RISC-V Patches for the 5.9 Merge Window, Part 1

We have a lot of new kernel features for this merge window:
 
 * ARCH_SUPPORTS_ATOMIC_RMW, to allow OSQ locks to be enabled.
 * The ability to enable NO_HZ_FULL
 * Support for enabling kcov, kmemleak, stack protector, and VM debugging.
 * JUMP_LABEL support.
 
 There are also a handful of cleanups.
 
 next points out a trivial Kconfig merge conflict.  I don't see any way to have
 done this better: the symbols are sorted, it just happens that
 HAVE_COPY_THREAD_TLS was in the middle of two new symbols.  In case it helps
 any, here's a pretty current conflict resolution:
 
 diff --cc arch/riscv/Kconfig
 index bc37241a6875,6c4bce7cad8a..7b5905529146
 --- a/arch/riscv/Kconfig
 +++ b/arch/riscv/Kconfig
 @@@ -57,9 -54,6 +59,8 @@@ config RISC
         select HAVE_ARCH_SECCOMP_FILTER
         select HAVE_ARCH_TRACEHOOK
         select HAVE_ASM_MODVERSIONS
  +      select HAVE_CONTEXT_TRACKING
 -       select HAVE_COPY_THREAD_TLS
  +      select HAVE_DEBUG_KMEMLEAK
         select HAVE_DMA_CONTIGUOUS if MMU
         select HAVE_EBPF_JIT if MMU
         select HAVE_FUTEX_CMPXCHG if FUTEX
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Merge tag 'riscv-for-linus-5.9-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:
 "We have a lot of new kernel features for this merge window:

   - ARCH_SUPPORTS_ATOMIC_RMW, to allow OSQ locks to be enabled

   - The ability to enable NO_HZ_FULL

   - Support for enabling kcov, kmemleak, stack protector, and VM
     debugging

   - JUMP_LABEL support

  There are also a handful of cleanups"

* tag 'riscv-for-linus-5.9-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (24 commits)
  riscv: disable stack-protector for vDSO
  RISC-V: Fix build warning for smpboot.c
  riscv: fix build warning of mm/pageattr
  riscv: Fix build warning for mm/init
  RISC-V: Setup exception vector early
  riscv: Select ARCH_HAS_DEBUG_VM_PGTABLE
  riscv: Use generic pgprot_* macros from <linux/pgtable.h>
  mm: pgtable: Make generic pgprot_* macros available for no-MMU
  riscv: Cleanup unnecessary define in asm-offset.c
  riscv: Add jump-label implementation
  riscv: Support R_RISCV_ADD64 and R_RISCV_SUB64 relocs
  Replace HTTP links with HTTPS ones: RISC-V
  riscv: Add STACKPROTECTOR supported
  riscv: Fix typo in asm/hwcap.h uapi header
  riscv: Add kmemleak support
  riscv: Allow building with kcov coverage
  riscv: Enable context tracking
  riscv: Support irq_work via self IPIs
  riscv: Enable LOCKDEP_SUPPORT & fixup TRACE_IRQFLAGS_SUPPORT
  riscv: Fixup lockdep_assert_held with wrong param cpu_running
  ...

Documentation/features/core/jump-labels/arch-support.txt

@@ -23,7 +23,7 @@
     |    openrisc: | TODO |
     |      parisc: |  ok  |
     |     powerpc: |  ok  |
-    |       riscv: | TODO |
+    |       riscv: |  ok  |
     |        s390: |  ok  |
     |          sh: | TODO |
     |       sparc: |  ok  |

Documentation/features/debug/debug-vm-pgtable/arch-support.txt

@@ -23,7 +23,7 @@
     |    openrisc: | TODO |
     |      parisc: | TODO |
     |     powerpc: |  ok  |
-    |       riscv: | TODO |
+    |       riscv: |  ok  |
     |        s390: |  ok  |
     |          sh: | TODO |
     |       sparc: | TODO |

arch/riscv/Kconfig

@@ -13,11 +13,14 @@ config 32BIT
 config RISCV
 	def_bool y
 	select ARCH_CLOCKSOURCE_INIT
+	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_HAS_BINFMT_FLAT
+	select ARCH_HAS_DEBUG_VM_PGTABLE
 	select ARCH_HAS_DEBUG_VIRTUAL if MMU
 	select ARCH_HAS_DEBUG_WX
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_GIGANTIC_PAGE
+	select ARCH_HAS_KCOV
 	select ARCH_HAS_MMIOWB
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_SET_DIRECT_MAP
@@ -47,6 +50,8 @@ config RISCV
 	select GENERIC_TIME_VSYSCALL if MMU && 64BIT
 	select HANDLE_DOMAIN_IRQ
 	select HAVE_ARCH_AUDITSYSCALL
+	select HAVE_ARCH_JUMP_LABEL
+	select HAVE_ARCH_JUMP_LABEL_RELATIVE
 	select HAVE_ARCH_KASAN if MMU && 64BIT
 	select HAVE_ARCH_KGDB
 	select HAVE_ARCH_KGDB_QXFER_PKT
@@ -54,14 +59,18 @@ config RISCV
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ASM_MODVERSIONS
+	select HAVE_CONTEXT_TRACKING
+	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DMA_CONTIGUOUS if MMU
 	select HAVE_EBPF_JIT if MMU
 	select HAVE_FUTEX_CMPXCHG if FUTEX
+	select HAVE_GCC_PLUGINS
 	select HAVE_GENERIC_VDSO if MMU && 64BIT
 	select HAVE_PCI
 	select HAVE_PERF_EVENTS
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
+	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select IRQ_DOMAIN
 	select MODULES_USE_ELF_RELA if MODULES
@@ -179,6 +188,9 @@ config PGTABLE_LEVELS
 	default 3 if 64BIT
 	default 2
 
+config LOCKDEP_SUPPORT
+	def_bool y
+
 source "arch/riscv/Kconfig.socs"
 
 menu "Platform type"

arch/riscv/boot/Makefile

@@ -14,6 +14,8 @@
 # Based on the ia64 and arm64 boot/Makefile.
 #
 
+KCOV_INSTRUMENT := n
+
 OBJCOPYFLAGS_Image :=-O binary -R .note -R .note.gnu.build-id -R .comment -S
 
 targets := Image loader

arch/riscv/configs/defconfig

@@ -17,6 +17,7 @@ CONFIG_BPF_SYSCALL=y
 CONFIG_SOC_SIFIVE=y
 CONFIG_SOC_VIRT=y
 CONFIG_SMP=y
+CONFIG_JUMP_LABEL=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_NET=y

arch/riscv/configs/nommu_k210_defconfig

@@ -33,6 +33,7 @@ CONFIG_SMP=y
 CONFIG_NR_CPUS=2
 CONFIG_CMDLINE="earlycon console=ttySIF0"
 CONFIG_CMDLINE_FORCE=y
+CONFIG_JUMP_LABEL=y
 # CONFIG_BLOCK is not set
 CONFIG_BINFMT_FLAT=y
 # CONFIG_COREDUMP is not set

arch/riscv/configs/nommu_virt_defconfig

@@ -30,6 +30,7 @@ CONFIG_MAXPHYSMEM_2GB=y
 CONFIG_SMP=y
 CONFIG_CMDLINE="root=/dev/vda rw earlycon=uart8250,mmio,0x10000000,115200n8 console=ttyS0"
 CONFIG_CMDLINE_FORCE=y
+CONFIG_JUMP_LABEL=y
 # CONFIG_BLK_DEV_BSG is not set
 CONFIG_PARTITION_ADVANCED=y
 # CONFIG_MSDOS_PARTITION is not set

arch/riscv/configs/rv32_defconfig

@@ -17,6 +17,7 @@ CONFIG_BPF_SYSCALL=y
 CONFIG_SOC_VIRT=y
 CONFIG_ARCH_RV32I=y
 CONFIG_SMP=y
+CONFIG_JUMP_LABEL=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_NET=y

arch/riscv/include/asm/irq_work.h

@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_RISCV_IRQ_WORK_H
+#define _ASM_RISCV_IRQ_WORK_H
+
+static inline bool arch_irq_work_has_interrupt(void)
+{
+	return true;
+}
+extern void arch_irq_work_raise(void);
+#endif /* _ASM_RISCV_IRQ_WORK_H */

arch/riscv/include/asm/jump_label.h

@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 Emil Renner Berthing
+ *
+ * Based on arch/arm64/include/asm/jump_label.h
+ */
+#ifndef __ASM_JUMP_LABEL_H
+#define __ASM_JUMP_LABEL_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+#include <asm/asm.h>
+
+#define JUMP_LABEL_NOP_SIZE 4
+
+static __always_inline bool arch_static_branch(struct static_key *key,
+					       bool branch)
+{
+	asm_volatile_goto(
+		"	.option push				\n\t"
+		"	.option norelax				\n\t"
+		"	.option norvc				\n\t"
+		"1:	nop					\n\t"
+		"	.option pop				\n\t"
+		"	.pushsection	__jump_table, \"aw\"	\n\t"
+		"	.align		" RISCV_LGPTR "		\n\t"
+		"	.long		1b - ., %l[label] - .	\n\t"
+		"	" RISCV_PTR "	%0 - .			\n\t"
+		"	.popsection				\n\t"
+		:  :  "i"(&((char *)key)[branch]) :  : label);
+
+	return false;
+label:
+	return true;
+}
+
+static __always_inline bool arch_static_branch_jump(struct static_key *key,
+						    bool branch)
+{
+	asm_volatile_goto(
+		"	.option push				\n\t"
+		"	.option norelax				\n\t"
+		"	.option norvc				\n\t"
+		"1:	jal		zero, %l[label]		\n\t"
+		"	.option pop				\n\t"
+		"	.pushsection	__jump_table, \"aw\"	\n\t"
+		"	.align		" RISCV_LGPTR "		\n\t"
+		"	.long		1b - ., %l[label] - .	\n\t"
+		"	" RISCV_PTR "	%0 - .			\n\t"
+		"	.popsection				\n\t"
+		:  :  "i"(&((char *)key)[branch]) :  : label);
+
+	return false;
+label:
+	return true;
+}
+
+#endif  /* __ASSEMBLY__ */
+#endif	/* __ASM_JUMP_LABEL_H */

arch/riscv/include/asm/mmio.h

@@ -14,12 +14,6 @@
 #include <linux/types.h>
 #include <asm/mmiowb.h>
 
-#ifndef CONFIG_MMU
-#define pgprot_noncached(x)	(x)
-#define pgprot_writecombine(x)	(x)
-#define pgprot_device(x)	(x)
-#endif /* CONFIG_MMU */
-
 /* Generic IO read/write.  These perform native-endian accesses. */
 #define __raw_writeb __raw_writeb
 static inline void __raw_writeb(u8 val, volatile void __iomem *addr)

arch/riscv/include/asm/smp.h

@@ -40,6 +40,9 @@ void arch_send_call_function_single_ipi(int cpu);
 int riscv_hartid_to_cpuid(int hartid);
 void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out);
 
+/* Secondary hart entry */
+asmlinkage void smp_callin(void);
+
 /*
  * Obtains the hart ID of the currently executing task.  This relies on
  * THREAD_INFO_IN_TASK, but we define that unconditionally.

arch/riscv/include/asm/stackprotector.h

@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _ASM_RISCV_STACKPROTECTOR_H
+#define _ASM_RISCV_STACKPROTECTOR_H
+
+#include <linux/random.h>
+#include <linux/version.h>
+#include <asm/timex.h>
+
+extern unsigned long __stack_chk_guard;
+
+/*
+ * Initialize the stackprotector canary value.
+ *
+ * NOTE: this must only be called from functions that never return,
+ * and it must always be inlined.
+ */
+static __always_inline void boot_init_stack_canary(void)
+{
+	unsigned long canary;
+	unsigned long tsc;
+
+	/* Try to get a semi random initial value. */
+	get_random_bytes(&canary, sizeof(canary));
+	tsc = get_cycles();
+	canary += tsc + (tsc << BITS_PER_LONG/2);
+	canary ^= LINUX_VERSION_CODE;
+	canary &= CANARY_MASK;
+
+	current->stack_canary = canary;
+	__stack_chk_guard = current->stack_canary;
+}
+#endif /* _ASM_RISCV_STACKPROTECTOR_H */

arch/riscv/include/uapi/asm/hwcap.h

@@ -11,7 +11,7 @@
 /*
  * Linux saves the floating-point registers according to the ISA Linux is
  * executing on, as opposed to the ISA the user program is compiled for.  This
- * is necessary for a handful of esoteric use cases: for example, userpsace
+ * is necessary for a handful of esoteric use cases: for example, userspace
  * threading libraries must be able to examine the actual machine state in
  * order to fully reconstruct the state of a thread.
  */

arch/riscv/include/uapi/asm/unistd.h

@@ -12,7 +12,7 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 #ifdef __LP64__

arch/riscv/kernel/Makefile

@@ -53,4 +53,6 @@ endif
 obj-$(CONFIG_HOTPLUG_CPU)	+= cpu-hotplug.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
 
+obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
+
 clean:

arch/riscv/kernel/asm-offsets.c

@@ -27,9 +27,6 @@ void asm_offsets(void)
 	OFFSET(TASK_THREAD_S9, task_struct, thread.s[9]);
 	OFFSET(TASK_THREAD_S10, task_struct, thread.s[10]);
 	OFFSET(TASK_THREAD_S11, task_struct, thread.s[11]);
-	OFFSET(TASK_THREAD_SP, task_struct, thread.sp);
-	OFFSET(TASK_STACK, task_struct, stack);
-	OFFSET(TASK_TI, task_struct, thread_info);
 	OFFSET(TASK_TI_FLAGS, task_struct, thread_info.flags);
 	OFFSET(TASK_TI_PREEMPT_COUNT, task_struct, thread_info.preempt_count);
 	OFFSET(TASK_TI_KERNEL_SP, task_struct, thread_info.kernel_sp);

arch/riscv/kernel/entry.S

@@ -97,19 +97,36 @@ _save_context:
 	la gp, __global_pointer$
 .option pop
 
-	la ra, ret_from_exception
+#ifdef CONFIG_TRACE_IRQFLAGS
+	call trace_hardirqs_off
+#endif
+
+#ifdef CONFIG_CONTEXT_TRACKING
+	/* If previous state is in user mode, call context_tracking_user_exit. */
+	li   a0, SR_PP
+	and a0, s1, a0
+	bnez a0, skip_context_tracking
+	call context_tracking_user_exit
+skip_context_tracking:
+#endif
+
 	/*
 	 * MSB of cause differentiates between
 	 * interrupts and exceptions
 	 */
 	bge s4, zero, 1f
 
+	la ra, ret_from_exception
+
 	/* Handle interrupts */
 	move a0, sp /* pt_regs */
 	la a1, handle_arch_irq
 	REG_L a1, (a1)
 	jr a1
 1:
+#ifdef CONFIG_TRACE_IRQFLAGS
+	call trace_hardirqs_on
+#endif
 	/*
 	 * Exceptions run with interrupts enabled or disabled depending on the
 	 * state of SR_PIE in m/sstatus.
@@ -119,6 +136,7 @@ _save_context:
 	csrs CSR_STATUS, SR_IE
 
 1:
+	la ra, ret_from_exception
 	/* Handle syscalls */
 	li t0, EXC_SYSCALL
 	beq s4, t0, handle_syscall
@@ -137,6 +155,17 @@ _save_context:
 	tail do_trap_unknown
 
 handle_syscall:
+#if defined(CONFIG_TRACE_IRQFLAGS) || defined(CONFIG_CONTEXT_TRACKING)
+	/* Recover a0 - a7 for system calls */
+	REG_L a0, PT_A0(sp)
+	REG_L a1, PT_A1(sp)
+	REG_L a2, PT_A2(sp)
+	REG_L a3, PT_A3(sp)
+	REG_L a4, PT_A4(sp)
+	REG_L a5, PT_A5(sp)
+	REG_L a6, PT_A6(sp)
+	REG_L a7, PT_A7(sp)
+#endif
 	 /* save the initial A0 value (needed in signal handlers) */
 	REG_S a0, PT_ORIG_A0(sp)
 	/*
@@ -190,6 +219,9 @@ ret_from_syscall_rejected:
 ret_from_exception:
 	REG_L s0, PT_STATUS(sp)
 	csrc CSR_STATUS, SR_IE
+#ifdef CONFIG_TRACE_IRQFLAGS
+	call trace_hardirqs_off
+#endif
 #ifdef CONFIG_RISCV_M_MODE
 	/* the MPP value is too large to be used as an immediate arg for addi */
 	li t0, SR_MPP
@@ -205,6 +237,10 @@ resume_userspace:
 	andi s1, s0, _TIF_WORK_MASK
 	bnez s1, work_pending
 
+#ifdef CONFIG_CONTEXT_TRACKING
+	call context_tracking_user_enter
+#endif
+
 	/* Save unwound kernel stack pointer in thread_info */
 	addi s0, sp, PT_SIZE_ON_STACK
 	REG_S s0, TASK_TI_KERNEL_SP(tp)
@@ -216,6 +252,16 @@ resume_userspace:
 	csrw CSR_SCRATCH, tp
 
 restore_all:
+#ifdef CONFIG_TRACE_IRQFLAGS
+	REG_L s1, PT_STATUS(sp)
+	andi t0, s1, SR_PIE
+	beqz t0, 1f
+	call trace_hardirqs_on
+	j 2f
+1:
+	call trace_hardirqs_off
+2:
+#endif
 	REG_L a0, PT_STATUS(sp)
 	/*
 	 * The current load reservation is effectively part of the processor's
@@ -389,12 +435,8 @@ ENTRY(__switch_to)
 	lw a4, TASK_TI_CPU(a1)
 	sw a3, TASK_TI_CPU(a1)
 	sw a4, TASK_TI_CPU(a0)
-#if TASK_TI != 0
-#error "TASK_TI != 0: tp will contain a 'struct thread_info', not a 'struct task_struct' so get_current() won't work."
-	addi tp, a1, TASK_TI
-#else
+	/* The offset of thread_info in task_struct is zero. */
 	move tp, a1
-#endif
 	ret
 ENDPROC(__switch_to)
 

arch/riscv/kernel/head.S

@@ -77,10 +77,16 @@ relocate:
 	csrw CSR_SATP, a0
 .align 2
 1:
-	/* Set trap vector to spin forever to help debug */
-	la a0, .Lsecondary_park
+	/* Set trap vector to exception handler */
+	la a0, handle_exception
 	csrw CSR_TVEC, a0
 
+	/*
+	 * Set sup0 scratch register to 0, indicating to exception vector that
+	 * we are presently executing in kernel.
+	 */
+	csrw CSR_SCRATCH, zero
+
 	/* Reload the global pointer */
 .option push
 .option norelax

arch/riscv/kernel/jump_label.c

@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Emil Renner Berthing
+ *
+ * Based on arch/arm64/kernel/jump_label.c
+ */
+#include <linux/jump_label.h>
+#include <linux/kernel.h>
+#include <linux/memory.h>
+#include <linux/mutex.h>
+#include <asm/bug.h>
+#include <asm/patch.h>
+
+#define RISCV_INSN_NOP 0x00000013U
+#define RISCV_INSN_JAL 0x0000006fU
+
+void arch_jump_label_transform(struct jump_entry *entry,
+			       enum jump_label_type type)
+{
+	void *addr = (void *)jump_entry_code(entry);
+	u32 insn;
+
+	if (type == JUMP_LABEL_JMP) {
+		long offset = jump_entry_target(entry) - jump_entry_code(entry);
+
+		if (WARN_ON(offset & 1 || offset < -524288 || offset >= 524288))
+			return;
+
+		insn = RISCV_INSN_JAL |
+			(((u32)offset & GENMASK(19, 12)) << (12 - 12)) |
+			(((u32)offset & GENMASK(11, 11)) << (20 - 11)) |
+			(((u32)offset & GENMASK(10,  1)) << (21 -  1)) |
+			(((u32)offset & GENMASK(20, 20)) << (31 - 20));
+	} else {
+		insn = RISCV_INSN_NOP;
+	}
+
+	mutex_lock(&text_mutex);
+	patch_text_nosync(addr, &insn, sizeof(insn));
+	mutex_unlock(&text_mutex);
+}
+
+void arch_jump_label_transform_static(struct jump_entry *entry,
+				      enum jump_label_type type)
+{
+	/*
+	 * We use the same instructions in the arch_static_branch and
+	 * arch_static_branch_jump inline functions, so there's no
+	 * need to patch them up here.
+	 * The core will call arch_jump_label_transform  when those
+	 * instructions need to be replaced.
+	 */
+}

arch/riscv/kernel/module.c

@@ -263,6 +263,13 @@ static int apply_r_riscv_add32_rela(struct module *me, u32 *location,
 	return 0;
 }
 
+static int apply_r_riscv_add64_rela(struct module *me, u32 *location,
+				    Elf_Addr v)
+{
+	*(u64 *)location += (u64)v;
+	return 0;
+}
+
 static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
 				    Elf_Addr v)
 {
@@ -270,6 +277,13 @@ static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
 	return 0;
 }
 
+static int apply_r_riscv_sub64_rela(struct module *me, u32 *location,
+				    Elf_Addr v)
+{
+	*(u64 *)location -= (u64)v;
+	return 0;
+}
+
 static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
 				Elf_Addr v) = {
 	[R_RISCV_32]			= apply_r_riscv_32_rela,
@@ -290,7 +304,9 @@ static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
 	[R_RISCV_RELAX]			= apply_r_riscv_relax_rela,
 	[R_RISCV_ALIGN]			= apply_r_riscv_align_rela,
 	[R_RISCV_ADD32]			= apply_r_riscv_add32_rela,
+	[R_RISCV_ADD64]			= apply_r_riscv_add64_rela,
 	[R_RISCV_SUB32]			= apply_r_riscv_sub32_rela,
+	[R_RISCV_SUB64]			= apply_r_riscv_sub64_rela,
 };
 
 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,

arch/riscv/kernel/process.c

@@ -24,6 +24,12 @@
 
 register unsigned long gp_in_global __asm__("gp");
 
+#ifdef CONFIG_STACKPROTECTOR
+#include <linux/stackprotector.h>
+unsigned long __stack_chk_guard __read_mostly;
+EXPORT_SYMBOL(__stack_chk_guard);
+#endif
+
 extern asmlinkage void ret_from_fork(void);
 extern asmlinkage void ret_from_kernel_thread(void);
 

arch/riscv/kernel/smp.c

@@ -16,6 +16,7 @@
 #include <linux/sched.h>
 #include <linux/seq_file.h>
 #include <linux/delay.h>
+#include <linux/irq_work.h>
 
 #include <asm/clint.h>
 #include <asm/sbi.h>
@@ -26,6 +27,7 @@ enum ipi_message_type {
 	IPI_RESCHEDULE,
 	IPI_CALL_FUNC,
 	IPI_CPU_STOP,
+	IPI_IRQ_WORK,
 	IPI_MAX
 };
 
@@ -123,6 +125,13 @@ static inline void clear_ipi(void)
 		clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id()));
 }
 
+#ifdef CONFIG_IRQ_WORK
+void arch_irq_work_raise(void)
+{
+	send_ipi_single(smp_processor_id(), IPI_IRQ_WORK);
+}
+#endif
+
 void handle_IPI(struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
@@ -158,6 +167,11 @@ void handle_IPI(struct pt_regs *regs)
 			ipi_stop();
 		}
 
+		if (ops & (1 << IPI_IRQ_WORK)) {
+			stats[IPI_IRQ_WORK]++;
+			irq_work_run();
+		}
+
 		BUG_ON((ops >> IPI_MAX) != 0);
 
 		/* Order data access and bit testing. */
@@ -173,6 +187,7 @@ static const char * const ipi_names[] = {
 	[IPI_RESCHEDULE]	= "Rescheduling interrupts",
 	[IPI_CALL_FUNC]		= "Function call interrupts",
 	[IPI_CPU_STOP]		= "CPU stop interrupts",
+	[IPI_IRQ_WORK]		= "IRQ work interrupts",
 };
 
 void show_ipi_stats(struct seq_file *p, int prec)

arch/riscv/kernel/smpboot.c

@@ -106,7 +106,7 @@ void __init setup_smp(void)
 	}
 }
 
-int start_secondary_cpu(int cpu, struct task_struct *tidle)
+static int start_secondary_cpu(int cpu, struct task_struct *tidle)
 {
 	if (cpu_ops[cpu]->cpu_start)
 		return cpu_ops[cpu]->cpu_start(cpu, tidle);
@@ -121,7 +121,6 @@ int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 
 	ret = start_secondary_cpu(cpu, tidle);
 	if (!ret) {
-		lockdep_assert_held(&cpu_running);
 		wait_for_completion_timeout(&cpu_running,
 					    msecs_to_jiffies(1000));
 
@@ -146,6 +145,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
 asmlinkage __visible void smp_callin(void)
 {
 	struct mm_struct *mm = &init_mm;
+	unsigned int curr_cpuid = smp_processor_id();
 
 	if (!IS_ENABLED(CONFIG_RISCV_SBI))
 		clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id()));
@@ -154,10 +154,10 @@ asmlinkage __visible void smp_callin(void)
 	mmgrab(mm);
 	current->active_mm = mm;
 
-	trap_init();
-	notify_cpu_starting(smp_processor_id());
-	update_siblings_masks(smp_processor_id());
-	set_cpu_online(smp_processor_id(), 1);
+	notify_cpu_starting(curr_cpuid);
+	update_siblings_masks(curr_cpuid);
+	set_cpu_online(curr_cpuid, 1);
+
 	/*
 	 * Remote TLB flushes are ignored while the CPU is offline, so emit
 	 * a local TLB flush right now just in case.

arch/riscv/kernel/traps.c

@@ -174,13 +174,7 @@ int is_valid_bugaddr(unsigned long pc)
 }
 #endif /* CONFIG_GENERIC_BUG */
 
+/* stvec & scratch is already set from head.S */
 void trap_init(void)
 {
-	/*
-	 * Set sup0 scratch register to 0, indicating to exception vector
-	 * that we are presently executing in the kernel
-	 */
-	csr_write(CSR_SCRATCH, 0);
-	/* Set the exception vector address */
-	csr_write(CSR_TVEC, &handle_exception);
 }

arch/riscv/kernel/vdso/Makefile

@@ -16,6 +16,8 @@ vdso-syms += flush_icache
 # Files to link into the vdso
 obj-vdso = $(patsubst %, %.o, $(vdso-syms)) note.o
 
+ccflags-y := -fno-stack-protector
+
 ifneq ($(c-gettimeofday-y),)
   CFLAGS_vgettimeofday.o += -fPIC -include $(c-gettimeofday-y)
 endif
@@ -32,6 +34,7 @@ CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os
 
 # Disable gcov profiling for VDSO code
 GCOV_PROFILE := n
+KCOV_INSTRUMENT := n
 
 # Force dependency
 $(obj)/vdso.o: $(obj)/vdso.so

arch/riscv/kernel/vmlinux.lds.S

@@ -22,6 +22,7 @@ SECTIONS
 	/* Beginning of code and text segment */
 	. = LOAD_OFFSET;
 	_start = .;
+	_stext = .;
 	HEAD_TEXT_SECTION
 	. = ALIGN(PAGE_SIZE);
 
@@ -54,7 +55,6 @@ SECTIONS
 	. = ALIGN(SECTION_ALIGN);
 	.text : {
 		_text = .;
-		_stext = .;
 		TEXT_TEXT
 		SCHED_TEXT
 		CPUIDLE_TEXT

arch/riscv/mm/Makefile

@@ -5,6 +5,8 @@ ifdef CONFIG_FTRACE
 CFLAGS_REMOVE_init.o = -pg
 endif
 
+KCOV_INSTRUMENT_init.o := n
+
 obj-y += init.o
 obj-y += extable.o
 obj-$(CONFIG_MMU) += fault.o pageattr.o

arch/riscv/mm/init.c

@@ -541,6 +541,32 @@ void mark_rodata_ro(void)
 }
 #endif
 
+static void __init resource_init(void)
+{
+	struct memblock_region *region;
+
+	for_each_memblock(memory, region) {
+		struct resource *res;
+
+		res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
+		if (!res)
+			panic("%s: Failed to allocate %zu bytes\n", __func__,
+			      sizeof(struct resource));
+
+		if (memblock_is_nomap(region)) {
+			res->name = "reserved";
+			res->flags = IORESOURCE_MEM;
+		} else {
+			res->name = "System RAM";
+			res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+		}
+		res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
+		res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;
+
+		request_resource(&iomem_resource, res);
+	}
+}
+
 void __init paging_init(void)
 {
 	setup_vm_final();
@@ -548,6 +574,7 @@ void __init paging_init(void)
 	sparse_init();
 	setup_zero_page();
 	zone_sizes_init();
+	resource_init();
 }
 
 #ifdef CONFIG_SPARSEMEM_VMEMMAP

arch/riscv/mm/pageattr.c

@@ -7,6 +7,7 @@
 #include <linux/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/bitops.h>
+#include <asm/set_memory.h>
 
 struct pageattr_masks {
 	pgprot_t set_mask;
@@ -94,7 +95,7 @@ static int pageattr_pte_hole(unsigned long addr, unsigned long next,
 	return 0;
 }
 
-const static struct mm_walk_ops pageattr_ops = {
+static const struct mm_walk_ops pageattr_ops = {
 	.pgd_entry = pageattr_pgd_entry,
 	.p4d_entry = pageattr_p4d_entry,
 	.pud_entry = pageattr_pud_entry,

include/linux/pgtable.h

@@ -647,40 +647,6 @@ static inline int arch_unmap_one(struct mm_struct *mm,
 #define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
 #endif
 
-#ifndef pgprot_nx
-#define pgprot_nx(prot)	(prot)
-#endif
-
-#ifndef pgprot_noncached
-#define pgprot_noncached(prot)	(prot)
-#endif
-
-#ifndef pgprot_writecombine
-#define pgprot_writecombine pgprot_noncached
-#endif
-
-#ifndef pgprot_writethrough
-#define pgprot_writethrough pgprot_noncached
-#endif
-
-#ifndef pgprot_device
-#define pgprot_device pgprot_noncached
-#endif
-
-#ifndef pgprot_modify
-#define pgprot_modify pgprot_modify
-static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
-{
-	if (pgprot_val(oldprot) == pgprot_val(pgprot_noncached(oldprot)))
-		newprot = pgprot_noncached(newprot);
-	if (pgprot_val(oldprot) == pgprot_val(pgprot_writecombine(oldprot)))
-		newprot = pgprot_writecombine(newprot);
-	if (pgprot_val(oldprot) == pgprot_val(pgprot_device(oldprot)))
-		newprot = pgprot_device(newprot);
-	return newprot;
-}
-#endif
-
 /*
  * When walking page tables, get the address of the next boundary,
  * or the end address of the range if that comes earlier.  Although no
@@ -840,6 +806,43 @@ static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
  * No-op macros that just return the current protection value. Defined here
  * because these macros can be used used even if CONFIG_MMU is not defined.
  */
+
+#ifndef pgprot_nx
+#define pgprot_nx(prot)	(prot)
+#endif
+
+#ifndef pgprot_noncached
+#define pgprot_noncached(prot)	(prot)
+#endif
+
+#ifndef pgprot_writecombine
+#define pgprot_writecombine pgprot_noncached
+#endif
+
+#ifndef pgprot_writethrough
+#define pgprot_writethrough pgprot_noncached
+#endif
+
+#ifndef pgprot_device
+#define pgprot_device pgprot_noncached
+#endif
+
+#ifdef CONFIG_MMU
+#ifndef pgprot_modify
+#define pgprot_modify pgprot_modify
+static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
+{
+	if (pgprot_val(oldprot) == pgprot_val(pgprot_noncached(oldprot)))
+		newprot = pgprot_noncached(newprot);
+	if (pgprot_val(oldprot) == pgprot_val(pgprot_writecombine(oldprot)))
+		newprot = pgprot_writecombine(newprot);
+	if (pgprot_val(oldprot) == pgprot_val(pgprot_device(oldprot)))
+		newprot = pgprot_device(newprot);
+	return newprot;
+}
+#endif
+#endif /* CONFIG_MMU */
+
 #ifndef pgprot_encrypted
 #define pgprot_encrypted(prot)	(prot)
 #endif

tools/arch/riscv/include/uapi/asm/unistd.h

@@ -12,7 +12,7 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 #ifdef __LP64__