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linux/arch/s390/kernel/entry64.S
Martin Schwidefsky 53e857f308 s390/mm,tlb: race of lazy TLB flush vs. recreation of TLB entries 
Git commit 050eef364a "[S390] fix tlb flushing vs. concurrent
/proc accesses" introduced the attach counter to avoid using the
mm_users value to decide between IPTE for every PTE and lazy TLB
flushing with IDTE. That fixed the problem with mm_users but it
introduced another subtle race, fortunately one that is very hard
to hit.
The background is the requirement of the architecture that a valid
PTE may not be changed while it can be used concurrently by another
cpu. The decision between IPTE and lazy TLB flushing needs to be
done while the PTE is still valid. Now if the virtual cpu is
temporarily stopped after the decision to use lazy TLB flushing but
before the invalid bit of the PTE has been set, another cpu can attach
the mm, find that flush_mm is set, do the IDTE, return to userspace,
and recreate a TLB that uses the PTE in question. When the first,
stopped cpu continues it will change the PTE while it is attached on
another cpu. The first cpu will do another IDTE shortly after the
modification of the PTE which makes the race window quite short.

To fix this race the CPU that wants to attach the address space of a
user space thread needs to wait for the end of the PTE modification.
The number of concurrent TLB flushers for an mm is tracked in the
upper 16 bits of the attach_count and finish_arch_post_lock_switch
is used to wait for the end of the flush operation if required.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-02-21 08:50:18 +01:00

1023 lines
28 KiB
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/*
* 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),
* Heiko Carstens <heiko.carstens@de.ibm.com>
*/
#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/processor.h>
#include <asm/cache.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>
__PT_R0 = __PT_GPRS
__PT_R1 = __PT_GPRS + 8
__PT_R2 = __PT_GPRS + 16
__PT_R3 = __PT_GPRS + 24
__PT_R4 = __PT_GPRS + 32
__PT_R5 = __PT_GPRS + 40
__PT_R6 = __PT_GPRS + 48
__PT_R7 = __PT_GPRS + 56
__PT_R8 = __PT_GPRS + 64
__PT_R9 = __PT_GPRS + 72
__PT_R10 = __PT_GPRS + 80
__PT_R11 = __PT_GPRS + 88
__PT_R12 = __PT_GPRS + 96
__PT_R13 = __PT_GPRS + 104
__PT_R14 = __PT_GPRS + 112
__PT_R15 = __PT_GPRS + 120
STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
STACK_SIZE = 1 << STACK_SHIFT
STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE
_TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
_TIF_MCCK_PENDING | _TIF_PER_TRAP )
_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
_TIF_MCCK_PENDING)
_TIF_TRACE = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
_TIF_SYSCALL_TRACEPOINT)
_TIF_TRANSFER = (_TIF_MCCK_PENDING | _TIF_TLB_WAIT)
#define BASED(name) name-system_call(%r13)
.macro TRACE_IRQS_ON
#ifdef CONFIG_TRACE_IRQFLAGS
basr %r2,%r0
brasl %r14,trace_hardirqs_on_caller
#endif
.endm
.macro TRACE_IRQS_OFF
#ifdef CONFIG_TRACE_IRQFLAGS
basr %r2,%r0
brasl %r14,trace_hardirqs_off_caller
#endif
.endm
.macro LOCKDEP_SYS_EXIT
#ifdef CONFIG_LOCKDEP
tm __PT_PSW+1(%r11),0x01 # returning to user ?
jz .+10
brasl %r14,lockdep_sys_exit
#endif
.endm
.macro LPP newpp
#if IS_ENABLED(CONFIG_KVM)
tm __LC_MACHINE_FLAGS+6,0x20 # MACHINE_FLAG_LPP
jz .+8
.insn s,0xb2800000,\newpp
#endif
.endm
.macro HANDLE_SIE_INTERCEPT scratch,reason
#if IS_ENABLED(CONFIG_KVM)
tmhh %r8,0x0001 # interrupting from user ?
jnz .+62
lgr \scratch,%r9
slg \scratch,BASED(.Lsie_critical)
clg \scratch,BASED(.Lsie_critical_length)
.if \reason==1
# Some program interrupts are suppressing (e.g. protection).
# We must also check the instruction after SIE in that case.
# do_protection_exception will rewind to rewind_pad
jh .+42
.else
jhe .+42
.endif
lg %r14,__SF_EMPTY(%r15) # get control block pointer
LPP __SF_EMPTY+16(%r15) # set host id
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
mvi __SF_EMPTY+31(%r15),\reason # set exit reason
#endif
.endm
.macro CHECK_STACK stacksize,savearea
#ifdef CONFIG_CHECK_STACK
tml %r15,\stacksize - CONFIG_STACK_GUARD
lghi %r14,\savearea
jz stack_overflow
#endif
.endm
.macro SWITCH_ASYNC savearea,stack,shift
tmhh %r8,0x0001 # interrupting from user ?
jnz 1f
lgr %r14,%r9
slg %r14,BASED(.Lcritical_start)
clg %r14,BASED(.Lcritical_length)
jhe 0f
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,\stack # are we already on the target stack?
slgr %r14,%r15
srag %r14,%r14,\shift
jnz 1f
CHECK_STACK 1<<\shift,\savearea
aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
j 2f
1: lg %r15,\stack # load target stack
2: la %r11,STACK_FRAME_OVERHEAD(%r15)
.endm
.macro UPDATE_VTIME scratch,enter_timer
lg \scratch,__LC_EXIT_TIMER
slg \scratch,\enter_timer
alg \scratch,__LC_USER_TIMER
stg \scratch,__LC_USER_TIMER
lg \scratch,__LC_LAST_UPDATE_TIMER
slg \scratch,__LC_EXIT_TIMER
alg \scratch,__LC_SYSTEM_TIMER
stg \scratch,__LC_SYSTEM_TIMER
mvc __LC_LAST_UPDATE_TIMER(8),\enter_timer
.endm
.macro LAST_BREAK scratch
srag \scratch,%r10,23
jz .+10
stg %r10,__TI_last_break(%r12)
.endm
.macro REENABLE_IRQS
stg %r8,__LC_RETURN_PSW
ni __LC_RETURN_PSW,0xbf
ssm __LC_RETURN_PSW
.endm
.macro STCK savearea
#ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
.insn s,0xb27c0000,\savearea # store clock fast
#else
.insn s,0xb2050000,\savearea # store clock
#endif
.endm
.section .kprobes.text, "ax"
/*
* 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
stg %r15,__THREAD_ksp(%r2) # store kernel stack of prev
lg %r4,__THREAD_info(%r2) # get thread_info of prev
lg %r5,__THREAD_info(%r3) # get thread_info of next
lgr %r15,%r5
aghi %r15,STACK_INIT # end of kernel stack of next
stg %r3,__LC_CURRENT # store task struct of next
stg %r5,__LC_THREAD_INFO # store thread info of next
stg %r15,__LC_KERNEL_STACK # store end of kernel stack
lctl %c4,%c4,__TASK_pid(%r3) # load pid to control reg. 4
mvc __LC_CURRENT_PID+4(4,%r0),__TASK_pid(%r3) # store pid of next
lg %r15,__THREAD_ksp(%r3) # load kernel stack of next
llill %r6,_TIF_TRANSFER # transfer TIF bits
ng %r6,__TI_flags(%r4) # isolate TIF bits
jz 0f
og %r6,__TI_flags(%r5) # set TIF bits of next
stg %r6,__TI_flags(%r5)
ni __TI_flags+7(%r4),255-_TIF_TRANSFER # clear TIF bits of prev
0: lmg %r6,%r15,__SF_GPRS(%r15) # load gprs of next task
br %r14
__critical_start:
/*
* SVC interrupt handler routine. System calls are synchronous events and
* are executed with interrupts enabled.
*/
ENTRY(system_call)
stpt __LC_SYNC_ENTER_TIMER
sysc_stmg:
stmg %r8,%r15,__LC_SAVE_AREA_SYNC
lg %r10,__LC_LAST_BREAK
lg %r12,__LC_THREAD_INFO
sysc_per:
lg %r15,__LC_KERNEL_STACK
la %r11,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs
sysc_vtime:
UPDATE_VTIME %r13,__LC_SYNC_ENTER_TIMER
LAST_BREAK %r13
stmg %r0,%r7,__PT_R0(%r11)
mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC
mvc __PT_PSW(16,%r11),__LC_SVC_OLD_PSW
mvc __PT_INT_CODE(4,%r11),__LC_SVC_ILC
sysc_do_svc:
oi __TI_flags+7(%r12),_TIF_SYSCALL
lg %r10,__TI_sysc_table(%r12) # address of system call table
llgh %r8,__PT_INT_CODE+2(%r11)
slag %r8,%r8,2 # shift and test for svc 0
jnz sysc_nr_ok
# svc 0: system call number in %r1
llgfr %r1,%r1 # clear high word in r1
cghi %r1,NR_syscalls
jnl sysc_nr_ok
sth %r1,__PT_INT_CODE+2(%r11)
slag %r8,%r1,2
sysc_nr_ok:
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
stg %r2,__PT_ORIG_GPR2(%r11)
stg %r7,STACK_FRAME_OVERHEAD(%r15)
lgf %r9,0(%r8,%r10) # get system call add.
tm __TI_flags+6(%r12),_TIF_TRACE >> 8
jnz sysc_tracesys
basr %r14,%r9 # call sys_xxxx
stg %r2,__PT_R2(%r11) # store return value
sysc_return:
LOCKDEP_SYS_EXIT
sysc_tif:
tm __PT_PSW+1(%r11),0x01 # returning to user ?
jno sysc_restore
tm __TI_flags+7(%r12),_TIF_WORK_SVC
jnz sysc_work # check for work
ni __TI_flags+7(%r12),255-_TIF_SYSCALL
sysc_restore:
lg %r14,__LC_VDSO_PER_CPU
lmg %r0,%r10,__PT_R0(%r11)
mvc __LC_RETURN_PSW(16),__PT_PSW(%r11)
stpt __LC_EXIT_TIMER
mvc __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER
lmg %r11,%r15,__PT_R11(%r11)
lpswe __LC_RETURN_PSW
sysc_done:
#
# One of the work bits is on. Find out which one.
#
sysc_work:
tm __TI_flags+7(%r12),_TIF_MCCK_PENDING
jo sysc_mcck_pending
tm __TI_flags+7(%r12),_TIF_NEED_RESCHED
jo sysc_reschedule
tm __TI_flags+7(%r12),_TIF_PER_TRAP
jo sysc_singlestep
tm __TI_flags+7(%r12),_TIF_SIGPENDING
jo sysc_sigpending
tm __TI_flags+7(%r12),_TIF_NOTIFY_RESUME
jo sysc_notify_resume
j sysc_return # beware of critical section cleanup
#
# _TIF_NEED_RESCHED is set, call schedule
#
sysc_reschedule:
larl %r14,sysc_return
jg schedule
#
# _TIF_MCCK_PENDING is set, call handler
#
sysc_mcck_pending:
larl %r14,sysc_return
jg s390_handle_mcck # TIF bit will be cleared by handler
#
# _TIF_SIGPENDING is set, call do_signal
#
sysc_sigpending:
lgr %r2,%r11 # pass pointer to pt_regs
brasl %r14,do_signal
tm __TI_flags+7(%r12),_TIF_SYSCALL
jno sysc_return
lmg %r2,%r7,__PT_R2(%r11) # load svc arguments
lg %r10,__TI_sysc_table(%r12) # address of system call table
lghi %r8,0 # svc 0 returns -ENOSYS
llgh %r1,__PT_INT_CODE+2(%r11) # load new svc number
cghi %r1,NR_syscalls
jnl sysc_nr_ok # invalid svc number -> do svc 0
slag %r8,%r1,2
j sysc_nr_ok # restart svc
#
# _TIF_NOTIFY_RESUME is set, call do_notify_resume
#
sysc_notify_resume:
lgr %r2,%r11 # pass pointer to pt_regs
larl %r14,sysc_return
jg do_notify_resume
#
# _TIF_PER_TRAP is set, call do_per_trap
#
sysc_singlestep:
ni __TI_flags+7(%r12),255-_TIF_PER_TRAP
lgr %r2,%r11 # pass pointer to pt_regs
larl %r14,sysc_return
jg do_per_trap
#
# call tracehook_report_syscall_entry/tracehook_report_syscall_exit before
# and after the system call
#
sysc_tracesys:
lgr %r2,%r11 # pass pointer to pt_regs
la %r3,0
llgh %r0,__PT_INT_CODE+2(%r11)
stg %r0,__PT_R2(%r11)
brasl %r14,do_syscall_trace_enter
lghi %r0,NR_syscalls
clgr %r0,%r2
jnh sysc_tracenogo
sllg %r8,%r2,2
lgf %r9,0(%r8,%r10)
sysc_tracego:
lmg %r3,%r7,__PT_R3(%r11)
stg %r7,STACK_FRAME_OVERHEAD(%r15)
lg %r2,__PT_ORIG_GPR2(%r11)
basr %r14,%r9 # call sys_xxx
stg %r2,__PT_R2(%r11) # store return value
sysc_tracenogo:
tm __TI_flags+6(%r12),_TIF_TRACE >> 8
jz sysc_return
lgr %r2,%r11 # pass pointer to pt_regs
larl %r14,sysc_return
jg do_syscall_trace_exit
#
# a new process exits the kernel with ret_from_fork
#
ENTRY(ret_from_fork)
la %r11,STACK_FRAME_OVERHEAD(%r15)
lg %r12,__LC_THREAD_INFO
brasl %r14,schedule_tail
TRACE_IRQS_ON
ssm __LC_SVC_NEW_PSW # reenable interrupts
tm __PT_PSW+1(%r11),0x01 # forking a kernel thread ?
jne sysc_tracenogo
# it's a kernel thread
lmg %r9,%r10,__PT_R9(%r11) # load gprs
ENTRY(kernel_thread_starter)
la %r2,0(%r10)
basr %r14,%r9
j sysc_tracenogo
/*
* Program check handler routine
*/
ENTRY(pgm_check_handler)
stpt __LC_SYNC_ENTER_TIMER
stmg %r8,%r15,__LC_SAVE_AREA_SYNC
lg %r10,__LC_LAST_BREAK
lg %r12,__LC_THREAD_INFO
larl %r13,system_call
lmg %r8,%r9,__LC_PGM_OLD_PSW
HANDLE_SIE_INTERCEPT %r14,1
tmhh %r8,0x0001 # test problem state bit
jnz 1f # -> fault in user space
tmhh %r8,0x4000 # PER bit set in old PSW ?
jnz 0f # -> enabled, can't be a double fault
tm __LC_PGM_ILC+3,0x80 # check for per exception
jnz pgm_svcper # -> single stepped svc
0: CHECK_STACK STACK_SIZE,__LC_SAVE_AREA_SYNC
aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
j 2f
1: UPDATE_VTIME %r14,__LC_SYNC_ENTER_TIMER
LAST_BREAK %r14
lg %r15,__LC_KERNEL_STACK
lg %r14,__TI_task(%r12)
lghi %r13,__LC_PGM_TDB
tm __LC_PGM_ILC+2,0x02 # check for transaction abort
jz 2f
mvc __THREAD_trap_tdb(256,%r14),0(%r13)
2: la %r11,STACK_FRAME_OVERHEAD(%r15)
stmg %r0,%r7,__PT_R0(%r11)
mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC
stmg %r8,%r9,__PT_PSW(%r11)
mvc __PT_INT_CODE(4,%r11),__LC_PGM_ILC
mvc __PT_INT_PARM_LONG(8,%r11),__LC_TRANS_EXC_CODE
stg %r10,__PT_ARGS(%r11)
tm __LC_PGM_ILC+3,0x80 # check for per exception
jz 0f
tmhh %r8,0x0001 # kernel per event ?
jz pgm_kprobe
oi __TI_flags+7(%r12),_TIF_PER_TRAP
mvc __THREAD_per_address(8,%r14),__LC_PER_ADDRESS
mvc __THREAD_per_cause(2,%r14),__LC_PER_CAUSE
mvc __THREAD_per_paid(1,%r14),__LC_PER_PAID
0: REENABLE_IRQS
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
larl %r1,pgm_check_table
llgh %r10,__PT_INT_CODE+2(%r11)
nill %r10,0x007f
sll %r10,2
je sysc_return
lgf %r1,0(%r10,%r1) # load address of handler routine
lgr %r2,%r11 # pass pointer to pt_regs
basr %r14,%r1 # branch to interrupt-handler
j sysc_return
#
# PER event in supervisor state, must be kprobes
#
pgm_kprobe:
REENABLE_IRQS
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
lgr %r2,%r11 # pass pointer to pt_regs
brasl %r14,do_per_trap
j sysc_return
#
# single stepped system call
#
pgm_svcper:
oi __TI_flags+7(%r12),_TIF_PER_TRAP
mvc __LC_RETURN_PSW(8),__LC_SVC_NEW_PSW
larl %r14,sysc_per
stg %r14,__LC_RETURN_PSW+8
lpswe __LC_RETURN_PSW # branch to sysc_per and enable irqs
/*
* IO interrupt handler routine
*/
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_THREAD_INFO
larl %r13,system_call
lmg %r8,%r9,__LC_IO_OLD_PSW
HANDLE_SIE_INTERCEPT %r14,2
SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT
tmhh %r8,0x0001 # interrupting from user?
jz io_skip
UPDATE_VTIME %r14,__LC_ASYNC_ENTER_TIMER
LAST_BREAK %r14
io_skip:
stmg %r0,%r7,__PT_R0(%r11)
mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
stmg %r8,%r9,__PT_PSW(%r11)
mvc __PT_INT_CODE(12,%r11),__LC_SUBCHANNEL_ID
TRACE_IRQS_OFF
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
io_loop:
lgr %r2,%r11 # pass pointer to pt_regs
lghi %r3,IO_INTERRUPT
tm __PT_INT_CODE+8(%r11),0x80 # adapter interrupt ?
jz io_call
lghi %r3,THIN_INTERRUPT
io_call:
brasl %r14,do_IRQ
tm __LC_MACHINE_FLAGS+6,0x10 # MACHINE_FLAG_LPAR
jz io_return
tpi 0
jz io_return
mvc __PT_INT_CODE(12,%r11),__LC_SUBCHANNEL_ID
j io_loop
io_return:
LOCKDEP_SYS_EXIT
TRACE_IRQS_ON
io_tif:
tm __TI_flags+7(%r12),_TIF_WORK_INT
jnz io_work # there is work to do (signals etc.)
io_restore:
lg %r14,__LC_VDSO_PER_CPU
lmg %r0,%r10,__PT_R0(%r11)
mvc __LC_RETURN_PSW(16),__PT_PSW(%r11)
stpt __LC_EXIT_TIMER
mvc __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER
lmg %r11,%r15,__PT_R11(%r11)
lpswe __LC_RETURN_PSW
io_done:
#
# There is work todo, find out in which context we have been interrupted:
# 1) if we return to user space we can do all _TIF_WORK_INT work
# 2) if we return to kernel code and kvm is enabled check if we need to
# modify the psw to leave SIE
# 3) if we return to kernel code and preemptive scheduling is enabled check
# the preemption counter and if it is zero call preempt_schedule_irq
# Before any work can be done, a switch to the kernel stack is required.
#
io_work:
tm __PT_PSW+1(%r11),0x01 # returning to user ?
jo io_work_user # yes -> do resched & signal
#ifdef CONFIG_PREEMPT
# check for preemptive scheduling
icm %r0,15,__TI_precount(%r12)
jnz io_restore # preemption is disabled
tm __TI_flags+7(%r12),_TIF_NEED_RESCHED
jno io_restore
# switch to kernel stack
lg %r1,__PT_R15(%r11)
aghi %r1,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
mvc STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
xc __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1)
la %r11,STACK_FRAME_OVERHEAD(%r1)
lgr %r15,%r1
# TRACE_IRQS_ON already done at io_return, call
# TRACE_IRQS_OFF to keep things symmetrical
TRACE_IRQS_OFF
brasl %r14,preempt_schedule_irq
j io_return
#else
j io_restore
#endif
#
# Need to do work before returning to userspace, switch to kernel stack
#
io_work_user:
lg %r1,__LC_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 %r15,%r1
#
# One of the work bits is on. Find out which one.
# Checked are: _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_NEED_RESCHED
# and _TIF_MCCK_PENDING
#
io_work_tif:
tm __TI_flags+7(%r12),_TIF_MCCK_PENDING
jo io_mcck_pending
tm __TI_flags+7(%r12),_TIF_NEED_RESCHED
jo io_reschedule
tm __TI_flags+7(%r12),_TIF_SIGPENDING
jo io_sigpending
tm __TI_flags+7(%r12),_TIF_NOTIFY_RESUME
jo io_notify_resume
j io_return # beware of critical section cleanup
#
# _TIF_MCCK_PENDING is set, call handler
#
io_mcck_pending:
# TRACE_IRQS_ON already done at io_return
brasl %r14,s390_handle_mcck # TIF bit will be cleared by handler
TRACE_IRQS_OFF
j io_return
#
# _TIF_NEED_RESCHED is set, call schedule
#
io_reschedule:
# TRACE_IRQS_ON already done at io_return
ssm __LC_SVC_NEW_PSW # reenable interrupts
brasl %r14,schedule # call scheduler
ssm __LC_PGM_NEW_PSW # disable I/O and ext. interrupts
TRACE_IRQS_OFF
j io_return
#
# _TIF_SIGPENDING or is set, call do_signal
#
io_sigpending:
# TRACE_IRQS_ON already done at io_return
ssm __LC_SVC_NEW_PSW # reenable interrupts
lgr %r2,%r11 # pass pointer to pt_regs
brasl %r14,do_signal
ssm __LC_PGM_NEW_PSW # disable I/O and ext. interrupts
TRACE_IRQS_OFF
j io_return
#
# _TIF_NOTIFY_RESUME or is set, call do_notify_resume
#
io_notify_resume:
# TRACE_IRQS_ON already done at io_return
ssm __LC_SVC_NEW_PSW # reenable interrupts
lgr %r2,%r11 # pass pointer to pt_regs
brasl %r14,do_notify_resume
ssm __LC_PGM_NEW_PSW # disable I/O and ext. interrupts
TRACE_IRQS_OFF
j io_return
/*
* External interrupt handler routine
*/
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_THREAD_INFO
larl %r13,system_call
lmg %r8,%r9,__LC_EXT_OLD_PSW
HANDLE_SIE_INTERCEPT %r14,3
SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT
tmhh %r8,0x0001 # interrupting from user ?
jz ext_skip
UPDATE_VTIME %r14,__LC_ASYNC_ENTER_TIMER
LAST_BREAK %r14
ext_skip:
stmg %r0,%r7,__PT_R0(%r11)
mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
stmg %r8,%r9,__PT_PSW(%r11)
lghi %r1,__LC_EXT_PARAMS2
mvc __PT_INT_CODE(4,%r11),__LC_EXT_CPU_ADDR
mvc __PT_INT_PARM(4,%r11),__LC_EXT_PARAMS
mvc __PT_INT_PARM_LONG(8,%r11),0(%r1)
TRACE_IRQS_OFF
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
lgr %r2,%r11 # pass pointer to pt_regs
lghi %r3,EXT_INTERRUPT
brasl %r14,do_IRQ
j io_return
/*
* Load idle PSW. The second "half" of this function is in cleanup_idle.
*/
ENTRY(psw_idle)
stg %r3,__SF_EMPTY(%r15)
larl %r1,psw_idle_lpsw+4
stg %r1,__SF_EMPTY+8(%r15)
STCK __CLOCK_IDLE_ENTER(%r2)
stpt __TIMER_IDLE_ENTER(%r2)
psw_idle_lpsw:
lpswe __SF_EMPTY(%r15)
br %r14
psw_idle_end:
__critical_end:
/*
* Machine check handler routines
*/
ENTRY(mcck_int_handler)
STCK __LC_MCCK_CLOCK
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_THREAD_INFO
larl %r13,system_call
lmg %r8,%r9,__LC_MCK_OLD_PSW
HANDLE_SIE_INTERCEPT %r14,4
tm __LC_MCCK_CODE,0x80 # system damage?
jo mcck_panic # yes -> rest of mcck code invalid
lghi %r14,__LC_CPU_TIMER_SAVE_AREA
mvc __LC_MCCK_ENTER_TIMER(8),0(%r14)
tm __LC_MCCK_CODE+5,0x02 # stored cpu timer value valid?
jo 3f
la %r14,__LC_SYNC_ENTER_TIMER
clc 0(8,%r14),__LC_ASYNC_ENTER_TIMER
jl 0f
la %r14,__LC_ASYNC_ENTER_TIMER
0: 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: tm __LC_MCCK_CODE+2,0x09 # mwp + ia of old psw valid?
jno mcck_panic # no -> skip cleanup critical
SWITCH_ASYNC __LC_GPREGS_SAVE_AREA+64,__LC_PANIC_STACK,PAGE_SHIFT
tm %r8,0x0001 # interrupting from user ?
jz mcck_skip
UPDATE_VTIME %r14,__LC_MCCK_ENTER_TIMER
LAST_BREAK %r14
mcck_skip:
lghi %r14,__LC_GPREGS_SAVE_AREA+64
stmg %r0,%r7,__PT_R0(%r11)
mvc __PT_R8(64,%r11),0(%r14)
stmg %r8,%r9,__PT_PSW(%r11)
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
lgr %r2,%r11 # pass pointer to pt_regs
brasl %r14,s390_do_machine_check
tm __PT_PSW+1(%r11),0x01 # returning to user ?
jno mcck_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 %r15,%r1
ssm __LC_PGM_NEW_PSW # turn dat on, keep irqs off
tm __TI_flags+7(%r12),_TIF_MCCK_PENDING
jno mcck_return
TRACE_IRQS_OFF
brasl %r14,s390_handle_mcck
TRACE_IRQS_ON
mcck_return:
lg %r14,__LC_VDSO_PER_CPU
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
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
mcck_panic:
lg %r14,__LC_PANIC_STACK
slgr %r14,%r15
srag %r14,%r14,PAGE_SHIFT
jz 0f
lg %r15,__LC_PANIC_STACK
0: aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
j mcck_skip
#
# PSW restart interrupt handler
#
ENTRY(restart_int_handler)
stg %r15,__LC_SAVE_AREA_RESTART
lg %r15,__LC_RESTART_STACK
aghi %r15,-__PT_SIZE # create pt_regs on stack
xc 0(__PT_SIZE,%r15),0(%r15)
stmg %r0,%r14,__PT_R0(%r15)
mvc __PT_R15(8,%r15),__LC_SAVE_AREA_RESTART
mvc __PT_PSW(16,%r15),__LC_RST_OLD_PSW # store restart old psw
aghi %r15,-STACK_FRAME_OVERHEAD # create stack frame on stack
xc 0(STACK_FRAME_OVERHEAD,%r15),0(%r15)
lg %r1,__LC_RESTART_FN # load fn, parm & source cpu
lg %r2,__LC_RESTART_DATA
lg %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
.section .kprobes.text, "ax"
#ifdef CONFIG_CHECK_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.
*/
stack_overflow:
lg %r15,__LC_PANIC_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
#endif
.align 8
cleanup_table:
.quad system_call
.quad sysc_do_svc
.quad sysc_tif
.quad sysc_restore
.quad sysc_done
.quad io_tif
.quad io_restore
.quad io_done
.quad psw_idle
.quad psw_idle_end
cleanup_critical:
clg %r9,BASED(cleanup_table) # system_call
jl 0f
clg %r9,BASED(cleanup_table+8) # sysc_do_svc
jl cleanup_system_call
clg %r9,BASED(cleanup_table+16) # sysc_tif
jl 0f
clg %r9,BASED(cleanup_table+24) # sysc_restore
jl cleanup_sysc_tif
clg %r9,BASED(cleanup_table+32) # sysc_done
jl cleanup_sysc_restore
clg %r9,BASED(cleanup_table+40) # io_tif
jl 0f
clg %r9,BASED(cleanup_table+48) # io_restore
jl cleanup_io_tif
clg %r9,BASED(cleanup_table+56) # io_done
jl cleanup_io_restore
clg %r9,BASED(cleanup_table+64) # psw_idle
jl 0f
clg %r9,BASED(cleanup_table+72) # psw_idle_end
jl cleanup_idle
0: br %r14
cleanup_system_call:
# check if stpt has been executed
clg %r9,BASED(cleanup_system_call_insn)
jh 0f
mvc __LC_SYNC_ENTER_TIMER(8),__LC_ASYNC_ENTER_TIMER
cghi %r11,__LC_SAVE_AREA_ASYNC
je 0f
mvc __LC_SYNC_ENTER_TIMER(8),__LC_MCCK_ENTER_TIMER
0: # check if stmg has been executed
clg %r9,BASED(cleanup_system_call_insn+8)
jh 0f
mvc __LC_SAVE_AREA_SYNC(64),0(%r11)
0: # check if base register setup + TIF bit load has been done
clg %r9,BASED(cleanup_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 thread-info pointer
0: # check if the user time update has been done
clg %r9,BASED(cleanup_system_call_insn+24)
jh 0f
lg %r15,__LC_EXIT_TIMER
slg %r15,__LC_SYNC_ENTER_TIMER
alg %r15,__LC_USER_TIMER
stg %r15,__LC_USER_TIMER
0: # check if the system time update has been done
clg %r9,BASED(cleanup_system_call_insn+32)
jh 0f
lg %r15,__LC_LAST_UPDATE_TIMER
slg %r15,__LC_EXIT_TIMER
alg %r15,__LC_SYSTEM_TIMER
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
mvc __TI_last_break(8,%r12),16(%r11)
0: # set up saved register r11
lg %r15,__LC_KERNEL_STACK
la %r9,STACK_FRAME_OVERHEAD(%r15)
stg %r9,24(%r11) # r11 pt_regs pointer
# fill pt_regs
mvc __PT_R8(64,%r9),__LC_SAVE_AREA_SYNC
stmg %r0,%r7,__PT_R0(%r9)
mvc __PT_PSW(16,%r9),__LC_SVC_OLD_PSW
mvc __PT_INT_CODE(4,%r9),__LC_SVC_ILC
# setup saved register r15
stg %r15,56(%r11) # r15 stack pointer
# set new psw address and exit
larl %r9,sysc_do_svc
br %r14
cleanup_system_call_insn:
.quad system_call
.quad sysc_stmg
.quad sysc_per
.quad sysc_vtime+18
.quad sysc_vtime+42
cleanup_sysc_tif:
larl %r9,sysc_tif
br %r14
cleanup_sysc_restore:
clg %r9,BASED(cleanup_sysc_restore_insn)
je 0f
lg %r9,24(%r11) # get saved pointer to pt_regs
mvc __LC_RETURN_PSW(16),__PT_PSW(%r9)
mvc 0(64,%r11),__PT_R8(%r9)
lmg %r0,%r7,__PT_R0(%r9)
0: lmg %r8,%r9,__LC_RETURN_PSW
br %r14
cleanup_sysc_restore_insn:
.quad sysc_done - 4
cleanup_io_tif:
larl %r9,io_tif
br %r14
cleanup_io_restore:
clg %r9,BASED(cleanup_io_restore_insn)
je 0f
lg %r9,24(%r11) # get saved r11 pointer to pt_regs
mvc __LC_RETURN_PSW(16),__PT_PSW(%r9)
mvc 0(64,%r11),__PT_R8(%r9)
lmg %r0,%r7,__PT_R0(%r9)
0: lmg %r8,%r9,__LC_RETURN_PSW
br %r14
cleanup_io_restore_insn:
.quad io_done - 4
cleanup_idle:
# copy interrupt clock & cpu timer
mvc __CLOCK_IDLE_EXIT(8,%r2),__LC_INT_CLOCK
mvc __TIMER_IDLE_EXIT(8,%r2),__LC_ASYNC_ENTER_TIMER
cghi %r11,__LC_SAVE_AREA_ASYNC
je 0f
mvc __CLOCK_IDLE_EXIT(8,%r2),__LC_MCCK_CLOCK
mvc __TIMER_IDLE_EXIT(8,%r2),__LC_MCCK_ENTER_TIMER
0: # check if stck & stpt have been executed
clg %r9,BASED(cleanup_idle_insn)
jhe 1f
mvc __CLOCK_IDLE_ENTER(8,%r2),__CLOCK_IDLE_EXIT(%r2)
mvc __TIMER_IDLE_ENTER(8,%r2),__TIMER_IDLE_EXIT(%r2)
1: # account system time going idle
lg %r9,__LC_STEAL_TIMER
alg %r9,__CLOCK_IDLE_ENTER(%r2)
slg %r9,__LC_LAST_UPDATE_CLOCK
stg %r9,__LC_STEAL_TIMER
mvc __LC_LAST_UPDATE_CLOCK(8),__CLOCK_IDLE_EXIT(%r2)
lg %r9,__LC_SYSTEM_TIMER
alg %r9,__LC_LAST_UPDATE_TIMER
slg %r9,__TIMER_IDLE_ENTER(%r2)
stg %r9,__LC_SYSTEM_TIMER
mvc __LC_LAST_UPDATE_TIMER(8),__TIMER_IDLE_EXIT(%r2)
# prepare return psw
nihh %r8,0xfcfd # clear irq & wait state bits
lg %r9,48(%r11) # return from psw_idle
br %r14
cleanup_idle_insn:
.quad psw_idle_lpsw
/*
* Integer constants
*/
.align 8
.Lcritical_start:
.quad __critical_start
.Lcritical_length:
.quad __critical_end - __critical_start
#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
stg %r2,__SF_EMPTY(%r15) # save control block pointer
stg %r3,__SF_EMPTY+8(%r15) # save guest register save area
xc __SF_EMPTY+16(16,%r15),__SF_EMPTY+16(%r15) # host id & reason
lmg %r0,%r13,0(%r3) # load guest gprs 0-13
lg %r14,__LC_GMAP # get gmap pointer
ltgr %r14,%r14
jz sie_gmap
lctlg %c1,%c1,__GMAP_ASCE(%r14) # load primary asce
sie_gmap:
lg %r14,__SF_EMPTY(%r15) # get control block pointer
oi __SIE_PROG0C+3(%r14),1 # we are going into SIE now
tm __SIE_PROG20+3(%r14),1 # last exit...
jnz sie_done
LPP __SF_EMPTY(%r15) # set guest id
sie 0(%r14)
sie_done:
LPP __SF_EMPTY+16(%r15) # set host id
ni __SIE_PROG0C+3(%r14),0xfe # no longer in SIE
lctlg %c1,%c1,__LC_USER_ASCE # load primary asce
# some program checks are suppressing. C code (e.g. do_protection_exception)
# will rewind the PSW by the ILC, which is 4 bytes in case of SIE. Other
# instructions between sie64a and sie_done should not cause program
# interrupts. So lets use a nop (47 00 00 00) as a landing pad.
# See also HANDLE_SIE_INTERCEPT
rewind_pad:
nop 0
.globl sie_exit
sie_exit:
lg %r14,__SF_EMPTY+8(%r15) # load guest register save area
stmg %r0,%r13,0(%r14) # save guest gprs 0-13
lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers
lg %r2,__SF_EMPTY+24(%r15) # return exit reason code
br %r14
sie_fault:
lghi %r14,-EFAULT
stg %r14,__SF_EMPTY+24(%r15) # set exit reason code
j sie_exit
.align 8
.Lsie_critical:
.quad sie_gmap
.Lsie_critical_length:
.quad sie_done - sie_gmap
EX_TABLE(rewind_pad,sie_fault)
EX_TABLE(sie_exit,sie_fault)
#endif
.section .rodata, "a"
#define SYSCALL(esa,esame,emu) .long esame
.globl sys_call_table
sys_call_table:
#include "syscalls.S"
#undef SYSCALL
#ifdef CONFIG_COMPAT
#define SYSCALL(esa,esame,emu) .long emu
.globl sys_call_table_emu
sys_call_table_emu:
#include "syscalls.S"
#undef SYSCALL
#endif
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