| Message ID | 20211204002038.113653-2-atishp@atishpatra.org |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | Sparse HART id support | expand |
On Sat, Dec 4, 2021 at 5:50 AM Atish Patra <atishp@atishpatra.org> wrote: > > From: Atish Patra <atishp@rivosinc.com> > > Currently both order booting and spinwait approach uses a per cpu > array to update stack & task pointer. This approach will not work for the > following cases. > 1. If NR_CPUs are configured to be less than highest hart id. > 2. A platform has sparse hartid. > > This issue can be fixed for ordered booting as the booting cpu brings up > one cpu at a time using SBI HSM extension which has opaque parameter > that is unused until now. > > Introduce a common secondary boot data structure that can store the stack > and task pointer. Secondary harts will use this data while booting up > to setup the sp & tp. > > Signed-off-by: Atish Patra <atishp@rivosinc.com> > --- > arch/riscv/include/asm/cpu_ops_sbi.h | 28 ++++++++++++++++++++++++++++ > arch/riscv/kernel/cpu_ops_sbi.c | 23 ++++++++++++++++++++--- > arch/riscv/kernel/head.S | 19 ++++++++++--------- > 3 files changed, 58 insertions(+), 12 deletions(-) > create mode 100644 arch/riscv/include/asm/cpu_ops_sbi.h > > diff --git a/arch/riscv/include/asm/cpu_ops_sbi.h b/arch/riscv/include/asm/cpu_ops_sbi.h > new file mode 100644 > index 000000000000..ccb9a6d30486 > --- /dev/null > +++ b/arch/riscv/include/asm/cpu_ops_sbi.h > @@ -0,0 +1,28 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (c) 2021 by Rivos Inc. > + */ > +#ifndef __ASM_CPU_OPS_SBI_H > +#define __ASM_CPU_OPS_SBI_H > + > +#ifndef __ASSEMBLY__ > +#include <linux/init.h> > +#include <linux/sched.h> > +#include <linux/threads.h> > + > +/** > + * struct sbi_hart_boot_data - Hart specific boot used during booting and > + * cpu hotplug. > + * @task_ptr: A pointer to the hart specific tp > + * @stack_ptr: A pointer to the hart specific sp > + */ > +struct sbi_hart_boot_data { > + void *task_ptr; > + void *stack_ptr; > +}; > +#endif > + > +#define SBI_HART_BOOT_TASK_PTR_OFFSET (0x00) > +#define SBI_HART_BOOT_STACK_PTR_OFFSET RISCV_SZPTR Don't manually create these defines instead generate this defines at compile time by adding entries in kernel/asm-offsets.c > + > +#endif /* ifndef __ASM_CPU_OPS_H */ > diff --git a/arch/riscv/kernel/cpu_ops_sbi.c b/arch/riscv/kernel/cpu_ops_sbi.c > index 685fae72b7f5..2e7a9dd9c2a7 100644 > --- a/arch/riscv/kernel/cpu_ops_sbi.c > +++ b/arch/riscv/kernel/cpu_ops_sbi.c > @@ -7,13 +7,22 @@ > > #include <linux/init.h> > #include <linux/mm.h> > +#include <linux/sched/task_stack.h> > #include <asm/cpu_ops.h> > +#include <asm/cpu_ops_sbi.h> > #include <asm/sbi.h> > #include <asm/smp.h> > > extern char secondary_start_sbi[]; > const struct cpu_operations cpu_ops_sbi; > > +/* > + * Ordered booting via HSM brings one cpu at a time. However, cpu hotplug can > + * be invoked from multiple threads in paralle. Define a per cpu data > + * to handle that. > + */ > +DEFINE_PER_CPU(struct sbi_hart_boot_data, boot_data); > + > static int sbi_hsm_hart_start(unsigned long hartid, unsigned long saddr, > unsigned long priv) > { > @@ -58,9 +67,17 @@ static int sbi_cpu_start(unsigned int cpuid, struct task_struct *tidle) > int rc; > unsigned long boot_addr = __pa_symbol(secondary_start_sbi); > int hartid = cpuid_to_hartid_map(cpuid); > - > - cpu_update_secondary_bootdata(cpuid, tidle); > - rc = sbi_hsm_hart_start(hartid, boot_addr, 0); > + unsigned long hsm_data; > + struct sbi_hart_boot_data *bdata = &per_cpu(boot_data, cpuid); > + > + /* Make sure tidle is updated */ > + smp_mb(); > + bdata->task_ptr = tidle; > + bdata->stack_ptr = task_stack_page(tidle) + THREAD_SIZE; > + /* Make sure boot data is updated */ > + smp_mb(); > + hsm_data = __pa(bdata); > + rc = sbi_hsm_hart_start(hartid, boot_addr, hsm_data); > > return rc; > } > diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S > index f52f01ecbeea..40d4c625513c 100644 > --- a/arch/riscv/kernel/head.S > +++ b/arch/riscv/kernel/head.S > @@ -11,6 +11,7 @@ > #include <asm/page.h> > #include <asm/pgtable.h> > #include <asm/csr.h> > +#include <asm/cpu_ops_sbi.h> > #include <asm/hwcap.h> > #include <asm/image.h> > #include "efi-header.S" > @@ -167,15 +168,15 @@ secondary_start_sbi: > la a3, .Lsecondary_park > csrw CSR_TVEC, a3 > > - slli a3, a0, LGREG > - la a4, __cpu_up_stack_pointer > - XIP_FIXUP_OFFSET a4 > - la a5, __cpu_up_task_pointer > - XIP_FIXUP_OFFSET a5 > - add a4, a3, a4 > - add a5, a3, a5 > - REG_L sp, (a4) > - REG_L tp, (a5) > + /* a0 contains the hartid & a1 contains boot data */ > + li a2, SBI_HART_BOOT_TASK_PTR_OFFSET > + XIP_FIXUP_OFFSET a2 > + add a2, a2, a1 > + REG_L tp, (a2) > + li a3, SBI_HART_BOOT_STACK_PTR_OFFSET > + XIP_FIXUP_OFFSET a3 > + add a3, a3, a1 > + REG_L sp, (a3) > > .global secondary_start_common > secondary_start_common: > -- > 2.33.1 > Regards, Anup
On Mon, Dec 13, 2021 at 4:49 AM Anup Patel <anup@brainfault.org> wrote: > > On Sat, Dec 4, 2021 at 5:50 AM Atish Patra <atishp@atishpatra.org> wrote: > > > > From: Atish Patra <atishp@rivosinc.com> > > > > Currently both order booting and spinwait approach uses a per cpu > > array to update stack & task pointer. This approach will not work for the > > following cases. > > 1. If NR_CPUs are configured to be less than highest hart id. > > 2. A platform has sparse hartid. > > > > This issue can be fixed for ordered booting as the booting cpu brings up > > one cpu at a time using SBI HSM extension which has opaque parameter > > that is unused until now. > > > > Introduce a common secondary boot data structure that can store the stack > > and task pointer. Secondary harts will use this data while booting up > > to setup the sp & tp. > > > > Signed-off-by: Atish Patra <atishp@rivosinc.com> > > --- > > arch/riscv/include/asm/cpu_ops_sbi.h | 28 ++++++++++++++++++++++++++++ > > arch/riscv/kernel/cpu_ops_sbi.c | 23 ++++++++++++++++++++--- > > arch/riscv/kernel/head.S | 19 ++++++++++--------- > > 3 files changed, 58 insertions(+), 12 deletions(-) > > create mode 100644 arch/riscv/include/asm/cpu_ops_sbi.h > > > > diff --git a/arch/riscv/include/asm/cpu_ops_sbi.h b/arch/riscv/include/asm/cpu_ops_sbi.h > > new file mode 100644 > > index 000000000000..ccb9a6d30486 > > --- /dev/null > > +++ b/arch/riscv/include/asm/cpu_ops_sbi.h > > @@ -0,0 +1,28 @@ > > +/* SPDX-License-Identifier: GPL-2.0-only */ > > +/* > > + * Copyright (c) 2021 by Rivos Inc. > > + */ > > +#ifndef __ASM_CPU_OPS_SBI_H > > +#define __ASM_CPU_OPS_SBI_H > > + > > +#ifndef __ASSEMBLY__ > > +#include <linux/init.h> > > +#include <linux/sched.h> > > +#include <linux/threads.h> > > + > > +/** > > + * struct sbi_hart_boot_data - Hart specific boot used during booting and > > + * cpu hotplug. > > + * @task_ptr: A pointer to the hart specific tp > > + * @stack_ptr: A pointer to the hart specific sp > > + */ > > +struct sbi_hart_boot_data { > > + void *task_ptr; > > + void *stack_ptr; > > +}; > > +#endif > > + > > +#define SBI_HART_BOOT_TASK_PTR_OFFSET (0x00) > > +#define SBI_HART_BOOT_STACK_PTR_OFFSET RISCV_SZPTR > > Don't manually create these defines instead generate this > defines at compile time by adding entries in kernel/asm-offsets.c > Sure. I will fix this in the next version. > > + > > +#endif /* ifndef __ASM_CPU_OPS_H */ > > diff --git a/arch/riscv/kernel/cpu_ops_sbi.c b/arch/riscv/kernel/cpu_ops_sbi.c > > index 685fae72b7f5..2e7a9dd9c2a7 100644 > > --- a/arch/riscv/kernel/cpu_ops_sbi.c > > +++ b/arch/riscv/kernel/cpu_ops_sbi.c > > @@ -7,13 +7,22 @@ > > > > #include <linux/init.h> > > #include <linux/mm.h> > > +#include <linux/sched/task_stack.h> > > #include <asm/cpu_ops.h> > > +#include <asm/cpu_ops_sbi.h> > > #include <asm/sbi.h> > > #include <asm/smp.h> > > > > extern char secondary_start_sbi[]; > > const struct cpu_operations cpu_ops_sbi; > > > > +/* > > + * Ordered booting via HSM brings one cpu at a time. However, cpu hotplug can > > + * be invoked from multiple threads in paralle. Define a per cpu data > > + * to handle that. > > + */ > > +DEFINE_PER_CPU(struct sbi_hart_boot_data, boot_data); > > + > > static int sbi_hsm_hart_start(unsigned long hartid, unsigned long saddr, > > unsigned long priv) > > { > > @@ -58,9 +67,17 @@ static int sbi_cpu_start(unsigned int cpuid, struct task_struct *tidle) > > int rc; > > unsigned long boot_addr = __pa_symbol(secondary_start_sbi); > > int hartid = cpuid_to_hartid_map(cpuid); > > - > > - cpu_update_secondary_bootdata(cpuid, tidle); > > - rc = sbi_hsm_hart_start(hartid, boot_addr, 0); > > + unsigned long hsm_data; > > + struct sbi_hart_boot_data *bdata = &per_cpu(boot_data, cpuid); > > + > > + /* Make sure tidle is updated */ > > + smp_mb(); > > + bdata->task_ptr = tidle; > > + bdata->stack_ptr = task_stack_page(tidle) + THREAD_SIZE; > > + /* Make sure boot data is updated */ > > + smp_mb(); > > + hsm_data = __pa(bdata); > > + rc = sbi_hsm_hart_start(hartid, boot_addr, hsm_data); > > > > return rc; > > } > > diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S > > index f52f01ecbeea..40d4c625513c 100644 > > --- a/arch/riscv/kernel/head.S > > +++ b/arch/riscv/kernel/head.S > > @@ -11,6 +11,7 @@ > > #include <asm/page.h> > > #include <asm/pgtable.h> > > #include <asm/csr.h> > > +#include <asm/cpu_ops_sbi.h> > > #include <asm/hwcap.h> > > #include <asm/image.h> > > #include "efi-header.S" > > @@ -167,15 +168,15 @@ secondary_start_sbi: > > la a3, .Lsecondary_park > > csrw CSR_TVEC, a3 > > > > - slli a3, a0, LGREG > > - la a4, __cpu_up_stack_pointer > > - XIP_FIXUP_OFFSET a4 > > - la a5, __cpu_up_task_pointer > > - XIP_FIXUP_OFFSET a5 > > - add a4, a3, a4 > > - add a5, a3, a5 > > - REG_L sp, (a4) > > - REG_L tp, (a5) > > + /* a0 contains the hartid & a1 contains boot data */ > > + li a2, SBI_HART_BOOT_TASK_PTR_OFFSET > > + XIP_FIXUP_OFFSET a2 > > + add a2, a2, a1 > > + REG_L tp, (a2) > > + li a3, SBI_HART_BOOT_STACK_PTR_OFFSET > > + XIP_FIXUP_OFFSET a3 > > + add a3, a3, a1 > > + REG_L sp, (a3) > > > > .global secondary_start_common > > secondary_start_common: > > -- > > 2.33.1 > > > > Regards, > Anup
diff --git a/arch/riscv/include/asm/cpu_ops_sbi.h b/arch/riscv/include/asm/cpu_ops_sbi.h new file mode 100644 index 000000000000..ccb9a6d30486 --- /dev/null +++ b/arch/riscv/include/asm/cpu_ops_sbi.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) 2021 by Rivos Inc. + */ +#ifndef __ASM_CPU_OPS_SBI_H +#define __ASM_CPU_OPS_SBI_H + +#ifndef __ASSEMBLY__ +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/threads.h> + +/** + * struct sbi_hart_boot_data - Hart specific boot used during booting and + * cpu hotplug. + * @task_ptr: A pointer to the hart specific tp + * @stack_ptr: A pointer to the hart specific sp + */ +struct sbi_hart_boot_data { + void *task_ptr; + void *stack_ptr; +}; +#endif + +#define SBI_HART_BOOT_TASK_PTR_OFFSET (0x00) +#define SBI_HART_BOOT_STACK_PTR_OFFSET RISCV_SZPTR + +#endif /* ifndef __ASM_CPU_OPS_H */ diff --git a/arch/riscv/kernel/cpu_ops_sbi.c b/arch/riscv/kernel/cpu_ops_sbi.c index 685fae72b7f5..2e7a9dd9c2a7 100644 --- a/arch/riscv/kernel/cpu_ops_sbi.c +++ b/arch/riscv/kernel/cpu_ops_sbi.c @@ -7,13 +7,22 @@ #include <linux/init.h> #include <linux/mm.h> +#include <linux/sched/task_stack.h> #include <asm/cpu_ops.h> +#include <asm/cpu_ops_sbi.h> #include <asm/sbi.h> #include <asm/smp.h> extern char secondary_start_sbi[]; const struct cpu_operations cpu_ops_sbi; +/* + * Ordered booting via HSM brings one cpu at a time. However, cpu hotplug can + * be invoked from multiple threads in paralle. Define a per cpu data + * to handle that. + */ +DEFINE_PER_CPU(struct sbi_hart_boot_data, boot_data); + static int sbi_hsm_hart_start(unsigned long hartid, unsigned long saddr, unsigned long priv) { @@ -58,9 +67,17 @@ static int sbi_cpu_start(unsigned int cpuid, struct task_struct *tidle) int rc; unsigned long boot_addr = __pa_symbol(secondary_start_sbi); int hartid = cpuid_to_hartid_map(cpuid); - - cpu_update_secondary_bootdata(cpuid, tidle); - rc = sbi_hsm_hart_start(hartid, boot_addr, 0); + unsigned long hsm_data; + struct sbi_hart_boot_data *bdata = &per_cpu(boot_data, cpuid); + + /* Make sure tidle is updated */ + smp_mb(); + bdata->task_ptr = tidle; + bdata->stack_ptr = task_stack_page(tidle) + THREAD_SIZE; + /* Make sure boot data is updated */ + smp_mb(); + hsm_data = __pa(bdata); + rc = sbi_hsm_hart_start(hartid, boot_addr, hsm_data); return rc; } diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index f52f01ecbeea..40d4c625513c 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -11,6 +11,7 @@ #include <asm/page.h> #include <asm/pgtable.h> #include <asm/csr.h> +#include <asm/cpu_ops_sbi.h> #include <asm/hwcap.h> #include <asm/image.h> #include "efi-header.S" @@ -167,15 +168,15 @@ secondary_start_sbi: la a3, .Lsecondary_park csrw CSR_TVEC, a3 - slli a3, a0, LGREG - la a4, __cpu_up_stack_pointer - XIP_FIXUP_OFFSET a4 - la a5, __cpu_up_task_pointer - XIP_FIXUP_OFFSET a5 - add a4, a3, a4 - add a5, a3, a5 - REG_L sp, (a4) - REG_L tp, (a5) + /* a0 contains the hartid & a1 contains boot data */ + li a2, SBI_HART_BOOT_TASK_PTR_OFFSET + XIP_FIXUP_OFFSET a2 + add a2, a2, a1 + REG_L tp, (a2) + li a3, SBI_HART_BOOT_STACK_PTR_OFFSET + XIP_FIXUP_OFFSET a3 + add a3, a3, a1 + REG_L sp, (a3) .global secondary_start_common secondary_start_common: