[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>

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)

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

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

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

arch/s390/kvm/sie64a.S

@@ -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