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</o:shapelayout></xml><![endif]--></head><body lang=KO link=blue vlink=purple><div class=WordSection1><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>Hello Fabio and all,<o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>I realized what was wrong.<o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>If I wanted to change ARCH_OPTIONAL_KERNEL_RWX to =y, I should have changed it in my defconfig.<o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>I’ve done doing that several times in the past but I temporarily forgot that.<o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>After putting ARCH_OPTIONAL_KERNEL_RWX=y in my xxx_defconfig (for my board), and reverting the source to the original, it builds ok.<o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>(of course after you change something with menuconfig, and if you want to save that config, you should use ‘make savedefconfig’ and store that generated defconfig file as arch/arm64/configs/xxx_defconfig)<o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>I think I don’t have to change the default setting for arm64 and there should be an error in my qemu code(this was to avoid an error during u-boot/linux test on qemu).<o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>Chan<o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri",sans-serif'> FMDF <fmdefrancesco@gmail.com> <br><b>Sent:</b> Saturday, March 19, 2022 7:24 PM<br><b>To:</b> Chan Kim <ckim@etri.re.kr><br><b>Cc:</b> kernelnewbies <kernelnewbies@kernelnewbies.org><br><b>Subject:</b> Re: arm64 code looking for variable rodata_enabled when STRICT_KERNEL_RWX = n<o:p></o:p></span></p></div></div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><div><div><div><div><p class=MsoNormal><span lang=EN-US>On Fri, 18 Mar 2022, 07:04 Chan Kim, <<a href="mailto:ckim@etri.re.kr">ckim@etri.re.kr</a>> wrote:<o:p></o:p></span></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm'><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>Hello all,<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>This is what I see when I search </span>“<span lang=EN-US>KERNEL_RWX</span>”<span lang=EN-US> during </span>“<span lang=EN-US>make menuconfig</span>”<span lang=EN-US> for arm64 kernel(5-10.0-rc5). <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>The Kconfig file says CONFIG_STRICT_KERNEL_RWX is for setting text and rodata read-only.<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> Symbol: ARCH_OPTIONAL_KERNEL_RWX [=n] <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> Type : bool <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> Defined at arch/Kconfig:928 <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=DE> Symbol: ARCH_OPTIONAL_KERNEL_RWX_DEFAULT [=n] </span><span lang=EN-US><o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=DE> </span><span lang=EN-US>Type : bool <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> Defined at arch/Kconfig:931 <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> Symbol: STRICT_KERNEL_RWX [=y] <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> Type : bool <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> Defined at arch/Kconfig:937 <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> Prompt: Make kernel text and rodata read-only <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> Depends on: ARCH_HAS_STRICT_KERNEL_RWX [=y] <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> Visible if: ARCH_HAS_STRICT_KERNEL_RWX [=y] && ARCH_OPTIONAL_KERNEL_RWX [=n] <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> Location: <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> (1) -> General architecture-dependent options <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>I wanted to try setting STRICT_KERNEL_RWX to =n. It says this option is visible when ARCH_OPTIONAL_KERNEL_RWX is =y which is now =n.<o:p></o:p></span></p></div></div></blockquote></div></div><div><p class=MsoNormal><span lang=EN-US>Now I'm a bit confused... why do you say that "It says this option is visible when ARCH_OPTIONAL_KERNEL_RWX is =y"?<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>I haven't ever written Kbuild rules but as far as I understand that message "Symbol: STRICT_KERNEL_RWX [=y] [is] Visible if: ARCH_HAS_STRICT_KERNEL_RWX [=y] && ARCH_OPTIONAL_KERNEL_RWX [=n]" seems to say that we can see and enable/disable STRICT_KERNEL_RWX if and only if ARCH_HAS_STRICT_KERNEL_RWX is set to "yes" AND ARCH_OPTIONAL_KERNEL_RWX is set to "no".<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>Is it me that I'm misunderstanding the above-mentioned message from "make menuconfig"?<o:p></o:p></span></p></div><div><div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm'><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>So I modified to ARCH_OPTIONAL_KERNEL_RWX=y in arch/Kconfig line 928. (BTW, is it correct to modify this Kconfig file directly? I</span>’<span lang=EN-US>m not sure at the moment)<o:p></o:p></span></p></div></div></blockquote></div></div><div><p class=MsoNormal><span lang=EN-US>For sure, I'd never do this. Why don't you simply use make menuconfig for enabling/disabling options? Options are strictly interrelated and largely depend on others. Why do you want to bypass dependency checks?<o:p></o:p></span></p></div><div><div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm'><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>Then I could see the STRICT_KERNEL_RWX menu in the menuconfig and I set it to =n as I wanted. <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>But when I build the kernel, I see this errors. <o:p></o:p></span></p></div></div></blockquote></div></div><div><p class=MsoNormal><span lang=EN-US>Again, if it's not me that I'm missing something, the following errors are simply explained by your weird way to enable/disable options.<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>Please correct me if I didn't get something that you wrote (I'm very tired now after a long night staying awoke :))<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>Regards,<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>Fabio M. De Francesco<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div><div><div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm'><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> <a href="mailto:ckim@ckim-ubuntu:~/ProjX/LinuxDevDrv/kernel-release-RD-INFRA-2020.11.30$">ckim@ckim-ubuntu:~/ProjX/LinuxDevDrv/kernel-release-RD-INFRA-2020.11.30$</a> makeit<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> CALL scripts/atomic/check-atomics.sh<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> CALL scripts/checksyscalls.sh<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> CHK include/generated/compile.h<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> CC arch/arm64/mm/mmu.o<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> arch/arm64/mm/mmu.c: In function 'parse_rodata':<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> arch/arm64/mm/mmu.c:595:28: error: 'rodata_enabled' undeclared (first use in this function)<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> 595 | int ret = strtobool(arg, &rodata_enabled);<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> | ^~~~~~~~~~~~~~<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> arch/arm64/mm/mmu.c:595:28: note: each undeclared identifier is reported only once for each function it appears in<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> arch/arm64/mm/mmu.c: In function 'map_entry_trampoline':<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> arch/arm64/mm/mmu.c:614:18: error: 'rodata_enabled' undeclared (first use in this function)<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> 614 | pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> | ^~~~~~~~~~~~~~<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> arch/arm64/mm/mmu.c: In function 'map_kernel':<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> arch/arm64/mm/mmu.c:669:23: error: 'rodata_enabled' undeclared (first use in this function)<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> 669 | pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> | ^~~~~~~~~~~~~~<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> make[2]: *** [scripts/Makefile.build:283: arch/arm64/mm/mmu.o] Error 1<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> make[1]: *** [scripts/Makefile.build:500: arch/arm64/mm] Error 2<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> make: *** [Makefile:1799: arch/arm64] Error 2<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>variable </span>“<span lang=EN-US>rodata_enabled</span>”<span lang=EN-US> is defined in init/main.c as below.<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> bool rodata_enabled __ro_after_init = true;<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> static int __init set_debug_rodata(char *str)<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> {<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> return strtobool(str, &rodata_enabled);<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> }<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> __setup("rodata=", set_debug_rodata);<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> #endif<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>But now since CONFIG_STRICT_KERNEL_RWX=n, it is not defined here(CONFIG_STRICT_MODULE_RWX=n too). <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>and arch/arm64/mm/mmu.c code is still using `rodata_enabled`. Is this a bug of the code? Or am I missing something?<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>I can modify init/main.c and include/linux/init.h so that this rodata_enabled and related functions be defined regardless of these CONFIG values and make the errors go away, but I</span>’<span lang=EN-US>m curious if this a kind of kernel bug raising compiler error.<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>Any comment will be really appreciated.<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>Thank you!<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US>Chan Kim<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US> <o:p></o:p></span></p></div></div><p class=MsoNormal><span lang=EN-US>_______________________________________________<br>Kernelnewbies mailing list<br><a href="mailto:Kernelnewbies@kernelnewbies.org" target="_blank">Kernelnewbies@kernelnewbies.org</a><br><a href="https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies" target="_blank">https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies</a><o:p></o:p></span></p></blockquote></div></div></div></div></div></body></html>