504 mvc __LC_MCCK_ENTER_TIMER(8),0(%r14)
505 TSTMSK __LC_MCCK_CODE,MCCK_CODE_CPU_TIMER_VALID
506 jo 3f
507 la %r14,__LC_SYS_ENTER_TIMER
508 clc 0(8,%r14),__LC_EXIT_TIMER
509 jl 1f
510 la %r14,__LC_EXIT_TIMER
5111: clc 0(8,%r14),__LC_LAST_UPDATE_TIMER
512 jl 2f
513 la %r14,__LC_LAST_UPDATE_TIMER
5142: spt 0(%r14)
515 mvc __LC_MCCK_ENTER_TIMER(8),0(%r14)
5163: TSTMSK __LC_MCCK_CODE,MCCK_CODE_PSW_MWP_VALID
517 jno .Lmcck_panic
518 tmhh %r8,0x0001 # interrupting from user ?
519 jnz .Lmcck_user
520 TSTMSK __LC_MCCK_CODE,MCCK_CODE_PSW_IA_VALID
521 jno .Lmcck_panic
522#if IS_ENABLED(CONFIG_KVM)
523 OUTSIDE %r9,.Lsie_gmap,.Lsie_done,.Lmcck_user
524 OUTSIDE %r9,.Lsie_entry,.Lsie_leave,4f
525 oi __LC_CPU_FLAGS+7, _CIF_MCCK_GUEST
5264: BPENTER __SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
527 SIEEXIT
528#endif
529.Lmcck_user:
530 lg %r15,__LC_MCCK_STACK
531 la %r11,STACK_FRAME_OVERHEAD(%r15)
532 stctg %c1,%c1,__PT_CR1(%r11)
533 lctlg %c1,%c1,__LC_KERNEL_ASCE
534 xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
535 lghi %r14,__LC_GPREGS_SAVE_AREA+64
536 stmg %r0,%r7,__PT_R0(%r11)
537 # clear user controlled registers to prevent speculative use
538 xgr %r0,%r0
539 xgr %r1,%r1
540 xgr %r3,%r3
541 xgr %r4,%r4
542 xgr %r5,%r5
543 xgr %r6,%r6
544 xgr %r7,%r7
545 xgr %r10,%r10
546 mvc __PT_R8(64,%r11),0(%r14)
547 stmg %r8,%r9,__PT_PSW(%r11)
548 xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
549 xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
550 lgr %r2,%r11 # pass pointer to pt_regs
551 brasl %r14,s390_do_machine_check
552 lctlg %c1,%c1,__PT_CR1(%r11)
553 lmg %r0,%r10,__PT_R0(%r11)
554 mvc __LC_RETURN_MCCK_PSW(16),__PT_PSW(%r11) # move return PSW
555 tm __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
556 jno 0f
557 BPON
558 stpt __LC_EXIT_TIMER
5590: ALTERNATIVE "nop", __stringify(lghi %r12,__LC_LAST_BREAK_SAVE_AREA),193
560 LBEAR 0(%r12)
561 lmg %r11,%r15,__PT_R11(%r11)
562 LPSWEY __LC_RETURN_MCCK_PSW,__LC_RETURN_MCCK_LPSWE
563
564.Lmcck_panic:
565 /*
566 * Iterate over all possible CPU addresses in the range 0..0xffff
567 * and stop each CPU using signal processor. Use compare and swap
568 * to allow just one CPU-stopper and prevent concurrent CPUs from
569 * stopping each other while leaving the others running.
570 */
571 lhi %r5,0
572 lhi %r6,1
573 larl %r7,stop_lock
574 cs %r5,%r6,0(%r7) # single CPU-stopper only
575 jnz 4f
576 larl %r7,this_cpu
577 stap 0(%r7) # this CPU address
578 lh %r4,0(%r7)
579 nilh %r4,0
580 lhi %r0,1
581 sll %r0,16 # CPU counter
582 lhi %r3,0 # next CPU address
5830: cr %r3,%r4
584 je 2f
5851: sigp %r1,%r3,SIGP_STOP # stop next CPU
586 brc SIGP_CC_BUSY,1b
5872: ahi %r3,1
588 brct %r0,0b
5893: sigp %r1,%r4,SIGP_STOP # stop this CPU
590 brc SIGP_CC_BUSY,3b
5914: j 4b
592SYM_CODE_END(mcck_int_handler)
593
594SYM_CODE_START(restart_int_handler)
595 ALTERNATIVE "nop", "lpp _LPP_OFFSET", 40
596 stg %r15,__LC_SAVE_AREA_RESTART
597 TSTMSK __LC_RESTART_FLAGS,RESTART_FLAG_CTLREGS,4
598 jz 0f
599 lctlg %c0,%c15,__LC_CREGS_SAVE_AREA
6000: larl %r15,daton_psw
601 lpswe 0(%r15) # turn dat on, keep irqs off
602.Ldaton:
603 lg %r15,__LC_RESTART_STACK
604 xc STACK_FRAME_OVERHEAD(__PT_SIZE,%r15),STACK_FRAME_OVERHEAD(%r15)
605 stmg %r0,%r14,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
606 mvc STACK_FRAME_OVERHEAD+__PT_R15(8,%r15),__LC_SAVE_AREA_RESTART
607 mvc STACK_FRAME_OVERHEAD+__PT_PSW(16,%r15),__LC_RST_OLD_PSW
608 xc 0(STACK_FRAME_OVERHEAD,%r15),0(%r15)
609 lg %r1,__LC_RESTART_FN # load fn, parm & source cpu
610 lg %r2,__LC_RESTART_DATA
611 lgf %r3,__LC_RESTART_SOURCE
612 ltgr %r3,%r3 # test source cpu address
613 jm 1f # negative -> skip source stop
6140: sigp %r4,%r3,SIGP_SENSE # sigp sense to source cpu
615 brc 10,0b # wait for status stored
6161: basr %r14,%r1 # call function
617 stap __SF_EMPTY(%r15) # store cpu address
618 llgh %r3,__SF_EMPTY(%r15)
6192: sigp %r4,%r3,SIGP_STOP # sigp stop to current cpu
620 brc 2,2b
6213: j 3b
622SYM_CODE_END(restart_int_handler)
623
624 .section .kprobes.text, "ax"
625
626#if defined(CONFIG_CHECK_STACK) || defined(CONFIG_VMAP_STACK)
627/*
628 * The synchronous or the asynchronous stack overflowed. We are dead.
629 * No need to properly save the registers, we are going to panic anyway.
630 * Setup a pt_regs so that show_trace can provide a good call trace.
631 */
632SYM_CODE_START(stack_overflow)
633 lg %r15,__LC_NODAT_STACK # change to panic stack
634 la %r11,STACK_FRAME_OVERHEAD(%r15)
635 stmg %r0,%r7,__PT_R0(%r11)
636 stmg %r8,%r9,__PT_PSW(%r11)
637 mvc __PT_R8(64,%r11),0(%r14)
638 stg %r10,__PT_ORIG_GPR2(%r11) # store last break to orig_gpr2
639 xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
640 lgr %r2,%r11 # pass pointer to pt_regs
641 jg kernel_stack_overflow
642SYM_CODE_END(stack_overflow)
643#endif
644
645 .section .data, "aw"
646 .balign 4
647SYM_DATA_LOCAL(stop_lock, .long 0)
648SYM_DATA_LOCAL(this_cpu, .short 0)
649 .balign 8
650SYM_DATA_START_LOCAL(daton_psw)
651 .quad PSW_KERNEL_BITS
652 .quad .Ldaton
653SYM_DATA_END(daton_psw)
654
655 .section .rodata, "a"
656#define SYSCALL(esame,emu) .quad __s390x_ ## esame
657SYM_DATA_START(sys_call_table)
658#include "asm/syscall_table.h"
659SYM_DATA_END(sys_call_table)
660#undef SYSCALL
661
662#ifdef CONFIG_COMPAT
663
664#define SYSCALL(esame,emu) .quad __s390_ ## emu
665SYM_DATA_START(sys_call_table_emu)
666#include "asm/syscall_table.h"
667SYM_DATA_END(sys_call_table_emu)
668#undef SYSCALL
669#endif
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * S390 low-level entry points.
4 *
5 * Copyright IBM Corp. 1999, 2012
6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
7 * Hartmut Penner (hp@de.ibm.com),
8 * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
9 */
10
11#include <linux/init.h>
12#include <linux/linkage.h>
13#include <asm/asm-extable.h>
14#include <asm/alternative-asm.h>
15#include <asm/processor.h>
16#include <asm/cache.h>
17#include <asm/dwarf.h>
18#include <asm/errno.h>
19#include <asm/ptrace.h>
20#include <asm/thread_info.h>
21#include <asm/asm-offsets.h>
22#include <asm/unistd.h>
23#include <asm/page.h>
24#include <asm/sigp.h>
25#include <asm/irq.h>
26#include <asm/vx-insn.h>
27#include <asm/setup.h>
28#include <asm/nmi.h>
29#include <asm/export.h>
30#include <asm/nospec-insn.h>
31
32STACK_SHIFT = PAGE_SHIFT + THREAD_SIZE_ORDER
33STACK_SIZE = 1 << STACK_SHIFT
34STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE
35
36_LPP_OFFSET = __LC_LPP
37
38 .macro STBEAR address
39 ALTERNATIVE "nop", ".insn s,0xb2010000,\address", 193
40 .endm
41
42 .macro LBEAR address
43 ALTERNATIVE "nop", ".insn s,0xb2000000,\address", 193
44 .endm
45
46 .macro LPSWEY address,lpswe
47 ALTERNATIVE "b \lpswe; nopr", ".insn siy,0xeb0000000071,\address,0", 193
48 .endm
49
50 .macro MBEAR reg
51 ALTERNATIVE "brcl 0,0", __stringify(mvc __PT_LAST_BREAK(8,\reg),__LC_LAST_BREAK), 193
52 .endm
53
54 .macro CHECK_STACK savearea
55#ifdef CONFIG_CHECK_STACK
56 tml %r15,STACK_SIZE - CONFIG_STACK_GUARD
57 lghi %r14,\savearea
58 jz stack_overflow
59#endif
60 .endm
61
62 .macro CHECK_VMAP_STACK savearea,oklabel
63#ifdef CONFIG_VMAP_STACK
64 lgr %r14,%r15
65 nill %r14,0x10000 - STACK_SIZE
66 oill %r14,STACK_INIT
67 clg %r14,__LC_KERNEL_STACK
68 je \oklabel
69 clg %r14,__LC_ASYNC_STACK
70 je \oklabel
71 clg %r14,__LC_MCCK_STACK
72 je \oklabel
73 clg %r14,__LC_NODAT_STACK
74 je \oklabel
75 clg %r14,__LC_RESTART_STACK
76 je \oklabel
77 lghi %r14,\savearea
78 j stack_overflow
79#else
80 j \oklabel
81#endif
82 .endm
83
84 /*
85 * The TSTMSK macro generates a test-under-mask instruction by
86 * calculating the memory offset for the specified mask value.
87 * Mask value can be any constant. The macro shifts the mask
88 * value to calculate the memory offset for the test-under-mask
89 * instruction.
90 */
91 .macro TSTMSK addr, mask, size=8, bytepos=0
92 .if (\bytepos < \size) && (\mask >> 8)
93 .if (\mask & 0xff)
94 .error "Mask exceeds byte boundary"
95 .endif
96 TSTMSK \addr, "(\mask >> 8)", \size, "(\bytepos + 1)"
97 .exitm
98 .endif
99 .ifeq \mask
100 .error "Mask must not be zero"
101 .endif
102 off = \size - \bytepos - 1
103 tm off+\addr, \mask
104 .endm
105
106 .macro BPOFF
107 ALTERNATIVE "nop", ".insn rrf,0xb2e80000,0,0,12,0", 82
108 .endm
109
110 .macro BPON
111 ALTERNATIVE "nop", ".insn rrf,0xb2e80000,0,0,13,0", 82
112 .endm
113
114 .macro BPENTER tif_ptr,tif_mask
115 ALTERNATIVE "TSTMSK \tif_ptr,\tif_mask; jz .+8; .insn rrf,0xb2e80000,0,0,13,0", \
116 "j .+12; nop; nop", 82
117 .endm
118
119 .macro BPEXIT tif_ptr,tif_mask
120 TSTMSK \tif_ptr,\tif_mask
121 ALTERNATIVE "jz .+8; .insn rrf,0xb2e80000,0,0,12,0", \
122 "jnz .+8; .insn rrf,0xb2e80000,0,0,13,0", 82
123 .endm
124
125#if IS_ENABLED(CONFIG_KVM)
126 /*
127 * The OUTSIDE macro jumps to the provided label in case the value
128 * in the provided register is outside of the provided range. The
129 * macro is useful for checking whether a PSW stored in a register
130 * pair points inside or outside of a block of instructions.
131 * @reg: register to check
132 * @start: start of the range
133 * @end: end of the range
134 * @outside_label: jump here if @reg is outside of [@start..@end)
135 */
136 .macro OUTSIDE reg,start,end,outside_label
137 lgr %r14,\reg
138 larl %r13,\start
139 slgr %r14,%r13
140#ifdef CONFIG_AS_IS_LLVM
141 clgfrl %r14,.Lrange_size\@
142#else
143 clgfi %r14,\end - \start
144#endif
145 jhe \outside_label
146#ifdef CONFIG_AS_IS_LLVM
147 .section .rodata, "a"
148 .align 4
149.Lrange_size\@:
150 .long \end - \start
151 .previous
152#endif
153 .endm
154
155 .macro SIEEXIT
156 lg %r9,__SF_SIE_CONTROL(%r15) # get control block pointer
157 ni __SIE_PROG0C+3(%r9),0xfe # no longer in SIE
158 lctlg %c1,%c1,__LC_KERNEL_ASCE # load primary asce
159 larl %r9,sie_exit # skip forward to sie_exit
160 .endm
161#endif
162
163 GEN_BR_THUNK %r14
164
165 .section .kprobes.text, "ax"
166.Ldummy:
167 /*
168 * This nop exists only in order to avoid that __bpon starts at
169 * the beginning of the kprobes text section. In that case we would
170 * have several symbols at the same address. E.g. objdump would take
171 * an arbitrary symbol name when disassembling this code.
172 * With the added nop in between the __bpon symbol is unique
173 * again.
174 */
175 nop 0
176
177ENTRY(__bpon)
178 .globl __bpon
179 BPON
180 BR_EX %r14
181ENDPROC(__bpon)
182
183/*
184 * Scheduler resume function, called by switch_to
185 * gpr2 = (task_struct *) prev
186 * gpr3 = (task_struct *) next
187 * Returns:
188 * gpr2 = prev
189 */
190ENTRY(__switch_to)
191 stmg %r6,%r15,__SF_GPRS(%r15) # store gprs of prev task
192 lghi %r4,__TASK_stack
193 lghi %r1,__TASK_thread
194 llill %r5,STACK_INIT
195 stg %r15,__THREAD_ksp(%r1,%r2) # store kernel stack of prev
196 lg %r15,0(%r4,%r3) # start of kernel stack of next
197 agr %r15,%r5 # end of kernel stack of next
198 stg %r3,__LC_CURRENT # store task struct of next
199 stg %r15,__LC_KERNEL_STACK # store end of kernel stack
200 lg %r15,__THREAD_ksp(%r1,%r3) # load kernel stack of next
201 aghi %r3,__TASK_pid
202 mvc __LC_CURRENT_PID(4,%r0),0(%r3) # store pid of next
203 lmg %r6,%r15,__SF_GPRS(%r15) # load gprs of next task
204 ALTERNATIVE "nop", "lpp _LPP_OFFSET", 40
205 BR_EX %r14
206ENDPROC(__switch_to)
207
208#if IS_ENABLED(CONFIG_KVM)
209/*
210 * __sie64a calling convention:
211 * %r2 pointer to sie control block phys
212 * %r3 pointer to sie control block virt
213 * %r4 guest register save area
214 */
215ENTRY(__sie64a)
216 stmg %r6,%r14,__SF_GPRS(%r15) # save kernel registers
217 lg %r12,__LC_CURRENT
218 stg %r2,__SF_SIE_CONTROL_PHYS(%r15) # save sie block physical..
219 stg %r3,__SF_SIE_CONTROL(%r15) # ...and virtual addresses
220 stg %r4,__SF_SIE_SAVEAREA(%r15) # save guest register save area
221 xc __SF_SIE_REASON(8,%r15),__SF_SIE_REASON(%r15) # reason code = 0
222 mvc __SF_SIE_FLAGS(8,%r15),__TI_flags(%r12) # copy thread flags
223 lmg %r0,%r13,0(%r4) # load guest gprs 0-13
224 lg %r14,__LC_GMAP # get gmap pointer
225 ltgr %r14,%r14
226 jz .Lsie_gmap
227 lctlg %c1,%c1,__GMAP_ASCE(%r14) # load primary asce
228.Lsie_gmap:
229 lg %r14,__SF_SIE_CONTROL(%r15) # get control block pointer
230 oi __SIE_PROG0C+3(%r14),1 # we are going into SIE now
231 tm __SIE_PROG20+3(%r14),3 # last exit...
232 jnz .Lsie_skip
233 TSTMSK __LC_CPU_FLAGS,_CIF_FPU
234 jo .Lsie_skip # exit if fp/vx regs changed
235 lg %r14,__SF_SIE_CONTROL_PHYS(%r15) # get sie block phys addr
236 BPEXIT __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
237.Lsie_entry:
238 sie 0(%r14)
239# Let the next instruction be NOP to avoid triggering a machine check
240# and handling it in a guest as result of the instruction execution.
241 nopr 7
242.Lsie_leave:
243 BPOFF
244 BPENTER __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
245.Lsie_skip:
246 lg %r14,__SF_SIE_CONTROL(%r15) # get control block pointer
247 ni __SIE_PROG0C+3(%r14),0xfe # no longer in SIE
248 lctlg %c1,%c1,__LC_KERNEL_ASCE # load primary asce
249.Lsie_done:
250# some program checks are suppressing. C code (e.g. do_protection_exception)
251# will rewind the PSW by the ILC, which is often 4 bytes in case of SIE. There
252# are some corner cases (e.g. runtime instrumentation) where ILC is unpredictable.
253# Other instructions between __sie64a and .Lsie_done should not cause program
254# interrupts. So lets use 3 nops as a landing pad for all possible rewinds.
255.Lrewind_pad6:
256 nopr 7
257.Lrewind_pad4:
258 nopr 7
259.Lrewind_pad2:
260 nopr 7
261 .globl sie_exit
262sie_exit:
263 lg %r14,__SF_SIE_SAVEAREA(%r15) # load guest register save area
264 stmg %r0,%r13,0(%r14) # save guest gprs 0-13
265 xgr %r0,%r0 # clear guest registers to
266 xgr %r1,%r1 # prevent speculative use
267 xgr %r3,%r3
268 xgr %r4,%r4
269 xgr %r5,%r5
270 lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers
271 lg %r2,__SF_SIE_REASON(%r15) # return exit reason code
272 BR_EX %r14
273.Lsie_fault:
274 lghi %r14,-EFAULT
275 stg %r14,__SF_SIE_REASON(%r15) # set exit reason code
276 j sie_exit
277
278 EX_TABLE(.Lrewind_pad6,.Lsie_fault)
279 EX_TABLE(.Lrewind_pad4,.Lsie_fault)
280 EX_TABLE(.Lrewind_pad2,.Lsie_fault)
281 EX_TABLE(sie_exit,.Lsie_fault)
282ENDPROC(__sie64a)
283EXPORT_SYMBOL(__sie64a)
284EXPORT_SYMBOL(sie_exit)
285#endif
286
287/*
288 * SVC interrupt handler routine. System calls are synchronous events and
289 * are entered with interrupts disabled.
290 */
291
292ENTRY(system_call)
293 stpt __LC_SYS_ENTER_TIMER
294 stmg %r8,%r15,__LC_SAVE_AREA_SYNC
295 BPOFF
296 lghi %r14,0
297.Lsysc_per:
298 STBEAR __LC_LAST_BREAK
299 lctlg %c1,%c1,__LC_KERNEL_ASCE
300 lg %r12,__LC_CURRENT
301 lg %r15,__LC_KERNEL_STACK
302 xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
303 stmg %r0,%r7,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
304 BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP
305 # clear user controlled register to prevent speculative use
306 xgr %r0,%r0
307 xgr %r1,%r1
308 xgr %r4,%r4
309 xgr %r5,%r5
310 xgr %r6,%r6
311 xgr %r7,%r7
312 xgr %r8,%r8
313 xgr %r9,%r9
314 xgr %r10,%r10
315 xgr %r11,%r11
316 la %r2,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs
317 mvc __PT_R8(64,%r2),__LC_SAVE_AREA_SYNC
318 MBEAR %r2
319 lgr %r3,%r14
320 brasl %r14,__do_syscall
321 lctlg %c1,%c1,__LC_USER_ASCE
322 mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
323 BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP
324 LBEAR STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
325 lmg %r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
326 stpt __LC_EXIT_TIMER
327 LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE
328ENDPROC(system_call)
329
330#
331# a new process exits the kernel with ret_from_fork
332#
333ENTRY(ret_from_fork)
334 lgr %r3,%r11
335 brasl %r14,__ret_from_fork
336 lctlg %c1,%c1,__LC_USER_ASCE
337 mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
338 BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP
339 LBEAR STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
340 lmg %r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
341 stpt __LC_EXIT_TIMER
342 LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE
343ENDPROC(ret_from_fork)
344
345/*
346 * Program check handler routine
347 */
348
349ENTRY(pgm_check_handler)
350 stpt __LC_SYS_ENTER_TIMER
351 BPOFF
352 stmg %r8,%r15,__LC_SAVE_AREA_SYNC
353 lg %r12,__LC_CURRENT
354 lghi %r10,0
355 lmg %r8,%r9,__LC_PGM_OLD_PSW
356 tmhh %r8,0x0001 # coming from user space?
357 jno .Lpgm_skip_asce
358 lctlg %c1,%c1,__LC_KERNEL_ASCE
359 j 3f # -> fault in user space
360.Lpgm_skip_asce:
361#if IS_ENABLED(CONFIG_KVM)
362 # cleanup critical section for program checks in __sie64a
363 OUTSIDE %r9,.Lsie_gmap,.Lsie_done,1f
364 SIEEXIT
365 lghi %r10,_PIF_GUEST_FAULT
366#endif
3671: tmhh %r8,0x4000 # PER bit set in old PSW ?
368 jnz 2f # -> enabled, can't be a double fault
369 tm __LC_PGM_ILC+3,0x80 # check for per exception
370 jnz .Lpgm_svcper # -> single stepped svc
3712: CHECK_STACK __LC_SAVE_AREA_SYNC
372 aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
373 # CHECK_VMAP_STACK branches to stack_overflow or 4f
374 CHECK_VMAP_STACK __LC_SAVE_AREA_SYNC,4f
3753: BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP
376 lg %r15,__LC_KERNEL_STACK
3774: la %r11,STACK_FRAME_OVERHEAD(%r15)
378 stg %r10,__PT_FLAGS(%r11)
379 xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
380 stmg %r0,%r7,__PT_R0(%r11)
381 mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC
382 mvc __PT_LAST_BREAK(8,%r11),__LC_PGM_LAST_BREAK
383 stmg %r8,%r9,__PT_PSW(%r11)
384
385 # clear user controlled registers to prevent speculative use
386 xgr %r0,%r0
387 xgr %r1,%r1
388 xgr %r3,%r3
389 xgr %r4,%r4
390 xgr %r5,%r5
391 xgr %r6,%r6
392 xgr %r7,%r7
393 lgr %r2,%r11
394 brasl %r14,__do_pgm_check
395 tmhh %r8,0x0001 # returning to user space?
396 jno .Lpgm_exit_kernel
397 lctlg %c1,%c1,__LC_USER_ASCE
398 BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP
399 stpt __LC_EXIT_TIMER
400.Lpgm_exit_kernel:
401 mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
402 LBEAR STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
403 lmg %r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
404 LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE
405
406#
407# single stepped system call
408#
409.Lpgm_svcper:
410 mvc __LC_RETURN_PSW(8),__LC_SVC_NEW_PSW
411 larl %r14,.Lsysc_per
412 stg %r14,__LC_RETURN_PSW+8
413 lghi %r14,1
414 LBEAR __LC_PGM_LAST_BREAK
415 LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE # branch to .Lsysc_per
416ENDPROC(pgm_check_handler)
417
418/*
419 * Interrupt handler macro used for external and IO interrupts.
420 */
421.macro INT_HANDLER name,lc_old_psw,handler
422ENTRY(\name)
423 stckf __LC_INT_CLOCK
424 stpt __LC_SYS_ENTER_TIMER
425 STBEAR __LC_LAST_BREAK
426 BPOFF
427 stmg %r8,%r15,__LC_SAVE_AREA_ASYNC
428 lg %r12,__LC_CURRENT
429 lmg %r8,%r9,\lc_old_psw
430 tmhh %r8,0x0001 # interrupting from user ?
431 jnz 1f
432#if IS_ENABLED(CONFIG_KVM)
433 OUTSIDE %r9,.Lsie_gmap,.Lsie_done,0f
434 BPENTER __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
435 SIEEXIT
436#endif
4370: CHECK_STACK __LC_SAVE_AREA_ASYNC
438 aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
439 j 2f
4401: BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP
441 lctlg %c1,%c1,__LC_KERNEL_ASCE
442 lg %r15,__LC_KERNEL_STACK
4432: xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
444 la %r11,STACK_FRAME_OVERHEAD(%r15)
445 stmg %r0,%r7,__PT_R0(%r11)
446 # clear user controlled registers to prevent speculative use
447 xgr %r0,%r0
448 xgr %r1,%r1
449 xgr %r3,%r3
450 xgr %r4,%r4
451 xgr %r5,%r5
452 xgr %r6,%r6
453 xgr %r7,%r7
454 xgr %r10,%r10
455 xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
456 mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
457 MBEAR %r11
458 stmg %r8,%r9,__PT_PSW(%r11)
459 lgr %r2,%r11 # pass pointer to pt_regs
460 brasl %r14,\handler
461 mvc __LC_RETURN_PSW(16),__PT_PSW(%r11)
462 tmhh %r8,0x0001 # returning to user ?
463 jno 2f
464 lctlg %c1,%c1,__LC_USER_ASCE
465 BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP
466 stpt __LC_EXIT_TIMER
4672: LBEAR __PT_LAST_BREAK(%r11)
468 lmg %r0,%r15,__PT_R0(%r11)
469 LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE
470ENDPROC(\name)
471.endm
472
473INT_HANDLER ext_int_handler,__LC_EXT_OLD_PSW,do_ext_irq
474INT_HANDLER io_int_handler,__LC_IO_OLD_PSW,do_io_irq
475
476/*
477 * Load idle PSW.
478 */
479ENTRY(psw_idle)
480 stg %r14,(__SF_GPRS+8*8)(%r15)
481 stg %r3,__SF_EMPTY(%r15)
482 larl %r1,psw_idle_exit
483 stg %r1,__SF_EMPTY+8(%r15)
484 larl %r1,smp_cpu_mtid
485 llgf %r1,0(%r1)
486 ltgr %r1,%r1
487 jz .Lpsw_idle_stcctm
488 .insn rsy,0xeb0000000017,%r1,5,__MT_CYCLES_ENTER(%r2)
489.Lpsw_idle_stcctm:
490 oi __LC_CPU_FLAGS+7,_CIF_ENABLED_WAIT
491 BPON
492 stckf __CLOCK_IDLE_ENTER(%r2)
493 stpt __TIMER_IDLE_ENTER(%r2)
494 lpswe __SF_EMPTY(%r15)
495.globl psw_idle_exit
496psw_idle_exit:
497 BR_EX %r14
498ENDPROC(psw_idle)
499
500/*
501 * Machine check handler routines
502 */
503ENTRY(mcck_int_handler)
504 stckf __LC_MCCK_CLOCK
505 BPOFF
506 la %r1,4095 # validate r1
507 spt __LC_CPU_TIMER_SAVE_AREA-4095(%r1) # validate cpu timer
508 LBEAR __LC_LAST_BREAK_SAVE_AREA-4095(%r1) # validate bear
509 lmg %r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r1)# validate gprs
510 lg %r12,__LC_CURRENT
511 lmg %r8,%r9,__LC_MCK_OLD_PSW
512 TSTMSK __LC_MCCK_CODE,MCCK_CODE_SYSTEM_DAMAGE
513 jo .Lmcck_panic # yes -> rest of mcck code invalid
514 TSTMSK __LC_MCCK_CODE,MCCK_CODE_CR_VALID
515 jno .Lmcck_panic # control registers invalid -> panic
516 la %r14,4095
517 lctlg %c0,%c15,__LC_CREGS_SAVE_AREA-4095(%r14) # validate ctl regs
518 ptlb
519 lghi %r14,__LC_CPU_TIMER_SAVE_AREA
520 mvc __LC_MCCK_ENTER_TIMER(8),0(%r14)
521 TSTMSK __LC_MCCK_CODE,MCCK_CODE_CPU_TIMER_VALID
522 jo 3f
523 la %r14,__LC_SYS_ENTER_TIMER
524 clc 0(8,%r14),__LC_EXIT_TIMER
525 jl 1f
526 la %r14,__LC_EXIT_TIMER
5271: clc 0(8,%r14),__LC_LAST_UPDATE_TIMER
528 jl 2f
529 la %r14,__LC_LAST_UPDATE_TIMER
5302: spt 0(%r14)
531 mvc __LC_MCCK_ENTER_TIMER(8),0(%r14)
5323: TSTMSK __LC_MCCK_CODE,MCCK_CODE_PSW_MWP_VALID
533 jno .Lmcck_panic
534 tmhh %r8,0x0001 # interrupting from user ?
535 jnz .Lmcck_user
536 TSTMSK __LC_MCCK_CODE,MCCK_CODE_PSW_IA_VALID
537 jno .Lmcck_panic
538#if IS_ENABLED(CONFIG_KVM)
539 OUTSIDE %r9,.Lsie_gmap,.Lsie_done,.Lmcck_stack
540 OUTSIDE %r9,.Lsie_entry,.Lsie_leave,4f
541 oi __LC_CPU_FLAGS+7, _CIF_MCCK_GUEST
5424: BPENTER __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
543 SIEEXIT
544 j .Lmcck_stack
545#endif
546.Lmcck_user:
547 BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP
548.Lmcck_stack:
549 lg %r15,__LC_MCCK_STACK
550 la %r11,STACK_FRAME_OVERHEAD(%r15)
551 stctg %c1,%c1,__PT_CR1(%r11)
552 lctlg %c1,%c1,__LC_KERNEL_ASCE
553 xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
554 lghi %r14,__LC_GPREGS_SAVE_AREA+64
555 stmg %r0,%r7,__PT_R0(%r11)
556 # clear user controlled registers to prevent speculative use
557 xgr %r0,%r0
558 xgr %r1,%r1
559 xgr %r3,%r3
560 xgr %r4,%r4
561 xgr %r5,%r5
562 xgr %r6,%r6
563 xgr %r7,%r7
564 xgr %r10,%r10
565 mvc __PT_R8(64,%r11),0(%r14)
566 stmg %r8,%r9,__PT_PSW(%r11)
567 xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
568 xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
569 lgr %r2,%r11 # pass pointer to pt_regs
570 brasl %r14,s390_do_machine_check
571 cghi %r2,0
572 je .Lmcck_return
573 lg %r1,__LC_KERNEL_STACK # switch to kernel stack
574 mvc STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
575 xc __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1)
576 la %r11,STACK_FRAME_OVERHEAD(%r1)
577 lgr %r2,%r11
578 lgr %r15,%r1
579 brasl %r14,s390_handle_mcck
580.Lmcck_return:
581 lctlg %c1,%c1,__PT_CR1(%r11)
582 lmg %r0,%r10,__PT_R0(%r11)
583 mvc __LC_RETURN_MCCK_PSW(16),__PT_PSW(%r11) # move return PSW
584 tm __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
585 jno 0f
586 BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP
587 stpt __LC_EXIT_TIMER
5880: ALTERNATIVE "nop", __stringify(lghi %r12,__LC_LAST_BREAK_SAVE_AREA),193
589 LBEAR 0(%r12)
590 lmg %r11,%r15,__PT_R11(%r11)
591 LPSWEY __LC_RETURN_MCCK_PSW,__LC_RETURN_MCCK_LPSWE
592
593.Lmcck_panic:
594 /*
595 * Iterate over all possible CPU addresses in the range 0..0xffff
596 * and stop each CPU using signal processor. Use compare and swap
597 * to allow just one CPU-stopper and prevent concurrent CPUs from
598 * stopping each other while leaving the others running.
599 */
600 lhi %r5,0
601 lhi %r6,1
602 larl %r7,.Lstop_lock
603 cs %r5,%r6,0(%r7) # single CPU-stopper only
604 jnz 4f
605 larl %r7,.Lthis_cpu
606 stap 0(%r7) # this CPU address
607 lh %r4,0(%r7)
608 nilh %r4,0
609 lhi %r0,1
610 sll %r0,16 # CPU counter
611 lhi %r3,0 # next CPU address
6120: cr %r3,%r4
613 je 2f
6141: sigp %r1,%r3,SIGP_STOP # stop next CPU
615 brc SIGP_CC_BUSY,1b
6162: ahi %r3,1
617 brct %r0,0b
6183: sigp %r1,%r4,SIGP_STOP # stop this CPU
619 brc SIGP_CC_BUSY,3b
6204: j 4b
621ENDPROC(mcck_int_handler)
622
623ENTRY(restart_int_handler)
624 ALTERNATIVE "nop", "lpp _LPP_OFFSET", 40
625 stg %r15,__LC_SAVE_AREA_RESTART
626 TSTMSK __LC_RESTART_FLAGS,RESTART_FLAG_CTLREGS,4
627 jz 0f
628 la %r15,4095
629 lctlg %c0,%c15,__LC_CREGS_SAVE_AREA-4095(%r15)
6300: larl %r15,.Lstosm_tmp
631 stosm 0(%r15),0x04 # turn dat on, keep irqs off
632 lg %r15,__LC_RESTART_STACK
633 xc STACK_FRAME_OVERHEAD(__PT_SIZE,%r15),STACK_FRAME_OVERHEAD(%r15)
634 stmg %r0,%r14,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
635 mvc STACK_FRAME_OVERHEAD+__PT_R15(8,%r15),__LC_SAVE_AREA_RESTART
636 mvc STACK_FRAME_OVERHEAD+__PT_PSW(16,%r15),__LC_RST_OLD_PSW
637 xc 0(STACK_FRAME_OVERHEAD,%r15),0(%r15)
638 lg %r1,__LC_RESTART_FN # load fn, parm & source cpu
639 lg %r2,__LC_RESTART_DATA
640 lgf %r3,__LC_RESTART_SOURCE
641 ltgr %r3,%r3 # test source cpu address
642 jm 1f # negative -> skip source stop
6430: sigp %r4,%r3,SIGP_SENSE # sigp sense to source cpu
644 brc 10,0b # wait for status stored
6451: basr %r14,%r1 # call function
646 stap __SF_EMPTY(%r15) # store cpu address
647 llgh %r3,__SF_EMPTY(%r15)
6482: sigp %r4,%r3,SIGP_STOP # sigp stop to current cpu
649 brc 2,2b
6503: j 3b
651ENDPROC(restart_int_handler)
652
653 .section .kprobes.text, "ax"
654
655#if defined(CONFIG_CHECK_STACK) || defined(CONFIG_VMAP_STACK)
656/*
657 * The synchronous or the asynchronous stack overflowed. We are dead.
658 * No need to properly save the registers, we are going to panic anyway.
659 * Setup a pt_regs so that show_trace can provide a good call trace.
660 */
661ENTRY(stack_overflow)
662 lg %r15,__LC_NODAT_STACK # change to panic stack
663 la %r11,STACK_FRAME_OVERHEAD(%r15)
664 stmg %r0,%r7,__PT_R0(%r11)
665 stmg %r8,%r9,__PT_PSW(%r11)
666 mvc __PT_R8(64,%r11),0(%r14)
667 stg %r10,__PT_ORIG_GPR2(%r11) # store last break to orig_gpr2
668 xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
669 lgr %r2,%r11 # pass pointer to pt_regs
670 jg kernel_stack_overflow
671ENDPROC(stack_overflow)
672#endif
673
674 .section .data, "aw"
675 .align 4
676.Lstop_lock: .long 0
677.Lthis_cpu: .short 0
678.Lstosm_tmp: .byte 0
679 .section .rodata, "a"
680#define SYSCALL(esame,emu) .quad __s390x_ ## esame
681 .globl sys_call_table
682sys_call_table:
683#include "asm/syscall_table.h"
684#undef SYSCALL
685
686#ifdef CONFIG_COMPAT
687
688#define SYSCALL(esame,emu) .quad __s390_ ## emu
689 .globl sys_call_table_emu
690sys_call_table_emu:
691#include "asm/syscall_table.h"
692#undef SYSCALL
693#endif