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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CA52EEB64DC for ; Fri, 30 Jun 2023 17:54:08 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qFIJl-0005mv-6y; Fri, 30 Jun 2023 13:54:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qFIJe-0005mg-LF for qemu-devel@nongnu.org; Fri, 30 Jun 2023 13:53:55 -0400 Received: from mail-wm1-x332.google.com ([2a00:1450:4864:20::332]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qFIJc-0001i4-FS for qemu-devel@nongnu.org; Fri, 30 Jun 2023 13:53:54 -0400 Received: by mail-wm1-x332.google.com with SMTP id 5b1f17b1804b1-3fbc244d384so16133575e9.0 for ; Fri, 30 Jun 2023 10:53:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1688147631; x=1690739631; h=content-transfer-encoding:in-reply-to:references:cc:to:from :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=+E5/GmJZEFT5oXi4hxVKg71Dc8uxEDQ2/WJiwyZ/1JA=; b=o5JRGDfe/QMhRxEjeImEB41L+kr0IeKXFGQRWYYUV+g8fEp2NVLPdlsmdD01Vnax4Q Kd4s4Yql7Nszjs00neB4WiQ1p/EPY68K8o38Z62CfB1F8C5b3sfDGTvw7EJhYH17wv9V M6W8ZLxUQaVsIECTyaXFKd36hj0PzwA/pDz2oNcLZBH4pMRuoaNM5LOynQ+wsFvcHYas QBAWxsil5qzAlkx30dXsv7RSXk2KRvGgtSgz2CHs0CKOQsvjW+ngwXqIYm7td2cn6nN4 40ozhaJzVGDi/OzbezIhsimCqP8ZiQd8dnDtBTW0WrDqIhtC0HzQKZx8o6vM04yyRk6+ GrEw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688147631; x=1690739631; h=content-transfer-encoding:in-reply-to:references:cc:to:from :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=+E5/GmJZEFT5oXi4hxVKg71Dc8uxEDQ2/WJiwyZ/1JA=; b=fXlheycsbg6ZNZOyLzG460zh0yyCoywR8RaFB93ye3JXcZKmQE72y/QAorYJ+T6twq FS0xLWkgkoeuEr1uLjMiYx5fhJMjlmf/4l3vL8wuSWQekzAMUvFnlp07QPGYouH+BEEv 6XctNbx4bB/OEEL8EmGgGH6911LUEDah4NIa13x5bLZSLNQvO1p+nrANrz4kVauQm3Cv ekxtT1ECX+J1cnHNbaW5Sctc8KLXw+S4u7YnPxOq8gXwKvkSDvg6XWchrkUoyLRTd65x 2TCxJXKt0EXm3Q//F6jRLCbHVvBCv6+7P9YQVSdPDc3xKta85a75/pGtB3zlHkOrkcui QFEw== X-Gm-Message-State: AC+VfDwnMZTXG2zqv7mIwwG+HwpV2Ab9iRtnepaG/4wQ1Y7LeuXQgfSU sUMU2u+a7Jo9KAxGERyZhibLrRt6nD/yxNap6ycLxg== X-Google-Smtp-Source: ACHHUZ7NXV5IEMJgYp1yyJwPRobFssqf2E0G387v29ndjV6hwLUmMDFEZFDiEFyG6rTG63XnTEj2rw== X-Received: by 2002:a05:600c:291:b0:3f5:39:240c with SMTP id 17-20020a05600c029100b003f50039240cmr2680068wmk.27.1688147630697; Fri, 30 Jun 2023 10:53:50 -0700 (PDT) Received: from [192.168.1.208] ([139.47.41.96]) by smtp.gmail.com with ESMTPSA id s25-20020a7bc399000000b003fa96fe2bebsm14558415wmj.41.2023.06.30.10.53.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 30 Jun 2023 10:53:50 -0700 (PDT) Message-ID: <9311fdff-325b-6591-99e8-7ea0cb027ae6@linaro.org> Date: Fri, 30 Jun 2023 19:53:48 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH] linux-user/i386: Properly align signal frame Content-Language: en-US From: Richard Henderson To: qemu-devel@nongnu.org Cc: laurent@vivier.eu References: <20230524054647.1093758-1-richard.henderson@linaro.org> <9d06173b-f739-df6b-263f-bb426e2fef97@linaro.org> In-Reply-To: <9d06173b-f739-df6b-263f-bb426e2fef97@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2a00:1450:4864:20::332; envelope-from=richard.henderson@linaro.org; helo=mail-wm1-x332.google.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.095, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Ping 2. On 6/20/23 15:26, Richard Henderson wrote: > Ping. > > On 5/24/23 07:46, Richard Henderson wrote: >> The beginning of the structure, with pretaddr, should be just below >> 16-byte alignment.  Disconnect fpstate from sigframe, just like the >> kernel does. >> >> Signed-off-by: Richard Henderson >> --- >>   linux-user/i386/signal.c         | 104 +++++++++++++++++-------------- >>   tests/tcg/x86_64/sigstack.c      |  33 ++++++++++ >>   tests/tcg/x86_64/Makefile.target |   1 + >>   3 files changed, 90 insertions(+), 48 deletions(-) >>   create mode 100644 tests/tcg/x86_64/sigstack.c >> >> diff --git a/linux-user/i386/signal.c b/linux-user/i386/signal.c >> index 60fa07d6f9..c49467de78 100644 >> --- a/linux-user/i386/signal.c >> +++ b/linux-user/i386/signal.c >> @@ -191,16 +191,7 @@ struct sigframe { >>       struct target_fpstate fpstate_unused; >>       abi_ulong extramask[TARGET_NSIG_WORDS-1]; >>       char retcode[8]; >> - >> -    /* >> -     * This field will be 16-byte aligned in memory.  Applying QEMU_ALIGNED >> -     * to it ensures that the base of the frame has an appropriate alignment >> -     * too. >> -     */ >> -    struct target_fpstate fpstate QEMU_ALIGNED(8); >>   }; >> -#define TARGET_SIGFRAME_FXSAVE_OFFSET (                                    \ >> -    offsetof(struct sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET) >>   struct rt_sigframe { >>       abi_ulong pretcode; >> @@ -210,27 +201,21 @@ struct rt_sigframe { >>       struct target_siginfo info; >>       struct target_ucontext uc; >>       char retcode[8]; >> -    struct target_fpstate fpstate QEMU_ALIGNED(8); >>   }; >> -#define TARGET_RT_SIGFRAME_FXSAVE_OFFSET (                                 \ >> -    offsetof(struct rt_sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET) >>   #else >> - >>   struct rt_sigframe { >>       abi_ulong pretcode; >>       struct target_ucontext uc; >>       struct target_siginfo info; >> -    struct target_fpstate fpstate QEMU_ALIGNED(16); >>   }; >> -#define TARGET_RT_SIGFRAME_FXSAVE_OFFSET (                                 \ >> -    offsetof(struct rt_sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET) >>   #endif >>   /* >>    * Set up a signal frame. >>    */ >> -static void xsave_sigcontext(CPUX86State *env, struct target_fpstate_fxsave *fxsave, >> +static void xsave_sigcontext(CPUX86State *env, >> +                             struct target_fpstate_fxsave *fxsave, >>                                abi_ulong fxsave_addr) >>   { >>       if (!(env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE)) { >> @@ -266,8 +251,9 @@ static void xsave_sigcontext(CPUX86State *env, struct >> target_fpstate_fxsave *fxs >>   } >>   static void setup_sigcontext(struct target_sigcontext *sc, >> -        struct target_fpstate *fpstate, CPUX86State *env, abi_ulong mask, >> -        abi_ulong fpstate_addr) >> +                             struct target_fpstate *fpstate, >> +                             CPUX86State *env, abi_ulong mask, >> +                             abi_ulong fpstate_addr) >>   { >>       CPUState *cs = env_cpu(env); >>   #ifndef TARGET_X86_64 >> @@ -347,10 +333,11 @@ static void setup_sigcontext(struct target_sigcontext *sc, >>    * Determine which stack to use.. >>    */ >> -static inline abi_ulong >> -get_sigframe(struct target_sigaction *ka, CPUX86State *env, size_t fxsave_offset) >> +static abi_ulong get_sigframe(struct target_sigaction *ka, CPUX86State *env, >> +                              size_t *frame_size, abi_ulong *fpsave_addr) >>   { >> -    unsigned long esp; >> +    abi_ulong esp, orig; >> +    size_t fpsave_size; >>       /* Default to using normal stack */ >>       esp = get_sp_from_cpustate(env); >> @@ -371,16 +358,23 @@ get_sigframe(struct target_sigaction *ka, CPUX86State *env, size_t >> fxsave_offset >>           } >>   #endif >>       } >> +    orig = esp; >> -    if (!(env->features[FEAT_1_EDX] & CPUID_FXSR)) { >> -        return (esp - (fxsave_offset + TARGET_FXSAVE_SIZE)) & -8ul; >> -    } else if (!(env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE)) { >> -        return ((esp - TARGET_FXSAVE_SIZE) & -16ul) - fxsave_offset; >> +    if (!(env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE)) { >> +        fpsave_size = TARGET_FXSAVE_SIZE; >> +        esp = ROUND_DOWN(esp - fpsave_size, 16); >>       } else { >> -        size_t xstate_size = >> -               xsave_area_size(env->xcr0, false) + TARGET_FP_XSTATE_MAGIC2_SIZE; >> -        return ((esp - xstate_size) & -64ul) - fxsave_offset; >> +        fpsave_size = xsave_area_size(env->xcr0, false) >> +                      + TARGET_FP_XSTATE_MAGIC2_SIZE; >> +        esp = ROUND_DOWN(esp - fpsave_size, 64); >>       } >> +    *fpsave_addr = esp; >> + >> +    esp = esp - *frame_size + sizeof(abi_ulong); >> +    esp = ROUND_DOWN(esp, 16) - sizeof(abi_ulong); >> + >> +    *frame_size = orig - esp; >> +    return esp; >>   } >>   #ifndef TARGET_X86_64 >> @@ -405,26 +399,34 @@ void setup_frame(int sig, struct target_sigaction *ka, >>                    target_sigset_t *set, CPUX86State *env) >>   { >>       abi_ulong frame_addr; >> +    abi_ulong fpstate_addr; >> +    size_t frame_size; >>       struct sigframe *frame; >> +    struct target_fpstate *fpstate; >>       int i; >> -    frame_addr = get_sigframe(ka, env, TARGET_SIGFRAME_FXSAVE_OFFSET); >> +    frame_size = sizeof(struct sigframe); >> +    frame_addr = get_sigframe(ka, env, &frame_size, &fpstate_addr); >>       trace_user_setup_frame(env, frame_addr); >> -    if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) >> +    frame = lock_user(VERIFY_WRITE, frame_addr, frame_size, false); >> +    if (!frame) { >>           goto give_sigsegv; >> +    } >> +    fpstate = (void *)frame + (fpstate_addr - frame_addr); >>       __put_user(sig, &frame->sig); >> -    setup_sigcontext(&frame->sc, &frame->fpstate, env, set->sig[0], >> -            frame_addr + offsetof(struct sigframe, fpstate)); >> +    setup_sigcontext(&frame->sc, fpstate, env, set->sig[0], fpstate_addr); >> -    for(i = 1; i < TARGET_NSIG_WORDS; i++) { >> +    for (i = 1; i < TARGET_NSIG_WORDS; i++) { >>           __put_user(set->sig[i], &frame->extramask[i - 1]); >>       } >> -    /* Set up to return from userspace.  If provided, use a stub >> -       already in userspace.  */ >> +    /* >> +     * Set up to return from userspace. >> +     * If provided, use a stub already in userspace. >> +     */ >>       if (ka->sa_flags & TARGET_SA_RESTORER) { >>           __put_user(ka->sa_restorer, &frame->pretcode); >>       } else { >> @@ -443,11 +445,10 @@ void setup_frame(int sig, struct target_sigaction *ka, >>       cpu_x86_load_seg(env, R_CS, __USER_CS); >>       env->eflags &= ~TF_MASK; >> -    unlock_user_struct(frame, frame_addr, 1); >> - >> +    unlock_user(frame, frame_addr, frame_size); >>       return; >> -give_sigsegv: >> + give_sigsegv: >>       force_sigsegv(sig); >>   } >>   #endif >> @@ -458,17 +459,24 @@ void setup_rt_frame(int sig, struct target_sigaction *ka, >>                       target_sigset_t *set, CPUX86State *env) >>   { >>       abi_ulong frame_addr; >> +    abi_ulong fpstate_addr; >> +    size_t frame_size; >>   #ifndef TARGET_X86_64 >>       abi_ulong addr; >>   #endif >>       struct rt_sigframe *frame; >> +    struct target_fpstate *fpstate; >>       int i; >> -    frame_addr = get_sigframe(ka, env, TARGET_RT_SIGFRAME_FXSAVE_OFFSET); >> +    frame_size = sizeof(struct rt_sigframe); >> +    frame_addr = get_sigframe(ka, env, &frame_size, &fpstate_addr); >>       trace_user_setup_rt_frame(env, frame_addr); >> -    if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) >> +    frame = lock_user(VERIFY_WRITE, frame_addr, frame_size, false); >> +    if (!frame) { >>           goto give_sigsegv; >> +    } >> +    fpstate = (void *)frame + (fpstate_addr - frame_addr); >>       /* These fields are only in rt_sigframe on 32 bit */ >>   #ifndef TARGET_X86_64 >> @@ -490,10 +498,10 @@ void setup_rt_frame(int sig, struct target_sigaction *ka, >>       } >>       __put_user(0, &frame->uc.tuc_link); >>       target_save_altstack(&frame->uc.tuc_stack, env); >> -    setup_sigcontext(&frame->uc.tuc_mcontext, &frame->fpstate, env, >> -            set->sig[0], frame_addr + offsetof(struct rt_sigframe, fpstate)); >> +    setup_sigcontext(&frame->uc.tuc_mcontext, fpstate, env, >> +                     set->sig[0], fpstate_addr); >> -    for(i = 0; i < TARGET_NSIG_WORDS; i++) { >> +    for (i = 0; i < TARGET_NSIG_WORDS; i++) { >>           __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]); >>       } >> @@ -533,15 +541,15 @@ void setup_rt_frame(int sig, struct target_sigaction *ka, >>       cpu_x86_load_seg(env, R_SS, __USER_DS); >>       env->eflags &= ~TF_MASK; >> -    unlock_user_struct(frame, frame_addr, 1); >> - >> +    unlock_user(frame, frame_addr, frame_size); >>       return; >> -give_sigsegv: >> + give_sigsegv: >>       force_sigsegv(sig); >>   } >> -static int xrstor_sigcontext(CPUX86State *env, struct target_fpstate_fxsave *fxsave, >> +static int xrstor_sigcontext(CPUX86State *env, >> +                             struct target_fpstate_fxsave *fxsave, >>                                abi_ulong fxsave_addr) >>   { >>       if (env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE) { >> diff --git a/tests/tcg/x86_64/sigstack.c b/tests/tcg/x86_64/sigstack.c >> new file mode 100644 >> index 0000000000..06cb847569 >> --- /dev/null >> +++ b/tests/tcg/x86_64/sigstack.c >> @@ -0,0 +1,33 @@ >> +#include >> +#include >> +#include >> +#include >> + >> +void __attribute__((noinline)) bar(void) >> +{ >> +    exit(EXIT_SUCCESS); >> +} >> + >> +void __attribute__((noinline, ms_abi)) foo(void) >> +{ >> +    /* >> +     * With ms_abi, there are call-saved xmm registers, which are forced >> +     * to the stack around the call to sysv_abi bar().  If the signal >> +     * stack frame is not properly aligned, movaps will raise #GP. >> +     */ >> +    bar(); >> +} >> + >> +void sighandler(int num) >> +{ >> +    void* sp = __builtin_dwarf_cfa(); >> +    assert((uintptr_t)sp % 16 == 0); >> +    foo(); >> +} >> + >> +int main(void) >> +{ >> +    signal(SIGUSR1, sighandler); >> +    raise(SIGUSR1); >> +    abort(); >> +} >> diff --git a/tests/tcg/x86_64/Makefile.target b/tests/tcg/x86_64/Makefile.target >> index e64aab1b81..d961599f64 100644 >> --- a/tests/tcg/x86_64/Makefile.target >> +++ b/tests/tcg/x86_64/Makefile.target >> @@ -13,6 +13,7 @@ X86_64_TESTS += vsyscall >>   X86_64_TESTS += noexec >>   X86_64_TESTS += cmpxchg >>   X86_64_TESTS += adox >> +X86_64_TESTS += sigstack >>   TESTS=$(MULTIARCH_TESTS) $(X86_64_TESTS) test-x86_64 >>   else >>   TESTS=$(MULTIARCH_TESTS) >