From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f181.google.com (mail-pl1-f181.google.com [209.85.214.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 670A164CFC for ; Fri, 3 May 2024 23:01:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714777318; cv=none; b=c5z/Ngtu2atNwaKaV1493VgSER51lyRSzk5hX9qzszRKk/RYgj7wPx3T/foqZ78sFoIZyF2SatUSjVZYhPGXTysWwKwISMPMlyJPD0AqWhkF5vrCOdcuSRvXkntbAO3Pjmtd1io7QVRMseJWfl2pQTWvvi0v6lH/cXyKniw4Lhg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714777318; c=relaxed/simple; bh=4+92T3dF1pCkzFJyIvWH9pdOMABziRyYEtERHQRUflQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SptrdcLP1ianSj5OSeA2qVp9QmW0rU8nd1afDbasbLg2aDXLer0EsomrVzF7a9LyQx26Awgg3zhXFqpN7mEP34wvKmmn2ne0DutrhMyxtlTh7yJ27PrvPnYdYObFAa5oz8ZKhoo3TBtH+kKErQOYE8Fuqz+lIPr+xFumPF8y7GU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=rivosinc.com; spf=pass smtp.mailfrom=rivosinc.com; dkim=pass (2048-bit key) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.b=zCe+/lF3; arc=none smtp.client-ip=209.85.214.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=rivosinc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rivosinc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.b="zCe+/lF3" Received: by mail-pl1-f181.google.com with SMTP id d9443c01a7336-1eb24e3a2d9so1641955ad.1 for ; Fri, 03 May 2024 16:01:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20230601.gappssmtp.com; s=20230601; t=1714777317; x=1715382117; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=4+92T3dF1pCkzFJyIvWH9pdOMABziRyYEtERHQRUflQ=; b=zCe+/lF34YSpkLm2TxtBbKSM5HvQTiKwAV3/44wZGfe5OEzwrVa15OMDxIqPZ6I5Ir fuY3gGUb1FAi2faOv0IGo2pG5+C0IrtWoAvDo27Rm59TDonSdrohlP/jS86LM+nBFEtr GQ3wWvTpg2+gE2rC84ee/b9iJ/8BqenQTpLVlydzmF1Q0OR+SG+iFBTc7vA2g6AR9wul m/yFYwnkqQjsc8A+msgyA4Sd2DrAZoqHoiIs/JMbDHBl0iLiHDMXXc9ty8yA5mVjjUPu NIXwFUvpRU7gKebDzlcSK+ISTKqFUA3d5KvW+ehUNElxgrnfJxbe9q+O7QQnllgNc6za k4nA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714777317; x=1715382117; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=4+92T3dF1pCkzFJyIvWH9pdOMABziRyYEtERHQRUflQ=; b=YWnyVtRl5ID7JRFfZ43o1YNebl/ZBTAW9jM1N6LnWP2xp9mQ6ORRD95Nhme706rpT0 o/ZCcJhZtgzleNUcXSkLT+MkghVvyJdz3Btke8moM3kJsYBTovUlINmI2o0GkAoyvPJp o+/hkUBhBoCi4uoVYqqa31dXhd4zwxd3Wu1Bx7TJ3va7GN40kD7nrpDEJbaNvpF/RBqj tBZ5Xc+PJwB2eMoUW6yAcF049+rthJQv3AbPopoB/8ARMBogBWOS3cZdJS19HSEKLl35 us1/eUONUwPyjP7TpjGekrQKZJuOkC5oIRGQUYpRbmNmyPViQ3DnvF0/CrQ2nePnWznq LunQ== X-Forwarded-Encrypted: i=1; AJvYcCVdVijDwxBnaO3hyifnVq8bwcqQQbOJo4s+2L+YmMDNaHuLpq+G07CHgLlI3/stERfrpX8stWcsvHqc2exgwPgvjaPTSZcsld6GjIYtT1gaALrs X-Gm-Message-State: AOJu0YxGypzsU6x/h8aJv68LOxVByGi+tQIdIf8WBDm3SmaGZreHkEDA SKsdekNKWEc4pf8+9ghftQnAtPhA5uAOCDW/FX2YO7XlHqZSGSVJVcrmYLejYp8= X-Google-Smtp-Source: AGHT+IHzq6AzE/NVvcqxm4ol0K1axCLWE5IjNbsp5PyIHu/cbS2sPY/kkICJk49x3bkJcMIgzsAwYg== X-Received: by 2002:a17:903:32cf:b0:1e2:ca65:68c2 with SMTP id i15-20020a17090332cf00b001e2ca6568c2mr5565119plr.51.1714777316672; Fri, 03 May 2024 16:01:56 -0700 (PDT) Received: from debug.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id f7-20020a170902684700b001eab1a1a752sm3841345pln.120.2024.05.03.16.01.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 May 2024 16:01:56 -0700 (PDT) Date: Fri, 3 May 2024 16:01:53 -0700 From: Deepak Gupta To: "Edgecombe, Rick P" Cc: "olsajiri@gmail.com" , "songliubraving@fb.com" , "luto@kernel.org" , "mhiramat@kernel.org" , "andrii@kernel.org" , "linux-api@vger.kernel.org" , "john.fastabend@gmail.com" , "linux-kernel@vger.kernel.org" , "mingo@redhat.com" , "rostedt@goodmis.org" , "ast@kernel.org" , "tglx@linutronix.de" , "yhs@fb.com" , "oleg@redhat.com" , "linux-man@vger.kernel.org" , "daniel@iogearbox.net" , "peterz@infradead.org" , "linux-trace-kernel@vger.kernel.org" , "bp@alien8.de" , "bpf@vger.kernel.org" , "x86@kernel.org" , "broonie@kernel.org" Subject: Re: [PATCHv4 bpf-next 2/7] uprobe: Add uretprobe syscall to speed up return probe Message-ID: References: <20240502122313.1579719-1-jolsa@kernel.org> <20240502122313.1579719-3-jolsa@kernel.org> <20240503113453.GK40213@noisy.programming.kicks-ass.net> <725e2000dc56d55da4097cface4109c17fe5ad1a.camel@intel.com> <6c143c648e2eff6c4d4b5e4700d1a8fbcc0f8cbc.camel@intel.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <6c143c648e2eff6c4d4b5e4700d1a8fbcc0f8cbc.camel@intel.com> On Fri, May 03, 2024 at 07:38:18PM +0000, Edgecombe, Rick P wrote: >+Some more shadow stack folks from other archs. We are discussing how uretprobes >work with shadow stack. > >Context: >https://lore.kernel.org/lkml/ZjU4ganRF1Cbiug6@krava/ Thanks Rick. Yeah I didn't give enough attention to uprobes either. Although now that I think for RISC-V shadow stack, it shouldn't be an issue. On RISC-V return addresses don't get pushed as part of call instruction. There is a distinct instruction "shadow stack push of return address" in prolog. Similarly in epilog there is distinct instruction "shadow stack pop and check with link register". On RISC-V, uretprobe would install a uprobe on function start and when it's hit. It'll replace pt_regs->ra = trampoline_handler. As function will resume, trampoline addr will get pushed and popped. Although trampoline_handler would have to be enlightened to eventually return to original return site. > >On Fri, 2024-05-03 at 21:18 +0200, Jiri Olsa wrote: >> >> hack below seems to fix it for the current uprobe setup, >> we need similar fix for the uretprobe syscall trampoline setup > >It seems like a reasonable direction. > >Security-wise, applications cannot do this on themselves, or it is an otherwise >privileged thing right? > >