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authorLinus Torvalds <torvalds@linux-foundation.org>2023-05-05 12:23:33 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-05-05 12:23:33 -0700
commit982365a8f5c453b3ecff131d60f254a7e67c9a2b (patch)
tree3d67bbf2299e13cf7f648dad24eb23cbfd6f801b
parent493804a6895d63240fe45d087cd14c4b77d8488b (diff)
parentc2d3c8441e3ddbfe41fea9282ddc6ee372e154cd (diff)
Merge tag 'riscv-for-linus-6.4-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull more RISC-V updates from Palmer Dabbelt: - Support for hibernation - The .rela.dyn section has been moved to the init area - A fix for the SBI probing to allow for implementation-defined behavior - Various other fixes and cleanups throughout the tree * tag 'riscv-for-linus-6.4-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: RISC-V: include cpufeature.h in cpufeature.c riscv: Move .rela.dyn to the init sections dt-bindings: riscv: explicitly mention assumption of Zicsr & Zifencei support riscv: compat_syscall_table: Fixup compile warning RISC-V: fixup in-flight collision with ARCH_WANT_OPTIMIZE_VMEMMAP rename RISC-V: fix sifive and thead section mismatches in errata RISC-V: Align SBI probe implementation with spec riscv: mm: remove redundant parameter of create_fdt_early_page_table riscv: Adjust dependencies of HAVE_DYNAMIC_FTRACE selection RISC-V: Add arch functions to support hibernation/suspend-to-disk RISC-V: mm: Enable huge page support to kernel_page_present() function RISC-V: Factor out common code of __cpu_resume_enter() RISC-V: Change suspend_save_csrs and suspend_restore_csrs to public function
-rw-r--r--Documentation/devicetree/bindings/riscv/cpus.yaml6
-rw-r--r--arch/riscv/Kconfig23
-rw-r--r--arch/riscv/errata/sifive/errata.c8
-rw-r--r--arch/riscv/errata/thead/errata.c6
-rw-r--r--arch/riscv/include/asm/assembler.h82
-rw-r--r--arch/riscv/include/asm/sbi.h2
-rw-r--r--arch/riscv/include/asm/suspend.h22
-rw-r--r--arch/riscv/kernel/Makefile2
-rw-r--r--arch/riscv/kernel/asm-offsets.c5
-rw-r--r--arch/riscv/kernel/cpu_ops.c2
-rw-r--r--arch/riscv/kernel/cpufeature.c1
-rw-r--r--arch/riscv/kernel/hibernate-asm.S77
-rw-r--r--arch/riscv/kernel/hibernate.c427
-rw-r--r--arch/riscv/kernel/sbi.c17
-rw-r--r--arch/riscv/kernel/suspend.c4
-rw-r--r--arch/riscv/kernel/suspend_entry.S34
-rw-r--r--arch/riscv/kernel/vmlinux.lds.S12
-rw-r--r--arch/riscv/kvm/main.c2
-rw-r--r--arch/riscv/mm/init.c6
-rw-r--r--arch/riscv/mm/pageattr.c8
-rw-r--r--drivers/cpuidle/cpuidle-riscv-sbi.c2
-rw-r--r--drivers/perf/riscv_pmu_sbi.c2
22 files changed, 682 insertions, 68 deletions
diff --git a/Documentation/devicetree/bindings/riscv/cpus.yaml b/Documentation/devicetree/bindings/riscv/cpus.yaml
index 25d6e8dbffb8..3d2934b15e80 100644
--- a/Documentation/devicetree/bindings/riscv/cpus.yaml
+++ b/Documentation/devicetree/bindings/riscv/cpus.yaml
@@ -86,6 +86,12 @@ properties:
User-Level ISA document, available from
https://riscv.org/specifications/
+ Due to revisions of the ISA specification, some deviations
+ have arisen over time.
+ Notably, riscv,isa was defined prior to the creation of the
+ Zicsr and Zifencei extensions and thus "i" implies
+ "zicsr_zifencei".
+
While the isa strings in ISA specification are case
insensitive, letters in the riscv,isa string must be all
lowercase to simplify parsing.
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index d2967fefa1d7..348c0fa1fc8c 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -47,16 +47,16 @@ config RISCV
select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
select ARCH_WANT_FRAME_POINTERS
select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT
- select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
select ARCH_WANT_LD_ORPHAN_WARN if !XIP_KERNEL
+ select ARCH_WANT_OPTIMIZE_VMEMMAP
select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE
select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU
select BUILDTIME_TABLE_SORT if MMU
select CLINT_TIMER if !MMU
select CLONE_BACKWARDS
select COMMON_CLK
- select CPU_PM if CPU_IDLE
+ select CPU_PM if CPU_IDLE || HIBERNATION
select EDAC_SUPPORT
select GENERIC_ARCH_TOPOLOGY
select GENERIC_ATOMIC64 if !64BIT
@@ -142,12 +142,23 @@ config RISCV
select TRACE_IRQFLAGS_SUPPORT
select UACCESS_MEMCPY if !MMU
select ZONE_DMA32 if 64BIT
- select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && $(cc-option,-fpatchable-function-entry=8)
+ select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE)
select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
+config CLANG_SUPPORTS_DYNAMIC_FTRACE
+ def_bool CC_IS_CLANG
+ # https://github.com/llvm/llvm-project/commit/6ab8927931851bb42b2c93a00801dc499d7d9b1e
+ depends on CLANG_VERSION >= 130000
+ # https://github.com/ClangBuiltLinux/linux/issues/1817
+ depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600))
+
+config GCC_SUPPORTS_DYNAMIC_FTRACE
+ def_bool CC_IS_GCC
+ depends on $(cc-option,-fpatchable-function-entry=8)
+
config ARCH_MMAP_RND_BITS_MIN
default 18 if 64BIT
default 8
@@ -788,6 +799,12 @@ menu "Power management options"
source "kernel/power/Kconfig"
+config ARCH_HIBERNATION_POSSIBLE
+ def_bool y
+
+config ARCH_HIBERNATION_HEADER
+ def_bool HIBERNATION
+
endmenu # "Power management options"
menu "CPU Power Management"
diff --git a/arch/riscv/errata/sifive/errata.c b/arch/riscv/errata/sifive/errata.c
index 8d8301d7b1ec..3d9a32d791f7 100644
--- a/arch/riscv/errata/sifive/errata.c
+++ b/arch/riscv/errata/sifive/errata.c
@@ -82,11 +82,9 @@ static void __init_or_module warn_miss_errata(u32 miss_errata)
pr_warn("----------------------------------------------------------------\n");
}
-void __init_or_module sifive_errata_patch_func(struct alt_entry *begin,
- struct alt_entry *end,
- unsigned long archid,
- unsigned long impid,
- unsigned int stage)
+void sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
+ unsigned long archid, unsigned long impid,
+ unsigned int stage)
{
struct alt_entry *alt;
u32 cpu_req_errata;
diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c
index a86c4facc2a6..c259dc925ec1 100644
--- a/arch/riscv/errata/thead/errata.c
+++ b/arch/riscv/errata/thead/errata.c
@@ -83,9 +83,9 @@ static u32 thead_errata_probe(unsigned int stage,
return cpu_req_errata;
}
-void __init_or_module thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
- unsigned long archid, unsigned long impid,
- unsigned int stage)
+void thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
+ unsigned long archid, unsigned long impid,
+ unsigned int stage)
{
struct alt_entry *alt;
u32 cpu_req_errata = thead_errata_probe(stage, archid, impid);
diff --git a/arch/riscv/include/asm/assembler.h b/arch/riscv/include/asm/assembler.h
new file mode 100644
index 000000000000..44b1457d3e95
--- /dev/null
+++ b/arch/riscv/include/asm/assembler.h
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 StarFive Technology Co., Ltd.
+ *
+ * Author: Jee Heng Sia <jeeheng.sia@starfivetech.com>
+ */
+
+#ifndef __ASSEMBLY__
+#error "Only include this from assembly code"
+#endif
+
+#ifndef __ASM_ASSEMBLER_H
+#define __ASM_ASSEMBLER_H
+
+#include <asm/asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/csr.h>
+
+/*
+ * suspend_restore_csrs - restore CSRs
+ */
+ .macro suspend_restore_csrs
+ REG_L t0, (SUSPEND_CONTEXT_REGS + PT_EPC)(a0)
+ csrw CSR_EPC, t0
+ REG_L t0, (SUSPEND_CONTEXT_REGS + PT_STATUS)(a0)
+ csrw CSR_STATUS, t0
+ REG_L t0, (SUSPEND_CONTEXT_REGS + PT_BADADDR)(a0)
+ csrw CSR_TVAL, t0
+ REG_L t0, (SUSPEND_CONTEXT_REGS + PT_CAUSE)(a0)
+ csrw CSR_CAUSE, t0
+ .endm
+
+/*
+ * suspend_restore_regs - Restore registers (except A0 and T0-T6)
+ */
+ .macro suspend_restore_regs
+ REG_L ra, (SUSPEND_CONTEXT_REGS + PT_RA)(a0)
+ REG_L sp, (SUSPEND_CONTEXT_REGS + PT_SP)(a0)
+ REG_L gp, (SUSPEND_CONTEXT_REGS + PT_GP)(a0)
+ REG_L tp, (SUSPEND_CONTEXT_REGS + PT_TP)(a0)
+ REG_L s0, (SUSPEND_CONTEXT_REGS + PT_S0)(a0)
+ REG_L s1, (SUSPEND_CONTEXT_REGS + PT_S1)(a0)
+ REG_L a1, (SUSPEND_CONTEXT_REGS + PT_A1)(a0)
+ REG_L a2, (SUSPEND_CONTEXT_REGS + PT_A2)(a0)
+ REG_L a3, (SUSPEND_CONTEXT_REGS + PT_A3)(a0)
+ REG_L a4, (SUSPEND_CONTEXT_REGS + PT_A4)(a0)
+ REG_L a5, (SUSPEND_CONTEXT_REGS + PT_A5)(a0)
+ REG_L a6, (SUSPEND_CONTEXT_REGS + PT_A6)(a0)
+ REG_L a7, (SUSPEND_CONTEXT_REGS + PT_A7)(a0)
+ REG_L s2, (SUSPEND_CONTEXT_REGS + PT_S2)(a0)
+ REG_L s3, (SUSPEND_CONTEXT_REGS + PT_S3)(a0)
+ REG_L s4, (SUSPEND_CONTEXT_REGS + PT_S4)(a0)
+ REG_L s5, (SUSPEND_CONTEXT_REGS + PT_S5)(a0)
+ REG_L s6, (SUSPEND_CONTEXT_REGS + PT_S6)(a0)
+ REG_L s7, (SUSPEND_CONTEXT_REGS + PT_S7)(a0)
+ REG_L s8, (SUSPEND_CONTEXT_REGS + PT_S8)(a0)
+ REG_L s9, (SUSPEND_CONTEXT_REGS + PT_S9)(a0)
+ REG_L s10, (SUSPEND_CONTEXT_REGS + PT_S10)(a0)
+ REG_L s11, (SUSPEND_CONTEXT_REGS + PT_S11)(a0)
+ .endm
+
+/*
+ * copy_page - copy 1 page (4KB) of data from source to destination
+ * @a0 - destination
+ * @a1 - source
+ */
+ .macro copy_page a0, a1
+ lui a2, 0x1
+ add a2, a2, a0
+1 :
+ REG_L t0, 0(a1)
+ REG_L t1, SZREG(a1)
+
+ REG_S t0, 0(a0)
+ REG_S t1, SZREG(a0)
+
+ addi a0, a0, 2 * SZREG
+ addi a1, a1, 2 * SZREG
+ bne a2, a0, 1b
+ .endm
+
+#endif /* __ASM_ASSEMBLER_H */
diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index acab4410ef2a..5b4a1bf5f439 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -295,7 +295,7 @@ int sbi_remote_hfence_vvma_asid(const struct cpumask *cpu_mask,
unsigned long start,
unsigned long size,
unsigned long asid);
-int sbi_probe_extension(int ext);
+long sbi_probe_extension(int ext);
/* Check if current SBI specification version is 0.1 or not */
static inline int sbi_spec_is_0_1(void)
diff --git a/arch/riscv/include/asm/suspend.h b/arch/riscv/include/asm/suspend.h
index 8be391c2aecb..02f87867389a 100644
--- a/arch/riscv/include/asm/suspend.h
+++ b/arch/riscv/include/asm/suspend.h
@@ -21,6 +21,11 @@ struct suspend_context {
#endif
};
+/*
+ * Used by hibernation core and cleared during resume sequence
+ */
+extern int in_suspend;
+
/* Low-level CPU suspend entry function */
int __cpu_suspend_enter(struct suspend_context *context);
@@ -33,4 +38,21 @@ int cpu_suspend(unsigned long arg,
/* Low-level CPU resume entry function */
int __cpu_resume_enter(unsigned long hartid, unsigned long context);
+/* Used to save and restore the CSRs */
+void suspend_save_csrs(struct suspend_context *context);
+void suspend_restore_csrs(struct suspend_context *context);
+
+/* Low-level API to support hibernation */
+int swsusp_arch_suspend(void);
+int swsusp_arch_resume(void);
+int arch_hibernation_header_save(void *addr, unsigned int max_size);
+int arch_hibernation_header_restore(void *addr);
+int __hibernate_cpu_resume(void);
+
+/* Used to resume on the CPU we hibernated on */
+int hibernate_resume_nonboot_cpu_disable(void);
+
+asmlinkage void hibernate_restore_image(unsigned long resume_satp, unsigned long satp_temp,
+ unsigned long cpu_resume);
+asmlinkage int hibernate_core_restore_code(void);
#endif
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 571f05958b41..fbdccc21418a 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -9,6 +9,7 @@ CFLAGS_REMOVE_patch.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_sbi.o = $(CC_FLAGS_FTRACE)
endif
CFLAGS_syscall_table.o += $(call cc-option,-Wno-override-init,)
+CFLAGS_compat_syscall_table.o += $(call cc-option,-Wno-override-init,)
ifdef CONFIG_KEXEC
AFLAGS_kexec_relocate.o := -mcmodel=medany $(call cc-option,-mno-relax)
@@ -64,6 +65,7 @@ obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_MODULE_SECTIONS) += module-sections.o
obj-$(CONFIG_CPU_PM) += suspend_entry.o suspend.o
+obj-$(CONFIG_HIBERNATION) += hibernate.o hibernate-asm.o
obj-$(CONFIG_FUNCTION_TRACER) += mcount.o ftrace.o
obj-$(CONFIG_DYNAMIC_FTRACE) += mcount-dyn.o
diff --git a/arch/riscv/kernel/asm-offsets.c b/arch/riscv/kernel/asm-offsets.c
index df9444397908..d6a75aac1d27 100644
--- a/arch/riscv/kernel/asm-offsets.c
+++ b/arch/riscv/kernel/asm-offsets.c
@@ -9,6 +9,7 @@
#include <linux/kbuild.h>
#include <linux/mm.h>
#include <linux/sched.h>
+#include <linux/suspend.h>
#include <asm/kvm_host.h>
#include <asm/thread_info.h>
#include <asm/ptrace.h>
@@ -116,6 +117,10 @@ void asm_offsets(void)
OFFSET(SUSPEND_CONTEXT_REGS, suspend_context, regs);
+ OFFSET(HIBERN_PBE_ADDR, pbe, address);
+ OFFSET(HIBERN_PBE_ORIG, pbe, orig_address);
+ OFFSET(HIBERN_PBE_NEXT, pbe, next);
+
OFFSET(KVM_ARCH_GUEST_ZERO, kvm_vcpu_arch, guest_context.zero);
OFFSET(KVM_ARCH_GUEST_RA, kvm_vcpu_arch, guest_context.ra);
OFFSET(KVM_ARCH_GUEST_SP, kvm_vcpu_arch, guest_context.sp);
diff --git a/arch/riscv/kernel/cpu_ops.c b/arch/riscv/kernel/cpu_ops.c
index 8275f237a59d..eb479a88a954 100644
--- a/arch/riscv/kernel/cpu_ops.c
+++ b/arch/riscv/kernel/cpu_ops.c
@@ -27,7 +27,7 @@ const struct cpu_operations cpu_ops_spinwait = {
void __init cpu_set_ops(int cpuid)
{
#if IS_ENABLED(CONFIG_RISCV_SBI)
- if (sbi_probe_extension(SBI_EXT_HSM) > 0) {
+ if (sbi_probe_extension(SBI_EXT_HSM)) {
if (!cpuid)
pr_info("SBI HSM extension detected\n");
cpu_ops[cpuid] = &cpu_ops_sbi;
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index fa8cfd1e5a4d..b1d6b7e4b829 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -14,6 +14,7 @@
#include <linux/of.h>
#include <asm/alternative.h>
#include <asm/cacheflush.h>
+#include <asm/cpufeature.h>
#include <asm/hwcap.h>
#include <asm/patch.h>
#include <asm/processor.h>
diff --git a/arch/riscv/kernel/hibernate-asm.S b/arch/riscv/kernel/hibernate-asm.S
new file mode 100644
index 000000000000..effaf5ca5da0
--- /dev/null
+++ b/arch/riscv/kernel/hibernate-asm.S
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Hibernation low level support for RISCV.
+ *
+ * Copyright (C) 2023 StarFive Technology Co., Ltd.
+ *
+ * Author: Jee Heng Sia <jeeheng.sia@starfivetech.com>
+ */
+
+#include <asm/asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/assembler.h>
+#include <asm/csr.h>
+
+#include <linux/linkage.h>
+
+/*
+ * int __hibernate_cpu_resume(void)
+ * Switch back to the hibernated image's page table prior to restoring the CPU
+ * context.
+ *
+ * Always returns 0
+ */
+ENTRY(__hibernate_cpu_resume)
+ /* switch to hibernated image's page table. */
+ csrw CSR_SATP, s0
+ sfence.vma
+
+ REG_L a0, hibernate_cpu_context
+
+ suspend_restore_csrs
+ suspend_restore_regs
+
+ /* Return zero value. */
+ mv a0, zero
+
+ ret
+END(__hibernate_cpu_resume)
+
+/*
+ * Prepare to restore the image.
+ * a0: satp of saved page tables.
+ * a1: satp of temporary page tables.
+ * a2: cpu_resume.
+ */
+ENTRY(hibernate_restore_image)
+ mv s0, a0
+ mv s1, a1
+ mv s2, a2
+ REG_L s4, restore_pblist
+ REG_L a1, relocated_restore_code
+
+ jalr a1
+END(hibernate_restore_image)
+
+/*
+ * The below code will be executed from a 'safe' page.
+ * It first switches to the temporary page table, then starts to copy the pages
+ * back to the original memory location. Finally, it jumps to __hibernate_cpu_resume()
+ * to restore the CPU context.
+ */
+ENTRY(hibernate_core_restore_code)
+ /* switch to temp page table. */
+ csrw satp, s1
+ sfence.vma
+.Lcopy:
+ /* The below code will restore the hibernated image. */
+ REG_L a1, HIBERN_PBE_ADDR(s4)
+ REG_L a0, HIBERN_PBE_ORIG(s4)
+
+ copy_page a0, a1
+
+ REG_L s4, HIBERN_PBE_NEXT(s4)
+ bnez s4, .Lcopy
+
+ jalr s2
+END(hibernate_core_restore_code)
diff --git a/arch/riscv/kernel/hibernate.c b/arch/riscv/kernel/hibernate.c
new file mode 100644
index 000000000000..264b2dcdd67e
--- /dev/null
+++ b/arch/riscv/kernel/hibernate.c
@@ -0,0 +1,427 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Hibernation support for RISCV
+ *
+ * Copyright (C) 2023 StarFive Technology Co., Ltd.
+ *
+ * Author: Jee Heng Sia <jeeheng.sia@starfivetech.com>
+ */
+
+#include <asm/barrier.h>
+#include <asm/cacheflush.h>
+#include <asm/mmu_context.h>
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/sections.h>
+#include <asm/set_memory.h>
+#include <asm/smp.h>
+#include <asm/suspend.h>
+
+#include <linux/cpu.h>
+#include <linux/memblock.h>
+#include <linux/pm.h>
+#include <linux/sched.h>
+#include <linux/suspend.h>
+#include <linux/utsname.h>
+
+/* The logical cpu number we should resume on, initialised to a non-cpu number. */
+static int sleep_cpu = -EINVAL;
+
+/* Pointer to the temporary resume page table. */
+static pgd_t *resume_pg_dir;
+
+/* CPU context to be saved. */
+struct suspend_context *hibernate_cpu_context;
+EXPORT_SYMBOL_GPL(hibernate_cpu_context);
+
+unsigned long relocated_restore_code;
+EXPORT_SYMBOL_GPL(relocated_restore_code);
+
+/**
+ * struct arch_hibernate_hdr_invariants - container to store kernel build version.
+ * @uts_version: to save the build number and date so that we do not resume with
+ * a different kernel.
+ */
+struct arch_hibernate_hdr_invariants {
+ char uts_version[__NEW_UTS_LEN + 1];
+};
+
+/**
+ * struct arch_hibernate_hdr - helper parameters that help us to restore the image.
+ * @invariants: container to store kernel build version.
+ * @hartid: to make sure same boot_cpu executes the hibernate/restore code.
+ * @saved_satp: original page table used by the hibernated image.
+ * @restore_cpu_addr: the kernel's image address to restore the CPU context.
+ */
+static struct arch_hibernate_hdr {
+ struct arch_hibernate_hdr_invariants invariants;
+ unsigned long hartid;
+ unsigned long saved_satp;
+ unsigned long restore_cpu_addr;
+} resume_hdr;
+
+static void arch_hdr_invariants(struct arch_hibernate_hdr_invariants *i)
+{
+ memset(i, 0, sizeof(*i));
+ memcpy(i->uts_version, init_utsname()->version, sizeof(i->uts_version));
+}
+
+/*
+ * Check if the given pfn is in the 'nosave' section.
+ */
+int pfn_is_nosave(unsigned long pfn)
+{
+ unsigned long nosave_begin_pfn = sym_to_pfn(&__nosave_begin);
+ unsigned long nosave_end_pfn = sym_to_pfn(&__nosave_end - 1);
+
+ return ((pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn));
+}
+
+void notrace save_processor_state(void)
+{
+ WARN_ON(num_online_cpus() != 1);
+}
+
+void notrace restore_processor_state(void)
+{
+}
+
+/*
+ * Helper parameters need to be saved to the hibernation image header.
+ */
+int arch_hibernation_header_save(void *addr, unsigned int max_size)
+{
+ struct arch_hibernate_hdr *hdr = addr;
+
+ if (max_size < sizeof(*hdr))
+ return -EOVERFLOW;
+
+ arch_hdr_invariants(&hdr->invariants);
+
+ hdr->hartid = cpuid_to_hartid_map(sleep_cpu);
+ hdr->saved_satp = csr_read(CSR_SATP);
+ hdr->restore_cpu_addr = (unsigned long)__hibernate_cpu_resume;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(arch_hibernation_header_save);
+
+/*
+ * Retrieve the helper parameters from the hibernation image header.
+ */
+int arch_hibernation_header_restore(void *addr)
+{
+ struct arch_hibernate_hdr_invariants invariants;
+ struct arch_hibernate_hdr *hdr = addr;
+ int ret = 0;
+
+ arch_hdr_invariants(&invariants);
+
+ if (memcmp(&hdr->invariants, &invariants, sizeof(invariants))) {
+ pr_crit("Hibernate image not generated by this kernel!\n");
+ return -EINVAL;
+ }
+
+ sleep_cpu = riscv_hartid_to_cpuid(hdr->hartid);
+ if (sleep_cpu < 0) {
+ pr_crit("Hibernated on a CPU not known to this kernel!\n");
+ sleep_cpu = -EINVAL;
+ return -EINVAL;
+ }
+
+#ifdef CONFIG_SMP
+ ret = bringup_hibernate_cpu(sleep_cpu);
+ if (ret) {
+ sleep_cpu = -EINVAL;
+ return ret;
+ }
+#endif
+ resume_hdr = *hdr;
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(arch_hibernation_header_restore);
+
+int swsusp_arch_suspend(void)
+{
+ int ret = 0;
+
+ if (__cpu_suspend_enter(hibernate_cpu_context)) {
+ sleep_cpu = smp_processor_id();
+ suspend_save_csrs(hibernate_cpu_context);
+ ret = swsusp_save();
+ } else {
+ suspend_restore_csrs(hibernate_cpu_context);
+ flush_tlb_all();
+ flush_icache_all();
+
+ /*
+ * Tell the hibernation core that we've just restored the memory.
+ */
+ in_suspend = 0;
+ sleep_cpu = -EINVAL;
+ }
+
+ return ret;
+}
+
+static int temp_pgtable_map_pte(pmd_t *dst_pmdp, pmd_t *src_pmdp, unsigned long start,
+ unsigned long end, pgprot_t prot)
+{
+ pte_t *src_ptep;
+ pte_t *dst_ptep;
+
+ if (pmd_none(READ_ONCE(*dst_pmdp))) {
+ dst_ptep = (pte_t *)get_safe_page(GFP_ATOMIC);
+ if (!dst_ptep)
+ return -ENOMEM;
+
+ pmd_populate_kernel(NULL, dst_pmdp, dst_ptep);
+ }
+
+ dst_ptep = pte_offset_kernel(dst_pmdp, start);
+ src_ptep = pte_offset_kernel(src_pmdp, start);
+
+ do {
+ pte_t pte = READ_ONCE(*src_ptep);
+
+ if (pte_present(pte))
+ set_pte(dst_ptep, __pte(pte_val(pte) | pgprot_val(prot)));
+ } while (dst_ptep++, src_ptep++, start += PAGE_SIZE, start < end);
+
+ return 0;
+}
+
+static int temp_pgtable_map_pmd(pud_t *dst_pudp, pud_t *src_pudp, unsigned long start,
+ unsigned long end, pgprot_t prot)
+{
+ unsigned long next;
+ unsigned long ret;
+ pmd_t *src_pmdp;
+ pmd_t *dst_pmdp;
+
+ if (pud_none(READ_ONCE(*dst_pudp))) {
+ dst_pmdp = (pmd_t *)get_safe_page(GFP_ATOMIC);
+ if (!dst_pmdp)
+ return -ENOMEM;
+
+ pud_populate(NULL, dst_pudp, dst_pmdp);
+ }
+
+ dst_pmdp = pmd_offset(dst_pudp, start);
+ src_pmdp = pmd_offset(src_pudp, start);
+
+ do {
+ pmd_t pmd = READ_ONCE(*src_pmdp);
+
+ next = pmd_addr_end(start, end);
+
+ if (pmd_none(pmd))
+ continue;
+
+ if (pmd_leaf(pmd)) {
+ set_pmd(dst_pmdp, __pmd(pmd_val(pmd) | pgprot_val(prot)));
+ } else {
+ ret = temp_pgtable_map_pte(dst_pmdp, src_pmdp, start, next, prot);
+ if (ret)
+ return -ENOMEM;
+ }
+ } while (dst_pmdp++, src_pmdp++, start = next, start != end);
+
+ return 0;
+}
+
+static int temp_pgtable_map_pud(p4d_t *dst_p4dp, p4d_t *src_p4dp, unsigned long start,
+ unsigned long end, pgprot_t prot)
+{
+ unsigned long next;
+ unsigned long ret;
+ pud_t *dst_pudp;
+ pud_t *src_pudp;
+
+ if (p4d_none(READ_ONCE(*dst_p4dp))) {
+ dst_pudp = (pud_t *)get_safe_page(GFP_ATOMIC);
+ if (!dst_pudp)
+ return -ENOMEM;
+
+ p4d_populate(NULL, dst_p4dp, dst_pudp);
+ }
+
+ dst_pudp = pud_offset(dst_p4dp, start);
+ src_pudp = pud_offset(src_p4dp, start);
+
+ do {
+ pud_t pud = READ_ONCE(*src_pudp);
+
+ next = pud_addr_end(start, end);
+
+ if (pud_none(pud))
+ continue;
+
+ if (pud_leaf(pud)) {
+ set_pud(dst_pudp, __pud(pud_val(pud) | pgprot_val(prot)));
+ } else {
+ ret = temp_pgtable_map_pmd(dst_pudp, src_pudp, start, next, prot);
+ if (ret)
+ return -ENOMEM;
+ }
+ } while (dst_pudp++, src_pudp++, start = next, start != end);
+
+ return 0;
+}
+
+static int temp_pgtable_map_p4d(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start,
+ unsigned long end, pgprot_t prot)
+{
+ unsigned long next;
+ unsigned long ret;
+ p4d_t *dst_p4dp;
+ p4d_t *src_p4dp;
+
+ if (pgd_none(READ_ONCE(*dst_pgdp))) {
+ dst_p4dp = (p4d_t *)get_safe_page(GFP_ATOMIC);
+ if (!dst_p4dp)
+ return -ENOMEM;
+
+ pgd_populate(NULL, dst_pgdp, dst_p4dp);
+ }
+
+ dst_p4dp = p4d_offset(dst_pgdp, start);
+ src_p4dp = p4d_offset(src_pgdp, start);
+
+ do {
+ p4d_t p4d = READ_ONCE(*src_p4dp);
+
+ next = p4d_addr_end(start, end);
+
+ if (p4d_none(p4d))
+ continue;
+
+ if (p4d_leaf(p4d)) {
+ set_p4d(dst_p4dp, __p4d(p4d_val(p4d) | pgprot_val(prot)));
+ } else {
+ ret = temp_pgtable_map_pud(dst_p4dp, src_p4dp, start, next, prot);
+ if (ret)
+ return -ENOMEM;
+ }
+ } while (dst_p4dp++, src_p4dp++, start = next, start != end);
+
+ return 0;
+}
+
+static int temp_pgtable_mapping(pgd_t *pgdp, unsigned long start, unsigned long end, pgprot_t prot)
+{
+ pgd_t *dst_pgdp = pgd_offset_pgd(pgdp, start);
+ pgd_t *src_pgdp = pgd_offset_k(start);
+ unsigned long next;
+ unsigned long ret;
+
+ do {
+ pgd_t pgd = READ_ONCE(*src_pgdp);
+
+ next = pgd_addr_end(start, end);
+
+ if (pgd_none(pgd))
+ continue;
+
+ if (pgd_leaf(pgd)) {
+ set_pgd(dst_pgdp, __pgd(pgd_val(pgd) | pgprot_val(prot)));
+ } else {
+ ret = temp_pgtable_map_p4d(dst_pgdp, src_pgdp, start, next, prot);
+ if (ret)
+ return -ENOMEM;
+ }
+ } while (dst_pgdp++, src_pgdp++, start = next, start != end);
+
+ return 0;
+}
+
+static unsigned long relocate_restore_code(void)
+{
+ void *page = (void *)get_safe_page(GFP_ATOMIC);
+
+ if (!page)
+ return -ENOMEM;
+
+ copy_page(page, hibernate_core_restore_code);
+
+ /* Make the page containing the relocated code executable. */
+ set_memory_x((unsigned long)page, 1);
+
+ return (unsigned long)page;
+}
+
+int swsusp_arch_resume(void)
+{
+ unsigned long end = (unsigned long)pfn_to_virt(max_low_pfn);
+ unsigned long start = PAGE_OFFSET;
+ int ret;
+
+ /*
+ * Memory allocated by get_safe_page() will be dealt with by the hibernation core,
+ * we don't need to free it here.
+ */
+ resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
+ if (!resume_pg_dir)
+ return -ENOMEM;
+
+ /*
+ * Create a temporary page table and map the whole linear region as executable and
+ * writable.
+ */
+ ret = temp_pgtable_mapping(resume_pg_dir, start, end, __pgprot(_PAGE_WRITE | _PAGE_EXEC));
+ if (ret)
+ return ret;
+
+ /* Move the restore code to a new page so that it doesn't get overwritten by itself. */
+ relocated_restore_code = relocate_restore_code();
+ if (relocated_restore_code == -ENOMEM)
+ return -ENOMEM;
+
+ /*
+ * Map the __hibernate_cpu_resume() address to the temporary page table so that the
+ * restore code can jumps to it after finished restore the image. The next execution
+ * code doesn't find itself in a different address space after switching over to the
+ * original page table used by the hibernated image.
+ * The __hibernate_cpu_resume() mapping is unnecessary for RV32 since the kernel and
+ * linear addresses are identical, but different for RV64. To ensure consistency, we
+ * map it for both RV32 and RV64 kernels.
+ * Additionally, we should ensure that the page is writable before restoring the image.
+ */
+ start = (unsigned long)resume_hdr.restore_cpu_addr;
+ end = start + PAGE_SIZE;
+
+ ret = temp_pgtable_mapping(resume_pg_dir, start, end, __pgprot(_PAGE_WRITE));
+ if (ret)
+ return ret;
+
+ hibernate_restore_image(resume_hdr.saved_satp, (PFN_DOWN(__pa(resume_pg_dir)) | satp_mode),
+ resume_hdr.restore_cpu_addr);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP_SMP
+int hibernate_resume_nonboot_cpu_disable(void)
+{
+ if (sleep_cpu < 0) {
+ pr_err("Failing to resume from hibernate on an unknown CPU\n");
+ return -ENODEV;
+ }
+
+ return freeze_secondary_cpus(sleep_cpu);
+}
+#endif
+
+static int __init riscv_hibernate_init(void)
+{
+ hibernate_cpu_context = kzalloc(sizeof(*hibernate_cpu_context), GFP_KERNEL);
+
+ if (WARN_ON(!hibernate_cpu_context))
+ return -ENOMEM;
+
+ return 0;
+}
+
+early_initcall(riscv_hibernate_init);
diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index 92b9b759ab3d..c672c8ba9a2a 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c
@@ -524,19 +524,18 @@ static void sbi_srst_power_off(void)
* sbi_probe_extension() - Check if an SBI extension ID is supported or not.
* @extid: The extension ID to be probed.
*
- * Return: Extension specific nonzero value f yes, -ENOTSUPP otherwise.
+ * Return: 1 or an extension specific nonzero value if yes, 0 otherwise.
*/
-int sbi_probe_extension(int extid)
+long sbi_probe_extension(int extid)
{
struct sbiret ret;
ret = sbi_ecall(SBI_EXT_BASE, SBI_EXT_BASE_PROBE_EXT, extid,
0, 0, 0, 0, 0);
if (!ret.error)
- if (ret.value)
- return ret.value;
+ return ret.value;
- return -ENOTSUPP;
+ return 0;
}
EXPORT_SYMBOL(sbi_probe_extension);
@@ -599,26 +598,26 @@ void __init sbi_init(void)
if (!sbi_spec_is_0_1()) {
pr_info("SBI implementation ID=0x%lx Version=0x%lx\n",
sbi_get_firmware_id(), sbi_get_firmware_version());
- if (sbi_probe_extension(SBI_EXT_TIME) > 0) {
+ if (sbi_probe_extension(SBI_EXT_TIME)) {
__sbi_set_timer = __sbi_set_timer_v02;
pr_info("SBI TIME extension detected\n");
} else {
__sbi_set_timer = __sbi_set_timer_v01;
}
- if (sbi_probe_extension(SBI_EXT_IPI) > 0) {
+ if (sbi_probe_extension(SBI_EXT_IPI)) {
__sbi_send_ipi = __sbi_send_ipi_v02;
pr_info("SBI IPI extension detected\n");
} else {
__sbi_send_ipi = __sbi_send_ipi_v01;
}
- if (sbi_probe_extension(SBI_EXT_RFENCE) > 0) {
+ if (sbi_probe_extension(SBI_EXT_RFENCE)) {
__sbi_rfence = __sbi_rfence_v02;
pr_info("SBI RFENCE extension detected\n");
} else {
__sbi_rfence = __sbi_rfence_v01;
}
if ((sbi_spec_version >= sbi_mk_version(0, 3)) &&
- (sbi_probe_extension(SBI_EXT_SRST) > 0)) {
+ sbi_probe_extension(SBI_EXT_SRST)) {
pr_info("SBI SRST extension detected\n");
pm_power_off = sbi_srst_power_off;
sbi_srst_reboot_nb.notifier_call = sbi_srst_reboot;
diff --git a/arch/riscv/kernel/suspend.c b/arch/riscv/kernel/suspend.c
index 9ba24fb8cc93..3c89b8ec69c4 100644
--- a/arch/riscv/kernel/suspend.c
+++ b/arch/riscv/kernel/suspend.c
@@ -8,7 +8,7 @@
#include <asm/csr.h>
#include <asm/suspend.h>
-static void suspend_save_csrs(struct suspend_context *context)
+void suspend_save_csrs(struct suspend_context *context)
{
context->scratch = csr_read(CSR_SCRATCH);
context->tvec = csr_read(CSR_TVEC);
@@ -29,7 +29,7 @@ static void suspend_save_csrs(struct suspend_context *context)
#endif
}
-static void suspend_restore_csrs(struct suspend_context *context)
+void suspend_restore_csrs(struct suspend_context *context)
{
csr_write(CSR_SCRATCH, context->scratch);
csr_write(CSR_TVEC, context->tvec);
diff --git a/arch/riscv/kernel/suspend_entry.S b/arch/riscv/kernel/suspend_entry.S
index aafcca58c19d..12b52afe09a4 100644
--- a/arch/riscv/kernel/suspend_entry.S
+++ b/arch/riscv/kernel/suspend_entry.S
@@ -7,6 +7,7 @@
#include <linux/linkage.h>
#include <asm/asm.h>
#include <asm/asm-offsets.h>
+#include <asm/assembler.h>
#include <asm/csr.h>
#include <asm/xip_fixup.h>
@@ -83,39 +84,10 @@ ENTRY(__cpu_resume_enter)
add a0, a1, zero
/* Restore CSRs */
- REG_L t0, (SUSPEND_CONTEXT_REGS + PT_EPC)(a0)
- csrw CSR_EPC, t0
- REG_L t0, (SUSPEND_CONTEXT_REGS + PT_STATUS)(a0)
- csrw CSR_STATUS, t0
- REG_L t0, (SUSPEND_CONTEXT_REGS + PT_BADADDR)(a0)
- csrw CSR_TVAL, t0
- REG_L t0, (SUSPEND_CONTEXT_REGS + PT_CAUSE)(a0)
- csrw CSR_CAUSE, t0
+ suspend_restore_csrs
/* Restore registers (except A0 and T0-T6) */
- REG_L ra, (SUSPEND_CONTEXT_REGS + PT_RA)(a0)
- REG_L sp, (SUSPEND_CONTEXT_REGS + PT_SP)(a0)
- REG_L gp, (SUSPEND_CONTEXT_REGS + PT_GP)(a0)
- REG_L tp, (SUSPEND_CONTEXT_REGS + PT_TP)(a0)
- REG_L s0, (SUSPEND_CONTEXT_REGS + PT_S0)(a0)
- REG_L s1, (SUSPEND_CONTEXT_REGS + PT_S1)(a0)
- REG_L a1, (SUSPEND_CONTEXT_REGS + PT_A1)(a0)
- REG_L a2, (SUSPEND_CONTEXT_REGS + PT_A2)(a0)
- REG_L a3, (SUSPEND_CONTEXT_REGS + PT_A3)(a0)
- REG_L a4, (SUSPEND_CONTEXT_REGS + PT_A4)(a0)
- REG_L a5, (SUSPEND_CONTEXT_REGS + PT_A5)(a0)
- REG_L a6, (SUSPEND_CONTEXT_REGS + PT_A6)(a0)
- REG_L a7, (SUSPEND_CONTEXT_REGS + PT_A7)(a0)
- REG_L s2, (SUSPEND_CONTEXT_REGS + PT_S2)(a0)
- REG_L s3, (SUSPEND_CONTEXT_REGS + PT_S3)(a0)
- REG_L s4, (SUSPEND_CONTEXT_REGS + PT_S4)(a0)
- REG_L s5, (SUSPEND_CONTEXT_REGS + PT_S5)(a0)
- REG_L s6, (SUSPEND_CONTEXT_REGS + PT_S6)(a0)
- REG_L s7, (SUSPEND_CONTEXT_REGS + PT_S7)(a0)
- REG_L s8, (SUSPEND_CONTEXT_REGS + PT_S8)(a0)
- REG_L s9, (SUSPEND_CONTEXT_REGS + PT_S9)(a0)
- REG_L s10, (SUSPEND_CONTEXT_REGS + PT_S10)(a0)
- REG_L s11, (SUSPEND_CONTEXT_REGS + PT_S11)(a0)
+ suspend_restore_regs
/* Return zero value */
add a0, zero, zero
diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S
index 305877d85e96..f03b5697f8e0 100644
--- a/arch/riscv/kernel/vmlinux.lds.S
+++ b/arch/riscv/kernel/vmlinux.lds.S
@@ -104,6 +104,12 @@ SECTIONS
*(.rel.dyn*)
}
+ .rela.dyn : ALIGN(8) {
+ __rela_dyn_start = .;
+ *(.rela .rela*)
+ __rela_dyn_end = .;
+ }
+
__init_data_end = .;
. = ALIGN(8);
@@ -130,12 +136,6 @@ SECTIONS
*(.sdata*)
}
- .rela.dyn : ALIGN(8) {
- __rela_dyn_start = .;
- *(.rela .rela*)
- __rela_dyn_end = .;
- }
-
.got : { *(.got*) }
#ifdef CONFIG_RELOCATABLE
diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c
index 6396352b4e4d..a7112d583637 100644
--- a/arch/riscv/kvm/main.c
+++ b/arch/riscv/kvm/main.c
@@ -80,7 +80,7 @@ static int __init riscv_kvm_init(void)
return -ENODEV;
}
- if (sbi_probe_extension(SBI_EXT_RFENCE) <= 0) {
+ if (!sbi_probe_extension(SBI_EXT_RFENCE)) {
kvm_info("require SBI RFENCE extension\n");
return -ENODEV;
}
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index a39fe42baf55..747e5b1ef02d 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -919,8 +919,7 @@ static void __init create_kernel_page_table(pgd_t *pgdir, bool early)
* this means 2 PMD entries whereas for 32-bit kernel, this is only 1 PGDIR
* entry.
*/
-static void __init create_fdt_early_page_table(pgd_t *pgdir,
- uintptr_t fix_fdt_va,
+static void __init create_fdt_early_page_table(uintptr_t fix_fdt_va,
uintptr_t dtb_pa)
{
uintptr_t pa = dtb_pa & ~(PMD_SIZE - 1);
@@ -1132,8 +1131,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
create_kernel_page_table(early_pg_dir, true);
/* Setup early mapping for FDT early scan */
- create_fdt_early_page_table(early_pg_dir,
- __fix_to_virt(FIX_FDT), dtb_pa);
+ create_fdt_early_page_table(__fix_to_virt(FIX_FDT), dtb_pa);
/*
* Bootime fixmap only can handle PMD_SIZE mapping. Thus, boot-ioremap
diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c
index 86c56616e5de..ea3d61de065b 100644
--- a/arch/riscv/mm/pageattr.c
+++ b/arch/riscv/mm/pageattr.c
@@ -217,18 +217,26 @@ bool kernel_page_present(struct page *page)
pgd = pgd_offset_k(addr);
if (!pgd_present(*pgd))
return false;
+ if (pgd_leaf(*pgd))
+ return true;
p4d = p4d_offset(pgd, addr);
if (!p4d_present(*p4d))
return false;
+ if (p4d_leaf(*p4d))
+ return true;
pud = pud_offset(p4d, addr);
if (!pud_present(*pud))
return false;
+ if (pud_leaf(*pud))
+ return true;
pmd = pmd_offset(pud, addr);
if (!pmd_present(*pmd))
return false;
+ if (pmd_leaf(*pmd))
+ return true;
pte = pte_offset_kernel(pmd, addr);
return pte_present(*pte);
diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.c b/drivers/cpuidle/cpuidle-riscv-sbi.c
index f2ccda2c3871..e8094fc92491 100644
--- a/drivers/cpuidle/cpuidle-riscv-sbi.c
+++ b/drivers/cpuidle/cpuidle-riscv-sbi.c
@@ -613,7 +613,7 @@ static int __init sbi_cpuidle_init(void)
* 2) SBI HSM extension is available
*/
if ((sbi_spec_version < sbi_mk_version(0, 3)) ||
- sbi_probe_extension(SBI_EXT_HSM) <= 0) {
+ !sbi_probe_extension(SBI_EXT_HSM)) {
pr_info("HSM suspend not available\n");
return 0;
}
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 70cb50fd41c2..4f3ac296b3e2 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -924,7 +924,7 @@ static int __init pmu_sbi_devinit(void)
struct platform_device *pdev;
if (sbi_spec_version < sbi_mk_version(0, 3) ||
- sbi_probe_extension(SBI_EXT_PMU) <= 0) {
+ !sbi_probe_extension(SBI_EXT_PMU)) {
return 0;
}