[bootlin/training-materials updates] master: Kernel slides: update CONFIG_STRICT_DEVMEM explanations (d66f6bcd)

[Michael Opdenacker]

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/d66f6bcdeb7fd58fbd315b0ab6598be06c75e84c

>---------------------------------------------------------------

commit d66f6bcdeb7fd58fbd315b0ab6598be06c75e84c
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>


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d66f6bcdeb7fd58fbd315b0ab6598be06c75e84c
 .../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}