| Message ID | 20240727063438.886155-1-ruanjinjie@huawei.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 983f12149942a58c66e9db7638a10667aae0d958 |
| Headers | show |
| Series | [v2] RISC-V: Implement kgdb_roundup_cpus() to enable future NMI Roundup | expand |
| Context | Check | Description |
|---|---|---|
| conchuod/vmtest-fixes-PR | fail | merge-conflict |
Ping. On 2024/7/27 14:34, Jinjie Ruan wrote: > Until now, the generic weak kgdb_roundup_cpus() has been used for kgdb on > RISCV. A custom one allows to debug CPUs that are stuck with interrupts > disabled with NMI support in the future. And using an IPI is better than > the generic one since it avoids the potential situation described in the > generic kgdb_call_nmi_hook(). As Andrew pointed out, once there is NMI > support, we can easily extend this and the CPU backtrace support > to use NMIs. > > After this patch, the kgdb test show that: > # echo g > /proc/sysrq-trigger > [2]kdb> btc > btc: cpu status: Currently on cpu 2 > Available cpus: 0-1(-), 2, 3(-) > Stack traceback for pid 0 > 0xffffffff81c13a40 0 0 1 0 - 0xffffffff81c14510 swapper/0 > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.10.0-g3120273055b6-dirty #51 > Hardware name: riscv-virtio,qemu (DT) > Call Trace: > [<ffffffff80006c48>] dump_backtrace+0x28/0x30 > [<ffffffff80fceb38>] show_stack+0x38/0x44 > [<ffffffff80fe6a04>] dump_stack_lvl+0x58/0x7a > [<ffffffff80fe6a3e>] dump_stack+0x18/0x20 > [<ffffffff801143fa>] kgdb_cpu_enter+0x682/0x6b2 > [<ffffffff801144ca>] kgdb_nmicallback+0xa0/0xac > [<ffffffff8000a392>] handle_IPI+0x9c/0x120 > [<ffffffff800a2baa>] handle_percpu_devid_irq+0xa4/0x1e4 > [<ffffffff8009cca8>] generic_handle_domain_irq+0x28/0x36 > [<ffffffff800a9e5c>] ipi_mux_process+0xe8/0x110 > [<ffffffff806e1e30>] imsic_handle_irq+0xf8/0x13a > [<ffffffff8009cca8>] generic_handle_domain_irq+0x28/0x36 > [<ffffffff806dff12>] riscv_intc_aia_irq+0x2e/0x40 > [<ffffffff80fe6ab0>] handle_riscv_irq+0x54/0x86 > [<ffffffff80ff2e4a>] call_on_irq_stack+0x32/0x40 > > Rebased on Ryo Takakura's "RISC-V: Enable IPI CPU Backtrace" patch. > > Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> > Reviewed-by: Andrew Jones <ajones@ventanamicro.com> > --- > v2: > - Update the commit title and message. > - Add Reviewed-by. > --- > arch/riscv/kernel/smp.c | 27 +++++++++++++++++++++++++-- > 1 file changed, 25 insertions(+), 2 deletions(-) > > diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c > index 9b047899791c..c180a647a30e 100644 > --- a/arch/riscv/kernel/smp.c > +++ b/arch/riscv/kernel/smp.c > @@ -13,6 +13,7 @@ > #include <linux/interrupt.h> > #include <linux/module.h> > #include <linux/kexec.h> > +#include <linux/kgdb.h> > #include <linux/percpu.h> > #include <linux/profile.h> > #include <linux/smp.h> > @@ -35,6 +36,7 @@ enum ipi_message_type { > IPI_IRQ_WORK, > IPI_TIMER, > IPI_CPU_BACKTRACE, > + IPI_KGDB_ROUNDUP, > IPI_MAX > }; > > @@ -115,6 +117,7 @@ void arch_irq_work_raise(void) > > static irqreturn_t handle_IPI(int irq, void *data) > { > + unsigned int cpu = smp_processor_id(); > int ipi = irq - ipi_virq_base; > > switch (ipi) { > @@ -128,7 +131,7 @@ static irqreturn_t handle_IPI(int irq, void *data) > ipi_stop(); > break; > case IPI_CPU_CRASH_STOP: > - ipi_cpu_crash_stop(smp_processor_id(), get_irq_regs()); > + ipi_cpu_crash_stop(cpu, get_irq_regs()); > break; > case IPI_IRQ_WORK: > irq_work_run(); > @@ -141,8 +144,11 @@ static irqreturn_t handle_IPI(int irq, void *data) > case IPI_CPU_BACKTRACE: > nmi_cpu_backtrace(get_irq_regs()); > break; > + case IPI_KGDB_ROUNDUP: > + kgdb_nmicallback(cpu, get_irq_regs()); > + break; > default: > - pr_warn("CPU%d: unhandled IPI%d\n", smp_processor_id(), ipi); > + pr_warn("CPU%d: unhandled IPI%d\n", cpu, ipi); > break; > } > > @@ -209,6 +215,7 @@ static const char * const ipi_names[] = { > [IPI_IRQ_WORK] = "IRQ work interrupts", > [IPI_TIMER] = "Timer broadcast interrupts", > [IPI_CPU_BACKTRACE] = "CPU backtrace interrupts", > + [IPI_KGDB_ROUNDUP] = "KGDB roundup interrupts", > }; > > void show_ipi_stats(struct seq_file *p, int prec) > @@ -339,3 +346,19 @@ void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu) > { > nmi_trigger_cpumask_backtrace(mask, exclude_cpu, riscv_backtrace_ipi); > } > + > +#ifdef CONFIG_KGDB > +void kgdb_roundup_cpus(void) > +{ > + int this_cpu = raw_smp_processor_id(); > + int cpu; > + > + for_each_online_cpu(cpu) { > + /* No need to roundup ourselves */ > + if (cpu == this_cpu) > + continue; > + > + send_ipi_single(cpu, IPI_KGDB_ROUNDUP); > + } > +} > +#endif
Hello: This patch was applied to riscv/linux.git (for-next) by Palmer Dabbelt <palmer@rivosinc.com>: On Sat, 27 Jul 2024 14:34:38 +0800 you wrote: > Until now, the generic weak kgdb_roundup_cpus() has been used for kgdb on > RISCV. A custom one allows to debug CPUs that are stuck with interrupts > disabled with NMI support in the future. And using an IPI is better than > the generic one since it avoids the potential situation described in the > generic kgdb_call_nmi_hook(). As Andrew pointed out, once there is NMI > support, we can easily extend this and the CPU backtrace support > to use NMIs. > > [...] Here is the summary with links: - [v2] RISC-V: Implement kgdb_roundup_cpus() to enable future NMI Roundup https://git.kernel.org/riscv/c/983f12149942 You are awesome, thank you!
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c index 9b047899791c..c180a647a30e 100644 --- a/arch/riscv/kernel/smp.c +++ b/arch/riscv/kernel/smp.c @@ -13,6 +13,7 @@ #include <linux/interrupt.h> #include <linux/module.h> #include <linux/kexec.h> +#include <linux/kgdb.h> #include <linux/percpu.h> #include <linux/profile.h> #include <linux/smp.h> @@ -35,6 +36,7 @@ enum ipi_message_type { IPI_IRQ_WORK, IPI_TIMER, IPI_CPU_BACKTRACE, + IPI_KGDB_ROUNDUP, IPI_MAX }; @@ -115,6 +117,7 @@ void arch_irq_work_raise(void) static irqreturn_t handle_IPI(int irq, void *data) { + unsigned int cpu = smp_processor_id(); int ipi = irq - ipi_virq_base; switch (ipi) { @@ -128,7 +131,7 @@ static irqreturn_t handle_IPI(int irq, void *data) ipi_stop(); break; case IPI_CPU_CRASH_STOP: - ipi_cpu_crash_stop(smp_processor_id(), get_irq_regs()); + ipi_cpu_crash_stop(cpu, get_irq_regs()); break; case IPI_IRQ_WORK: irq_work_run(); @@ -141,8 +144,11 @@ static irqreturn_t handle_IPI(int irq, void *data) case IPI_CPU_BACKTRACE: nmi_cpu_backtrace(get_irq_regs()); break; + case IPI_KGDB_ROUNDUP: + kgdb_nmicallback(cpu, get_irq_regs()); + break; default: - pr_warn("CPU%d: unhandled IPI%d\n", smp_processor_id(), ipi); + pr_warn("CPU%d: unhandled IPI%d\n", cpu, ipi); break; } @@ -209,6 +215,7 @@ static const char * const ipi_names[] = { [IPI_IRQ_WORK] = "IRQ work interrupts", [IPI_TIMER] = "Timer broadcast interrupts", [IPI_CPU_BACKTRACE] = "CPU backtrace interrupts", + [IPI_KGDB_ROUNDUP] = "KGDB roundup interrupts", }; void show_ipi_stats(struct seq_file *p, int prec) @@ -339,3 +346,19 @@ void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu) { nmi_trigger_cpumask_backtrace(mask, exclude_cpu, riscv_backtrace_ipi); } + +#ifdef CONFIG_KGDB +void kgdb_roundup_cpus(void) +{ + int this_cpu = raw_smp_processor_id(); + int cpu; + + for_each_online_cpu(cpu) { + /* No need to roundup ourselves */ + if (cpu == this_cpu) + continue; + + send_ipi_single(cpu, IPI_KGDB_ROUNDUP); + } +} +#endif