From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6769FC433EF for ; Sat, 30 Oct 2021 21:34:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4318460F4B for ; Sat, 30 Oct 2021 21:34:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232192AbhJ3Vgv (ORCPT ); Sat, 30 Oct 2021 17:36:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57838 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232042AbhJ3VgK (ORCPT ); Sat, 30 Oct 2021 17:36:10 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 84597C0797B6; Sat, 30 Oct 2021 14:32:25 -0700 (PDT) Date: Sat, 30 Oct 2021 21:32:23 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1635629544; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=v4DkWvVjThW7duWCs5Ez/pFvXLxLx9Y5fu5BNHGrb1I=; b=t6ZW9ycARmb0nsyYHfsc3p+p1yd1db9BhJANnSy1u5xUh3AmPIn3nQLXnU+Kf4K3+NysfR 0S67xyOkGygphtr9wzFqJucjek78RJMN0MYNnc6Ktmq6HMn3yZC047IFN1RMWDeNkZVT7H g4w2RbfUD37Ws6n7S3LDNKCKxWKYWEUOi5h5vIM8BFlt3las7pGaz+xtooYURkALhN+JBs p+NYXl7md+TkrabF4PWIGDEyoPoR75NpGyx34J+sKCAhtkwuYyNK93R1g7btdkwnk9Hubk yfaUavKc06rIR3FhDuwvoVi1znje1F5wvGsJ53jUH7s0AksRQ6zGEg2DNCE+Sg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1635629544; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=v4DkWvVjThW7duWCs5Ez/pFvXLxLx9Y5fu5BNHGrb1I=; b=7PPObh6W6P4/wK/f0Oaedylmh67O0Ox8Ph0Yh+wPkrygLScQaK1rj90JC092ZtuXxSFlcB kI/qC6u9GixFklDw== From: "tip-bot2 for Borislav Petkov" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/core] selftests/x86/iopl: Adjust to the faked iopl CLI/STI usage Cc: Thomas Gleixner , Borislav Petkov , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20211030083939.13073-1-bp@alien8.de> References: <20211030083939.13073-1-bp@alien8.de> MIME-Version: 1.0 Message-ID: <163562954308.626.8903154576094573633.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/core branch of tip: Commit-ID: a72fdfd21e01c626273ddcf5ab740d4caef4be54 Gitweb: https://git.kernel.org/tip/a72fdfd21e01c626273ddcf5ab740d4caef4be54 Author: Borislav Petkov AuthorDate: Fri, 29 Oct 2021 19:27:32 +02:00 Committer: Borislav Petkov CommitterDate: Sat, 30 Oct 2021 23:18:04 +02:00 selftests/x86/iopl: Adjust to the faked iopl CLI/STI usage Commit in Fixes changed the iopl emulation to not #GP on CLI and STI because it would break some insane luserspace tools which would toggle interrupts. The corresponding selftest would rely on the fact that executing CLI/STI would trigger a #GP and thus detect it this way but since that #GP is not happening anymore, the detection is now wrong too. Extend the test to actually look at the IF flag and whether executing those insns had any effect on it. The STI detection needs to have the fact that interrupts were previously disabled, passed in so do that from the previous CLI test, i.e., STI test needs to follow a previous CLI one for it to make sense. Fixes: b968e84b509d ("x86/iopl: Fake iopl(3) CLI/STI usage") Suggested-by: Thomas Gleixner Signed-off-by: Borislav Petkov Acked-by: Thomas Gleixner Link: https://lore.kernel.org/r/20211030083939.13073-1-bp@alien8.de --- tools/testing/selftests/x86/iopl.c | 78 +++++++++++++++++++++-------- 1 file changed, 58 insertions(+), 20 deletions(-) diff --git a/tools/testing/selftests/x86/iopl.c b/tools/testing/selftests/x86/iopl.c index bab2f6e..7e3e09c 100644 --- a/tools/testing/selftests/x86/iopl.c +++ b/tools/testing/selftests/x86/iopl.c @@ -85,48 +85,88 @@ static void expect_gp_outb(unsigned short port) printf("[OK]\toutb to 0x%02hx failed\n", port); } -static bool try_cli(void) +#define RET_FAULTED 0 +#define RET_FAIL 1 +#define RET_EMUL 2 + +static int try_cli(void) { + unsigned long flags; + sethandler(SIGSEGV, sigsegv, SA_RESETHAND); if (sigsetjmp(jmpbuf, 1) != 0) { - return false; + return RET_FAULTED; } else { - asm volatile ("cli"); - return true; + asm volatile("cli; pushf; pop %[flags]" + : [flags] "=rm" (flags)); + + /* X86_FLAGS_IF */ + if (!(flags & (1 << 9))) + return RET_FAIL; + else + return RET_EMUL; } clearhandler(SIGSEGV); } -static bool try_sti(void) +static int try_sti(bool irqs_off) { + unsigned long flags; + sethandler(SIGSEGV, sigsegv, SA_RESETHAND); if (sigsetjmp(jmpbuf, 1) != 0) { - return false; + return RET_FAULTED; } else { - asm volatile ("sti"); - return true; + asm volatile("sti; pushf; pop %[flags]" + : [flags] "=rm" (flags)); + + /* X86_FLAGS_IF */ + if (irqs_off && (flags & (1 << 9))) + return RET_FAIL; + else + return RET_EMUL; } clearhandler(SIGSEGV); } -static void expect_gp_sti(void) +static void expect_gp_sti(bool irqs_off) { - if (try_sti()) { + int ret = try_sti(irqs_off); + + switch (ret) { + case RET_FAULTED: + printf("[OK]\tSTI faulted\n"); + break; + case RET_EMUL: + printf("[OK]\tSTI NOPped\n"); + break; + default: printf("[FAIL]\tSTI worked\n"); nerrs++; - } else { - printf("[OK]\tSTI faulted\n"); } } -static void expect_gp_cli(void) +/* + * Returns whether it managed to disable interrupts. + */ +static bool test_cli(void) { - if (try_cli()) { + int ret = try_cli(); + + switch (ret) { + case RET_FAULTED: + printf("[OK]\tCLI faulted\n"); + break; + case RET_EMUL: + printf("[OK]\tCLI NOPped\n"); + break; + default: printf("[FAIL]\tCLI worked\n"); nerrs++; - } else { - printf("[OK]\tCLI faulted\n"); + return true; } + + return false; } int main(void) @@ -152,8 +192,7 @@ int main(void) } /* Make sure that CLI/STI are blocked even with IOPL level 3 */ - expect_gp_cli(); - expect_gp_sti(); + expect_gp_sti(test_cli()); expect_ok_outb(0x80); /* Establish an I/O bitmap to test the restore */ @@ -204,8 +243,7 @@ int main(void) printf("[RUN]\tparent: write to 0x80 (should fail)\n"); expect_gp_outb(0x80); - expect_gp_cli(); - expect_gp_sti(); + expect_gp_sti(test_cli()); /* Test the capability checks. */ printf("\tiopl(3)\n");