From nobody Sat Nov 30 16:51:07 2024 X-Original-To: dev-commits-src-all@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 4Y0wzb6rJ9z5fJ4k; Sat, 30 Nov 2024 16:51:07 +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 "R10" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4Y0wzb3nZxz4nSb; Sat, 30 Nov 2024 16:51:07 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1732985467; 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=RFIl3nP1T1W/WDlXXokrUiHAlh+RubMA+fba8jhMtS8=; b=lpUl2gUxRr7cMpPFeow5/H/9xHDFLrfOHCF0LQW57NTXFnwwmqYzE3Vs7i4Xk8zQ8W840b Lx4SdtvEPm4uXVjicAXqKxkFMJGDdrbaLBEgA23exKweR5ftepDfVgU6B3wuJlp537/0JT gE0phUTnb25yWwtVsrEtOwhPCv5194kX1QXlJpbm5wWZFy4XVvarPxlgFoTSRy4i7SLg8c Z5RlmOPprqBO4ztlInNo70u36qvwQ9uYhFbODZIQSf/iNCPXBMEqbAt7HkZ12yuNuua2GA P5ZApEiIWtkyI6DQaYmIxyi2IFHE9WvQ1l0DX7Z9iw3cE5+94ZZXA22sVBazWQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1732985467; 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=RFIl3nP1T1W/WDlXXokrUiHAlh+RubMA+fba8jhMtS8=; b=V3taq7fWy/qooPjlXYdqklIlO1UTIzIG5Npqdc+4lkflYFH/nq3EpGkRNkeGKl11pg4Oh4 F8+LYfEmWkBHk+9v4SFYDq/ErjKSVz4KPaCqBwjtrN8lN6w7XbjoDheKIuxVkjQgLVnuSS zN6t2p+yGC6WwxLXNbbIYF3pNUEDTUdRA5yjbESzpIiojjfCPlQ6b0MvWs5VnS+R+RyyYd BXittsF09o9xxE3r2ppTiNf2D6ZQ3TPrCODQPgwZnqbzKzjN2CBX21GqkXKOee5YdzIZoB iiFpxKIUS8TsjggHD7/0qUw1D38vC5HFTyFCLDQH8ulHt2yCDbV2hsNaX2Lqdg== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1732985467; a=rsa-sha256; cv=none; b=xPkRcEstMJFO95aZ/pAAbH2WZHBJfWwdV8OUXqUPeaITVrHFztwuDt95crxsMIiD2fk31O 6eOawA5YKb06F2KNmHIfUcu2TXJ8kHFFLfe8cYFFoKO3E91uNWtIRjgGcm4kfeYPy4ShgP 0Fh8sO2IQOvgWmIUrOghMfmKp+8KuLRBlZAfdMkEGGuupyENck2tldJE8NbcBQGnPeKscp ok5JF7vb3MRDV9hvfwUh3ww+hvWYo4ontK1/r9Kdo/+vuBC4x4WrHL4amn3Mhby4dKtX0C 3D0FQeB2wccn0MhjrRcK2JqtYnc7U0iC/uOXvec51aoi72QsQLHPe8/5rvNhSw== 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 4Y0wzb3PXYzGNj; Sat, 30 Nov 2024 16:51:07 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.18.1/8.18.1) with ESMTP id 4AUGp7wF043274; Sat, 30 Nov 2024 16:51:07 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 4AUGp7vV043271; Sat, 30 Nov 2024 16:51:07 GMT (envelope-from git) Date: Sat, 30 Nov 2024 16:51:07 GMT Message-Id: <202411301651.4AUGp7vV043271@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: John Baldwin Subject: git: d95675349a67 - stable/14 - linuxkpi: Provide a non-NULL value for THIS_MODULE List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-all@freebsd.org Sender: owner-dev-commits-src-all@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/stable/14 X-Git-Reftype: branch X-Git-Commit: d95675349a67b884db47b7861191bc3246a0d772 Auto-Submitted: auto-generated The branch stable/14 has been updated by jhb: URL: https://cgit.FreeBSD.org/src/commit/?id=d95675349a67b884db47b7861191bc3246a0d772 commit d95675349a67b884db47b7861191bc3246a0d772 Author: Austin Shafer AuthorDate: 2024-03-06 17:48:07 +0000 Commit: John Baldwin CommitDate: 2024-11-30 13:55:57 +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 (cherry picked from commit 28a59100b54ff245a45fbd328266266f1c14eb8c) --- 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 3018ba2fb8a4..df34843657db 100644 --- a/sys/compat/linuxkpi/common/include/linux/module.h +++ b/sys/compat/linuxkpi/common/include/linux/module.h @@ -33,6 +33,8 @@ #include #include #include +#include +#include #include #include @@ -52,7 +54,26 @@ #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 53a743f29459..a04dd4cec563 100644 --- a/sys/kern/kern_linker.c +++ b/sys/kern/kern_linker.c @@ -849,6 +849,20 @@ 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 e9073dab236c..664df2147bec 100644 --- a/sys/sys/linker.h +++ b/sys/sys/linker.h @@ -132,6 +132,12 @@ 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. */