From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brendan Higgins Subject: Re: [RFC v3 08/19] arch: um: add shim to trap to allow installing a fault catcher for tests Date: Mon, 3 Dec 2018 15:34:57 -0800 Message-ID: References: <20181128193636.254378-1-brendanhiggins@google.com> <20181128193636.254378-9-brendanhiggins@google.com> <20181130033429.GK18410@garbanzo.do-not-panic.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20181130033429.GK18410-dAjH6bxAqesAS62YNPtMr3dQhYtBYE6JAL8bYrjMMd8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" To: mcgrof-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org Cc: brakmo-b10kYP2dOMg@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, linux-kselftest-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, shuah-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, Rob Herring , Frank Rowand , linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, richard-/L3Ra7n9ekc@public.gmane.org, Knut Omang , kieran.bingham-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org, Joel Stanley , jdike-OPE4K8JWMJJBDgjK7y7TUQ@public.gmane.org, Tim.Bird-7U/KSKJipcs@public.gmane.org, Kees Cook , linux-um-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org, Julia Lawall , kunit-dev-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, Greg KH , Linux Kernel Mailing List , Daniel Vetter , mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org, joe-6d6DIl74uiNBDgjK7y7TUQ@public.gmane.org, khilman-rdvid1DuHRBWk0Htik3J/w@public.gmane.org List-Id: linux-nvdimm@lists.01.org On Thu, Nov 29, 2018 at 7:34 PM Luis Chamberlain wrote: > > On Wed, Nov 28, 2018 at 11:36:25AM -0800, Brendan Higgins wrote: > > diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c > > index cced829460427..bf90e678b3d71 100644 > > --- a/arch/um/kernel/trap.c > > +++ b/arch/um/kernel/trap.c > > @@ -201,6 +201,12 @@ void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs) > > segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs); > > } > > > > +static void segv_run_catcher(jmp_buf *catcher, void *fault_addr) > > +{ > > + current->thread.fault_addr = fault_addr; > > + UML_LONGJMP(catcher, 1); > > +} > > + > > /* > > * We give a *copy* of the faultinfo in the regs to segv. > > * This must be done, since nesting SEGVs could overwrite > > @@ -219,7 +225,10 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > > if (!is_user && regs) > > current->thread.segv_regs = container_of(regs, struct pt_regs, regs); > > > > - if (!is_user && (address >= start_vm) && (address < end_vm)) { > > + catcher = current->thread.fault_catcher; > > This and.. > > > + if (catcher && current->thread.is_running_test) > > + segv_run_catcher(catcher, (void *) address); > > + else if (!is_user && (address >= start_vm) && (address < end_vm)) { > > flush_tlb_kernel_vm(); > > goto out; > > } > > *not this* I don't understand. Are you saying the previous block of code is good and this one is bad? > > > @@ -246,12 +255,10 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > > address = 0; > > } > > > > - catcher = current->thread.fault_catcher; > > if (!err) > > goto out; > > else if (catcher != NULL) { > > - current->thread.fault_addr = (void *) address; > > - UML_LONGJMP(catcher, 1); > > + segv_run_catcher(catcher, (void *) address); > > } > > else if (current->thread.fault_addr != NULL) > > panic("fault_addr set but no fault catcher"); > > But with this seems one atomic change which should be submitted > separately, its just a helper. Think it would make the actual > change needed easier to review, ie, your needed changes would > be smaller and clearer for what you need. Are you suggesting that I pull out the bits needed to implement abort in the next patch and squash it into this one? 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 X-Spam-Level: X-Spam-Status: No, score=-11.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F589C04EB9 for ; Mon, 3 Dec 2018 23:35:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E83772087F for ; Mon, 3 Dec 2018 23:35:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="mHlF9LhP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E83772087F Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; 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charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 29, 2018 at 7:34 PM Luis Chamberlain wrote: > > On Wed, Nov 28, 2018 at 11:36:25AM -0800, Brendan Higgins wrote: > > diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c > > index cced829460427..bf90e678b3d71 100644 > > --- a/arch/um/kernel/trap.c > > +++ b/arch/um/kernel/trap.c > > @@ -201,6 +201,12 @@ void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs) > > segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs); > > } > > > > +static void segv_run_catcher(jmp_buf *catcher, void *fault_addr) > > +{ > > + current->thread.fault_addr = fault_addr; > > + UML_LONGJMP(catcher, 1); > > +} > > + > > /* > > * We give a *copy* of the faultinfo in the regs to segv. > > * This must be done, since nesting SEGVs could overwrite > > @@ -219,7 +225,10 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > > if (!is_user && regs) > > current->thread.segv_regs = container_of(regs, struct pt_regs, regs); > > > > - if (!is_user && (address >= start_vm) && (address < end_vm)) { > > + catcher = current->thread.fault_catcher; > > This and.. > > > + if (catcher && current->thread.is_running_test) > > + segv_run_catcher(catcher, (void *) address); > > + else if (!is_user && (address >= start_vm) && (address < end_vm)) { > > flush_tlb_kernel_vm(); > > goto out; > > } > > *not this* I don't understand. Are you saying the previous block of code is good and this one is bad? > > > @@ -246,12 +255,10 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > > address = 0; > > } > > > > - catcher = current->thread.fault_catcher; > > if (!err) > > goto out; > > else if (catcher != NULL) { > > - current->thread.fault_addr = (void *) address; > > - UML_LONGJMP(catcher, 1); > > + segv_run_catcher(catcher, (void *) address); > > } > > else if (current->thread.fault_addr != NULL) > > panic("fault_addr set but no fault catcher"); > > But with this seems one atomic change which should be submitted > separately, its just a helper. Think it would make the actual > change needed easier to review, ie, your needed changes would > be smaller and clearer for what you need. Are you suggesting that I pull out the bits needed to implement abort in the next patch and squash it into this one? From mboxrd@z Thu Jan 1 00:00:00 1970 From: brendanhiggins at google.com (Brendan Higgins) Date: Mon, 3 Dec 2018 15:34:57 -0800 Subject: [RFC v3 08/19] arch: um: add shim to trap to allow installing a fault catcher for tests In-Reply-To: <20181130033429.GK18410@garbanzo.do-not-panic.com> References: <20181128193636.254378-1-brendanhiggins@google.com> <20181128193636.254378-9-brendanhiggins@google.com> <20181130033429.GK18410@garbanzo.do-not-panic.com> Message-ID: On Thu, Nov 29, 2018 at 7:34 PM Luis Chamberlain wrote: > > On Wed, Nov 28, 2018 at 11:36:25AM -0800, Brendan Higgins wrote: > > diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c > > index cced829460427..bf90e678b3d71 100644 > > --- a/arch/um/kernel/trap.c > > +++ b/arch/um/kernel/trap.c > > @@ -201,6 +201,12 @@ void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs) > > segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs); > > } > > > > +static void segv_run_catcher(jmp_buf *catcher, void *fault_addr) > > +{ > > + current->thread.fault_addr = fault_addr; > > + UML_LONGJMP(catcher, 1); > > +} > > + > > /* > > * We give a *copy* of the faultinfo in the regs to segv. > > * This must be done, since nesting SEGVs could overwrite > > @@ -219,7 +225,10 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > > if (!is_user && regs) > > current->thread.segv_regs = container_of(regs, struct pt_regs, regs); > > > > - if (!is_user && (address >= start_vm) && (address < end_vm)) { > > + catcher = current->thread.fault_catcher; > > This and.. > > > + if (catcher && current->thread.is_running_test) > > + segv_run_catcher(catcher, (void *) address); > > + else if (!is_user && (address >= start_vm) && (address < end_vm)) { > > flush_tlb_kernel_vm(); > > goto out; > > } > > *not this* I don't understand. Are you saying the previous block of code is good and this one is bad? > > > @@ -246,12 +255,10 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > > address = 0; > > } > > > > - catcher = current->thread.fault_catcher; > > if (!err) > > goto out; > > else if (catcher != NULL) { > > - current->thread.fault_addr = (void *) address; > > - UML_LONGJMP(catcher, 1); > > + segv_run_catcher(catcher, (void *) address); > > } > > else if (current->thread.fault_addr != NULL) > > panic("fault_addr set but no fault catcher"); > > But with this seems one atomic change which should be submitted > separately, its just a helper. Think it would make the actual > change needed easier to review, ie, your needed changes would > be smaller and clearer for what you need. Are you suggesting that I pull out the bits needed to implement abort in the next patch and squash it into this one? From mboxrd@z Thu Jan 1 00:00:00 1970 From: brendanhiggins@google.com (Brendan Higgins) Date: Mon, 3 Dec 2018 15:34:57 -0800 Subject: [RFC v3 08/19] arch: um: add shim to trap to allow installing a fault catcher for tests In-Reply-To: <20181130033429.GK18410@garbanzo.do-not-panic.com> References: <20181128193636.254378-1-brendanhiggins@google.com> <20181128193636.254378-9-brendanhiggins@google.com> <20181130033429.GK18410@garbanzo.do-not-panic.com> Message-ID: Content-Type: text/plain; charset="UTF-8" Message-ID: <20181203233457.mjHw-jOZiToa8cymOP0q0f7VoaTSxGuK_QySlPRu36w@z> On Thu, Nov 29, 2018@7:34 PM Luis Chamberlain wrote: > > On Wed, Nov 28, 2018@11:36:25AM -0800, Brendan Higgins wrote: > > diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c > > index cced829460427..bf90e678b3d71 100644 > > --- a/arch/um/kernel/trap.c > > +++ b/arch/um/kernel/trap.c > > @@ -201,6 +201,12 @@ void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs) > > segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs); > > } > > > > +static void segv_run_catcher(jmp_buf *catcher, void *fault_addr) > > +{ > > + current->thread.fault_addr = fault_addr; > > + UML_LONGJMP(catcher, 1); > > +} > > + > > /* > > * We give a *copy* of the faultinfo in the regs to segv. > > * This must be done, since nesting SEGVs could overwrite > > @@ -219,7 +225,10 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > > if (!is_user && regs) > > current->thread.segv_regs = container_of(regs, struct pt_regs, regs); > > > > - if (!is_user && (address >= start_vm) && (address < end_vm)) { > > + catcher = current->thread.fault_catcher; > > This and.. > > > + if (catcher && current->thread.is_running_test) > > + segv_run_catcher(catcher, (void *) address); > > + else if (!is_user && (address >= start_vm) && (address < end_vm)) { > > flush_tlb_kernel_vm(); > > goto out; > > } > > *not this* I don't understand. Are you saying the previous block of code is good and this one is bad? > > > @@ -246,12 +255,10 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > > address = 0; > > } > > > > - catcher = current->thread.fault_catcher; > > if (!err) > > goto out; > > else if (catcher != NULL) { > > - current->thread.fault_addr = (void *) address; > > - UML_LONGJMP(catcher, 1); > > + segv_run_catcher(catcher, (void *) address); > > } > > else if (current->thread.fault_addr != NULL) > > panic("fault_addr set but no fault catcher"); > > But with this seems one atomic change which should be submitted > separately, its just a helper. Think it would make the actual > change needed easier to review, ie, your needed changes would > be smaller and clearer for what you need. Are you suggesting that I pull out the bits needed to implement abort in the next patch and squash it into this one? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi1-x242.google.com ([2607:f8b0:4864:20::242]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gTxkF-0001NV-Ga for linux-um@lists.infradead.org; Mon, 03 Dec 2018 23:35:20 +0000 Received: by mail-oi1-x242.google.com with SMTP id b141so12608075oii.12 for ; Mon, 03 Dec 2018 15:35:09 -0800 (PST) MIME-Version: 1.0 References: <20181128193636.254378-1-brendanhiggins@google.com> <20181128193636.254378-9-brendanhiggins@google.com> <20181130033429.GK18410@garbanzo.do-not-panic.com> In-Reply-To: <20181130033429.GK18410@garbanzo.do-not-panic.com> From: Brendan Higgins Date: Mon, 3 Dec 2018 15:34:57 -0800 Message-ID: Subject: Re: [RFC v3 08/19] arch: um: add shim to trap to allow installing a fault catcher for tests List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: mcgrof@kernel.org Cc: brakmo@fb.com, dri-devel@lists.freedesktop.org, linux-kselftest@vger.kernel.org, shuah@kernel.org, Rob Herring , Frank Rowand , linux-nvdimm@lists.01.org, richard@nod.at, Knut Omang , kieran.bingham@ideasonboard.com, Joel Stanley , jdike@addtoit.com, Tim.Bird@sony.com, Kees Cook , linux-um@lists.infradead.org, rostedt@goodmis.org, Julia Lawall , dan.j.williams@intel.com, kunit-dev@googlegroups.com, Greg KH , Linux Kernel Mailing List , Daniel Vetter , mpe@ellerman.id.au, joe@perches.com, khilman@baylibre.com On Thu, Nov 29, 2018 at 7:34 PM Luis Chamberlain wrote: > > On Wed, Nov 28, 2018 at 11:36:25AM -0800, Brendan Higgins wrote: > > diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c > > index cced829460427..bf90e678b3d71 100644 > > --- a/arch/um/kernel/trap.c > > +++ b/arch/um/kernel/trap.c > > @@ -201,6 +201,12 @@ void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs) > > segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs); > > } > > > > +static void segv_run_catcher(jmp_buf *catcher, void *fault_addr) > > +{ > > + current->thread.fault_addr = fault_addr; > > + UML_LONGJMP(catcher, 1); > > +} > > + > > /* > > * We give a *copy* of the faultinfo in the regs to segv. > > * This must be done, since nesting SEGVs could overwrite > > @@ -219,7 +225,10 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > > if (!is_user && regs) > > current->thread.segv_regs = container_of(regs, struct pt_regs, regs); > > > > - if (!is_user && (address >= start_vm) && (address < end_vm)) { > > + catcher = current->thread.fault_catcher; > > This and.. > > > + if (catcher && current->thread.is_running_test) > > + segv_run_catcher(catcher, (void *) address); > > + else if (!is_user && (address >= start_vm) && (address < end_vm)) { > > flush_tlb_kernel_vm(); > > goto out; > > } > > *not this* I don't understand. Are you saying the previous block of code is good and this one is bad? > > > @@ -246,12 +255,10 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, > > address = 0; > > } > > > > - catcher = current->thread.fault_catcher; > > if (!err) > > goto out; > > else if (catcher != NULL) { > > - current->thread.fault_addr = (void *) address; > > - UML_LONGJMP(catcher, 1); > > + segv_run_catcher(catcher, (void *) address); > > } > > else if (current->thread.fault_addr != NULL) > > panic("fault_addr set but no fault catcher"); > > But with this seems one atomic change which should be submitted > separately, its just a helper. Think it would make the actual > change needed easier to review, ie, your needed changes would > be smaller and clearer for what you need. Are you suggesting that I pull out the bits needed to implement abort in the next patch and squash it into this one? _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um