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Device tree source description? #1

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JetForMe opened this issue Sep 20, 2015 · 2 comments
Open

Device tree source description? #1

JetForMe opened this issue Sep 20, 2015 · 2 comments

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@JetForMe
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Hi Derek. Your book, on page 83 (iBooks version) says “The full description for the BBB device tree source for Linux 3.x.x is available with the source code distribution of this book in the Chapter 3 directory."

But I only see a Hello World program in that directory.
@dineshmadhup
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Hi Derek,
I didn't see the test code for led one. I am learning device driver by running your sample code. Very good example.
Can you post the test code for led.
Thank you

@derekmolloy
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Thanks, please see:

http://derekmolloy.ie/kernel-gpio-programming-buttons-and-leds/

On Sun, Nov 8, 2015 at 11:44 PM, dineshmadhup notifications@github.com
wrote:

Hi Derek,
I didn't see the test code for led one. I am learning device driver by
running your sample code. Very good example.
Can you post the test code for led.
Thank you

—
Reply to this email directly or view it on GitHub
#1 (comment)
.

@ZoranStojsavljevic ZoranStojsavljevic mentioned this issue Apr 3, 2019
Open
LyleLee added a commit to LyleLee/exploringBB that referenced this issue Aug 7, 2019
@LyleLee
use copy_from_user() to fix: Internal error: Accessing user space mem…
06b24ad 
…ory outside uaccess.h routines: 96000004 [derekmolloy#1] SMP

when I using an ARM server to test on ebbchar, I found segment fault and had kern.log as follow. It is because the const char* buffer point to user space address. And the later version of kernel seem to not allowed it.

My enviroment:

ARM64 server
Linux ubuntu 4.15.0-29-generic derekmolloy#31-Ubuntu SMP Tue Jul 17 15:41:03 UTC 2018 aarch64 aarch64 aarch64 GNU/Linux

The log:

EBBChar: Initializing the EBBChar LKM
EBBChar: registered correctly with major number 240
EBBChar: device class registered correctly
EBBChar: device class created correctly
EBBChar: Device has been opened 1 time(s)
Internal error: Accessing user space memory outside uaccess.h routines: 96000004 [derekmolloy#1] SMP
Modules linked in: ebbchar(OE) binfmt_misc nls_iso8859_1 joydev input_leds ipmi_ssif ipmi_si ipmi_devintf shpchp ipmi_msghandler sch_fq_codel ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ppdev lp parport nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables x_tables autofs4 btrfs zstd_compress raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear hid_generic usbhid hid ses enclosure marvell hibmc_drm aes_ce_blk ttm aes_ce_cipher crc32_ce drm_kms_helper crct10dif_ce ghash_ce syscopyarea sha2_ce sysfillrect sysimgblt sha256_arm64 fb_sys_fops sha1_ce drm hisi_sas_v2_hw hisi_sas_main ehci_platform libsas scsi_transport_sas hns_dsaf hns_enet_drv hns_mdio hnae aes_neon_bs aes_neon_blk
 crypto_simd cryptd aes_arm64 [last unloaded: ebbchar]
CPU: 17 PID: 10803 Comm: test Tainted: G        W  OE    4.15.0-29-generic derekmolloy#31-Ubuntu
Hardware name: BC11SPCD, BIOS 1.58 10/24/2018
pstate: 20400005 (nzCv daif +PAN -UAO)
pc : string+0x28/0xa0
lr : vsnprintf+0x5d4/0x730
sp : ffff000026ccbc90
x29: ffff000026ccbc90 x28: ffff000002ad40b2
x27: ffff000002ad40b2 x26: ffff000002ad5508
x25: 00000000ffffffd8 x24: 0000000000000020
x23: 000000007fffffff x22: ffff0000094f8000
x21: ffff000008c54b00 x20: ffff000082ad5507
x19: ffff000002ad5508 x18: 0000ffff8c2fda70
x17: 0000ffff8c26cb80 x16: ffff0000082e3a80
x15: 0000000000000000 x14: 0000000000000001
x13: 0000000000000000 x12: 0000000000000020
x11: ffff000026ccbdd0 x10: ffff000026ccbdd0
x9 : 00000000ffffffd0 x8 : fffffffffffffffe
x7 : ffff000002ad5508 x6 : 0000ffffe94b6b18
x5 : 0000000000000000 x4 : 0000000000000043
x3 : ffff0a00ffffff04 x2 : ffff000082ad5507
x1 : ffff000082ad5507 x0 : ffffffffffffffff
Process test (pid: 10803, stack limit = 0x00000000e31169af)
Call trace:
 string+0x28/0xa0
 vsnprintf+0x5d4/0x730
 sprintf+0x68/0x88
 dev_write+0x3c/0xb0 [ebbchar]
 __vfs_write+0x48/0x80
 vfs_write+0xac/0x1b0
 SyS_write+0x6c/0xd8
 el0_svc_naked+0x30/0x34
Code: f13ffcdf d1000408 540002c9 b4000320 (394000c5)
---[ end trace 2b89326b0d5f8b9f ]---
EBBChar: Device successfully closed
@LyleLee LyleLee mentioned this issue Aug 7, 2019
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3 participants
@JetForMe @derekmolloy @dineshmadhup