| Message ID | 20240417050711.41930-1-takakura@valinux.co.jp (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | RISC-V: Enable IPI CPU Backtrace | expand |
takakura@valinux.co.jp writes: > From: Ryo Takakura <takakura@valinux.co.jp> > > Add CPU backtrace feature using IPI on riscv. > Currently, riscv doesn't yet support the feature while other > architectures do. As IPI multiplexing allows to handle > multiple IPIs, I think this feature can also be enabled > on riscv by adding IPI. > > This patch defines arch_trigger_all_cpu_backtrace() which triggers > the IPI for CPU backtrace. > It will be triggered in the events of oops/panic when options > (oops_all_cpu_backtrace/panic_print) are set accordingly. > > Below is the case of oops with the oops_all_cpu_backtrace > enabled. > > $ sysctl kernel.oops_all_cpu_backtrace=1 > > triggering oops shows: > [ 435.716754] NMI backtrace for cpu 3 > [ 435.716893] CPU: 3 PID: 621 Comm: in:imklog Tainted: G OE 6.9.0-rc4 #1 > [ 435.717086] Hardware name: riscv-virtio,qemu (DT) > [ 435.717182] epc : fallback_scalar_usercopy+0x8/0xdc > [ 435.717300] ra : _copy_to_user+0x32/0x58 > [ 435.717391] epc : ffffffff80c33d88 ra : ffffffff80598e3c sp : ff20000000e83b50 > [ 435.717544] gp : ffffffff82066bf0 tp : ff60000091fd7000 t0 : 3363303866660000 > [ 435.717711] t1 : 000000000000005b t2 : 3363303866666666 s0 : ff20000000e83b60 > [ 435.717874] s1 : 00000000000001af a0 : 00007ff74d3df74f a1 : ff60000082cdc800 > [ 435.718040] a2 : 000000000000003c a3 : 0000000000000000 a4 : 0000000000000000 > [ 435.718196] a5 : 00ffffffffffffc4 a6 : 0000000000000000 a7 : 0000000000000010 > [ 435.718333] s2 : ff60000082cdc800 s3 : ffffffff82066910 s4 : 0000000000001df1 > [ 435.718475] s5 : ffffffff8206a5b8 s6 : 00007ff74d3df74f s7 : ffffffff8206a5b0 > [ 435.718616] s8 : ff60000082cdc800 s9 : ffffffff81e26208 s10: 000000000000003c > [ 435.718760] s11: ffffffff8206a5ad t3 : ff60000082cdc812 t4 : ff60000082cdc812 > [ 435.718909] t5 : ff60000082cdc818 t6 : 0000000000040000 > [ 435.719019] status: 0000000000040120 badaddr: 0000000000000000 cause: 8000000000000001 > [ 435.719191] [<ffffffff80c33d88>] fallback_scalar_usercopy+0x8/0xdc > [ 435.719330] [<ffffffff80094eee>] syslog_print+0x1f4/0x2b2 > [ 435.719446] [<ffffffff80095e10>] do_syslog.part.0+0xb0/0x326 > [ 435.719594] [<ffffffff8009692e>] do_syslog+0x66/0x88 > [ 435.719816] [<ffffffff803a1a80>] kmsg_read+0x44/0x5c > [ 435.720017] [<ffffffff8038ea92>] proc_reg_read+0x7a/0xa8 > [ 435.720251] [<ffffffff802fae20>] vfs_read+0x94/0x264 > [ 435.720478] [<ffffffff802fb906>] ksys_read+0x64/0xe4 > [ 435.720709] [<ffffffff802fb9a6>] __riscv_sys_read+0x20/0x2c > [ 435.720880] [<ffffffff80c43ea2>] do_trap_ecall_u+0x60/0x1d4 > [ 435.721236] [<ffffffff80c4f74c>] ret_from_exception+0x0/0x64 > > Signed-off-by: Ryo Takakura <takakura@valinux.co.jp> Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
diff --git a/arch/riscv/include/asm/irq.h b/arch/riscv/include/asm/irq.h index 8e10a94430a2..ed8f76879270 100644 --- a/arch/riscv/include/asm/irq.h +++ b/arch/riscv/include/asm/irq.h @@ -12,6 +12,9 @@ #include <asm-generic/irq.h> +void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu); +#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace + void riscv_set_intc_hwnode_fn(struct fwnode_handle *(*fn)(void)); struct fwnode_handle *riscv_get_intc_hwnode(void); diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c index 45dd4035416e..6e297b9eb641 100644 --- a/arch/riscv/kernel/smp.c +++ b/arch/riscv/kernel/smp.c @@ -21,6 +21,7 @@ #include <linux/delay.h> #include <linux/irq.h> #include <linux/irq_work.h> +#include <linux/nmi.h> #include <asm/tlbflush.h> #include <asm/cacheflush.h> @@ -33,6 +34,7 @@ enum ipi_message_type { IPI_CPU_CRASH_STOP, IPI_IRQ_WORK, IPI_TIMER, + IPI_CPU_BACKTRACE, IPI_MAX }; @@ -136,6 +138,9 @@ static irqreturn_t handle_IPI(int irq, void *data) tick_receive_broadcast(); break; #endif + case IPI_CPU_BACKTRACE: + nmi_cpu_backtrace(get_irq_regs()); + break; default: pr_warn("CPU%d: unhandled IPI%d\n", smp_processor_id(), ipi); break; @@ -212,6 +217,7 @@ static const char * const ipi_names[] = { [IPI_CPU_CRASH_STOP] = "CPU stop (for crash dump) interrupts", [IPI_IRQ_WORK] = "IRQ work interrupts", [IPI_TIMER] = "Timer broadcast interrupts", + [IPI_CPU_BACKTRACE] = "CPU backtrace interrupts", }; void show_ipi_stats(struct seq_file *p, int prec) @@ -332,3 +338,13 @@ void arch_smp_send_reschedule(int cpu) send_ipi_single(cpu, IPI_RESCHEDULE); } EXPORT_SYMBOL_GPL(arch_smp_send_reschedule); + +static void riscv_backtrace_ipi(cpumask_t *mask) +{ + send_ipi_mask(mask, IPI_CPU_BACKTRACE); +} + +void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu) +{ + nmi_trigger_cpumask_backtrace(mask, exclude_cpu, riscv_backtrace_ipi); +}