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-rw-r--r--arch/s390/kernel/entry.S715
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diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
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+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * S390 low-level entry points.
+ *
+ * Copyright IBM Corp. 1999, 2012
+ * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
+ * Hartmut Penner (hp@de.ibm.com),
+ * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
+ */
+
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <asm/asm-extable.h>
+#include <asm/alternative-asm.h>
+#include <asm/processor.h>
+#include <asm/cache.h>
+#include <asm/dwarf.h>
+#include <asm/errno.h>
+#include <asm/ptrace.h>
+#include <asm/thread_info.h>
+#include <asm/asm-offsets.h>
+#include <asm/unistd.h>
+#include <asm/page.h>
+#include <asm/sigp.h>
+#include <asm/irq.h>
+#include <asm/vx-insn.h>
+#include <asm/setup.h>
+#include <asm/nmi.h>
+#include <asm/export.h>
+#include <asm/nospec-insn.h>
+
+STACK_SHIFT = PAGE_SHIFT + THREAD_SIZE_ORDER
+STACK_SIZE = 1 << STACK_SHIFT
+STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE
+
+_LPP_OFFSET = __LC_LPP
+
+ .macro STBEAR address
+ ALTERNATIVE "nop", ".insn s,0xb2010000,\address", 193
+ .endm
+
+ .macro LBEAR address
+ ALTERNATIVE "nop", ".insn s,0xb2000000,\address", 193
+ .endm
+
+ .macro LPSWEY address,lpswe
+ ALTERNATIVE "b \lpswe; nopr", ".insn siy,0xeb0000000071,\address,0", 193
+ .endm
+
+ .macro MBEAR reg
+ ALTERNATIVE "brcl 0,0", __stringify(mvc __PT_LAST_BREAK(8,\reg),__LC_LAST_BREAK), 193
+ .endm
+
+ .macro CHECK_STACK savearea
+#ifdef CONFIG_CHECK_STACK
+ tml %r15,STACK_SIZE - CONFIG_STACK_GUARD
+ lghi %r14,\savearea
+ jz stack_overflow
+#endif
+ .endm
+
+ .macro CHECK_VMAP_STACK savearea,oklabel
+#ifdef CONFIG_VMAP_STACK
+ lgr %r14,%r15
+ nill %r14,0x10000 - STACK_SIZE
+ oill %r14,STACK_INIT
+ clg %r14,__LC_KERNEL_STACK
+ je \oklabel
+ clg %r14,__LC_ASYNC_STACK
+ je \oklabel
+ clg %r14,__LC_MCCK_STACK
+ je \oklabel
+ clg %r14,__LC_NODAT_STACK
+ je \oklabel
+ clg %r14,__LC_RESTART_STACK
+ je \oklabel
+ lghi %r14,\savearea
+ j stack_overflow
+#else
+ j \oklabel
+#endif
+ .endm
+
+ /*
+ * The TSTMSK macro generates a test-under-mask instruction by
+ * calculating the memory offset for the specified mask value.
+ * Mask value can be any constant. The macro shifts the mask
+ * value to calculate the memory offset for the test-under-mask
+ * instruction.
+ */
+ .macro TSTMSK addr, mask, size=8, bytepos=0
+ .if (\bytepos < \size) && (\mask >> 8)
+ .if (\mask & 0xff)
+ .error "Mask exceeds byte boundary"
+ .endif
+ TSTMSK \addr, "(\mask >> 8)", \size, "(\bytepos + 1)"
+ .exitm
+ .endif
+ .ifeq \mask
+ .error "Mask must not be zero"
+ .endif
+ off = \size - \bytepos - 1
+ tm off+\addr, \mask
+ .endm
+
+ .macro BPOFF
+ ALTERNATIVE "nop", ".insn rrf,0xb2e80000,0,0,12,0", 82
+ .endm
+
+ .macro BPON
+ ALTERNATIVE "nop", ".insn rrf,0xb2e80000,0,0,13,0", 82
+ .endm
+
+ .macro BPENTER tif_ptr,tif_mask
+ ALTERNATIVE "TSTMSK \tif_ptr,\tif_mask; jz .+8; .insn rrf,0xb2e80000,0,0,13,0", \
+ "j .+12; nop; nop", 82
+ .endm
+
+ .macro BPEXIT tif_ptr,tif_mask
+ TSTMSK \tif_ptr,\tif_mask
+ ALTERNATIVE "jz .+8; .insn rrf,0xb2e80000,0,0,12,0", \
+ "jnz .+8; .insn rrf,0xb2e80000,0,0,13,0", 82
+ .endm
+
+ /*
+ * The CHKSTG macro jumps to the provided label in case the
+ * machine check interruption code reports one of unrecoverable
+ * storage errors:
+ * - Storage error uncorrected
+ * - Storage key error uncorrected
+ * - Storage degradation with Failing-storage-address validity
+ */
+ .macro CHKSTG errlabel
+ TSTMSK __LC_MCCK_CODE,(MCCK_CODE_STG_ERROR|MCCK_CODE_STG_KEY_ERROR)
+ jnz \errlabel
+ TSTMSK __LC_MCCK_CODE,MCCK_CODE_STG_DEGRAD
+ jz .Loklabel\@
+ TSTMSK __LC_MCCK_CODE,MCCK_CODE_STG_FAIL_ADDR
+ jnz \errlabel
+.Loklabel\@:
+ .endm
+
+#if IS_ENABLED(CONFIG_KVM)
+ /*
+ * The OUTSIDE macro jumps to the provided label in case the value
+ * in the provided register is outside of the provided range. The
+ * macro is useful for checking whether a PSW stored in a register
+ * pair points inside or outside of a block of instructions.
+ * @reg: register to check
+ * @start: start of the range
+ * @end: end of the range
+ * @outside_label: jump here if @reg is outside of [@start..@end)
+ */
+ .macro OUTSIDE reg,start,end,outside_label
+ lgr %r14,\reg
+ larl %r13,\start
+ slgr %r14,%r13
+#ifdef CONFIG_AS_IS_LLVM
+ clgfrl %r14,.Lrange_size\@
+#else
+ clgfi %r14,\end - \start
+#endif
+ jhe \outside_label
+#ifdef CONFIG_AS_IS_LLVM
+ .section .rodata, "a"
+ .align 4
+.Lrange_size\@:
+ .long \end - \start
+ .previous
+#endif
+ .endm
+
+ .macro SIEEXIT
+ lg %r9,__SF_SIE_CONTROL(%r15) # get control block pointer
+ ni __SIE_PROG0C+3(%r9),0xfe # no longer in SIE
+ lctlg %c1,%c1,__LC_KERNEL_ASCE # load primary asce
+ larl %r9,sie_exit # skip forward to sie_exit
+ .endm
+#endif
+
+ GEN_BR_THUNK %r14
+
+ .section .kprobes.text, "ax"
+.Ldummy:
+ /*
+ * This nop exists only in order to avoid that __bpon starts at
+ * the beginning of the kprobes text section. In that case we would
+ * have several symbols at the same address. E.g. objdump would take
+ * an arbitrary symbol name when disassembling this code.
+ * With the added nop in between the __bpon symbol is unique
+ * again.
+ */
+ nop 0
+
+ENTRY(__bpon)
+ .globl __bpon
+ BPON
+ BR_EX %r14
+ENDPROC(__bpon)
+
+/*
+ * Scheduler resume function, called by switch_to
+ * gpr2 = (task_struct *) prev
+ * gpr3 = (task_struct *) next
+ * Returns:
+ * gpr2 = prev
+ */
+ENTRY(__switch_to)
+ stmg %r6,%r15,__SF_GPRS(%r15) # store gprs of prev task
+ lghi %r4,__TASK_stack
+ lghi %r1,__TASK_thread
+ llill %r5,STACK_INIT
+ stg %r15,__THREAD_ksp(%r1,%r2) # store kernel stack of prev
+ lg %r15,0(%r4,%r3) # start of kernel stack of next
+ agr %r15,%r5 # end of kernel stack of next
+ stg %r3,__LC_CURRENT # store task struct of next
+ stg %r15,__LC_KERNEL_STACK # store end of kernel stack
+ lg %r15,__THREAD_ksp(%r1,%r3) # load kernel stack of next
+ aghi %r3,__TASK_pid
+ mvc __LC_CURRENT_PID(4,%r0),0(%r3) # store pid of next
+ lmg %r6,%r15,__SF_GPRS(%r15) # load gprs of next task
+ ALTERNATIVE "nop", "lpp _LPP_OFFSET", 40
+ BR_EX %r14
+ENDPROC(__switch_to)
+
+#if IS_ENABLED(CONFIG_KVM)
+/*
+ * sie64a calling convention:
+ * %r2 pointer to sie control block
+ * %r3 guest register save area
+ */
+ENTRY(sie64a)
+ stmg %r6,%r14,__SF_GPRS(%r15) # save kernel registers
+ lg %r12,__LC_CURRENT
+ stg %r2,__SF_SIE_CONTROL(%r15) # save control block pointer
+ stg %r3,__SF_SIE_SAVEAREA(%r15) # save guest register save area
+ xc __SF_SIE_REASON(8,%r15),__SF_SIE_REASON(%r15) # reason code = 0
+ mvc __SF_SIE_FLAGS(8,%r15),__TI_flags(%r12) # copy thread flags
+ lmg %r0,%r13,0(%r3) # load guest gprs 0-13
+ lg %r14,__LC_GMAP # get gmap pointer
+ ltgr %r14,%r14
+ jz .Lsie_gmap
+ lctlg %c1,%c1,__GMAP_ASCE(%r14) # load primary asce
+.Lsie_gmap:
+ lg %r14,__SF_SIE_CONTROL(%r15) # get control block pointer
+ oi __SIE_PROG0C+3(%r14),1 # we are going into SIE now
+ tm __SIE_PROG20+3(%r14),3 # last exit...
+ jnz .Lsie_skip
+ TSTMSK __LC_CPU_FLAGS,_CIF_FPU
+ jo .Lsie_skip # exit if fp/vx regs changed
+ BPEXIT __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
+.Lsie_entry:
+ sie 0(%r14)
+# Let the next instruction be NOP to avoid triggering a machine check
+# and handling it in a guest as result of the instruction execution.
+ nopr 7
+.Lsie_leave:
+ BPOFF
+ BPENTER __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
+.Lsie_skip:
+ ni __SIE_PROG0C+3(%r14),0xfe # no longer in SIE
+ lctlg %c1,%c1,__LC_KERNEL_ASCE # load primary asce
+.Lsie_done:
+# some program checks are suppressing. C code (e.g. do_protection_exception)
+# will rewind the PSW by the ILC, which is often 4 bytes in case of SIE. There
+# are some corner cases (e.g. runtime instrumentation) where ILC is unpredictable.
+# Other instructions between sie64a and .Lsie_done should not cause program
+# interrupts. So lets use 3 nops as a landing pad for all possible rewinds.
+.Lrewind_pad6:
+ nopr 7
+.Lrewind_pad4:
+ nopr 7
+.Lrewind_pad2:
+ nopr 7
+ .globl sie_exit
+sie_exit:
+ lg %r14,__SF_SIE_SAVEAREA(%r15) # load guest register save area
+ stmg %r0,%r13,0(%r14) # save guest gprs 0-13
+ xgr %r0,%r0 # clear guest registers to
+ xgr %r1,%r1 # prevent speculative use
+ xgr %r3,%r3
+ xgr %r4,%r4
+ xgr %r5,%r5
+ lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers
+ lg %r2,__SF_SIE_REASON(%r15) # return exit reason code
+ BR_EX %r14
+.Lsie_fault:
+ lghi %r14,-EFAULT
+ stg %r14,__SF_SIE_REASON(%r15) # set exit reason code
+ j sie_exit
+
+ EX_TABLE(.Lrewind_pad6,.Lsie_fault)
+ EX_TABLE(.Lrewind_pad4,.Lsie_fault)
+ EX_TABLE(.Lrewind_pad2,.Lsie_fault)
+ EX_TABLE(sie_exit,.Lsie_fault)
+ENDPROC(sie64a)
+EXPORT_SYMBOL(sie64a)
+EXPORT_SYMBOL(sie_exit)
+#endif
+
+/*
+ * SVC interrupt handler routine. System calls are synchronous events and
+ * are entered with interrupts disabled.
+ */
+
+ENTRY(system_call)
+ stpt __LC_SYS_ENTER_TIMER
+ stmg %r8,%r15,__LC_SAVE_AREA_SYNC
+ BPOFF
+ lghi %r14,0
+.Lsysc_per:
+ STBEAR __LC_LAST_BREAK
+ lctlg %c1,%c1,__LC_KERNEL_ASCE
+ lg %r12,__LC_CURRENT
+ lg %r15,__LC_KERNEL_STACK
+ xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
+ stmg %r0,%r7,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
+ BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP
+ # clear user controlled register to prevent speculative use
+ xgr %r0,%r0
+ xgr %r1,%r1
+ xgr %r4,%r4
+ xgr %r5,%r5
+ xgr %r6,%r6
+ xgr %r7,%r7
+ xgr %r8,%r8
+ xgr %r9,%r9
+ xgr %r10,%r10
+ xgr %r11,%r11
+ la %r2,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs
+ mvc __PT_R8(64,%r2),__LC_SAVE_AREA_SYNC
+ MBEAR %r2
+ lgr %r3,%r14
+ brasl %r14,__do_syscall
+ lctlg %c1,%c1,__LC_USER_ASCE
+ mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
+ BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP
+ LBEAR STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
+ lmg %r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
+ stpt __LC_EXIT_TIMER
+ LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE
+ENDPROC(system_call)
+
+#
+# a new process exits the kernel with ret_from_fork
+#
+ENTRY(ret_from_fork)
+ lgr %r3,%r11
+ brasl %r14,__ret_from_fork
+ lctlg %c1,%c1,__LC_USER_ASCE
+ mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
+ BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP
+ LBEAR STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
+ lmg %r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
+ stpt __LC_EXIT_TIMER
+ LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE
+ENDPROC(ret_from_fork)
+
+/*
+ * Program check handler routine
+ */
+
+ENTRY(pgm_check_handler)
+ stpt __LC_SYS_ENTER_TIMER
+ BPOFF
+ stmg %r8,%r15,__LC_SAVE_AREA_SYNC
+ lg %r12,__LC_CURRENT
+ lghi %r10,0
+ lmg %r8,%r9,__LC_PGM_OLD_PSW
+ tmhh %r8,0x0001 # coming from user space?
+ jno .Lpgm_skip_asce
+ lctlg %c1,%c1,__LC_KERNEL_ASCE
+ j 3f # -> fault in user space
+.Lpgm_skip_asce:
+#if IS_ENABLED(CONFIG_KVM)
+ # cleanup critical section for program checks in sie64a
+ OUTSIDE %r9,.Lsie_gmap,.Lsie_done,1f
+ SIEEXIT
+ lghi %r10,_PIF_GUEST_FAULT
+#endif
+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
+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
+3: BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP
+ lg %r15,__LC_KERNEL_STACK
+4: la %r11,STACK_FRAME_OVERHEAD(%r15)
+ stg %r10,__PT_FLAGS(%r11)
+ xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
+ stmg %r0,%r7,__PT_R0(%r11)
+ mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC
+ mvc __PT_LAST_BREAK(8,%r11),__LC_PGM_LAST_BREAK
+ stmg %r8,%r9,__PT_PSW(%r11)
+
+ # clear user controlled registers to prevent speculative use
+ xgr %r0,%r0
+ xgr %r1,%r1
+ xgr %r3,%r3
+ xgr %r4,%r4
+ xgr %r5,%r5
+ xgr %r6,%r6
+ xgr %r7,%r7
+ lgr %r2,%r11
+ brasl %r14,__do_pgm_check
+ tmhh %r8,0x0001 # returning to user space?
+ jno .Lpgm_exit_kernel
+ lctlg %c1,%c1,__LC_USER_ASCE
+ BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP
+ stpt __LC_EXIT_TIMER
+.Lpgm_exit_kernel:
+ mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
+ LBEAR STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
+ lmg %r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
+ LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE
+
+#
+# single stepped system call
+#
+.Lpgm_svcper:
+ mvc __LC_RETURN_PSW(8),__LC_SVC_NEW_PSW
+ larl %r14,.Lsysc_per
+ stg %r14,__LC_RETURN_PSW+8
+ lghi %r14,1
+ LBEAR __LC_PGM_LAST_BREAK
+ LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE # branch to .Lsysc_per
+ENDPROC(pgm_check_handler)
+
+/*
+ * Interrupt handler macro used for external and IO interrupts.
+ */
+.macro INT_HANDLER name,lc_old_psw,handler
+ENTRY(\name)
+ stckf __LC_INT_CLOCK
+ stpt __LC_SYS_ENTER_TIMER
+ STBEAR __LC_LAST_BREAK
+ BPOFF
+ stmg %r8,%r15,__LC_SAVE_AREA_ASYNC
+ lg %r12,__LC_CURRENT
+ lmg %r8,%r9,\lc_old_psw
+ tmhh %r8,0x0001 # interrupting from user ?
+ jnz 1f
+#if IS_ENABLED(CONFIG_KVM)
+ OUTSIDE %r9,.Lsie_gmap,.Lsie_done,0f
+ BPENTER __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
+ SIEEXIT
+#endif
+0: CHECK_STACK __LC_SAVE_AREA_ASYNC
+ aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
+ j 2f
+1: BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP
+ lctlg %c1,%c1,__LC_KERNEL_ASCE
+ lg %r15,__LC_KERNEL_STACK
+2: xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
+ la %r11,STACK_FRAME_OVERHEAD(%r15)
+ stmg %r0,%r7,__PT_R0(%r11)
+ # clear user controlled registers to prevent speculative use
+ xgr %r0,%r0
+ xgr %r1,%r1
+ xgr %r3,%r3
+ xgr %r4,%r4
+ xgr %r5,%r5
+ xgr %r6,%r6
+ xgr %r7,%r7
+ xgr %r10,%r10
+ xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
+ mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
+ MBEAR %r11
+ stmg %r8,%r9,__PT_PSW(%r11)
+ lgr %r2,%r11 # pass pointer to pt_regs
+ brasl %r14,\handler
+ mvc __LC_RETURN_PSW(16),__PT_PSW(%r11)
+ tmhh %r8,0x0001 # returning to user ?
+ jno 2f
+ lctlg %c1,%c1,__LC_USER_ASCE
+ BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP
+ stpt __LC_EXIT_TIMER
+2: LBEAR __PT_LAST_BREAK(%r11)
+ lmg %r0,%r15,__PT_R0(%r11)
+ LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE
+ENDPROC(\name)
+.endm
+
+INT_HANDLER ext_int_handler,__LC_EXT_OLD_PSW,do_ext_irq
+INT_HANDLER io_int_handler,__LC_IO_OLD_PSW,do_io_irq
+
+/*
+ * Load idle PSW.
+ */
+ENTRY(psw_idle)
+ stg %r14,(__SF_GPRS+8*8)(%r15)
+ stg %r3,__SF_EMPTY(%r15)
+ larl %r1,psw_idle_exit
+ stg %r1,__SF_EMPTY+8(%r15)
+ larl %r1,smp_cpu_mtid
+ llgf %r1,0(%r1)
+ ltgr %r1,%r1
+ jz .Lpsw_idle_stcctm
+ .insn rsy,0xeb0000000017,%r1,5,__MT_CYCLES_ENTER(%r2)
+.Lpsw_idle_stcctm:
+ oi __LC_CPU_FLAGS+7,_CIF_ENABLED_WAIT
+ BPON
+ stckf __CLOCK_IDLE_ENTER(%r2)
+ stpt __TIMER_IDLE_ENTER(%r2)
+ lpswe __SF_EMPTY(%r15)
+.globl psw_idle_exit
+psw_idle_exit:
+ BR_EX %r14
+ENDPROC(psw_idle)
+
+/*
+ * Machine check handler routines
+ */
+ENTRY(mcck_int_handler)
+ stckf __LC_MCCK_CLOCK
+ BPOFF
+ la %r1,4095 # validate r1
+ spt __LC_CPU_TIMER_SAVE_AREA-4095(%r1) # validate cpu timer
+ LBEAR __LC_LAST_BREAK_SAVE_AREA-4095(%r1) # validate bear
+ lmg %r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r1)# validate gprs
+ lg %r12,__LC_CURRENT
+ lmg %r8,%r9,__LC_MCK_OLD_PSW
+ TSTMSK __LC_MCCK_CODE,MCCK_CODE_SYSTEM_DAMAGE
+ jo .Lmcck_panic # yes -> rest of mcck code invalid
+ TSTMSK __LC_MCCK_CODE,MCCK_CODE_CR_VALID
+ jno .Lmcck_panic # control registers invalid -> panic
+ la %r14,4095
+ lctlg %c0,%c15,__LC_CREGS_SAVE_AREA-4095(%r14) # validate ctl regs
+ ptlb
+ lghi %r14,__LC_CPU_TIMER_SAVE_AREA
+ mvc __LC_MCCK_ENTER_TIMER(8),0(%r14)
+ TSTMSK __LC_MCCK_CODE,MCCK_CODE_CPU_TIMER_VALID
+ jo 3f
+ la %r14,__LC_SYS_ENTER_TIMER
+ clc 0(8,%r14),__LC_EXIT_TIMER
+ jl 1f
+ la %r14,__LC_EXIT_TIMER
+1: clc 0(8,%r14),__LC_LAST_UPDATE_TIMER
+ jl 2f
+ la %r14,__LC_LAST_UPDATE_TIMER
+2: spt 0(%r14)
+ mvc __LC_MCCK_ENTER_TIMER(8),0(%r14)
+3: TSTMSK __LC_MCCK_CODE,MCCK_CODE_PSW_MWP_VALID
+ jno .Lmcck_panic
+ tmhh %r8,0x0001 # interrupting from user ?
+ jnz 6f
+ TSTMSK __LC_MCCK_CODE,MCCK_CODE_PSW_IA_VALID
+ jno .Lmcck_panic
+#if IS_ENABLED(CONFIG_KVM)
+ OUTSIDE %r9,.Lsie_gmap,.Lsie_done,6f
+ OUTSIDE %r9,.Lsie_entry,.Lsie_leave,4f
+ oi __LC_CPU_FLAGS+7, _CIF_MCCK_GUEST
+ j 5f
+4: CHKSTG .Lmcck_panic
+5: larl %r14,.Lstosm_tmp
+ stosm 0(%r14),0x04 # turn dat on, keep irqs off
+ BPENTER __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
+ SIEEXIT
+ j .Lmcck_stack
+#endif
+6: CHKSTG .Lmcck_panic
+ larl %r14,.Lstosm_tmp
+ stosm 0(%r14),0x04 # turn dat on, keep irqs off
+ tmhh %r8,0x0001 # interrupting from user ?
+ jz .Lmcck_stack
+ BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP
+.Lmcck_stack:
+ lg %r15,__LC_MCCK_STACK
+ la %r11,STACK_FRAME_OVERHEAD(%r15)
+ stctg %c1,%c1,__PT_CR1(%r11)
+ lctlg %c1,%c1,__LC_KERNEL_ASCE
+ xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
+ lghi %r14,__LC_GPREGS_SAVE_AREA+64
+ stmg %r0,%r7,__PT_R0(%r11)
+ # clear user controlled registers to prevent speculative use
+ xgr %r0,%r0
+ xgr %r1,%r1
+ xgr %r3,%r3
+ xgr %r4,%r4
+ xgr %r5,%r5
+ xgr %r6,%r6
+ xgr %r7,%r7
+ xgr %r10,%r10
+ mvc __PT_R8(64,%r11),0(%r14)
+ stmg %r8,%r9,__PT_PSW(%r11)
+ xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
+ xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
+ lgr %r2,%r11 # pass pointer to pt_regs
+ brasl %r14,s390_do_machine_check
+ cghi %r2,0
+ je .Lmcck_return
+ lg %r1,__LC_KERNEL_STACK # switch to kernel stack
+ mvc STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
+ xc __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1)
+ la %r11,STACK_FRAME_OVERHEAD(%r1)
+ lgr %r2,%r11
+ lgr %r15,%r1
+ brasl %r14,s390_handle_mcck
+.Lmcck_return:
+ lctlg %c1,%c1,__PT_CR1(%r11)
+ lmg %r0,%r10,__PT_R0(%r11)
+ mvc __LC_RETURN_MCCK_PSW(16),__PT_PSW(%r11) # move return PSW
+ tm __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
+ jno 0f
+ BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP
+ stpt __LC_EXIT_TIMER
+0: ALTERNATIVE "nop", __stringify(lghi %r12,__LC_LAST_BREAK_SAVE_AREA),193
+ LBEAR 0(%r12)
+ lmg %r11,%r15,__PT_R11(%r11)
+ LPSWEY __LC_RETURN_MCCK_PSW,__LC_RETURN_MCCK_LPSWE
+
+.Lmcck_panic:
+ /*
+ * Iterate over all possible CPU addresses in the range 0..0xffff
+ * and stop each CPU using signal processor. Use compare and swap
+ * to allow just one CPU-stopper and prevent concurrent CPUs from
+ * stopping each other while leaving the others running.
+ */
+ lhi %r5,0
+ lhi %r6,1
+ larl %r7,.Lstop_lock
+ cs %r5,%r6,0(%r7) # single CPU-stopper only
+ jnz 4f
+ larl %r7,.Lthis_cpu
+ stap 0(%r7) # this CPU address
+ lh %r4,0(%r7)
+ nilh %r4,0
+ lhi %r0,1
+ sll %r0,16 # CPU counter
+ lhi %r3,0 # next CPU address
+0: cr %r3,%r4
+ je 2f
+1: sigp %r1,%r3,SIGP_STOP # stop next CPU
+ brc SIGP_CC_BUSY,1b
+2: ahi %r3,1
+ brct %r0,0b
+3: sigp %r1,%r4,SIGP_STOP # stop this CPU
+ brc SIGP_CC_BUSY,3b
+4: j 4b
+ENDPROC(mcck_int_handler)
+
+ENTRY(restart_int_handler)
+ ALTERNATIVE "nop", "lpp _LPP_OFFSET", 40
+ stg %r15,__LC_SAVE_AREA_RESTART
+ TSTMSK __LC_RESTART_FLAGS,RESTART_FLAG_CTLREGS,4
+ jz 0f
+ la %r15,4095
+ lctlg %c0,%c15,__LC_CREGS_SAVE_AREA-4095(%r15)
+0: larl %r15,.Lstosm_tmp
+ stosm 0(%r15),0x04 # turn dat on, keep irqs off
+ lg %r15,__LC_RESTART_STACK
+ xc STACK_FRAME_OVERHEAD(__PT_SIZE,%r15),STACK_FRAME_OVERHEAD(%r15)
+ stmg %r0,%r14,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
+ mvc STACK_FRAME_OVERHEAD+__PT_R15(8,%r15),__LC_SAVE_AREA_RESTART
+ mvc STACK_FRAME_OVERHEAD+__PT_PSW(16,%r15),__LC_RST_OLD_PSW
+ xc 0(STACK_FRAME_OVERHEAD,%r15),0(%r15)
+ lg %r1,__LC_RESTART_FN # load fn, parm & source cpu
+ lg %r2,__LC_RESTART_DATA
+ lgf %r3,__LC_RESTART_SOURCE
+ ltgr %r3,%r3 # test source cpu address
+ jm 1f # negative -> skip source stop
+0: sigp %r4,%r3,SIGP_SENSE # sigp sense to source cpu
+ brc 10,0b # wait for status stored
+1: basr %r14,%r1 # call function
+ stap __SF_EMPTY(%r15) # store cpu address
+ llgh %r3,__SF_EMPTY(%r15)
+2: sigp %r4,%r3,SIGP_STOP # sigp stop to current cpu
+ brc 2,2b
+3: j 3b
+ENDPROC(restart_int_handler)
+
+ .section .kprobes.text, "ax"
+
+#if defined(CONFIG_CHECK_STACK) || defined(CONFIG_VMAP_STACK)
+/*
+ * The synchronous or the asynchronous stack overflowed. We are dead.
+ * No need to properly save the registers, we are going to panic anyway.
+ * Setup a pt_regs so that show_trace can provide a good call trace.
+ */
+ENTRY(stack_overflow)
+ lg %r15,__LC_NODAT_STACK # change to panic stack
+ la %r11,STACK_FRAME_OVERHEAD(%r15)
+ stmg %r0,%r7,__PT_R0(%r11)
+ stmg %r8,%r9,__PT_PSW(%r11)
+ mvc __PT_R8(64,%r11),0(%r14)
+ stg %r10,__PT_ORIG_GPR2(%r11) # store last break to orig_gpr2
+ xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
+ lgr %r2,%r11 # pass pointer to pt_regs
+ jg kernel_stack_overflow
+ENDPROC(stack_overflow)
+#endif
+
+ .section .data, "aw"
+ .align 4
+.Lstop_lock: .long 0
+.Lthis_cpu: .short 0
+.Lstosm_tmp: .byte 0
+ .section .rodata, "a"
+#define SYSCALL(esame,emu) .quad __s390x_ ## esame
+ .globl sys_call_table
+sys_call_table:
+#include "asm/syscall_table.h"
+#undef SYSCALL
+
+#ifdef CONFIG_COMPAT
+
+#define SYSCALL(esame,emu) .quad __s390_ ## emu
+ .globl sys_call_table_emu
+sys_call_table_emu:
+#include "asm/syscall_table.h"
+#undef SYSCALL
+#endif