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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
| commit | cf9610f9116d55c5a66ef9f1faecacabd93a9322 (patch) | |
| tree | 757a3d280760c654767631cab5ad8af2d86d1848 /samples/kprobes/kretprobe_example.c | |
| download | linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.tar.gz linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.zip | |
Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij:
"Core changes:
- Use the non-blocking mux_state_try_select() in the generic MUX pin
control back-end
- Free pin maps on pinctrl_generic_to_map() failure in the core
helpers
New hardware pin control:
- Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC
(this is for the low power audio, LPASS = Low Power Audio SubSystem
portions)
- Upboard support on top of the Intel pin controller
- Apple T6030 and T6031 support (just compatible strings)
- Samsung Exynos 8855 SoC
- Mediatek MT6858 SoC
- Rockchip RK3308B and RV1106 SoCs
- Airoha EN7523 and AN7563 SoCs
Improvements:
- Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable
- Qualcomm improvements on top of the Qualcomm PDC (power domain
controller) irqchip improvements from tglx:s tree
- Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups
- The NPCM8xx driver has been put into shape fixing many pin and
group definitions
- Some non-urgent Tegra 264 pin assignments are fixed up
- Some non-urgent fixups to Airoha AN7581 and AN7583 registers and
pin assignments, missing features etc"
* tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits)
dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema
pinctrl: meson: sync some modify from A4
pinctrl: meson: a4: Add input enable pin configuration
pinctrl: realtek: rtd1625: remove unused group name spdif_sel
pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13
dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema
Revert "Merge branch 'ib-rsk7204' into devel"
pinctrl: rockchip: Add RV1106 pinctrl support
dt-bindings: pinctrl: rockchip: Add RV1106 compatible
pinctrl: rockchip: Decode drive strength in the get function
pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable
pinctrl: airoha: add support of an7563 SoC
dt-bindings: pinctrl: airoha: add support of an7563 pin controller
pinctrl: airoha: try to find chip scu node by phandle first
pinctrl: airoha: add support of en7523 SoC
dt-bindings: pinctrl: airoha: add support of en7523 pin controller
pinctrl: airoha: an7583: add support for olt pinmux
pinctrl: airoha: an7583: add support for pon_alt pinmux
pinctrl: airoha: an7583: add support for npu_uart pinmux
dt-bindings: pinctrl: airoha: an7583: add missed features
...
Diffstat (limited to 'samples/kprobes/kretprobe_example.c')
| -rw-r--r-- | samples/kprobes/kretprobe_example.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/samples/kprobes/kretprobe_example.c b/samples/kprobes/kretprobe_example.c new file mode 100644 index 000000000..65d6dcafd --- /dev/null +++ b/samples/kprobes/kretprobe_example.c @@ -0,0 +1,108 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * kretprobe_example.c + * + * Here's a sample kernel module showing the use of return probes to + * report the return value and total time taken for probed function + * to run. + * + * usage: insmod kretprobe_example.ko func=<func_name> + * + * If no func_name is specified, kernel_clone is instrumented + * + * For more information on theory of operation of kretprobes, see + * Documentation/trace/kprobes.rst + * + * Build and insert the kernel module as done in the kprobe example. + * You will see the trace data in /var/log/messages and on the console + * whenever the probed function returns. (Some messages may be suppressed + * if syslogd is configured to eliminate duplicate messages.) + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/kprobes.h> +#include <linux/ktime.h> +#include <linux/sched.h> + +static char func_name[KSYM_NAME_LEN] = "kernel_clone"; +module_param_string(func, func_name, KSYM_NAME_LEN, 0644); +MODULE_PARM_DESC(func, "Function to kretprobe; this module will report the" + " function's execution time"); + +/* per-instance private data */ +struct my_data { + ktime_t entry_stamp; +}; + +/* Here we use the entry_handler to timestamp function entry */ +static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs) +{ + struct my_data *data; + + if (!current->mm) + return 1; /* Skip kernel threads */ + + data = (struct my_data *)ri->data; + data->entry_stamp = ktime_get(); + return 0; +} +NOKPROBE_SYMBOL(entry_handler); + +/* + * Return-probe handler: Log the return value and duration. Duration may turn + * out to be zero consistently, depending upon the granularity of time + * accounting on the platform. + */ +static int ret_handler(struct kretprobe_instance *ri, struct pt_regs *regs) +{ + unsigned long retval = regs_return_value(regs); + struct my_data *data = (struct my_data *)ri->data; + s64 delta; + ktime_t now; + + now = ktime_get(); + delta = ktime_to_ns(ktime_sub(now, data->entry_stamp)); + pr_info("%s returned %lu and took %lld ns to execute\n", + func_name, retval, (long long)delta); + return 0; +} +NOKPROBE_SYMBOL(ret_handler); + +static struct kretprobe my_kretprobe = { + .handler = ret_handler, + .entry_handler = entry_handler, + .data_size = sizeof(struct my_data), + /* Probe up to 20 instances concurrently. */ + .maxactive = 20, +}; + +static int __init kretprobe_init(void) +{ + int ret; + + my_kretprobe.kp.symbol_name = func_name; + ret = register_kretprobe(&my_kretprobe); + if (ret < 0) { + pr_err("register_kretprobe failed, returned %d\n", ret); + return ret; + } + pr_info("Planted return probe at %s: %p\n", + my_kretprobe.kp.symbol_name, my_kretprobe.kp.addr); + return 0; +} + +static void __exit kretprobe_exit(void) +{ + unregister_kretprobe(&my_kretprobe); + pr_info("kretprobe at %p unregistered\n", my_kretprobe.kp.addr); + + /* nmissed > 0 suggests that maxactive was set too low. */ + pr_info("Missed probing %d instances of %s\n", + my_kretprobe.nmissed, my_kretprobe.kp.symbol_name); +} + +module_init(kretprobe_init) +module_exit(kretprobe_exit) +MODULE_DESCRIPTION("sample kernel module showing the use of return probes"); +MODULE_LICENSE("GPL"); |
