[bootlin/training-materials updates] master: Kernel slides: update CONFIG_STRICT_DEVMEM explanations (96c3cd12)
Thomas Petazzoni
thomas.petazzoni at bootlin.com
Fri Oct 29 10:46:36 CEST 2021
Repository : https://github.com/bootlin/training-materials
On branch : master
Link : https://github.com/bootlin/training-materials/commit/96c3cd12db84a2e229645a357725e2b8e0b1943a
>---------------------------------------------------------------
commit 96c3cd12db84a2e229645a357725e2b8e0b1943a
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date: Fri Apr 23 10:54:57 2021 +0200
Kernel slides: update CONFIG_STRICT_DEVMEM explanations
Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>
>---------------------------------------------------------------
96c3cd12db84a2e229645a357725e2b8e0b1943a
.../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 0d3482ef..231f3e89 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 @@ writel(c & 0xff, port->membase + 4);
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}
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