GSoC Warm Up Kernel Task #234
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hartkopp/can-isotp@ced84ca Signed-off-by: Robert Nelson <[email protected]>
Signed-off-by: Robert Nelson <[email protected]>
…all-multi-tce for DDW" This reverts commit c4faf62.
This reverts commit 2875109.
patch-5.4.19-rt11.patch.xz Signed-off-by: Robert Nelson <[email protected]>
https://git.zx2c4.com/WireGuard/commit/edad0d6e99e5133b1e8e865d727a25fff6399cb4 Signed-off-by: Robert Nelson <[email protected]>
Reference: v5.6-rc5 Signed-off-by: Robert Nelson <[email protected]>
Reference: v5.5.8 Signed-off-by: Robert Nelson <[email protected]>
Signed-off-by: Robert Nelson <[email protected]>
Signed-off-by: Robert Nelson <[email protected]>
5.4.20-ti-rt-r6 bb.org_defconfig 5.4 TI Delta: RobertCNelson/ti-linux-kernel@68481af...738552d BBDTBS: beagleboard/BeagleBoard-DeviceTrees@cffe558 CAN-ISOTP: hartkopp/can-isotp@ced84ca RT: patch-5.4.19-rt11.patch.xz TI_AMX3_CM3: http://git.ti.com/gitweb/?p=processor-firmware/ti-amx3-cm3-pm-firmware.git;a=commit;h=6a849767df85ce9399494f53fb5c753665396653 WIREGUARD: https://git.zx2c4.com/WireGuard/commit/edad0d6e99e5133b1e8e865d727a25fff6399cb4 Signed-off-by: Robert Nelson <[email protected]>
dlech
reviewed
May 31, 2020
| config GSOC_DUMMY_CHAR_DEVICE | ||
| tristate "GSoC Warmup Driver" | ||
| help | ||
| This builds the GSoC Dummy Char Driver, which is required for the warmup task. |
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Help lines should be indented with 1 tab + 2 spaces
drivers/char/Kconfig
Outdated
| only mixes the entropy pool. |
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Watch out for unintentional changes like editors that automatically add a newline at the end of the file.
| * Dummy character driver by | ||
| * John Madieu <[email protected]> | ||
| * | ||
| * This program is free software; you can redistribute it and/or |
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Using SPDX license identifier is used nowdays instead of license paragraphs.
https://www.kernel.org/doc/html/latest/process/license-rules.html
| #include <linux/cdev.h> | ||
| #include <linux/uaccess.h> | ||
|
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| static int gsoc_char_dev_open(struct inode * inode, struct file * file); |
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It probably depends on the area of the kernel but most code I have seen tries to avoid forward declarations if possible by rearranging the code.
| // register a range of char dev numbers 0 to 1 in this case | ||
| err = alloc_chrdev_region(&gsoc_dev, 0, 1, "gsoc_dummy_char_dev"); | ||
| if (err < 0) { | ||
| pr_err("Can't get major number\n"); |
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It is a good idea to include the module name in the error message so users know which module the error came from.
| static ssize_t gsoc_char_dev_read(struct file *file, char __user * buf, size_t count, | ||
| loff_t * offset) | ||
| { | ||
| pr_info("Read function of GSoC dummy driver called.\n"); |
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It could be fun to actually put something in the buffer so that you can actually read something from the character device.
|
Hey David, thank you very much for these helpful tricks. Best, |
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commit 6a97f41 upstream. die() can be called in exception handler, and therefore cannot sleep. However, die() takes spinlock_t which can sleep with PREEMPT_RT enabled. That causes the following warning: BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 285, name: mutex preempt_count: 110001, expected: 0 RCU nest depth: 0, expected: 0 CPU: 0 UID: 0 PID: 285 Comm: mutex Not tainted 6.12.0-rc7-00022-ge19049cf7d56-dirty #234 Hardware name: riscv-virtio,qemu (DT) Call Trace: dump_backtrace+0x1c/0x24 show_stack+0x2c/0x38 dump_stack_lvl+0x5a/0x72 dump_stack+0x14/0x1c __might_resched+0x130/0x13a rt_spin_lock+0x2a/0x5c die+0x24/0x112 do_trap_insn_illegal+0xa0/0xea _new_vmalloc_restore_context_a0+0xcc/0xd8 Oops - illegal instruction [#1] Switch to use raw_spinlock_t, which does not sleep even with PREEMPT_RT enabled. Fixes: 76d2a04 ("RISC-V: Init and Halt Code") Signed-off-by: Nam Cao <[email protected]> Cc: [email protected] Reviewed-by: Sebastian Andrzej Siewior <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Palmer Dabbelt <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
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This is the pull request for Media Ip Streaming project, which implements a dummy kernel driver for the GSoC 2020 warm up task.