Date: Thu, 04 Jun 2026 00:36:25 +0000 From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 5377cd66852c - stable/15 - sys: add safe_read(9) Message-ID: <6a20c889.20824.3034595d@gitrepo.freebsd.org>
index | next in thread | raw e-mail
The branch stable/15 has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=5377cd66852c13e3a5f29f2ccc0c0e14b7431c11 commit 5377cd66852c13e3a5f29f2ccc0c0e14b7431c11 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2025-03-29 17:17:01 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2026-06-04 00:34:43 +0000 sys: add safe_read(9) (cherry picked from commit 7b2702ee25f5230011fa7f8f650b65b37248fcca) --- 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 d51e5501aca9..e337337fd8e7 100644 --- a/sys/amd64/amd64/machdep.c +++ b/sys/amd64/amd64/machdep.c @@ -1866,6 +1866,24 @@ wrmsr_early_safe_end(void) memset_early(&idt0[i], 0, sizeof(idt0[0])); } +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 c4e0aafac452..d6488f45acae 100644 --- a/sys/sys/systm.h +++ b/sys/sys/systm.h @@ -563,6 +563,14 @@ 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. */home | help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?6a20c889.20824.3034595d>