Markus Stockhausen 21d3722c40 realtek: don't disable MIPS counter on secondary VPEs ... After observation that timer interrupt 7 always fires on secondary VPEs the counter was disabled in the startup code. This is a bad idea when building the kernel with jitterentropy. To generate entropy it makes use of function random_get_entropy(). On MIPS architecture this simply reads the counter register on the current core. With a disabled counter it always returns the same value and the entropy initialization stalls the core if it runs on a secondary VPE. See backtrace [ 21.736246] rcu: INFO: rcu_sched self-detected stall on CPU [ 21.736246] rcu: INFO: rcu_sched self-detected stall on CPU [ 21.748594] rcu: 1-....: (2100 ticks this GP) idle=064c/1/0x40000002 softirq=7/7 fqs=1050 [ 21.748594] rcu: 1-....: (2100 ticks this GP) idle=064c/1/0x40000002 softirq=7/7 fqs=1050 [ 21.766871] rcu: (t=2102 jiffies g=-1187 q=25 ncpus=2) [ 21.766871] rcu: (t=2102 jiffies g=-1187 q=25 ncpus=2) [ 21.778429] CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.39 #482 [ 21.778429] CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.39 #482 [ 21.778461] Hardware name: Zyxel GS1900-48 [ 21.778461] Hardware name: Zyxel GS1900-48 ... [ 21.779757] [<8029b968>] jent_measure_jitter+0xc8/0x10c [ 21.779757] [<8029b968>] jent_measure_jitter+0xc8/0x10c [ 21.779779] [<8029b9e8>] jent_gen_entropy+0x3c/0xb0 [ 21.779779] [<8029b9e8>] jent_gen_entropy+0x3c/0xb0 [ 21.779800] [<8029bcc0>] jent_entropy_collector_alloc+0x104/0x118 [ 21.779800] [<8029bcc0>] jent_entropy_collector_alloc+0x104/0x118 [ 21.779822] [<8029bd6c>] jent_entropy_init+0x4c/0x2ec [ 21.779822] [<8029bd6c>] jent_entropy_init+0x4c/0x2ec [ 21.779844] [<8086f184>] jent_mod_init+0x58/0xac [ 21.779844] [<8086f184>] jent_mod_init+0x58/0xac [ 21.779865] [<80100200>] do_one_initcall+0x70/0x250 [ 21.779865] [<80100200>] do_one_initcall+0x70/0x250 [ 21.779883] [<8085c018>] kernel_init_freeable+0x1f0/0x280 [ 21.779883] [<8085c018>] kernel_init_freeable+0x1f0/0x280 [ 21.779905] [<8067cba4>] kernel_init+0x20/0xb0 [ 21.779905] [<8067cba4>] kernel_init+0x20/0xb0 [ 21.779926] [<80101158>] ret_from_kernel_thread+0x14/0x1c [ 21.779926] [<80101158>] ret_from_kernel_thread+0x14/0x1c This bit of entropy is helpful on these low end devices. Reenable the counter and simply disable the interrupt. Fixes: b7aab19585 ("realtek: SMP handling of R4K timer interrupts") Reported-by: Sebastian Gottschall <s.gottschall@dd-wrt.com> Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Link: https://github.com/openwrt/openwrt/pull/19499 Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>		2025-07-26 15:51:23 +02:00
..
imagebuilder	imagebuilder: implement STRIP_ABI option for manifest target	2025-07-03 12:45:59 +02:00
linux	realtek: don't disable MIPS counter on secondary VPEs	2025-07-26 15:51:23 +02:00
llvm-bpf	build: use zstd for IB, toolchain, SDK and LLVM compression	2024-04-13 08:05:04 +02:00
sdk	build: fix building llvm tarball	2025-02-10 22:10:50 +01:00
toolchain	build: use zstd for IB, toolchain, SDK and LLVM compression	2024-04-13 08:05:04 +02:00
Config.in	targets: add USES_PM auto-feature	2025-07-20 12:16:13 +01:00
Makefile	build: add $(STAGING_DIR) and $(BIN_DIR) preparation to target and package subdir compile dependencies	2024-03-03 23:13:59 +01:00