From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZrxewSwi9ud+0AjLwP8jE8qoh3xa6/m405R/vm1auLd9CKfGWu8xjpLfXBvmGAJjbFms8ht ARC-Seal: i=1; a=rsa-sha256; t=1524837858; cv=none; d=google.com; s=arc-20160816; b=U4Q/wakNve0avPM6u9uVOTwGGUowiE6kla2JT7cV2Ozf4yyH7aaiBBUd/K3QLjz0bF dCnpXVD84+mqeY4r0Q/Pf5cxFycYGprRhWn9kiTYooiwtgL8u80JtUdPZQxmxGDJmEzm GXpFNZzox829KkjhwCm0b4o/JIsz5ggKkYs4hIBqrcCs8pzV5go4Pe7eJiLAlJUNs8Ab Md5NDM6u/6CquYq0b579unHmogpm81a1RSfUtG4XeK/sgzrQQ5+RlvBMIjQBMl7dLs0w CKhe+CeHEcpOPu2M+Yplsm929bS4cILZOAPY4Uf7wYP4Im/m+lkqj4ucg66ISKJOQDeL WDUQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:dmarc-filter:arc-authentication-results; bh=rH8OQ0bGop5e6b6WXStioy+rGUSjD48VWizqoumI3a8=; b=rZJvSB0rLBeZkSB/s+Lbs8eqhPHaAPrsAnHRwT3O7qamooj2Do0cME6mc8vQJnmnP8 Eg3+yTsoaQPZnftUf7H+QtUm+P4gRiceH2ifJPJjcZTBbyGE1okBqDskkTNlc1kH8N7h YF4JI3ClXiPyEaJsfydgdGEaxXe1C4fS90BJW2UY/p6H1qn2vDYna7I4Z0WmC6vquefu iqmtZb+bxKfbnep/fSGtiwEllubYSMy5sio/SvLaHh0sea3X7veEgEyM/TfdjAU77j66 6xbK7v7vHLiXebhSmyg6YyesSpdlp9No9qAsla37v3wjLvduVRF2M3u90Z7PngYyz2IE Kvjw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of srs0=4/0d=hq=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=SRS0=4/0d=HQ=linuxfoundation.org=gregkh@kernel.org Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of srs0=4/0d=hq=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=SRS0=4/0d=HQ=linuxfoundation.org=gregkh@kernel.org DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EBA892189F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=fail smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Schwidefsky Subject: [PATCH 4.9 42/74] s390: add automatic detection of the spectre defense Date: Fri, 27 Apr 2018 15:58:32 +0200 Message-Id: <20180427135711.670389532@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180427135709.899303463@linuxfoundation.org> References: <20180427135709.899303463@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1598908186714193846?= X-GMAIL-MSGID: =?utf-8?q?1598908383149938839?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin Schwidefsky [ 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 Signed-off-by: Greg Kroah-Hartman --- 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 @@ -741,7 +741,7 @@ 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 @@ -85,7 +85,7 @@ 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 -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 #include #include +#include #define MAX_PATCH_LEN (255 - 1) --- a/arch/s390/kernel/module.c +++ b/arch/s390/kernel/module.c @@ -171,7 +171,7 @@ 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; } @@ -330,8 +330,7 @@ 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 + @@ -452,7 +451,7 @@ 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 + @@ -479,11 +478,11 @@ 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 */