From 96c3cd12db84a2e229645a357725e2b8e0b1943a Mon Sep 17 00:00:00 2001 From: Michael Opdenacker Date: Fri, 23 Apr 2021 10:54:57 +0200 Subject: [PATCH] Kernel slides: update CONFIG_STRICT_DEVMEM explanations Signed-off-by: Michael Opdenacker --- .../kernel-driver-development-io-memory.tex | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/slides/kernel-driver-development-io-memory/kernel-driver-development-io-memory.tex b/slides/kernel-driver-development-io-memory/kernel-driver-development-io-memory.tex index 0d3482efa..231f3e899 100644 --- a/slides/kernel-driver-development-io-memory/kernel-driver-development-io-memory.tex +++ b/slides/kernel-driver-development-io-memory/kernel-driver-development-io-memory.tex @@ -266,9 +266,11 @@ \section{I/O Memory and Ports} address. \item Used by applications such as the X server to write directly to device memory. - \item On \code{x86}, \code{arm}, \code{arm64}, - \code{powerpc}, \code{s390}: + \item On \code{x86}, \code{arm}, \code{arm64}, \code{riscv}, + \code{powerpc}, \code{parisc}, \code{s390}: \kconfig{CONFIG_STRICT_DEVMEM} option to restrict \code{/dev/mem} - to non-RAM addresses, for security reasons (Linux 4.20 status). + to non-RAM addresses, for security reasons (Linux 5.12 status). + \kconfig{CONFIG_IO_STRICT_DEVMEM} goes beyond and only allows to access + {\em idle} I/O ranges (not appearing in \code{/proc/iomem}). \end{itemize} \end{frame}