From nobody Thu May 16 17:37:24 2024 X-Original-To: dev-commits-src-main@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4VgHNN3vy8z5LbVm; Thu, 16 May 2024 17:37:24 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4VgHNN3QRlz4Ssg; Thu, 16 May 2024 17:37:24 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1715881044; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=wI9830nsIb41jRKPLfztvTmyA78W4x+HOzJg8qolPiw=; b=hm6FgpSVHkGoRkEwFM1iwcd9VJGc3KOQ6zZfMLBUQlup6zHxkekmDc85of/wMdWZjrKNWz 7aaRV3WC+eepb1SX0gfum0otYDHFDUDdiyEOOF0xGNMLc7M8o47HTzL78+D8CHaguatd9l T1sF3QDEPQT+HExssd6UUl2Sh30AjsI1rlYpYNPZq7QrfYZ71G3rHOLzgnzjy5OcuWciOC jcozMEnLkX8mjHa9Ml/45LuyXXaOJJthip4/RXbhC6pMJb/57T4FbpdmN15DDfnkcvHBJi 9lDeguuiK/rqp0scr1ZKzdcIXZM9LwI4izd93s4PumoBq/DzqmTgF64dYgFU8w== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1715881044; a=rsa-sha256; cv=none; b=VlYruSx4jIBUn3umh7DmoulyowxuKTdXfxlXqMnQUBsgIUBbWjzZf7It9Qb9YGO/8T2rzq ENzxxO6CrJbMxy/bO7mTV/Wnqd8c69E3FUqg3LVhIhUPV+N895EZV5BWd213FbGPdW9RiC sejFFNlCkES8h1rP+08G6Bdtm8gqDU2QlfsObF9l7Sh+Rqn9tuBy9W7Dg6Kh77HTR18kN8 WnWeGCK3eHe1q9jpv02aBiOaN9B8AvxZS6qb/rqNIP5Nl3qux23KVSJW0CXrpVdA8wd8zi ggwg9ZKKE9MSm53Mt+0FEEJMsfK8D2JLpy+UxnyPfie4Uz7SuJrs36Ct7a4fKA== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1715881044; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=wI9830nsIb41jRKPLfztvTmyA78W4x+HOzJg8qolPiw=; b=ozC45s4gYTS54if9nEpcXkV51iPzIMh0j+j1TNdAVR40C9DgFJJMsEj261rmw+NXidxk3V /tibwRZuYnErs3fYoy7sFrpfasdGalJuFNokKcgb2pLntMtJMdco4vdmL+8pg2v/Z7E3W7 p6Gte6sYAfiWI5/jYnqfWAo1A+E5Z+L+as6bhWsC7qd4fpAF8oQVCey8N8bnYOVroTI3nV KyenMvKvBWRqjCQQ9rhIq30QssZlmFH9rVJQ44lSEnBUkIcxw4fbmCUGfjYsLRWYEVAo2y QCIXGQn/sXdRBseLv79GGMXNVjbbnmKo4RbghWSQDMfcZw0vnsZd69dqVQCh4A== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4VgHNN316pz177w; Thu, 16 May 2024 17:37:24 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.17.1/8.17.1) with ESMTP id 44GHbO11070793; Thu, 16 May 2024 17:37:24 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.17.1/8.17.1/Submit) id 44GHbOEa070790; Thu, 16 May 2024 17:37:24 GMT (envelope-from git) Date: Thu, 16 May 2024 17:37:24 GMT Message-Id: <202405161737.44GHbOEa070790@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: John Baldwin Subject: git: 28a59100b54f - main - linuxkpi: Provide a non-NULL value for THIS_MODULE List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-main@freebsd.org Sender: owner-dev-commits-src-main@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: jhb X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 28a59100b54ff245a45fbd328266266f1c14eb8c Auto-Submitted: auto-generated The branch main has been updated by jhb: URL: https://cgit.FreeBSD.org/src/commit/?id=28a59100b54ff245a45fbd328266266f1c14eb8c commit 28a59100b54ff245a45fbd328266266f1c14eb8c Author: Austin Shafer AuthorDate: 2024-03-06 17:48:07 +0000 Commit: John Baldwin CommitDate: 2024-05-16 17:36:36 +0000 linuxkpi: Provide a non-NULL value for THIS_MODULE THIS_MODULE is used to differentiate modules on Linux. We currently completely stub out any Linux struct module usage, but THIS_MODULE is still used to populate the "owner" fields of various drivers. Even though we don't actually dereference these "owner" fields they are still used by drivers to check if devices/dmabufs/etc come from different modules. For example, during DRM GEM import some drivers check if the dmabuf's owner matches the dev's owner. If they match because they are both NULL drivers may incorrectly think two resources come from the same module. This adds a general purpose __this_linker_file which will point to the linker file of the module that uses it. We can then use that pointer to have a valid value for THIS_MODULE. Reviewed by: bz, jhb Differential Revision: https://reviews.freebsd.org/D44306 --- sys/compat/linuxkpi/common/include/linux/module.h | 21 +++++++++++++++++++++ sys/kern/kern_linker.c | 14 ++++++++++++++ sys/sys/linker.h | 6 ++++++ 3 files changed, 41 insertions(+) diff --git a/sys/compat/linuxkpi/common/include/linux/module.h b/sys/compat/linuxkpi/common/include/linux/module.h index 9d98ef7cf3db..079dacf8df6c 100644 --- a/sys/compat/linuxkpi/common/include/linux/module.h +++ b/sys/compat/linuxkpi/common/include/linux/module.h @@ -32,6 +32,8 @@ #include #include #include +#include +#include #include #include @@ -51,7 +53,26 @@ #define MODULE_SUPPORTED_DEVICE(name) #define MODULE_IMPORT_NS(_name) +/* + * THIS_MODULE is used to differentiate modules on Linux. We currently + * completely stub out any Linux struct module usage, but THIS_MODULE is still + * used to populate the "owner" fields of various drivers. Even though we + * don't actually dereference these "owner" fields they are still used by + * drivers to check if devices/dmabufs/etc come from different modules. For + * example, during DRM GEM import some drivers check if the dmabuf's owner + * matches the dev's owner. If they match because they are both NULL drivers + * may incorrectly think two resources come from the same module. + * + * To handle this we specify an undefined symbol __this_linker_file, which + * will get special treatment from the linker when resolving. This will + * populate the usages of __this_linker_file with the linker_file_t of the + * module. + */ +#ifdef KLD_MODULE +#define THIS_MODULE ((struct module *)&__this_linker_file) +#else #define THIS_MODULE ((struct module *)0) +#endif #define __MODULE_STRING(x) __stringify(x) diff --git a/sys/kern/kern_linker.c b/sys/kern/kern_linker.c index 08b85867d781..3f34bb12aeaa 100644 --- a/sys/kern/kern_linker.c +++ b/sys/kern/kern_linker.c @@ -906,6 +906,20 @@ linker_file_lookup_symbol_internal(linker_file_t file, const char *name, KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n", file, name, deps)); + /* + * Treat the __this_linker_file as a special symbol. This is a + * global that linuxkpi uses to populate the THIS_MODULE + * value. In this case we can simply return the linker_file_t. + * + * Modules compiled statically into the kernel are assigned NULL. + */ + if (strcmp(name, "__this_linker_file") == 0) { + address = (file == linker_kernel_file) ? NULL : (caddr_t)file; + KLD_DPF(SYM, ("linker_file_lookup_symbol: resolving special " + "symbol __this_linker_file to %p\n", address)); + return (address); + } + if (LINKER_LOOKUP_SYMBOL(file, name, &sym) == 0) { LINKER_SYMBOL_VALUES(file, sym, &symval); if (symval.value == 0) diff --git a/sys/sys/linker.h b/sys/sys/linker.h index 52fbeb5584ff..06e950f7affe 100644 --- a/sys/sys/linker.h +++ b/sys/sys/linker.h @@ -130,6 +130,12 @@ typedef int linker_predicate_t(linker_file_t, void *); */ extern linker_file_t linker_kernel_file; +/* + * Special symbol which will be replaced by a reference to the linker_file_t + * of the module it is used in. + */ +extern linker_file_t __this_linker_file; + /* * Obtain a reference to a module, loading it if required. */