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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Hi
</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">community</span><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">I recently ran into a blocked commit due to warnings reported by checkpatch.pl.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">In this particular case I wanted to add the “ATSR” structure to the DMAR tables. To do that, I need to define a new structure<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">which reflects the per specification needed layout of this table entry.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">I did that in the same style how other structures are defined in the same file (src/arch/x86/include/arch/acpi.h):<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">typedef struct dmar_atsr_entry {<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">
</span><span lang="ES" style="font-size:10.0pt;font-family:"Arial","sans-serif"">u16 type;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="ES" style="font-size:10.0pt;font-family:"Arial","sans-serif""> u16 length;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="ES" style="font-size:10.0pt;font-family:"Arial","sans-serif""> u8 flags;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="ES" style="font-size:10.0pt;font-family:"Arial","sans-serif"">
</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">u8 reserved;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> u16 segment;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">} __attribute__ ((packed)) dmar_atsr_entry_t;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">This change resulted in two warnings caused by util/lint/checkpatch.pl when I was trying to do a git commit:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">WARNING: do not add new typedefs<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">#34: FILE: src/arch/x86/include/arch/acpi.h:288:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">+typedef struct dmar_atsr_entry {<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">WARNING: __packed is preferred over __attribute__((packed))<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">#40: FILE: src/arch/x86/include/arch/acpi.h:294:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">+} __attribute__ ((packed)) dmar_atsr_entry_t;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">So the first warning tells me that I should not use “typedef” in my code.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">The second one tells me not to use __attribute__ ((packed) but instead __packed!<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">If one take a closer look to the coreboot tree, one will not find a macro definition called __packed at all.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">After a short discussion on IRC with Stefan it was clear that although we have this checkpatch.pl script in the tree and the git hook “pre-commit”<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">activates it, the script does not perfectly match current coreboot coding style.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">So in the end there needs to be a change somewhere:<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">We can adapt the script to match current coreboot coding style<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">We can start to refactor the coreboot tree to match the demands of checkpatch.pl<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">We can align only new patches to the demands of the script<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><span style="mso-list:Ignore">4.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">We can show warnings from the script but prevent them from aborting the git commit<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">While 1. would be the best, straight forward approach for the project, it might cause high effort for a person who knows the code base very well.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">2. will lead to a lot of changes in the tree while the reason/goal is still questionable (at least to me).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">3. will lead to different code style all over the tree (even in the same file) and in the end will result in fragmented code. I personally would not like it.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">4. can be a short term solution while we are seeking for the best way to deal with this issue.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">There may be other ways to go, too, which I have overseen now.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">I just want to start this discussion officially as this is not the first time I ran into issues with checkpatch.pl.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">What do you think about it, what would be the best way to handle this case?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">Your ideas and thoughts are appreciated.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">Werner<o:p></o:p></span></p>
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