From nobody Thu May 28 12:38:33 2026 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 4gR5d545Nhz6fgXm for ; Thu, 28 May 2026 12:38:33 +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 "R13" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4gR5d50TWBz3TZR for ; Thu, 28 May 2026 12:38:33 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1779971913; 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=mrnOM+XHG2kgSKZ6k1giOBtgKVRnZg47U2jInl7ZLaM=; b=y3B7BE/1+zbIddzzKjp8xu+Y/f+tIgJgj47khCD8jPGzA/Y6/pOY/wlxV4ZfPOBqPQYpS/ WpHNTp+aUhFkOOx8cjuDjjihwnITp0so5fh3/AOP7sINC+NGViKUYezAMcJ6eAnZKfoY+k XfqEG7p8+ehXm3+f6s94J1ygmo5pdN96Svhhxw4y3Q70ugvvIjYoVUhveDN+i9zlgMbTew JfaKR0f4PVW1wrZK+AKX/XVLMyjTsprKPYEpA6ok2/gVSDiXwCIi/bTNLzbf13SaJrNJho 6uKf17mSG03sGEQavGkmoKFHmdfgmPRoOqBqBFKXQy+0TYq3YZtTakHBxyTKCA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1779971913; a=rsa-sha256; cv=none; b=O4Wa2xHDMdEhmjqxuljtrJeMpQ9ewGVDavgok7O8QD1KzpyDEUF95iHShEITxmmvEK9UT9 fs9pBkWqeJ+wfPAeuZn5QCExgB2UiP9c6HWHSH/upqtrh7S+f6NG+ZccHLWWJkonxm7WzH l46jcLOixw0adFQL4Y/bwvga1Vg8XCBhQ0NW9mdKaBVn4jjimxOIpepbtWL6NfOlLq11Jo Y5Sb3smb5cwpEsyCJAkgAI87hUpP3oQjaR1qQvjpqV1X6SduObTQkJx4W5lMzVpEs3IHlV 8X4jcmfnE1t4NLIGQCsnNyMpJ7OL3k69ba5y2rRAcjL8Ptex1RoEflifm9TRjg== 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=1779971913; 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=mrnOM+XHG2kgSKZ6k1giOBtgKVRnZg47U2jInl7ZLaM=; b=kkFy2+ce/+RwAKjDXii+f1ZskHcMKOrmoDqQekOPeApnFDc5ZHpoPBeLJQ2P+0BAUmHjK1 7UbuGiBN0SYmgj4/r5mnNlD7Gwjgd3+IAjmM01PJ4l/8ogWW0vEe9D63AEsKmNSrO8+sAP aoOrQRBq4rRrmXBrS4zYLSn68dr4ZSWH5gOCli2rF28yf53Ojn1IZN2qEMSeQ22+DzkO/y 2dB8aWojljJvEno2F8jd6+7yN6UaYFb8FPBLBHBfRXLtZyqnwIgepxiWqowgtsajAXR2c1 e8MOxluwSpL7eFUa8u1x5B98N0juWB91U3I2TGt5YEnyaDXRtaE72Bq34El8GQ== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4gR5d504BPzn53 for ; Thu, 28 May 2026 12:38:33 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 45808 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Thu, 28 May 2026 12:38:33 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Konstantin Belousov Subject: git: 7b2702ee25f5 - main - sys: add safe_read(9) 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 List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: kib X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 7b2702ee25f5230011fa7f8f650b65b37248fcca Auto-Submitted: auto-generated Date: Thu, 28 May 2026 12:38:33 +0000 Message-Id: <6a183749.45808.5d99f3ce@gitrepo.freebsd.org> The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=7b2702ee25f5230011fa7f8f650b65b37248fcca commit 7b2702ee25f5230011fa7f8f650b65b37248fcca Author: Konstantin Belousov AuthorDate: 2025-03-29 17:17:01 +0000 Commit: Konstantin Belousov CommitDate: 2026-05-28 12:38:25 +0000 sys: add safe_read(9) The MD function with MI interface to provide a way to read arbitrary (canonical) KVA. amd64 only for now. Reviewed by: markj Tested by: aokblast Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D49566 --- sys/amd64/amd64/machdep.c | 18 ++++++++++++++++++ sys/sys/systm.h | 8 ++++++++ 2 files changed, 26 insertions(+) diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c index dbad85096a1d..db2fd5927f7f 100644 --- a/sys/amd64/amd64/machdep.c +++ b/sys/amd64/amd64/machdep.c @@ -1852,6 +1852,24 @@ wrmsr_early_safe_end(void) memset_early(gpf_descr, 0, sizeof(*gpf_descr)); } +int +safe_read(vm_offset_t addr, char *valp) +{ + struct uio uio; + struct iovec iov; + + iov.iov_base = valp; + iov.iov_len = 1; + uio.uio_offset = addr; + uio.uio_iov = &iov; + uio.uio_iovcnt = 1; + uio.uio_resid = 1; + uio.uio_segflg = UIO_SYSSPACE; + uio.uio_rw = UIO_READ; + uio.uio_td = NULL; + return (uiomove_mem(UIO_MEM_KMEM, &uio)); +} + #ifdef KDB /* diff --git a/sys/sys/systm.h b/sys/sys/systm.h index 7f655b48ba08..88c25f06e0cb 100644 --- a/sys/sys/systm.h +++ b/sys/sys/systm.h @@ -553,6 +553,14 @@ void intr_prof_stack_use(struct thread *td, struct trapframe *frame); void counted_warning(unsigned *counter, const char *msg); +/* + * Safely read one byte of kernel memory at address addr, placing the + * value into *valp. Returns 0 on success, EFAULT if read was + * impossible, e.g. due to the address not being mapped or not having + * necessary permissions. + */ +int safe_read(vm_offset_t addr, char *valp); + /* * APIs to manage deprecation and obsolescence. */