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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
commitf4cdf7ca9a1fdcca413157df19753f388a5a224e (patch)
tree60a31895b2446cd7fa27514e8c2843534a0de0da /lib/percpu_test.c
downloadlinux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz
linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab: - v4l2-core: added ISP statistics support and per-block validation - v4l2-core: Allow unknown HDR10 white point and luminance - New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor - New codec: Milos: VPU v2.0 codec support - isp driver: gained support for Dreamchip RPPX1 ISP framework - vsp1 driver: gained support for RZ/T2H and RZ/N2H - Novalake driver: gained CVS support for new NVL hardware - dvb-core: fix feed leak on failed DMX_ADD_PID - several driver fixes, cleanups and minor improvements * tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits) media: ipu-bridge: check all DMI entries when overriding sensor rotation media: v4l2-async: avoid deleting unlinked ASC entry on link error media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement media: intel/ipu6: fix async notifier cleanup leak on parse error media: staging/ipu7: fix async notifier UAF on probe error path media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem() media: rcar-isp: Fix VSPX reference leaks media: rcar-isp: Release ISPCORE resources media: i2c: imx415: Release runtime PM reference on VBLANK error media: i2c: imx415: Return test pattern write errors media: renesas: vsp1: Declare index variables in for loop statement media: renesas: vsp1: Make reset control optional to support platforms without a reset line media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs media: nxp: imx8-isi: Add additional 32-bit RGB format support media: nxp: imx8-isi: Add 16-bit raw Bayer format support media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks media: nxp: imx8-isi: Correct color map between V4L2 and ISI ...
Diffstat (limited to 'lib/percpu_test.c')
-rw-r--r--lib/percpu_test.c148
1 files changed, 148 insertions, 0 deletions
diff --git a/lib/percpu_test.c b/lib/percpu_test.c
new file mode 100644
index 000000000..ce7124b16
--- /dev/null
+++ b/lib/percpu_test.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/limits.h>
+#include <linux/module.h>
+
+/* validate @native and @pcp counter values match @expected */
+#define CHECK(native, pcp, expected) \
+ do { \
+ WARN((native) != (expected), \
+ "raw %ld (0x%lx) != expected %lld (0x%llx)", \
+ (native), (native), \
+ (long long)(expected), (long long)(expected)); \
+ WARN(__this_cpu_read(pcp) != (expected), \
+ "pcp %ld (0x%lx) != expected %lld (0x%llx)", \
+ __this_cpu_read(pcp), __this_cpu_read(pcp), \
+ (long long)(expected), (long long)(expected)); \
+ } while (0)
+
+static DEFINE_PER_CPU(long, long_counter);
+static DEFINE_PER_CPU(unsigned long, ulong_counter);
+
+static int __init percpu_test_init(void)
+{
+ /*
+ * volatile prevents compiler from optimizing it uses, otherwise the
+ * +ul_one/-ul_one below would replace with inc/dec instructions.
+ */
+ volatile unsigned int ui_one = 1;
+ unsigned long long ull = 0;
+ unsigned long ul = 0;
+ long l = 0;
+
+ pr_info("percpu test start\n");
+
+ preempt_disable();
+
+ l += -1;
+ __this_cpu_add(long_counter, -1);
+ CHECK(l, long_counter, -1);
+
+ l += 1;
+ __this_cpu_add(long_counter, 1);
+ CHECK(l, long_counter, 0);
+
+ ul = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul += 1UL;
+ __this_cpu_add(ulong_counter, 1UL);
+ CHECK(ul, ulong_counter, 1);
+
+ ul += -1UL;
+ __this_cpu_add(ulong_counter, -1UL);
+ CHECK(ul, ulong_counter, 0);
+
+ ul += -(unsigned long)1;
+ __this_cpu_add(ulong_counter, -(unsigned long)1);
+ CHECK(ul, ulong_counter, -1);
+
+ ul = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul -= 1;
+ __this_cpu_dec(ulong_counter);
+ CHECK(ul, ulong_counter, -1);
+ CHECK(ul, ulong_counter, ULONG_MAX);
+
+ l += -ui_one;
+ __this_cpu_add(long_counter, -ui_one);
+ CHECK(l, long_counter, 0xffffffff);
+
+ l += ui_one;
+ __this_cpu_add(long_counter, ui_one);
+ CHECK(l, long_counter, (long)0x100000000LL);
+
+
+ l = 0;
+ __this_cpu_write(long_counter, 0);
+
+ l -= ui_one;
+ __this_cpu_sub(long_counter, ui_one);
+ CHECK(l, long_counter, -1);
+
+ l = 0;
+ __this_cpu_write(long_counter, 0);
+
+ l += ui_one;
+ __this_cpu_add(long_counter, ui_one);
+ CHECK(l, long_counter, 1);
+
+ l += -ui_one;
+ __this_cpu_add(long_counter, -ui_one);
+ CHECK(l, long_counter, (long)0x100000000LL);
+
+ l = 0;
+ __this_cpu_write(long_counter, 0);
+
+ l -= ui_one;
+ this_cpu_sub(long_counter, ui_one);
+ CHECK(l, long_counter, -1);
+ CHECK(l, long_counter, ULONG_MAX);
+
+ ul = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul += ui_one;
+ __this_cpu_add(ulong_counter, ui_one);
+ CHECK(ul, ulong_counter, 1);
+
+ ul = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul -= ui_one;
+ __this_cpu_sub(ulong_counter, ui_one);
+ CHECK(ul, ulong_counter, -1);
+ CHECK(ul, ulong_counter, ULONG_MAX);
+
+ ul = ull = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul = ull += UINT_MAX;
+ __this_cpu_add(ulong_counter, ull);
+ CHECK(ul, ulong_counter, UINT_MAX);
+
+ ul = 3;
+ __this_cpu_write(ulong_counter, 3);
+
+ ul = this_cpu_sub_return(ulong_counter, ui_one);
+ CHECK(ul, ulong_counter, 2);
+
+ ul = __this_cpu_sub_return(ulong_counter, ui_one);
+ CHECK(ul, ulong_counter, 1);
+
+ preempt_enable();
+
+ pr_info("percpu test done\n");
+ return -EAGAIN; /* Fail will directly unload the module */
+}
+
+static void __exit percpu_test_exit(void)
+{
+}
+
+module_init(percpu_test_init)
+module_exit(percpu_test_exit)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Greg Thelen");
+MODULE_DESCRIPTION("percpu operations test");