From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x227wrzs3mudIngrpHfH+XtYXN25JcyAdAxQf8OTh27iVB1lWHxpBS4bx9cVC+PwH+Koa2cj5 ARC-Seal: i=1; a=rsa-sha256; t=1516712839; cv=none; d=google.com; s=arc-20160816; b=dG7HeEqQgD5M6FgWQ1eNLI373HIsjgRLC/2GeMm6HFDy/tBEc/9Q3oawc15cg8Lmbp cRF/szuBJLSAy5Wk7UnnHE9CQwIGaTT+7vXdU/6u2jGxZMzp5hrDniih4DE4ZXIiZNTj p4JuwGEnPUohkGFKXwq6kaI4dV3R0Oqr6mkvHlN20pmI2mAJBeyIWoYK5lobYgRp3744 npS1It92Xmiuw7Br49e8mC7b0PDcOpV70HftEiBm9iGAW/vIFNC+gtD3Hteyc+Cp1Tq5 7ysO9UQjFuuyuyoXPyU44TJDkJOz+Q89LagHNX9j970vy7TtumoFXvIiz4cEotIsYo// oIkA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:references:in-reply-to:date:subject:cc:to:from :arc-authentication-results; bh=T8nH+9zYe867bMX6pwwoH13jXe+OXnKf0yZoFes/xBg=; b=W8nsAGXhjQtnZ686Ix2KKwgh/qjSLIlC93WLRTVTg+/gvUMcpzyPMS28jx/mALI73k rbH/Er0arBxSlbRMu9BVJULb9CuE/uQ+03XLc8kgQEWSQyWwZ+kCxzmr1PgFe4VcW7u3 5iDS1Moy3Owx1HWrS8/NdBLu5jCofW7t8f98EtKIeemupxByQWGG+vatwMzAOhBRVz87 B7LSJOHFAsAwsyevEuAztyCo/I6oYbNFtsZ97ACtnZp6uonmwYHBvbZ0wy+IcnPeZHkL 5jx5NZqC7J/Rrh0T0yUKNCvmf8OeQoR3W5WckPnjI0Ftwv26DZh23V2bMwK69w7VLk8v H4iQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of schwidefsky@de.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=schwidefsky@de.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of schwidefsky@de.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=schwidefsky@de.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com From: Martin Schwidefsky To: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org Cc: Heiko Carstens , Christian Borntraeger , Paolo Bonzini , Cornelia Huck , David Hildenbrand , Greg Kroah-Hartman , Jon Masters , Marcus Meissner , Jiri Kosina Subject: [PATCH 5/5] s390: scrub registers on kernel entry and KVM exit Date: Tue, 23 Jan 2018 14:07:05 +0100 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1516712825-2917-1-git-send-email-schwidefsky@de.ibm.com> References: <1516712825-2917-1-git-send-email-schwidefsky@de.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18012313-0008-0000-0000-000004C4E89A X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18012313-0009-0000-0000-00001E586860 Message-Id: <1516712825-2917-6-git-send-email-schwidefsky@de.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-01-23_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1801230179 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1590388682391591944?= X-GMAIL-MSGID: =?utf-8?q?1590388682391591944?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Clear all user space registers on entry to the kernel and all KVM guest registers on KVM guest exit if the register does not contain either a parameter or a result value. Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/entry.S | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 07e4e46..0ee9408 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -322,6 +322,12 @@ ENTRY(sie64a) sie_exit: lg %r14,__SF_EMPTY+8(%r15) # load guest register save area stmg %r0,%r13,0(%r14) # save guest gprs 0-13 + xgr %r0,%r0 # clear guest registers + xgr %r1,%r1 + xgr %r2,%r2 + xgr %r3,%r3 + xgr %r4,%r4 + xgr %r5,%r5 lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers lg %r2,__SF_EMPTY+16(%r15) # return exit reason code br %r14 @@ -358,6 +364,7 @@ ENTRY(system_call) UPDATE_VTIME %r8,%r9,__LC_SYNC_ENTER_TIMER BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP stmg %r0,%r7,__PT_R0(%r11) + xgr %r0,%r0 mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC mvc __PT_PSW(16,%r11),__LC_SVC_OLD_PSW mvc __PT_INT_CODE(4,%r11),__LC_SVC_ILC @@ -640,6 +647,14 @@ ENTRY(pgm_check_handler) 4: lgr %r13,%r11 la %r11,STACK_FRAME_OVERHEAD(%r15) stmg %r0,%r7,__PT_R0(%r11) + xgr %r0,%r0 # clear user space registers + xgr %r1,%r1 + xgr %r2,%r2 + xgr %r3,%r3 + xgr %r4,%r4 + xgr %r5,%r5 + xgr %r6,%r6 + xgr %r7,%r7 mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC stmg %r8,%r9,__PT_PSW(%r11) mvc __PT_INT_CODE(4,%r11),__LC_PGM_ILC @@ -706,6 +721,15 @@ ENTRY(io_int_handler) lmg %r8,%r9,__LC_IO_OLD_PSW SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_ENTER_TIMER stmg %r0,%r7,__PT_R0(%r11) + xgr %r0,%r0 # clear user space registers + xgr %r1,%r1 + xgr %r2,%r2 + xgr %r3,%r3 + xgr %r4,%r4 + xgr %r5,%r5 + xgr %r6,%r6 + xgr %r7,%r7 + xgr %r10,%r10 mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC stmg %r8,%r9,__PT_PSW(%r11) mvc __PT_INT_CODE(12,%r11),__LC_SUBCHANNEL_ID @@ -924,6 +948,15 @@ ENTRY(ext_int_handler) lmg %r8,%r9,__LC_EXT_OLD_PSW SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_ENTER_TIMER stmg %r0,%r7,__PT_R0(%r11) + xgr %r0,%r0 # clear user space registers + xgr %r1,%r1 + xgr %r2,%r2 + xgr %r3,%r3 + xgr %r4,%r4 + xgr %r5,%r5 + xgr %r6,%r6 + xgr %r7,%r7 + xgr %r10,%r10 mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC stmg %r8,%r9,__PT_PSW(%r11) lghi %r1,__LC_EXT_PARAMS2 @@ -1133,6 +1166,14 @@ ENTRY(mcck_int_handler) .Lmcck_skip: lghi %r14,__LC_GPREGS_SAVE_AREA+64 stmg %r0,%r7,__PT_R0(%r11) + xgr %r0,%r0 # clear user space registers + xgr %r2,%r2 + xgr %r3,%r3 + xgr %r4,%r4 + xgr %r5,%r5 + xgr %r6,%r6 + xgr %r7,%r7 + xgr %r10,%r10 mvc __PT_R8(64,%r11),0(%r14) stmg %r8,%r9,__PT_PSW(%r11) xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11) -- 2.7.4