docs: Make syscalls' helpers naming consistent

The documentation explains the need to create internal syscalls' helpers,
and that they should be called `kern_xyzzy()`. However, the comment at
include/linux/syscalls.h says that they should be named as
`ksys_xyzzy()`, and so are all the helpers declared bellow it. Change the
documentation to reflect this.

Fixes: 819671ff849b ("syscalls: define and explain goal to not call syscalls in the kernel")
Signed-off-by: André Almeida <andrealmeid@collabora.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Link: https://lore.kernel.org/r/20210130014547.123006-1-andrealmeid@collabora.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation: Replace lkml.org links with lore

Replace the lkml.org links with lore to better use a single source
that's more likely to stay available long-term.

Done by bash script:

cvt_lkml_to_lore ()
{
tmpfile=$(mktemp ./.cvt_links.XXXXXXX)

header=$(echo $1 | sed 's@/lkml/@/lkml/headers/@')

wget -qO - $header > $tmpfile
if [[ $? == 0 ]] ; then
link=$(grep -i '^Message-Id:' $tmpfile | head -1 | \
sed -r -e 's/^\s*Message-Id:\s*<\s*//' -e 's/\s*>\s*$//' -e 's@^@https://lore.kernel.org/r/@')
# echo "testlink: $link"
if [ -n "$link" ] ; then
wget -qO - $link > /dev/null
if [[ $? == 0 ]] ; then
echo $link
fi
fi
fi

rm -f $tmpfile
}

git grep -P -o "\bhttps?://(?:www.)?lkml.org/lkml[\/\w]+" $@ |
while read line ; do
echo $line
file=$(echo $line | cut -f1 -d':')
link=$(echo $line | cut -f2- -d':')
newlink=$(cvt_lkml_to_lore $link)
if [[ -n "$newlink" ]] ; then
sed -i -e "s#\b$link\b#$newlink#" $file
fi
done

Link: https://lore.kernel.org/patchwork/patch/1265849/#1462688
Signed-off-by: Joe Perches <joe@perches.com>
Link: https://lore.kernel.org/r/77cdb7f32cfb087955bfc3600b86c40bed5d4104.camel@perches.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Replace HTTP links with HTTPS ones: documentation

Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministic algorithm:
For each file:
For each line:
If doesn't contain `\bxmlns\b`:
For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
If both the HTTP and HTTPS versions
return 200 OK and serve the same content:
Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Link: https://lore.kernel.org/r/20200526060544.25127-1-grandmaster@al2klimov.de
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

docs: filesystems: fix renamed references

Some filesystem references got broken by a previous patch
series I submitted. Address those.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: David Sterba <dsterba@suse.com> # fs/affs/Kconfig
Link: https://lore.kernel.org/r/57318c53008dbda7f6f4a5a9e5787f4d37e8565a.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

doc:it_IT: add some process/* translations

This patch does not translate entirely the subfolder "process/"
but only part of it (to begin with).

In order to avoid broken links, I included empty documents
for those which are not yet translated.

In order to be able to refer to all documents in "process/",
I added a sphinx label to those which had not one.

Translated documents:
- howto
- 1.Intro
- clang-format
- coding-style
- kernel-driver-statement
- magic-number
- volatile-considered-harmful
- development-process

Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it>
Signed-off-by: Alessia Mantegazza <amantegazza@vaga.pv.it>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

doc: fix a typo in adding-syscalls.rst

There was a typo in adding-syscalls.rst that could mislead developers
to add a C filename in a makefile instead of an object filename.
This error, while not keeping developers from contributing could slow
the development process down by introducing build errors.

Signed-off-by: Guillaume Dore <corwin@poussif.eu>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

syscalls/core, syscalls/x86: Clean up compat syscall stub naming convention

Tidy the naming convention for compat syscall subs. Hints which describe
the purpose of the stub go in front and receive a double underscore to
denote that they are generated on-the-fly by the COMPAT_SYSCALL_DEFINEx()
macro.

For the generic case, this means:

t kernel_waitid # common C function (see kernel/exit.c)

__do_compat_sys_waitid # inlined helper doing the actual work
# (takes original parameters as declared)

T __se_compat_sys_waitid # sign-extending C function calling inlined
# helper (takes parameters of type long,
# casts them to unsigned long and then to
# the declared type)

T compat_sys_waitid # alias to __se_compat_sys_waitid()
# (taking parameters as declared), to
# be included in syscall table

For x86, the naming is as follows:

t kernel_waitid # common C function (see kernel/exit.c)

__do_compat_sys_waitid # inlined helper doing the actual work
# (takes original parameters as declared)

t __se_compat_sys_waitid # sign-extending C function calling inlined
# helper (takes parameters of type long,
# casts them to unsigned long and then to
# the declared type)

T __ia32_compat_sys_waitid # IA32_EMULATION 32-bit-ptregs -> C stub,
# calls __se_compat_sys_waitid(); to be
# included in syscall table

T __x32_compat_sys_waitid # x32 64-bit-ptregs -> C stub, calls
# __se_compat_sys_waitid(); to be included
# in syscall table

If only one of IA32_EMULATION and x32 is enabled, __se_compat_sys_waitid()
may be inlined into the stub __{ia32,x32}_compat_sys_waitid().

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180409105145.5364-3-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sys_ni: remove {sys_,sys_compat} from cond_syscall definitions

This keeps it in line with the SYSCALL_DEFINEx() / COMPAT_SYSCALL_DEFINEx()
calling convention.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

syscalls: define and explain goal to not call syscalls in the kernel

The syscall entry points to the kernel defined by SYSCALL_DEFINEx()
and COMPAT_SYSCALL_DEFINEx() should only be called from userspace
through kernel entry points, but not from the kernel itself. This
will allow cleanups and optimizations to the entry paths *and* to
the parts of the kernel code which currently need to pretend to be
userspace in order to make use of syscalls.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

docs: fix locations of several documents that got moved

The previous patch renamed several files that are cross-referenced
along the Kernel documentation. Adjust the links to point to
the right places.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

docs-rst: add documents to development-process

Add several documents to the development-process ReST book.

As we don't want renames, use symlinks instead, keeping those
documents on their original place.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>