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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	Martin Schwidefsky <schwidefsky@de.ibm.com>
Subject: [PATCH 4.4 17/50] s390: run user space and KVM guests with modified branch prediction
Date: Fri, 27 Apr 2018 15:58:19 +0200	[thread overview]
Message-ID: <20180427135656.746610071@linuxfoundation.org> (raw)
In-Reply-To: <20180427135655.623669681@linuxfoundation.org>

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Martin Schwidefsky <schwidefsky@de.ibm.com>


[ Upstream commit 6b73044b2b0081ee3dd1cd6eaab7dee552601efb ]

Define TIF_ISOLATE_BP and TIF_ISOLATE_BP_GUEST and add the necessary
plumbing in entry.S to be able to run user space and KVM guests with
limited branch prediction.

To switch a user space process to limited branch prediction the
s390_isolate_bp() function has to be call, and to run a vCPU of a KVM
guest associated with the current task with limited branch prediction
call s390_isolate_bp_guest().

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/s390/include/asm/processor.h   |    3 ++
 arch/s390/include/asm/thread_info.h |    4 ++
 arch/s390/kernel/entry.S            |   49 +++++++++++++++++++++++++++++++++---
 arch/s390/kernel/processor.c        |   18 +++++++++++++
 4 files changed, 70 insertions(+), 4 deletions(-)

--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -316,6 +316,9 @@ extern void memcpy_absolute(void *, void
 	memcpy_absolute(&(dest), &__tmp, sizeof(__tmp));	\
 }
 
+extern int s390_isolate_bp(void);
+extern int s390_isolate_bp_guest(void);
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __ASM_S390_PROCESSOR_H */
--- a/arch/s390/include/asm/thread_info.h
+++ b/arch/s390/include/asm/thread_info.h
@@ -78,6 +78,8 @@ void arch_release_task_struct(struct tas
 #define TIF_SECCOMP		5	/* secure computing */
 #define TIF_SYSCALL_TRACEPOINT	6	/* syscall tracepoint instrumentation */
 #define TIF_UPROBE		7	/* breakpointed or single-stepping */
+#define TIF_ISOLATE_BP		8	/* Run process with isolated BP */
+#define TIF_ISOLATE_BP_GUEST	9	/* Run KVM guests with isolated BP */
 #define TIF_31BIT		16	/* 32bit process */
 #define TIF_MEMDIE		17	/* is terminating due to OOM killer */
 #define TIF_RESTORE_SIGMASK	18	/* restore signal mask in do_signal() */
@@ -93,6 +95,8 @@ void arch_release_task_struct(struct tas
 #define _TIF_SECCOMP		_BITUL(TIF_SECCOMP)
 #define _TIF_SYSCALL_TRACEPOINT	_BITUL(TIF_SYSCALL_TRACEPOINT)
 #define _TIF_UPROBE		_BITUL(TIF_UPROBE)
+#define _TIF_ISOLATE_BP		_BITUL(TIF_ISOLATE_BP)
+#define _TIF_ISOLATE_BP_GUEST	_BITUL(TIF_ISOLATE_BP_GUEST)
 #define _TIF_31BIT		_BITUL(TIF_31BIT)
 #define _TIF_SINGLE_STEP	_BITUL(TIF_SINGLE_STEP)
 
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -104,6 +104,7 @@ _PIF_WORK	= (_PIF_PER_TRAP)
 	j	3f
 1:	LAST_BREAK %r14
 	UPDATE_VTIME %r14,%r15,\timer
+	BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP
 2:	lg	%r15,__LC_ASYNC_STACK	# load async stack
 3:	la	%r11,STACK_FRAME_OVERHEAD(%r15)
 	.endm
@@ -190,6 +191,40 @@ _PIF_WORK	= (_PIF_PER_TRAP)
 	.popsection
 	.endm
 
+	.macro BPENTER tif_ptr,tif_mask
+	.pushsection .altinstr_replacement, "ax"
+662:	.word	0xc004, 0x0000, 0x0000	# 6 byte nop
+	.word	0xc004, 0x0000, 0x0000	# 6 byte nop
+	.popsection
+664:	TSTMSK	\tif_ptr,\tif_mask
+	jz	. + 8
+	.long	0xb2e8d000
+	.pushsection .altinstructions, "a"
+	.long 664b - .
+	.long 662b - .
+	.word 82
+	.byte 12
+	.byte 12
+	.popsection
+	.endm
+
+	.macro BPEXIT tif_ptr,tif_mask
+	TSTMSK	\tif_ptr,\tif_mask
+	.pushsection .altinstr_replacement, "ax"
+662:	jnz	. + 8
+	.long	0xb2e8d000
+	.popsection
+664:	jz	. + 8
+	.long	0xb2e8c000
+	.pushsection .altinstructions, "a"
+	.long 664b - .
+	.long 662b - .
+	.word 82
+	.byte 8
+	.byte 8
+	.popsection
+	.endm
+
 	.section .kprobes.text, "ax"
 
 ENTRY(__bpon)
@@ -237,9 +272,11 @@ ENTRY(__switch_to)
  */
 ENTRY(sie64a)
 	stmg	%r6,%r14,__SF_GPRS(%r15)	# save kernel registers
+	lg	%r12,__LC_CURRENT
 	stg	%r2,__SF_EMPTY(%r15)		# save control block pointer
 	stg	%r3,__SF_EMPTY+8(%r15)		# save guest register save area
 	xc	__SF_EMPTY+16(8,%r15),__SF_EMPTY+16(%r15) # reason code = 0
+	mvc	__SF_EMPTY+24(8,%r15),__TI_flags(%r12) # copy thread flags
 	TSTMSK	__LC_CPU_FLAGS,_CIF_FPU		# load guest fp/vx registers ?
 	jno	.Lsie_load_guest_gprs
 	brasl	%r14,load_fpu_regs		# load guest fp/vx regs
@@ -256,10 +293,11 @@ ENTRY(sie64a)
 	jnz	.Lsie_skip
 	TSTMSK	__LC_CPU_FLAGS,_CIF_FPU
 	jo	.Lsie_skip			# exit if fp/vx regs changed
-	BPON
+	BPEXIT	__SF_EMPTY+24(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
 	sie	0(%r14)
 .Lsie_exit:
 	BPOFF
+	BPENTER	__SF_EMPTY+24(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
 .Lsie_skip:
 	ni	__SIE_PROG0C+3(%r14),0xfe	# no longer in SIE
 	lctlg	%c1,%c1,__LC_USER_ASCE		# load primary asce
@@ -319,6 +357,7 @@ ENTRY(system_call)
 	LAST_BREAK %r13
 .Lsysc_vtime:
 	UPDATE_VTIME %r10,%r13,__LC_SYNC_ENTER_TIMER
+	BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP
 	stmg	%r0,%r7,__PT_R0(%r11)
 	# clear user controlled register to prevent speculative use
 	xgr	%r0,%r0
@@ -356,7 +395,7 @@ ENTRY(system_call)
 	jnz	.Lsysc_work			# check for work
 	TSTMSK	__LC_CPU_FLAGS,_CIF_WORK
 	jnz	.Lsysc_work
-	BPON
+	BPEXIT	__TI_flags(%r12),_TIF_ISOLATE_BP
 .Lsysc_restore:
 	lg	%r14,__LC_VDSO_PER_CPU
 	lmg	%r0,%r10,__PT_R0(%r11)
@@ -542,6 +581,7 @@ ENTRY(pgm_check_handler)
 	j	3f
 2:	LAST_BREAK %r14
 	UPDATE_VTIME %r14,%r15,__LC_SYNC_ENTER_TIMER
+	BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP
 	lg	%r15,__LC_KERNEL_STACK
 	lg	%r14,__TI_task(%r12)
 	aghi	%r14,__TASK_thread	# pointer to thread_struct
@@ -670,7 +710,7 @@ ENTRY(io_int_handler)
 	mvc	__LC_RETURN_PSW(16),__PT_PSW(%r11)
 	tm	__PT_PSW+1(%r11),0x01	# returning to user ?
 	jno	.Lio_exit_kernel
-	BPON
+	BPEXIT	__TI_flags(%r12),_TIF_ISOLATE_BP
 .Lio_exit_timer:
 	stpt	__LC_EXIT_TIMER
 	mvc	__VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER
@@ -1027,7 +1067,7 @@ 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
-	BPON
+	BPEXIT	__TI_flags(%r12),_TIF_ISOLATE_BP
 	stpt	__LC_EXIT_TIMER
 	mvc	__VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER
 0:	lmg	%r11,%r15,__PT_R11(%r11)
@@ -1148,6 +1188,7 @@ cleanup_critical:
 	.quad	.Lsie_done
 
 .Lcleanup_sie:
+	BPENTER __SF_EMPTY+24(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
 	lg	%r9,__SF_EMPTY(%r15)		# get control block pointer
 	ni	__SIE_PROG0C+3(%r9),0xfe	# no longer in SIE
 	lctlg	%c1,%c1,__LC_USER_ASCE		# load primary asce
--- a/arch/s390/kernel/processor.c
+++ b/arch/s390/kernel/processor.c
@@ -13,6 +13,7 @@
 #include <linux/cpu.h>
 #include <asm/diag.h>
 #include <asm/elf.h>
+#include <asm/facility.h>
 #include <asm/lowcore.h>
 #include <asm/param.h>
 #include <asm/smp.h>
@@ -113,3 +114,20 @@ 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))
+		return -EOPNOTSUPP;
+	set_thread_flag(TIF_ISOLATE_BP_GUEST);
+	return 0;
+}
+EXPORT_SYMBOL(s390_isolate_bp_guest);

  parent reply	other threads:[~2018-04-27 13:58 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-27 13:58 [PATCH 4.4 00/50] 4.4.130-stable review Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 01/50] cifs: do not allow creating sockets except with SMB1 posix exensions Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 02/50] x86/tsc: Prevent 32bit truncation in calc_hpet_ref() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 03/50] perf: Return proper values for user stack errors Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 04/50] staging: ion : Donnot wakeup kswapd in ion system alloc Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 05/50] r8152: add Linksys USB3GIGV1 id Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 06/50] Input: drv260x - fix initializing overdrive voltage Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 07/50] ath9k_hw: check if the chip failed to wake up Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 08/50] jbd2: fix use after free in kjournald2() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 09/50] Revert "ath10k: send (re)assoc peer command when NSS changed" Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 10/50] s390: introduce CPU alternatives Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 11/50] s390: enable CPU alternatives unconditionally Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 12/50] KVM: s390: wire up bpb feature Greg Kroah-Hartman
2018-04-27 15:10   ` Christian Borntraeger
2018-04-27 15:17     ` Greg Kroah-Hartman
2018-04-27 15:46       ` Greg Kroah-Hartman
2018-04-27 15:53         ` Christian Borntraeger
2018-04-29  7:51           ` Martin Schwidefsky
2018-04-30 18:17             ` Greg Kroah-Hartman
2018-04-30 18:30               ` Christian Borntraeger
2018-04-27 13:58 ` [PATCH 4.4 13/50] s390: scrub registers on kernel entry and KVM exit Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 14/50] s390: add optimized array_index_mask_nospec Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 15/50] s390/alternative: use a copy of the facility bit mask Greg Kroah-Hartman
2018-05-04  7:37   ` Jiri Slaby
2018-05-04  7:41     ` Jiri Slaby
2018-05-04 22:18     ` Greg Kroah-Hartman
2018-05-07  6:07       ` Martin Schwidefsky
2018-05-08  7:20         ` Greg Kroah-Hartman
2018-05-12 19:44           ` Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 16/50] s390: add options to change branch prediction behaviour for the kernel Greg Kroah-Hartman
2018-04-27 13:58 ` Greg Kroah-Hartman [this message]
2018-04-27 13:58 ` [PATCH 4.4 18/50] s390: introduce execute-trampolines for branches Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 19/50] s390: Replace IS_ENABLED(EXPOLINE_*) with IS_ENABLED(CONFIG_EXPOLINE_*) Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 20/50] s390: do not bypass BPENTER for interrupt system calls Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 21/50] s390/entry.S: fix spurious zeroing of r0 Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 22/50] s390: move nobp parameter functions to nospec-branch.c Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 23/50] s390: add automatic detection of the spectre defense Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 24/50] s390: report spectre mitigation via syslog Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 25/50] s390: add sysfs attributes for spectre Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 26/50] s390: correct nospec auto detection init order Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 27/50] s390: correct module section names for expoline code revert Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 28/50] bonding: do not set slave_dev npinfo before slave_enable_netpoll in bond_enslave Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 29/50] KEYS: DNS: limit the length of option strings Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 30/50] l2tp: check sockaddr length in pppol2tp_connect() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 31/50] net: validate attribute sizes in neigh_dump_table() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 32/50] llc: delete timers synchronously in llc_sk_free() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 33/50] tcp: dont read out-of-bounds opsize Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 34/50] team: avoid adding twice the same option to the event list Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 35/50] team: fix netconsole setup over team Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 36/50] packet: fix bitfield update race Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 37/50] pppoe: check sockaddr length in pppoe_connect() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 38/50] vlan: Fix reading memory beyond skb->tail in skb_vlan_tagged_multi Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 39/50] sctp: do not check port in sctp_inet6_cmp_addr Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 40/50] llc: hold llc_sap before release_sock() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 41/50] llc: fix NULL pointer deref for SOCK_ZAPPED Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 42/50] tipc: add policy for TIPC_NLA_NET_ADDR Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 43/50] net: fix deadlock while clearing neighbor proxy table Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 44/50] tcp: md5: reject TCP_MD5SIG or TCP_MD5SIG_EXT on established sockets Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 45/50] net: af_packet: fix race in PACKET_{R|T}X_RING Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 46/50] ipv6: add RTA_TABLE and RTA_PREFSRC to rtm_ipv6_policy Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 47/50] scsi: mptsas: Disable WRITE SAME Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 48/50] cdrom: information leak in cdrom_ioctl_media_changed() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 49/50] s390/cio: update chpid descriptor after resource accessibility event Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.4 50/50] s390/uprobes: implement arch_uretprobe_is_alive() Greg Kroah-Hartman
2018-04-27 18:15 ` [PATCH 4.4 00/50] 4.4.130-stable review Shuah Khan
2018-04-27 18:57 ` Nathan Chancellor
2018-04-27 19:43 ` kernelci.org bot
2018-04-27 20:31 ` Dan Rue
2018-04-28 14:25 ` Guenter Roeck

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