s390/bp: remove TIF_ISOLATE_BP

TIF_ISOLATE_BP is unused since it was introduced with commit 6b73044b
("s390: run user space and KVM guests with modified branch prediction").
Given that there is no use case remove it again.
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/include/asm/processor.h

@@ -329,7 +329,6 @@ static __always_inline void __noreturn disabled_wait(void)
 
 #define ARCH_LOW_ADDRESS_LIMIT	0x7fffffffUL
 
-extern int s390_isolate_bp(void);
 extern int s390_isolate_bp_guest(void);
 
 static __always_inline bool regs_irqs_disabled(struct pt_regs *regs)

arch/s390/include/asm/thread_info.h

@@ -70,7 +70,6 @@ void arch_setup_new_exec(void);
 #define TIF_PATCH_PENDING	5	/* pending live patching update */
 #define TIF_PGSTE		6	/* New mm's will use 4K page tables */
 #define TIF_NOTIFY_SIGNAL	7	/* signal notifications exist */
-#define TIF_ISOLATE_BP		8	/* Run process with isolated BP */
 #define TIF_ISOLATE_BP_GUEST	9	/* Run KVM guests with isolated BP */
 #define TIF_PER_TRAP		10	/* Need to handle PER trap on exit to usermode */
 
@@ -94,7 +93,6 @@ void arch_setup_new_exec(void);
 #define _TIF_UPROBE		BIT(TIF_UPROBE)
 #define _TIF_GUARDED_STORAGE	BIT(TIF_GUARDED_STORAGE)
 #define _TIF_PATCH_PENDING	BIT(TIF_PATCH_PENDING)
-#define _TIF_ISOLATE_BP		BIT(TIF_ISOLATE_BP)
 #define _TIF_ISOLATE_BP_GUEST	BIT(TIF_ISOLATE_BP_GUEST)
 #define _TIF_PER_TRAP		BIT(TIF_PER_TRAP)
 

arch/s390/kernel/entry.S

@@ -227,7 +227,7 @@ ENTRY(__sie64a)
 	TSTMSK	__LC_CPU_FLAGS,_CIF_FPU
 	jo	.Lsie_skip			# exit if fp/vx regs changed
 	lg	%r14,__SF_SIE_CONTROL_PHYS(%r15)	# get sie block phys addr
-	BPEXIT	__SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
+	BPEXIT	__SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
 .Lsie_entry:
 	sie	0(%r14)
 # Let the next instruction be NOP to avoid triggering a machine check
@@ -235,7 +235,7 @@ ENTRY(__sie64a)
 	nopr	7
 .Lsie_leave:
 	BPOFF
-	BPENTER	__SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
+	BPENTER	__SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
 .Lsie_skip:
 	lg	%r14,__SF_SIE_CONTROL(%r15)	# get control block pointer
 	ni	__SIE_PROG0C+3(%r14),0xfe	# no longer in SIE
@@ -291,11 +291,9 @@ ENTRY(system_call)
 .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
@@ -314,7 +312,7 @@ ENTRY(system_call)
 	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
+	BPON
 	LBEAR	STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
 	lmg	%r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
 	stpt	__LC_EXIT_TIMER
@@ -329,7 +327,7 @@ ENTRY(ret_from_fork)
 	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
+	BPON
 	LBEAR	STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
 	lmg	%r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
 	stpt	__LC_EXIT_TIMER
@@ -344,7 +342,6 @@ 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?
@@ -355,7 +352,7 @@ ENTRY(pgm_check_handler)
 #if IS_ENABLED(CONFIG_KVM)
 	# cleanup critical section for program checks in __sie64a
 	OUTSIDE	%r9,.Lsie_gmap,.Lsie_done,1f
-	BPENTER	__SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
+	BPENTER	__SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
 	SIEEXIT
 	lghi	%r10,_PIF_GUEST_FAULT
 #endif
@@ -367,8 +364,7 @@ ENTRY(pgm_check_handler)
 	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
+3:	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)
@@ -390,7 +386,7 @@ ENTRY(pgm_check_handler)
 	tmhh	%r8,0x0001		# returning to user space?
 	jno	.Lpgm_exit_kernel
 	lctlg	%c1,%c1,__LC_USER_ASCE
-	BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP
+	BPON
 	stpt	__LC_EXIT_TIMER
 .Lpgm_exit_kernel:
 	mvc	__LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
@@ -420,20 +416,18 @@ ENTRY(\name)
 	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)
+	BPENTER	__SF_SIE_FLAGS(%r15),_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
+1:	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)
@@ -457,7 +451,7 @@ ENTRY(\name)
 	tmhh	%r8,0x0001		# returning to user ?
 	jno	2f
 	lctlg	%c1,%c1,__LC_USER_ASCE
-	BPEXIT	__TI_flags(%r12),_TIF_ISOLATE_BP
+	BPON
 	stpt	__LC_EXIT_TIMER
 2:	LBEAR	__PT_LAST_BREAK(%r11)
 	lmg	%r0,%r15,__PT_R0(%r11)
@@ -502,7 +496,6 @@ ENTRY(mcck_int_handler)
 	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
@@ -531,16 +524,13 @@ ENTRY(mcck_int_handler)
 	TSTMSK	__LC_MCCK_CODE,MCCK_CODE_PSW_IA_VALID
 	jno	.Lmcck_panic
 #if IS_ENABLED(CONFIG_KVM)
-	OUTSIDE	%r9,.Lsie_gmap,.Lsie_done,.Lmcck_stack
+	OUTSIDE	%r9,.Lsie_gmap,.Lsie_done,.Lmcck_user
 	OUTSIDE	%r9,.Lsie_entry,.Lsie_leave,4f
 	oi	__LC_CPU_FLAGS+7, _CIF_MCCK_GUEST
-4:	BPENTER	__SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
+4:	BPENTER	__SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
 	SIEEXIT
-	j	.Lmcck_stack
 #endif
 .Lmcck_user:
-	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)
@@ -568,7 +558,7 @@ ENTRY(mcck_int_handler)
 	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
+	BPON
 	stpt	__LC_EXIT_TIMER
 0:	ALTERNATIVE "nop", __stringify(lghi %r12,__LC_LAST_BREAK_SAVE_AREA),193
 	LBEAR	0(%r12)

arch/s390/kernel/processor.c

@@ -365,15 +365,6 @@ const struct seq_operations cpuinfo_op = {
 	.show	= show_cpuinfo,
 };
 
-int s390_isolate_bp(void)
-{
-	if (!test_facility(82))
-		return -EOPNOTSUPP;
-	set_thread_flag(TIF_ISOLATE_BP);
-	return 0;
-}
-EXPORT_SYMBOL(s390_isolate_bp);
-
 int s390_isolate_bp_guest(void)
 {
 	if (!test_facility(82))