linux/samples
Rong Tao 4a1e885c6d samples/bpf: sampleip: Replace PAGE_OFFSET with _text address
Macro PAGE_OFFSET(0xffff880000000000) in sampleip_user.c is inaccurate,
for example, in aarch64 architecture, this value depends on the
CONFIG_ARM64_VA_BITS compilation configuration, this value defaults to 48,
the corresponding PAGE_OFFSET is 0xffff800000000000, if we use the value
defined in sampleip_user.c, then all KSYMs obtained by sampleip are (user)

Symbol error due to PAGE_OFFSET error:

    $ sudo ./sampleip 1
    Sampling at 99 Hertz for 1 seconds. Ctrl-C also ends.
    ADDR                KSYM                             COUNT
    0xffff80000810ceb8  (user)                           1
    0xffffb28ec880      (user)                           1
    0xffff8000080c82b8  (user)                           1
    0xffffb23fed24      (user)                           1
    0xffffb28944fc      (user)                           1
    0xffff8000084628bc  (user)                           1
    0xffffb2a935c0      (user)                           1
    0xffff80000844677c  (user)                           1
    0xffff80000857a3a4  (user)                           1
    ...

A few examples of addresses in the CONFIG_ARM64_VA_BITS=48 environment in
the aarch64 environment:

    $ sudo head /proc/kallsyms
    ffff8000080a0000 T _text
    ffff8000080b0000 t gic_handle_irq
    ffff8000080b0000 T _stext
    ffff8000080b0000 T __irqentry_text_start
    ffff8000080b00b0 t gic_handle_irq
    ffff8000080b0230 t gic_handle_irq
    ffff8000080b03b4 T __irqentry_text_end
    ffff8000080b03b8 T __softirqentry_text_start
    ffff8000080b03c0 T __do_softirq
    ffff8000080b0718 T __entry_text_start

We just need to replace the PAGE_OFFSET with the address _text in
/proc/kallsyms to solve this problem:

    $ sudo ./sampleip 1
    Sampling at 99 Hertz for 1 seconds. Ctrl-C also ends.
    ADDR                KSYM                             COUNT
    0xffffb2892ab0      (user)                           1
    0xffffb2b1edfc      (user)                           1
    0xffff800008462834  __arm64_sys_ppoll                1
    0xffff8000084b87f4  eventfd_read                     1
    0xffffb28e6788      (user)                           1
    0xffff8000081e96d8  rcu_all_qs                       1
    0xffffb2ada878      (user)                           1
    ...

Signed-off-by: Rong Tao <rongtao@cestc.cn>
Link: https://lore.kernel.org/r/tencent_A0E82E0BEE925285F8156D540731DF805F05@qq.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-04-13 21:57:11 -07:00
..
acrn virt: acrn: Mark the uuid field as unused 2022-11-23 19:55:22 +01:00
auxdisplay .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
binderfs .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
bpf samples/bpf: sampleip: Replace PAGE_OFFSET with _text address 2023-04-13 21:57:11 -07:00
configfs treewide: remove editor modelines and cruft 2021-05-07 00:26:34 -07:00
connector .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
coresight coresight: syscfg: Example CoreSight configuration loadable module 2021-11-26 11:34:07 -07:00
fanotify Add gitignore file for samples/fanotify/ subdirectory 2021-11-07 11:19:24 -08:00
fprobe Fixes and minor clean ups for tracing: 2022-07-12 16:17:40 -07:00
ftrace samples: ftrace: Make some global variables static 2023-02-07 12:48:00 -05:00
hid samples/hid: Fix spelling mistake "wihout" -> "without" 2022-11-21 22:11:52 +01:00
hidraw .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
hw_breakpoint samples/hw_breakpoint: drop use of kallsyms_lookup_name() 2020-04-07 10:43:44 -07:00
kdb kdb: Rename members of struct kdbtab_t 2021-07-27 17:05:06 +01:00
kfifo samples/kfifo: Rename read_lock/write_lock 2021-10-13 14:36:48 +02:00
kmemleak mm,kmemleak-test.c: move kmemleak-test.c to samples dir 2020-10-13 18:38:27 -07:00
kobject samples/kobject: make kobj_type structure constant 2023-02-08 13:34:41 +01:00
kprobes samples/kprobes: Add LoongArch support 2023-02-25 22:12:17 +08:00
landlock samples/landlock: Document best-effort approach for LANDLOCK_ACCESS_FS_REFER 2022-11-07 20:49:50 +01:00
livepatch livepatch: Reorder to use before freeing a pointer 2022-03-23 13:51:11 +01:00
mei samples: mei: don't wait on read completion upon write. 2021-08-01 09:54:22 +02:00
nitro_enclaves nitro_enclaves: Add fixes for checkpatch blank line reports 2021-09-14 11:11:20 +02:00
pidfd .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
pktgen samples: pktgen: Use "grep -E" instead of "egrep" 2022-11-22 13:23:48 +01:00
qmi soc: qcom: qmi: use const for struct qmi_elem_info 2022-08-29 17:33:01 -05:00
rpmsg samples/rpmsg: Introduce a module parameter for message count 2019-08-26 22:10:39 -07:00
rust rust: macros: take string literals in module! 2022-12-04 01:59:15 +01:00
seccomp samples/seccomp: Adjust sample to also provide kill option 2022-02-10 19:09:12 -08:00
timers .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
trace_events tracing: Fix cpumask() example typo 2022-12-14 11:17:55 -05:00
trace_printk samples/trace_printk: Wait for IRQ work to finish 2019-12-21 16:08:22 -05:00
uhid kbuild: introduce hostprogs-always-y and userprogs-always-y 2020-08-10 01:32:59 +09:00
user_events tracing: Always use canonical ftrace path 2023-02-18 14:34:09 -05:00
v4l treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_168.RULE (part 2) 2022-06-10 14:51:36 +02:00
vfio-mdev VFIO updates for v6.3-rc1 2023-02-25 11:52:57 -08:00
vfs .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
watch_queue .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
watchdog .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
Kconfig VFIO updates for v6.3-rc1 2023-02-25 11:52:57 -08:00
Makefile ftrace: Add sample with custom ops 2023-01-25 10:31:23 -05:00