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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 4.14 56/80] s390: add automatic detection of the spectre defense
Date: Fri, 27 Apr 2018 15:58:49 +0200	[thread overview]
Message-ID: <20180427135735.788426777@linuxfoundation.org> (raw)
In-Reply-To: <20180427135732.928644313@linuxfoundation.org>

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

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

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


[ Upstream commit 6e179d64126b909f0b288fa63cdbf07c531e9b1d ]

Automatically decide between nobp vs. expolines if the spectre_v2=auto
kernel parameter is specified or CONFIG_EXPOLINE_AUTO=y is set.

The decision made at boot time due to CONFIG_EXPOLINE_AUTO=y being set
can be overruled with the nobp, nospec and spectre_v2 kernel parameters.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/s390/Kconfig                     |    2 -
 arch/s390/Makefile                    |    2 -
 arch/s390/include/asm/nospec-branch.h |    6 +--
 arch/s390/kernel/alternative.c        |    1 
 arch/s390/kernel/module.c             |   11 ++---
 arch/s390/kernel/nospec-branch.c      |   68 +++++++++++++++++++++-------------
 6 files changed, 52 insertions(+), 38 deletions(-)

--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -575,7 +575,7 @@ choice
 config EXPOLINE_OFF
 	bool "spectre_v2=off"
 
-config EXPOLINE_MEDIUM
+config EXPOLINE_AUTO
 	bool "spectre_v2=auto"
 
 config EXPOLINE_FULL
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -87,7 +87,7 @@ ifdef CONFIG_EXPOLINE
     CC_FLAGS_EXPOLINE += -mfunction-return=thunk
     CC_FLAGS_EXPOLINE += -mindirect-branch-table
     export CC_FLAGS_EXPOLINE
-    cflags-y += $(CC_FLAGS_EXPOLINE)
+    cflags-y += $(CC_FLAGS_EXPOLINE) -DCC_USING_EXPOLINE
   endif
 endif
 
--- a/arch/s390/include/asm/nospec-branch.h
+++ b/arch/s390/include/asm/nospec-branch.h
@@ -6,12 +6,10 @@
 
 #include <linux/types.h>
 
-extern int nospec_call_disable;
-extern int nospec_return_disable;
+extern int nospec_disable;
 
 void nospec_init_branches(void);
-void nospec_call_revert(s32 *start, s32 *end);
-void nospec_return_revert(s32 *start, s32 *end);
+void nospec_revert(s32 *start, s32 *end);
 
 #endif /* __ASSEMBLY__ */
 
--- a/arch/s390/kernel/alternative.c
+++ b/arch/s390/kernel/alternative.c
@@ -1,6 +1,7 @@
 #include <linux/module.h>
 #include <asm/alternative.h>
 #include <asm/facility.h>
+#include <asm/nospec-branch.h>
 
 #define MAX_PATCH_LEN (255 - 1)
 
--- a/arch/s390/kernel/module.c
+++ b/arch/s390/kernel/module.c
@@ -172,7 +172,7 @@ int module_frob_arch_sections(Elf_Ehdr *
 	me->core_layout.size += me->arch.got_size;
 	me->arch.plt_offset = me->core_layout.size;
 	if (me->arch.plt_size) {
-		if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_call_disable)
+		if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable)
 			me->arch.plt_size += PLT_ENTRY_SIZE;
 		me->core_layout.size += me->arch.plt_size;
 	}
@@ -331,8 +331,7 @@ static int apply_rela(Elf_Rela *rela, El
 				info->plt_offset;
 			ip[0] = 0x0d10e310;	/* basr 1,0  */
 			ip[1] = 0x100a0004;	/* lg	1,10(1) */
-			if (IS_ENABLED(CONFIG_EXPOLINE) &&
-			    !nospec_call_disable) {
+			if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable) {
 				unsigned int *ij;
 				ij = me->core_layout.base +
 					me->arch.plt_offset +
@@ -453,7 +452,7 @@ int module_finalize(const Elf_Ehdr *hdr,
 	void *aseg;
 
 	if (IS_ENABLED(CONFIG_EXPOLINE) &&
-	    !nospec_call_disable && me->arch.plt_size) {
+	    !nospec_disable && me->arch.plt_size) {
 		unsigned int *ij;
 
 		ij = me->core_layout.base + me->arch.plt_offset +
@@ -480,11 +479,11 @@ int module_finalize(const Elf_Ehdr *hdr,
 
 		if (IS_ENABLED(CONFIG_EXPOLINE) &&
 		    (!strcmp(".nospec_call_table", secname)))
-			nospec_call_revert(aseg, aseg + s->sh_size);
+			nospec_revert(aseg, aseg + s->sh_size);
 
 		if (IS_ENABLED(CONFIG_EXPOLINE) &&
 		    (!strcmp(".nospec_return_table", secname)))
-			nospec_return_revert(aseg, aseg + s->sh_size);
+			nospec_revert(aseg, aseg + s->sh_size);
 	}
 
 	jump_label_apply_nops(me);
--- a/arch/s390/kernel/nospec-branch.c
+++ b/arch/s390/kernel/nospec-branch.c
@@ -11,10 +11,17 @@ static int __init nobp_setup_early(char
 	rc = kstrtobool(str, &enabled);
 	if (rc)
 		return rc;
-	if (enabled && test_facility(82))
+	if (enabled && test_facility(82)) {
+		/*
+		 * The user explicitely requested nobp=1, enable it and
+		 * disable the expoline support.
+		 */
 		__set_facility(82, S390_lowcore.alt_stfle_fac_list);
-	else
+		if (IS_ENABLED(CONFIG_EXPOLINE))
+			nospec_disable = 1;
+	} else {
 		__clear_facility(82, S390_lowcore.alt_stfle_fac_list);
+	}
 	return 0;
 }
 early_param("nobp", nobp_setup_early);
@@ -28,31 +35,46 @@ early_param("nospec", nospec_setup_early
 
 #ifdef CONFIG_EXPOLINE
 
-int nospec_call_disable = IS_ENABLED(CONFIG_EXPOLINE_OFF);
-int nospec_return_disable = !IS_ENABLED(CONFIG_EXPOLINE_FULL);
+int nospec_disable = IS_ENABLED(CONFIG_EXPOLINE_OFF);
 
 static int __init nospectre_v2_setup_early(char *str)
 {
-	nospec_call_disable = 1;
-	nospec_return_disable = 1;
+	nospec_disable = 1;
 	return 0;
 }
 early_param("nospectre_v2", nospectre_v2_setup_early);
 
+static int __init spectre_v2_auto_early(void)
+{
+	if (IS_ENABLED(CC_USING_EXPOLINE)) {
+		/*
+		 * The kernel has been compiled with expolines.
+		 * Keep expolines enabled and disable nobp.
+		 */
+		nospec_disable = 0;
+		__clear_facility(82, S390_lowcore.alt_stfle_fac_list);
+	}
+	/*
+	 * If the kernel has not been compiled with expolines the
+	 * nobp setting decides what is done, this depends on the
+	 * CONFIG_KERNEL_NP option and the nobp/nospec parameters.
+	 */
+	return 0;
+}
+#ifdef CONFIG_EXPOLINE_AUTO
+early_initcall(spectre_v2_auto_early);
+#endif
+
 static int __init spectre_v2_setup_early(char *str)
 {
 	if (str && !strncmp(str, "on", 2)) {
-		nospec_call_disable = 0;
-		nospec_return_disable = 0;
-	}
-	if (str && !strncmp(str, "off", 3)) {
-		nospec_call_disable = 1;
-		nospec_return_disable = 1;
-	}
-	if (str && !strncmp(str, "auto", 4)) {
-		nospec_call_disable = 0;
-		nospec_return_disable = 1;
+		nospec_disable = 0;
+		__clear_facility(82, S390_lowcore.alt_stfle_fac_list);
 	}
+	if (str && !strncmp(str, "off", 3))
+		nospec_disable = 1;
+	if (str && !strncmp(str, "auto", 4))
+		spectre_v2_auto_early();
 	return 0;
 }
 early_param("spectre_v2", spectre_v2_setup_early);
@@ -105,15 +127,9 @@ static void __init_or_module __nospec_re
 	}
 }
 
-void __init_or_module nospec_call_revert(s32 *start, s32 *end)
-{
-	if (nospec_call_disable)
-		__nospec_revert(start, end);
-}
-
-void __init_or_module nospec_return_revert(s32 *start, s32 *end)
+void __init_or_module nospec_revert(s32 *start, s32 *end)
 {
-	if (nospec_return_disable)
+	if (nospec_disable)
 		__nospec_revert(start, end);
 }
 
@@ -121,8 +137,8 @@ extern s32 __nospec_call_start[], __nosp
 extern s32 __nospec_return_start[], __nospec_return_end[];
 void __init nospec_init_branches(void)
 {
-	nospec_call_revert(__nospec_call_start, __nospec_call_end);
-	nospec_return_revert(__nospec_return_start, __nospec_return_end);
+	nospec_revert(__nospec_call_start, __nospec_call_end);
+	nospec_revert(__nospec_return_start, __nospec_return_end);
 }
 
 #endif /* CONFIG_EXPOLINE */

  parent reply	other threads:[~2018-04-27 14:08 UTC|newest]

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-27 13:57 [PATCH 4.14 00/80] 4.14.38-stable review Greg Kroah-Hartman
2018-04-27 13:57 ` [PATCH 4.14 01/80] Revert "pinctrl: intel: Initialize GPIO properly when used through irqchip" Greg Kroah-Hartman
2018-04-27 13:57 ` [PATCH 4.14 02/80] drm: bridge: dw-hdmi: Fix overflow workaround for Amlogic Meson GX SoCs Greg Kroah-Hartman
2018-04-27 13:57 ` [PATCH 4.14 03/80] i40e: Fix attach VF to VM issue Greg Kroah-Hartman
2018-04-27 13:57 ` [PATCH 4.14 04/80] tpm: cmd_ready command can be issued only after granting locality Greg Kroah-Hartman
2018-04-27 13:57 ` [PATCH 4.14 05/80] tpm: tpm-interface: fix tpm_transmit/_cmd kdoc Greg Kroah-Hartman
2018-04-27 13:57 ` [PATCH 4.14 06/80] tpm: add retry logic Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 07/80] Revert "ath10k: send (re)assoc peer command when NSS changed" Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 08/80] bonding: do not set slave_dev npinfo before slave_enable_netpoll in bond_enslave Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 09/80] ipv6: add RTA_TABLE and RTA_PREFSRC to rtm_ipv6_policy Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 10/80] ipv6: sr: fix NULL pointer dereference in seg6_do_srh_encap()- v4 pkts Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 11/80] KEYS: DNS: limit the length of option strings Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 12/80] l2tp: check sockaddr length in pppol2tp_connect() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 13/80] net: validate attribute sizes in neigh_dump_table() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 14/80] llc: delete timers synchronously in llc_sk_free() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 15/80] tcp: dont read out-of-bounds opsize Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 16/80] net: af_packet: fix race in PACKET_{R|T}X_RING Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 17/80] tcp: md5: reject TCP_MD5SIG or TCP_MD5SIG_EXT on established sockets Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 18/80] net: fix deadlock while clearing neighbor proxy table Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 19/80] team: avoid adding twice the same option to the event list Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 20/80] net/smc: fix shutdown in state SMC_LISTEN Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 21/80] team: fix netconsole setup over team Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 22/80] packet: fix bitfield update race Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 23/80] tipc: add policy for TIPC_NLA_NET_ADDR Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 24/80] pppoe: check sockaddr length in pppoe_connect() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 25/80] vlan: Fix reading memory beyond skb->tail in skb_vlan_tagged_multi Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 26/80] amd-xgbe: Add pre/post auto-negotiation phy hooks Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 27/80] sctp: do not check port in sctp_inet6_cmp_addr Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 28/80] amd-xgbe: Improve KR auto-negotiation and training Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 29/80] strparser: Do not call mod_delayed_work with a timeout of LONG_MAX Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 30/80] amd-xgbe: Only use the SFP supported transceiver signals Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 31/80] strparser: Fix incorrect strp->need_bytes value Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 32/80] net: sched: ife: signal not finding metaid Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 33/80] tcp: clear tp->packets_out when purging write queue Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 34/80] net: sched: ife: handle malformed tlv length Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 35/80] net: sched: ife: check on metadata length Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 36/80] llc: hold llc_sap before release_sock() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 37/80] llc: fix NULL pointer deref for SOCK_ZAPPED Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 38/80] net: ethernet: ti: cpsw: fix tx vlan priority mapping Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 39/80] virtio_net: split out ctrl buffer Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 40/80] virtio_net: fix adding vids on big-endian Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 41/80] Revert "microblaze: fix endian handling" Greg Kroah-Hartman
2018-04-27 15:43   ` Guenter Roeck
2018-04-27 16:25   ` Guenter Roeck
2018-04-28  5:50     ` Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 42/80] s390: introduce CPU alternatives Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 43/80] s390: enable CPU alternatives unconditionally Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 44/80] KVM: s390: wire up bpb feature Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 45/80] s390: scrub registers on kernel entry and KVM exit Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 46/80] s390: add optimized array_index_mask_nospec Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 47/80] s390/alternative: use a copy of the facility bit mask Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 48/80] s390: add options to change branch prediction behaviour for the kernel Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 49/80] s390: run user space and KVM guests with modified branch prediction Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 50/80] s390: introduce execute-trampolines for branches Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 51/80] KVM: s390: force bp isolation for VSIE Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 52/80] s390: Replace IS_ENABLED(EXPOLINE_*) with IS_ENABLED(CONFIG_EXPOLINE_*) Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 53/80] s390: do not bypass BPENTER for interrupt system calls Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 54/80] s390/entry.S: fix spurious zeroing of r0 Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 55/80] s390: move nobp parameter functions to nospec-branch.c Greg Kroah-Hartman
2018-04-27 13:58 ` Greg Kroah-Hartman [this message]
2018-04-27 13:58 ` [PATCH 4.14 57/80] s390: report spectre mitigation via syslog Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 58/80] s390: add sysfs attributes for spectre Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 59/80] s390: correct nospec auto detection init order Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 60/80] s390: correct module section names for expoline code revert Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 61/80] microblaze: Setup dependencies for ASM optimized lib functions Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 62/80] arm64: dts: rockchip: remove vdd_log from rk3399-puma Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 63/80] Revert "mm/hmm: fix header file if/else/endif maze" Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 64/80] commoncap: Handle memory allocation failure Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 65/80] scsi: mptsas: Disable WRITE SAME Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.14 66/80] cdrom: information leak in cdrom_ioctl_media_changed() Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 67/80] fsnotify: Fix fsnotify_mark_connector race Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 68/80] m68k/mac: Dont remap SWIM MMIO region Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 69/80] block/swim: Check drive type Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 70/80] block/swim: Dont log an error message for an invalid ioctl Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 71/80] block/swim: Remove extra put_disk() call from error path Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 72/80] block/swim: Rename macros to avoid inconsistent inverted logic Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 73/80] block/swim: Select appropriate drive on device open Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 74/80] block/swim: Fix array bounds check Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 75/80] block/swim: Fix IO error at end of medium Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 76/80] tracing: Fix missing tab for hwlat_detector print format Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 77/80] s390/cio: update chpid descriptor after resource accessibility event Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 78/80] s390/dasd: fix IO error for newly defined devices Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 79/80] s390/uprobes: implement arch_uretprobe_is_alive() Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.14 80/80] ACPI / video: Only default only_lcd to true on Win8-ready _desktops_ Greg Kroah-Hartman
2018-04-27 18:14 ` [PATCH 4.14 00/80] 4.14.38-stable review Shuah Khan
2018-04-27 19:24 ` kernelci.org bot
2018-04-27 19:33 ` Nathan Chancellor
2018-04-28  5:06   ` Greg Kroah-Hartman
2018-04-27 20:37 ` Dan Rue
2018-04-28 14:28 ` Guenter Roeck

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