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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 454ACC282CE for ; Tue, 12 Feb 2019 23:46:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 056082084E for ; Tue, 12 Feb 2019 23:46:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731272AbfBLXqW (ORCPT ); Tue, 12 Feb 2019 18:46:22 -0500 Received: from mx0a-002e3701.pphosted.com ([148.163.147.86]:44740 "EHLO mx0a-002e3701.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727039AbfBLXqW (ORCPT ); Tue, 12 Feb 2019 18:46:22 -0500 Received: from pps.filterd (m0134421.ppops.net [127.0.0.1]) by mx0b-002e3701.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x1CNfGXB027854; Tue, 12 Feb 2019 23:46:07 GMT Received: from g4t3425.houston.hpe.com (g4t3425.houston.hpe.com [15.241.140.78]) by mx0b-002e3701.pphosted.com with ESMTP id 2qm2r3t5wv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 12 Feb 2019 23:46:07 +0000 Received: from sarge.linuxathome.me (unknown [16.99.162.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by g4t3425.houston.hpe.com (Postfix) with ESMTPS id CEB07A1; Tue, 12 Feb 2019 23:46:03 +0000 (UTC) Date: Tue, 12 Feb 2019 23:46:00 +0000 From: Hedi Berriche To: Ard Biesheuvel Cc: Linux Kernel Mailing List , Thomas Gleixner , Bhupesh Sharma , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , linux-efi , the arch/x86 maintainers , Russ Anderson , Mike Travis , Dimitri Sivanich , Steve Wahl , stable Subject: Re: [Patch v2 1/4] efi/x86: turn EFI runtime semaphore into a global lock Message-ID: <20190212234600.GL6398@sarge.linuxathome.me> Mail-Followup-To: Ard Biesheuvel , Linux Kernel Mailing List , Thomas Gleixner , Bhupesh Sharma , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , linux-efi , the arch/x86 maintainers , Russ Anderson , Mike Travis , Dimitri Sivanich , Steve Wahl , stable References: <20190207042234.25109-1-hedi.berriche@hpe.com> <20190207042234.25109-2-hedi.berriche@hpe.com> <20190207173808.GE6398@sarge.linuxathome.me> <20190212172500.GB6398@sarge.linuxathome.me> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline In-Reply-To: <20190212172500.GB6398@sarge.linuxathome.me> User-Agent: Mutt/1.10.1 (2018-07-13) X-HPE-SCL: -1 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-02-12_13:,, 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 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1902120160 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 12, 2019 at 17:25 Hedi Berriche wrote: >On Thu, Feb 07, 2019 at 17:38 Hedi Berriche wrote: >>On Thu, Feb 07, 2019 at 16:05 Ard Biesheuvel wrote: >>>On Thu, 7 Feb 2019 at 05:23, Hedi Berriche wrote: >>>> >>>>Make efi_runtime_lock semaphore global so that it can be used by EFI >>>>runtime callers that may be defined outside efi/runtime-wrappers.c. >>>> >>>>Also now that efi_runtime_lock semaphore is no longer static, rename it >>>>to efi_runtime_sem so it doesn't clash with the efi_runtime_lock spinlock >>>>defined in arch/x86/platform/efi/efi_64.c when CONFIG_EFI_MIXED is >>>>enabled. >>>> >>>>The immediate motivation of this change is to serialise UV platform BIOS >>>>calls using the efi_runtime_sem semaphore. >>>> >>>>No functional changes. >>>> >>>>Cc: Russ Anderson >>>>Cc: Mike Travis >>>>Cc: Dimitri Sivanich >>>>Cc: Steve Wahl >>>>Cc: stable@vger.kernel.org >>>>Signed-off-by: Hedi Berriche >>> >>>Hello Hedi, >> >>Hi Ard, >> >>>Same feedback as on v1: please don't rename the lock. >> >>With the efi_runtime_lock semaphore being no longer static, not renaming it >>will cause a compile failure as it will clash with the declaration of the >>efi_runtime_lock *spinlock* in arch/x86/platform/efi/efi_64.c in the >>CONFIG_EFI_MIXED case. > >Ard, > >Any comments on whether resolving the conflict between > > {efi_runtime_lock, drivers/firmware/efi/runtime-wrappers.c} > >and > {efi_runtime_lock, arch/x86/platform/efi/efi_64.c} > >provides the required justification for renaming the efi_runtime_lock semaphore? Ard, Apologies for sending this email which must have come across as absurd given the *second* email you sent on 2019-02-07 19:38:42. The trouble is that I *never* received that email (nor the one you sent today 2019-02-12 17:26:06 as reply to this one) because for some reason my email address was dropped from the distribution list. It's only about 30 minutes ago that a colleague brought it up to my attention and forwarded both emails: Thu, 7 Feb 2019 20:38:42 +0100 Tue, 12 Feb 2019 18:26:06 +0100 No idea how my email address got dropped but I wanted to make sure to explain the seemingly absurd email I sent today as well as the lack of comment on your earlier email. Cheers, Hedi. >>>>--- >>>>drivers/firmware/efi/runtime-wrappers.c | 60 ++++++++++++------------- >>>>include/linux/efi.h | 3 ++ >>>>2 files changed, 33 insertions(+), 30 deletions(-) >>>> >>>>diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c >>>>index 8903b9ccfc2b..ec60d6227925 100644 >>>>--- a/drivers/firmware/efi/runtime-wrappers.c >>>>+++ b/drivers/firmware/efi/runtime-wrappers.c >>>>@@ -53,7 +53,7 @@ struct efi_runtime_work efi_rts_work; >>>> * @rts_arg<1-5>: efi_runtime_service() function arguments >>>> * >>>> * Accesses to efi_runtime_services() are serialized by a binary >>>>- * semaphore (efi_runtime_lock) and caller waits until the work is >>>>+ * semaphore (efi_runtime_sem) and caller waits until the work is >>>> * finished, hence _only_ one work is queued at a time and the caller >>>> * thread waits for completion. >>>> */ >>>>@@ -144,7 +144,7 @@ void efi_call_virt_check_flags(unsigned long flags, const char *call) >>>> * none of the remaining functions are actually ever called at runtime. >>>> * So let's just use a single lock to serialize all Runtime Services calls. >>>> */ >>>>-static DEFINE_SEMAPHORE(efi_runtime_lock); >>>>+DEFINE_SEMAPHORE(efi_runtime_sem); >>>> >>>>/* >>>> * Calls the appropriate efi_runtime_service() with the appropriate >>>>@@ -233,10 +233,10 @@ static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc) >>>>{ >>>> efi_status_t status; >>>> >>>>- if (down_interruptible(&efi_runtime_lock)) >>>>+ if (down_interruptible(&efi_runtime_sem)) >>>> return EFI_ABORTED; >>>> status = efi_queue_work(GET_TIME, tm, tc, NULL, NULL, NULL); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>> return status; >>>>} >>>> >>>>@@ -244,10 +244,10 @@ static efi_status_t virt_efi_set_time(efi_time_t *tm) >>>>{ >>>> efi_status_t status; >>>> >>>>- if (down_interruptible(&efi_runtime_lock)) >>>>+ if (down_interruptible(&efi_runtime_sem)) >>>> return EFI_ABORTED; >>>> status = efi_queue_work(SET_TIME, tm, NULL, NULL, NULL, NULL); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>> return status; >>>>} >>>> >>>>@@ -257,11 +257,11 @@ static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled, >>>>{ >>>> efi_status_t status; >>>> >>>>- if (down_interruptible(&efi_runtime_lock)) >>>>+ if (down_interruptible(&efi_runtime_sem)) >>>> return EFI_ABORTED; >>>> status = efi_queue_work(GET_WAKEUP_TIME, enabled, pending, tm, NULL, >>>> NULL); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>> return status; >>>>} >>>> >>>>@@ -269,11 +269,11 @@ static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm) >>>>{ >>>> efi_status_t status; >>>> >>>>- if (down_interruptible(&efi_runtime_lock)) >>>>+ if (down_interruptible(&efi_runtime_sem)) >>>> return EFI_ABORTED; >>>> status = efi_queue_work(SET_WAKEUP_TIME, &enabled, tm, NULL, NULL, >>>> NULL); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>> return status; >>>>} >>>> >>>>@@ -285,11 +285,11 @@ static efi_status_t virt_efi_get_variable(efi_char16_t *name, >>>>{ >>>> efi_status_t status; >>>> >>>>- if (down_interruptible(&efi_runtime_lock)) >>>>+ if (down_interruptible(&efi_runtime_sem)) >>>> return EFI_ABORTED; >>>> status = efi_queue_work(GET_VARIABLE, name, vendor, attr, data_size, >>>> data); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>> return status; >>>>} >>>> >>>>@@ -299,11 +299,11 @@ static efi_status_t virt_efi_get_next_variable(unsigned long *name_size, >>>>{ >>>> efi_status_t status; >>>> >>>>- if (down_interruptible(&efi_runtime_lock)) >>>>+ if (down_interruptible(&efi_runtime_sem)) >>>> return EFI_ABORTED; >>>> status = efi_queue_work(GET_NEXT_VARIABLE, name_size, name, vendor, >>>> NULL, NULL); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>> return status; >>>>} >>>> >>>>@@ -315,11 +315,11 @@ static efi_status_t virt_efi_set_variable(efi_char16_t *name, >>>>{ >>>> efi_status_t status; >>>> >>>>- if (down_interruptible(&efi_runtime_lock)) >>>>+ if (down_interruptible(&efi_runtime_sem)) >>>> return EFI_ABORTED; >>>> status = efi_queue_work(SET_VARIABLE, name, vendor, &attr, &data_size, >>>> data); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>> return status; >>>>} >>>> >>>>@@ -330,12 +330,12 @@ virt_efi_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor, >>>>{ >>>> efi_status_t status; >>>> >>>>- if (down_trylock(&efi_runtime_lock)) >>>>+ if (down_trylock(&efi_runtime_sem)) >>>> return EFI_NOT_READY; >>>> >>>> status = efi_call_virt(set_variable, name, vendor, attr, data_size, >>>> data); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>> return status; >>>>} >>>> >>>>@@ -350,11 +350,11 @@ static efi_status_t virt_efi_query_variable_info(u32 attr, >>>> if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) >>>> return EFI_UNSUPPORTED; >>>> >>>>- if (down_interruptible(&efi_runtime_lock)) >>>>+ if (down_interruptible(&efi_runtime_sem)) >>>> return EFI_ABORTED; >>>> status = efi_queue_work(QUERY_VARIABLE_INFO, &attr, storage_space, >>>> remaining_space, max_variable_size, NULL); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>> return status; >>>>} >>>> >>>>@@ -369,12 +369,12 @@ virt_efi_query_variable_info_nonblocking(u32 attr, >>>> if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) >>>> return EFI_UNSUPPORTED; >>>> >>>>- if (down_trylock(&efi_runtime_lock)) >>>>+ if (down_trylock(&efi_runtime_sem)) >>>> return EFI_NOT_READY; >>>> >>>> status = efi_call_virt(query_variable_info, attr, storage_space, >>>> remaining_space, max_variable_size); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>> return status; >>>>} >>>> >>>>@@ -382,11 +382,11 @@ static efi_status_t virt_efi_get_next_high_mono_count(u32 *count) >>>>{ >>>> efi_status_t status; >>>> >>>>- if (down_interruptible(&efi_runtime_lock)) >>>>+ if (down_interruptible(&efi_runtime_sem)) >>>> return EFI_ABORTED; >>>> status = efi_queue_work(GET_NEXT_HIGH_MONO_COUNT, count, NULL, NULL, >>>> NULL, NULL); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>> return status; >>>>} >>>> >>>>@@ -395,14 +395,14 @@ static void virt_efi_reset_system(int reset_type, >>>> unsigned long data_size, >>>> efi_char16_t *data) >>>>{ >>>>- if (down_interruptible(&efi_runtime_lock)) { >>>>+ if (down_interruptible(&efi_runtime_sem)) { >>>> pr_warn("failed to invoke the reset_system() runtime service:\n" >>>> "could not get exclusive access to the firmware\n"); >>>> return; >>>> } >>>> efi_rts_work.efi_rts_id = RESET_SYSTEM; >>>> __efi_call_virt(reset_system, reset_type, status, data_size, data); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>>} >>>> >>>>static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules, >>>>@@ -414,11 +414,11 @@ static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules, >>>> if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) >>>> return EFI_UNSUPPORTED; >>>> >>>>- if (down_interruptible(&efi_runtime_lock)) >>>>+ if (down_interruptible(&efi_runtime_sem)) >>>> return EFI_ABORTED; >>>> status = efi_queue_work(UPDATE_CAPSULE, capsules, &count, &sg_list, >>>> NULL, NULL); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>> return status; >>>>} >>>> >>>>@@ -432,11 +432,11 @@ static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules, >>>> if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) >>>> return EFI_UNSUPPORTED; >>>> >>>>- if (down_interruptible(&efi_runtime_lock)) >>>>+ if (down_interruptible(&efi_runtime_sem)) >>>> return EFI_ABORTED; >>>> status = efi_queue_work(QUERY_CAPSULE_CAPS, capsules, &count, >>>> max_size, reset_type, NULL); >>>>- up(&efi_runtime_lock); >>>>+ up(&efi_runtime_sem); >>>> return status; >>>>} >>>> >>>>diff --git a/include/linux/efi.h b/include/linux/efi.h >>>>index 45ff763fba76..930cd20842b8 100644 >>>>--- a/include/linux/efi.h >>>>+++ b/include/linux/efi.h >>>>@@ -1745,6 +1745,9 @@ extern struct efi_runtime_work efi_rts_work; >>>>/* Workqueue to queue EFI Runtime Services */ >>>>extern struct workqueue_struct *efi_rts_wq; >>>> >>>>+/* EFI runtime semaphore */ >>>>+extern struct semaphore efi_runtime_sem; >>>>+ >>>>struct linux_efi_memreserve { >>>> int size; // allocated size of the array >>>> atomic_t count; // number of entries used >>>>-- >>>>2.20.1 >>>> >> >>-- >>Be careful of reading health books, you might die of a misprint. >> -- Mark Twain > >-- >Be careful of reading health books, you might die of a misprint. > -- Mark Twain -- Be careful of reading health books, you might die of a misprint. -- Mark Twain