[S390] move sie code to entry.S

The entry to / exit from sie has subtle dependencies to the first level
interrupt handler. Move the sie assembler code to entry64.S and replace
the SIE_HOOK callback with a test and the new _TIF_SIE bit.
In addition this patch fixes several problems in regard to the check for
the_TIF_EXIT_SIE bits. The old code checked the TIF bits before executing
the interrupt handler and it only modified the instruction address if it
pointed directly to the sie instruction. In both cases it could miss
a TIF bit that normally would cause an exit from the guest and would
reenter the guest context.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

5 files changed, 79 insertions, 107 deletions

diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h
index ad1382f7932e..1a5dbb6f1495 100644
--- a/arch/s390/include/asm/thread_info.h
+++ b/arch/s390/include/asm/thread_info.h
@@ -94,6 +94,7 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_SYSCALL_AUDIT       9       /* syscall auditing active */
 #define TIF_SECCOMP             10      /* secure computing */
 #define TIF_SYSCALL_TRACEPOINT  11      /* syscall tracepoint instrumentation */
+#define TIF_SIE                 12      /* guest execution active */
 #define TIF_POLLING_NRFLAG      16      /* true if poll_idle() is polling
                                            TIF_NEED_RESCHED */
 #define TIF_31BIT               17      /* 32bit process */
@@ -113,6 +114,7 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
 #define _TIF_SECCOMP            (1<<TIF_SECCOMP)
 #define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
+#define _TIF_SIE                (1<<TIF_SIE)
 #define _TIF_POLLING_NRFLAG     (1<<TIF_POLLING_NRFLAG)
 #define _TIF_31BIT              (1<<TIF_31BIT)
 #define _TIF_SINGLE_STEP        (1<<TIF_FREEZE)
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index d61967e2eab0..ab596a865300 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -56,15 +56,28 @@ _TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
                  _TIF_MCCK_PENDING)
 _TIF_SYSCALL = (_TIF_SYSCALL_TRACE>>8 | _TIF_SYSCALL_AUDIT>>8 | \
                 _TIF_SECCOMP>>8 | _TIF_SYSCALL_TRACEPOINT>>8)
+_TIF_EXIT_SIE = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING)
 
 #define BASED(name) name-system_call(%r13)
 
+        .macro SPP newpp
+#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
+        tm      __LC_MACHINE_FLAGS+6,0x20       # MACHINE_FLAG_SPP
+        jz      .+8
+        .insn   s,0xb2800000,\newpp
+#endif
+        .endm
+
         .macro  HANDLE_SIE_INTERCEPT
 #if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
-        lg      %r3,__LC_SIE_HOOK
-        ltgr    %r3,%r3
+        tm      __TI_flags+6(%r12),_TIF_SIE>>8
         jz      0f
-        basr    %r14,%r3
+        SPP     __LC_CMF_HPP                    # set host id
+        clc     SP_PSW+8(8,%r15),BASED(.Lsie_loop)
+        jl      0f
+        clc     SP_PSW+8(8,%r15),BASED(.Lsie_done)
+        jhe     0f
+        mvc     SP_PSW+8(8,%r15),BASED(.Lsie_loop)
 0:
 #endif
         .endm
@@ -465,6 +478,7 @@ pgm_check_handler:
         xc      SP_ILC(4,%r15),SP_ILC(%r15)
         mvc     SP_PSW(16,%r15),__LC_PGM_OLD_PSW
         lg      %r12,__LC_THREAD_INFO   # load pointer to thread_info struct
+        HANDLE_SIE_INTERCEPT
         tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
         jz      pgm_no_vtime
         UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
@@ -472,7 +486,6 @@ pgm_check_handler:
         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
         LAST_BREAK
 pgm_no_vtime:
-        HANDLE_SIE_INTERCEPT
         stg     %r11,SP_ARGS(%r15)
         lgf     %r3,__LC_PGM_ILC        # load program interruption code
         lg      %r4,__LC_TRANS_EXC_CODE
@@ -507,6 +520,7 @@ pgm_per_std:
         CREATE_STACK_FRAME __LC_SAVE_AREA
         mvc     SP_PSW(16,%r15),__LC_PGM_OLD_PSW
         lg      %r12,__LC_THREAD_INFO   # load pointer to thread_info struct
+        HANDLE_SIE_INTERCEPT
         tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
         jz      pgm_no_vtime2
         UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
@@ -514,7 +528,6 @@ pgm_per_std:
         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
         LAST_BREAK
 pgm_no_vtime2:
-        HANDLE_SIE_INTERCEPT
         lg      %r1,__TI_task(%r12)
         tm      SP_PSW+1(%r15),0x01     # kernel per event ?
         jz      kernel_per
@@ -579,6 +592,7 @@ io_int_handler:
         CREATE_STACK_FRAME __LC_SAVE_AREA+40
         mvc     SP_PSW(16,%r15),0(%r12) # move user PSW to stack
         lg      %r12,__LC_THREAD_INFO   # load pointer to thread_info struct
+        HANDLE_SIE_INTERCEPT
         tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
         jz      io_no_vtime
         UPDATE_VTIME __LC_EXIT_TIMER,__LC_ASYNC_ENTER_TIMER,__LC_USER_TIMER
@@ -586,7 +600,6 @@ io_int_handler:
         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
         LAST_BREAK
 io_no_vtime:
-        HANDLE_SIE_INTERCEPT
         TRACE_IRQS_OFF
         la      %r2,SP_PTREGS(%r15)     # address of register-save area
         brasl   %r14,do_IRQ             # call standard irq handler
@@ -714,6 +727,7 @@ ext_int_handler:
         CREATE_STACK_FRAME __LC_SAVE_AREA+40
         mvc     SP_PSW(16,%r15),0(%r12) # move user PSW to stack
         lg      %r12,__LC_THREAD_INFO   # load pointer to thread_info struct
+        HANDLE_SIE_INTERCEPT
         tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
         jz      ext_no_vtime
         UPDATE_VTIME __LC_EXIT_TIMER,__LC_ASYNC_ENTER_TIMER,__LC_USER_TIMER
@@ -721,7 +735,6 @@ ext_int_handler:
         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
         LAST_BREAK
 ext_no_vtime:
-        HANDLE_SIE_INTERCEPT
         TRACE_IRQS_OFF
         lghi    %r1,4096
         la      %r2,SP_PTREGS(%r15)     # address of register-save area
@@ -785,6 +798,7 @@ mcck_int_main:
         lg      %r12,__LC_THREAD_INFO   # load pointer to thread_info struct
         tm      __LC_MCCK_CODE+2,0x08   # mwp of old psw valid?
         jno     mcck_no_vtime           # no -> no timer update
+        HANDLE_SIE_INTERCEPT
         tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
         jz      mcck_no_vtime
         UPDATE_VTIME __LC_EXIT_TIMER,__LC_MCCK_ENTER_TIMER,__LC_USER_TIMER
@@ -804,7 +818,6 @@ mcck_no_vtime:
         stosm   __SF_EMPTY(%r15),0x04   # turn dat on
         tm      __TI_flags+7(%r12),_TIF_MCCK_PENDING
         jno     mcck_return
-        HANDLE_SIE_INTERCEPT
         TRACE_IRQS_OFF
         brasl   %r14,s390_handle_mcck
         TRACE_IRQS_ON
@@ -1036,6 +1049,57 @@ cleanup_io_restore_insn:
 .Lcritical_end:
                 .quad   __critical_end
 
+#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
+/*
+ * sie64a calling convention:
+ * %r2 pointer to sie control block
+ * %r3 guest register save area
+ */
+        .globl  sie64a
+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
+        lmg     %r0,%r13,0(%r3)                 # load guest gprs 0-13
+        lg      %r14,__LC_THREAD_INFO           # pointer thread_info struct
+        oi      __TI_flags+6(%r14),_TIF_SIE>>8
+sie_loop:
+        lg      %r14,__LC_THREAD_INFO           # pointer thread_info struct
+        tm      __TI_flags+7(%r14),_TIF_EXIT_SIE
+        jnz     sie_exit
+        lg      %r14,__SF_EMPTY(%r15)           # get control block pointer
+        SPP     __SF_EMPTY(%r15)                # set guest id
+        sie     0(%r14)
+sie_done:
+        SPP     __LC_CMF_HPP                    # set host id
+        lg      %r14,__LC_THREAD_INFO           # pointer thread_info struct
+sie_exit:
+        ni      __TI_flags+6(%r14),255-(_TIF_SIE>>8)
+        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
+        lghi    %r2,0
+        br      %r14
+sie_fault:
+        lg      %r14,__LC_THREAD_INFO           # pointer thread_info struct
+        ni      __TI_flags+6(%r14),255-(_TIF_SIE>>8)
+        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
+        lghi    %r2,-EFAULT
+        br      %r14
+
+        .align  8
+.Lsie_loop:
+        .quad   sie_loop
+.Lsie_done:
+        .quad   sie_done
+
+        .section __ex_table,"a"
+        .quad   sie_loop,sie_fault
+        .previous
+#endif
+
                 .section .rodata, "a"
 #define SYSCALL(esa,esame,emu)  .long esame
         .globl  sys_call_table
diff --git a/arch/s390/kernel/s390_ksyms.c b/arch/s390/kernel/s390_ksyms.c
index 656fcbb9bd83..57b536649b00 100644
--- a/arch/s390/kernel/s390_ksyms.c
+++ b/arch/s390/kernel/s390_ksyms.c
@@ -1,6 +1,10 @@
 #include <linux/module.h>
+#include <linux/kvm_host.h>
 #include <asm/ftrace.h>
 
 #ifdef CONFIG_FUNCTION_TRACER
 EXPORT_SYMBOL(_mcount);
 #endif
+#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
+EXPORT_SYMBOL(sie64a);
+#endif
diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile
index 860d26514c08..3975722bb19d 100644
--- a/arch/s390/kvm/Makefile
+++ b/arch/s390/kvm/Makefile
@@ -10,5 +10,5 @@ common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o)
 
 ccflags-y := -Ivirt/kvm -Iarch/s390/kvm
 
-kvm-objs := $(common-objs) kvm-s390.o sie64a.o intercept.o interrupt.o priv.o sigp.o diag.o
+kvm-objs := $(common-objs) kvm-s390.o intercept.o interrupt.o priv.o sigp.o diag.o
 obj-$(CONFIG_KVM) += kvm.o
diff --git a/arch/s390/kvm/sie64a.S b/arch/s390/kvm/sie64a.S
deleted file mode 100644
index 5faa1b1b23fa..000000000000
--- a/arch/s390/kvm/sie64a.S
+++ /dev/null
@@ -1,98 +0,0 @@
-/*
- * sie64a.S - low level sie call
- *
- * Copyright IBM Corp. 2008,2010
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License (version 2 only)
- * as published by the Free Software Foundation.
- *
- *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
- *               Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
- */
-
-#include <linux/errno.h>
-#include <asm/asm-offsets.h>
-#include <asm/setup.h>
-#include <asm/asm-offsets.h>
-#include <asm/ptrace.h>
-#include <asm/thread_info.h>
-
-_TIF_EXIT_SIE = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING)
-
-/*
- * offsets into stackframe
- * SP_  = offsets into stack sie64 is called with
- * SPI_ = offsets into irq stack
- */
-SP_GREGS = __SF_EMPTY
-SP_HOOK  = __SF_EMPTY+8
-SP_GPP   = __SF_EMPTY+16
-SPI_PSW  = STACK_FRAME_OVERHEAD + __PT_PSW
-
-
-        .macro SPP newpp
-        tm      __LC_MACHINE_FLAGS+6,0x20       # MACHINE_FLAG_SPP
-        jz      0f
-        .insn   s,0xb2800000,\newpp
-0:
-        .endm
-
-sie_irq_handler:
-        SPP     __LC_CMF_HPP                    # set host id
-        larl    %r2,sie_inst
-        clg     %r2,SPI_PSW+8(0,%r15)           # intercepted sie
-        jne     1f
-        xc      __LC_SIE_HOOK(8),__LC_SIE_HOOK
-        lg      %r2,__LC_THREAD_INFO            # pointer thread_info struct
-        tm      __TI_flags+7(%r2),_TIF_EXIT_SIE
-        jz      0f
-        larl    %r2,sie_exit                    # work pending, leave sie
-        stg     %r2,SPI_PSW+8(0,%r15)
-        br      %r14
-0:      larl    %r2,sie_reenter                 # re-enter with guest id
-        stg     %r2,SPI_PSW+8(0,%r15)
-1:      br      %r14
-
-/*
- * sie64a calling convention:
- * %r2 pointer to sie control block
- * %r3 guest register save area
- */
-        .globl  sie64a
-sie64a:
-        stg     %r3,SP_GREGS(%r15)              # save guest register save area
-        stmg    %r6,%r14,__SF_GPRS(%r15)        # save registers on entry
-        lgr     %r14,%r2                        # pointer to sie control block
-        larl    %r5,sie_irq_handler
-        stg     %r2,SP_GPP(%r15)
-        stg     %r5,SP_HOOK(%r15)               # save hook target
-        lmg     %r0,%r13,0(%r3)                 # load guest gprs 0-13
-sie_reenter:
-        mvc     __LC_SIE_HOOK(8),SP_HOOK(%r15)
-        SPP     SP_GPP(%r15)                    # set guest id
-sie_inst:
-        sie     0(%r14)
-        xc      __LC_SIE_HOOK(8),__LC_SIE_HOOK
-        SPP     __LC_CMF_HPP                    # set host id
-sie_exit:
-        lg      %r14,SP_GREGS(%r15)
-        stmg    %r0,%r13,0(%r14)                # save guest gprs 0-13
-        lghi    %r2,0
-        lmg     %r6,%r14,__SF_GPRS(%r15)
-        br      %r14
-
-sie_err:
-        xc      __LC_SIE_HOOK(8),__LC_SIE_HOOK
-        SPP     __LC_CMF_HPP                    # set host id
-        lg      %r14,SP_GREGS(%r15)
-        stmg    %r0,%r13,0(%r14)                # save guest gprs 0-13
-        lghi    %r2,-EFAULT
-        lmg     %r6,%r14,__SF_GPRS(%r15)
-        br      %r14
-
-        .section __ex_table,"a"
-        .quad   sie_inst,sie_err
-        .quad   sie_exit,sie_err
-        .quad   sie_reenter,sie_err
-        .previous