March 2019 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

CMA allocation failure
by Pankaj Suryawanshi March 7, 2019

March 7, 2019

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undefined reference to `ioctl_tty'
by Jeffrey Walton March 7, 2019

March 7, 2019

Hi Everyone, I'm working from http://man7.org/linux/man-pages/man4/tty_ioctl.4.html . According to the man page: TIOCEXCL void Put the terminal into exclusive mode. No further open(2) operations on the terminal are permitted. (They fail with EBUSY, except for a process with the CAP_SYS_ADMIN capability.) The page goes on to say in the colophon it is part of the 4.16 kernel. I am running on the 4.20 kernel: $ uname -a Linux silo 4.20.13-200.fc29.x86_64 #1 ... GNU/Linux However: gcc -D_GNU_SOURCE -g2 -std=gnu99 test.c -o tttt -lrt test.c: In function ‘main’: test.c:11:7: warning: implicit declaration of function ‘ioctl_tty’; did you mean ‘ioctl’? [-Wimplicit-function-declaration] if (ioctl_tty(1 /*STDOUT_FILENO*/, TIOCEXCL, NULL) == -1) { ^~~~~~~~~ ioctl /usr/bin/ld: /tmp/ccCNNyG3.o: in function `main': /home/test/test.c:11: undefined reference to `ioctl_tty' collect2: error: ld returned 1 exit status Search is producing a lot of non-relevant hits. Any ideas why I can't find ioctl_tty during link when using a 4.20 kernel? Thanks in advance. ---------- $ cat test.c #include <stdio.h> #include <string.h> #include <errno.h> #include <termios.h> #include <fcntl.h> #include <sys/ioctl.h> int main(int argc, char* argv[]) { if (ioctl_tty(1 /*STDOUT_FILENO*/, TIOCEXCL, NULL) == -1) { fprintf(stderr, "%s\n", strerror(errno)); return 1; } return 0; }

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Re: [RFC] LKML Archive in Maildir Format
by Bjorn Helgaas March 7, 2019

March 7, 2019

OK, so I understand how to clone archives from lore.kernel.org and how to convert a git archive to a maildir (thanks, Konstantin!) What I *don't* understand is how to effectively read this locally. Ideally I'd like to run mutt, possibly with notmuch for indexing. But a maildir with 3M files seems impractical. I did actually try it (without notmuch), but it takes mutt about 5 minutes to start up. And the maildir is about 23G, compared with 7.5G for the git archive. Any pointers? I guess there's no mutt backend that can read a public-inbox archive directly?

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HIPAA Updates for the Exceptions for Law Enforcement Purposes
by Aqscence.com March 6, 2019

March 6, 2019

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Fwd: undefined reference to `ioctl_tty'
by Alexander Kapshuk March 6, 2019

March 6, 2019

---------- Forwarded message --------- From: Alexander Kapshuk <alexander.kapshuk(a)gmail.com> Date: Wed, Mar 6, 2019 at 9:30 AM Subject: Re: undefined reference to `ioctl_tty' To: <noloader(a)gmail.com> On Wed, Mar 6, 2019 at 9:00 AM Jeffrey Walton <noloader(a)gmail.com> wrote: > > Hi Everyone, > > I'm working from http://man7.org/linux/man-pages/man4/tty_ioctl.4.html > . According to the man page: > > TIOCEXCL void > Put the terminal into exclusive mode. No further open(2) > operations on the terminal are permitted. (They fail with > EBUSY, except for a process with the CAP_SYS_ADMIN > capability.) > > The page goes on to say in the colophon it is part of the 4.16 kernel. > I am running on the 4.20 kernel: > > $ uname -a > Linux silo 4.20.13-200.fc29.x86_64 #1 ... GNU/Linux > > However: > > gcc -D_GNU_SOURCE -g2 -std=gnu99 test.c -o tttt -lrt > test.c: In function ‘main’: > test.c:11:7: warning: implicit declaration of function ‘ioctl_tty’; > did you mean ‘ioctl’? [-Wimplicit-function-declaration] > if (ioctl_tty(1 /*STDOUT_FILENO*/, TIOCEXCL, NULL) == -1) { > ^~~~~~~~~ > ioctl > /usr/bin/ld: /tmp/ccCNNyG3.o: in function `main': > /home/test/test.c:11: undefined reference to `ioctl_tty' > collect2: error: ld returned 1 exit status > > Search is producing a lot of non-relevant hits. > > Any ideas why I can't find ioctl_tty during link when using a 4.20 kernel? > > Thanks in advance. > > ---------- > > $ cat test.c > #include <stdio.h> > #include <string.h> > #include <errno.h> > #include <termios.h> > #include <fcntl.h> > #include <sys/ioctl.h> > > int main(int argc, char* argv[]) > { > if (ioctl_tty(1 /*STDOUT_FILENO*/, TIOCEXCL, NULL) == -1) { > fprintf(stderr, "%s\n", strerror(errno)); > return 1; > } > return 0; > } > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies(a)kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies While the man page does refer to this function as ioctl_tty, the actual signature, as shown in the man page, is: int ioctl(int fd, int cmd, ...); Not ioctl_tty. The example section of the man pages gives this usage example: fd = open("/dev/ttyS0", O_RDONLY); ioctl(fd, TIOCMGET, &serial); Hope this helps.

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Unimplemented system call
by Umair Khan March 6, 2019

March 6, 2019

Hello, I was just roaming around the linux source code when I stumbled upon this line - https://github.com/torvalds/linux/blob/master/include/linux/syscalls.h#L1200 May I know what is the use of this system call? Thank you, Umair

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make modules_install install is failing
by Bharath Vedartham March 5, 2019

March 5, 2019

Hi all, I am unable to execute make modules_install install. I get the following error: ln: target 'linux-00096-gd1aa1a8/source' is not a directory Makefile:1281: recipe for target '_modinst_' failed make[1]: *** [_modinst_] Error 1 Makefile:296: recipe for target '__build_one_by_one' failed make: *** [__build_one_by_one] Error 2 I made a change to a driver and did not commit the changes. I then built the kernel and two weird looking files appeared in my root directory: linux-00095-g94832d9-dirty linux-00096-gd1aa1a8 Since then , I have commited my changes and made the kernel again. The dirs still exist. I have tried manually removing them but they reappear whenever I make the kernel again. I am running the version: 5.0.0-rc2+ I am not able to make the kernel modules because of this. Is this a common problem? Any answers? Thank you

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Re: tty: uart: custom speed
by Subhashini Rao Beerisetty March 4, 2019

March 4, 2019

On Mon, Mar 4, 2019 at 6:53 PM Greg KH <gregkh(a)linuxfoundation.org> wrote: > > On Mon, Mar 04, 2019 at 05:46:54PM +0530, Subhashini Rao Beerisetty wrote: > > Hi All, > > > > > > I’ve an UART ports on Xilinx FPGA board and it gets connected to PC > > via PCIe bus. I could not find any kernel serial driver which supports > > our hardware so I plan to develop a new driver. I see two approaches > > to develop an UART driver i.e. either by using tty_register_driver() > > or an uart_register_driver(). > > > > > > Regarding my UART module, it has a counter of 16 bits and runs on a > > 32Mhz clock. It supports all the standard & non-standard baud’s up to > > 4Mbps. > > What type of UART is it? Odds are it is based on an existing design, no > one creates a brand-new UART anymore. Hopefully. If not, what a > waste... For UART type, I see the permitted types are none, 8250, 16450, 16550, 16550A, 16650, 16650V2, 16654, 16750, 16850, 16950, and 16954 etc. Looking into the data sheet I haven’t found any register or parameter defining any of those UART types. Is ‘UART type’ is determined from a register settings point of view or a pinout point of view? > > > If I used struct tty_operations, I noticed that baud rate changing is > > done via “.set_termios” API, but this method only supports standard > > baud rates. I’d like to know why this API does not support > > non-standard baud rates? > > Why do you think it does not? >From data sheet point of view I'm clear on how to set the non-standard baud rate, even I exposed a custom Ioctl for this. But here I’m trying to understand how it is achieved by using available UART kernel framework. For non-standard baud rate requests, observed that tty->termios.c_ispeed & tty->termios.c_ospeed set to 38400. I did not understood why it changes? > > Anyway, use the uart interface as odds are your uart is already > supported. Get the data sheet and start reading :) > > good luck, > > greg k-h

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tty: uart: custom speed
by Subhashini Rao Beerisetty March 4, 2019

March 4, 2019

Hi All, I’ve an UART ports on Xilinx FPGA board and it gets connected to PC via PCIe bus. I could not find any kernel serial driver which supports our hardware so I plan to develop a new driver. I see two approaches to develop an UART driver i.e. either by using tty_register_driver() or an uart_register_driver(). Regarding my UART module, it has a counter of 16 bits and runs on a 32Mhz clock. It supports all the standard & non-standard baud’s up to 4Mbps. If I used struct tty_operations, I noticed that baud rate changing is done via “.set_termios” API, but this method only supports standard baud rates. I’d like to know why this API does not support non-standard baud rates? Okay, what methods a good driver should implement to support non-standard baud rates? Thanks

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