Merge tag 'csky-for-linus-5.9-rc1' of https://github.com/c-sky/csky-linux

Pull arch/csky updates from Guo Ren:
 "New features:
   - seccomp-filter
   - err-injection
   - top-down&random mmap-layout
   - irq_work
   - show_ipi
   - context-tracking

  Fixes & Optimizations:
   - kprobe_on_ftrace
   - optimize panic print"

* tag 'csky-for-linus-5.9-rc1' of https://github.com/c-sky/csky-linux:
  csky: Add context tracking support
  csky: Add arch_show_interrupts for IPI interrupts
  csky: Add irq_work support
  csky: Fixup warning by EXPORT_SYMBOL(kmap)
  csky: Set CONFIG_NR_CPU 4 as default
  csky: Use top-down mmap layout
  csky: Optimize the trap processing flow
  csky: Add support for function error injection
  csky: Fixup kprobes handler couldn't change pc
  csky: Fixup duplicated restore sp in RESTORE_REGS_FTRACE
  csky: Add cpu feature register hint for smp
  csky: Add SECCOMP_FILTER supported
  csky: remove unusued thread_saved_pc and *_segments functions/macros

Author: torvalds

arch/csky/Kconfig

@@ -9,6 +9,7 @@ config CSKY
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_QUEUED_RWLOCKS if NR_CPUS>2
 	select ARCH_WANT_FRAME_POINTERS if !CPU_CK610
+	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
 	select COMMON_CLK
 	select CLKSRC_MMIO
 	select CSKY_MPINTC if CPU_CK860
@@ -38,11 +39,16 @@ config CSKY
 	select GX6605S_TIMER if CPU_CK610
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_AUDITSYSCALL
+	select HAVE_ARCH_MMAP_RND_BITS
+	select HAVE_ARCH_SECCOMP_FILTER
+	select HAVE_CONTEXT_TRACKING
+	select HAVE_VIRT_CPU_ACCOUNTING_GEN
 	select HAVE_DEBUG_BUGVERBOSE
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUNCTION_GRAPH_TRACER
+	select HAVE_FUNCTION_ERROR_INJECTION
 	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_KERNEL_GZIP
 	select HAVE_KERNEL_LZO
@@ -148,6 +154,14 @@ config L1_CACHE_SHIFT
 	default "5"	if (CPU_CK807 || CPU_CK810)
 	default "6"	if (CPU_CK860)
 
+config ARCH_MMAP_RND_BITS_MIN
+	default 8
+
+# max bits determined by the following formula:
+#  VA_BITS - PAGE_SHIFT - 3
+config ARCH_MMAP_RND_BITS_MAX
+	default 17
+
 menu "Processor type and features"
 
 choice
@@ -266,7 +280,7 @@ config NR_CPUS
 	int "Maximum number of CPUs (2-32)"
 	range 2 32
 	depends on SMP
-	default "2"
+	default "4"
 
 config HIGHMEM
 	bool "High Memory Support"
@@ -295,3 +309,16 @@ endmenu
 source "arch/csky/Kconfig.platforms"
 
 source "kernel/Kconfig.hz"
+
+config SECCOMP
+	bool "Enable seccomp to safely compute untrusted bytecode"
+	help
+	  This kernel feature is useful for number crunching applications
+	  that may need to compute untrusted bytecode during their
+	  execution. By using pipes or other transports made available to
+	  the process as file descriptors supporting the read/write
+	  syscalls, it's possible to isolate those applications in
+	  their own address space using seccomp. Once seccomp is
+	  enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
+	  and the task is only allowed to execute a few safe syscalls
+	  defined by each seccomp mode.

arch/csky/abiv2/inc/abi/entry.h

@@ -136,8 +136,6 @@
 
 .macro	RESTORE_REGS_FTRACE
 	ldw	tls, (sp, 0)
-	ldw	a0, (sp, 16)
-	mtcr	a0, ss0
 
 #ifdef CONFIG_CPU_HAS_HILO
 	ldw	a0, (sp, 140)
@@ -158,7 +156,6 @@
 	addi    sp, 40
 	ldm     r16-r30, (sp)
 	addi    sp, 72
-	mfcr	sp, ss0
 .endm
 
 .macro SAVE_SWITCH_STACK

arch/csky/abiv2/mcount.S

@@ -55,7 +55,9 @@
 
 .macro mcount_exit_regs
 	RESTORE_REGS_FTRACE
-	ldw	t1, (sp, 0)
+	subi	sp, 152
+	ldw	t1, (sp, 4)
+	addi	sp, 152
 	ldw	r8, (sp, 4)
 	ldw	lr, (sp, 8)
 	addi	sp, 12

arch/csky/include/asm/Kbuild

@@ -4,5 +4,6 @@ generic-y += gpio.h
 generic-y += kvm_para.h
 generic-y += local64.h
 generic-y += qrwlock.h
+generic-y += seccomp.h
 generic-y += user.h
 generic-y += vmlinux.lds.h

arch/csky/include/asm/bug.h

@@ -20,7 +20,8 @@ do {					\
 
 struct pt_regs;
 
-void die_if_kernel(char *str, struct pt_regs *regs, int nr);
+void die(struct pt_regs *regs, const char *str);
 void show_regs(struct pt_regs *regs);
+void show_code(struct pt_regs *regs);
 
 #endif /* __ASM_CSKY_BUG_H */

arch/csky/include/asm/irq_work.h

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_CSKY_IRQ_WORK_H
+#define __ASM_CSKY_IRQ_WORK_H
+
+static inline bool arch_irq_work_has_interrupt(void)
+{
+	return true;
+}
+extern void arch_irq_work_raise(void);
+#endif /* __ASM_CSKY_IRQ_WORK_H */

arch/csky/include/asm/processor.h

@@ -82,12 +82,6 @@ static inline void release_thread(struct task_struct *dead_task)
 
 extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 
-#define copy_segments(tsk, mm)		do { } while (0)
-#define release_segments(mm)		do { } while (0)
-#define forget_segments()		do { } while (0)
-
-extern unsigned long thread_saved_pc(struct task_struct *tsk);
-
 unsigned long get_wchan(struct task_struct *p);
 
 #define KSTK_EIP(tsk)		(task_pt_regs(tsk)->pc)

arch/csky/include/asm/ptrace.h

@@ -24,6 +24,7 @@
 #define user_mode(regs) (!((regs)->sr & PS_S))
 #define instruction_pointer(regs) ((regs)->pc)
 #define profile_pc(regs) instruction_pointer(regs)
+#define trap_no(regs) ((regs->sr >> 16) & 0xff)
 
 static inline void instruction_pointer_set(struct pt_regs *regs,
 					   unsigned long val)
@@ -52,6 +53,12 @@ static inline unsigned long regs_return_value(struct pt_regs *regs)
 	return regs->a0;
 }
 
+static inline void regs_set_return_value(struct pt_regs *regs,
+					 unsigned long val)
+{
+	regs->a0 = val;
+}
+
 /* Valid only for Kernel mode traps. */
 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
 {

arch/csky/include/asm/thread_info.h

@@ -85,6 +85,6 @@ static inline struct thread_info *current_thread_info(void)
 				 _TIF_NOTIFY_RESUME | _TIF_UPROBE)
 
 #define _TIF_SYSCALL_WORK	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
-				 _TIF_SYSCALL_TRACEPOINT)
+				 _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP)
 
 #endif	/* _ASM_CSKY_THREAD_INFO_H */

arch/csky/kernel/entry.S

@@ -23,6 +23,24 @@
 #endif
 .endm
 
+.macro	context_tracking
+#ifdef CONFIG_CONTEXT_TRACKING
+	mfcr	a0, epsr
+	btsti	a0, 31
+	bt	1f
+	jbsr	context_tracking_user_exit
+	ldw	a0, (sp, LSAVE_A0)
+	ldw	a1, (sp, LSAVE_A1)
+	ldw	a2, (sp, LSAVE_A2)
+	ldw	a3, (sp, LSAVE_A3)
+#if defined(__CSKYABIV1__)
+	ldw	r6, (sp, LSAVE_A4)
+	ldw	r7, (sp, LSAVE_A5)
+#endif
+1:
+#endif
+.endm
+
 .macro tlbop_begin name, val0, val1, val2
 ENTRY(csky_\name)
 	mtcr    a3, ss2
@@ -103,6 +121,7 @@ ENTRY(csky_\name)
 .endm
 .macro tlbop_end is_write
 	zero_fp
+	context_tracking
 	RD_MEH	a2
 	psrset  ee, ie
 	mov     a0, sp
@@ -128,6 +147,7 @@ tlbop_end 1
 ENTRY(csky_systemcall)
 	SAVE_ALL TRAP0_SIZE
 	zero_fp
+	context_tracking
 	psrset  ee, ie
 
 	lrw     r9, __NR_syscalls
@@ -168,6 +188,8 @@ ENTRY(csky_systemcall)
 csky_syscall_trace:
 	mov	a0, sp                  /* sp = pt_regs pointer */
 	jbsr	syscall_trace_enter
+	cmpnei	a0, 0
+	bt	1f
 	/* Prepare args before do system call */
 	ldw	a0, (sp, LSAVE_A0)
 	ldw	a1, (sp, LSAVE_A1)
@@ -188,6 +210,7 @@ csky_syscall_trace:
 #endif
 	stw	a0, (sp, LSAVE_A0)	/* Save return value */
 
+1:
 #ifdef CONFIG_DEBUG_RSEQ
 	mov	a0, sp
 	jbsr	rseq_syscall
@@ -234,6 +257,9 @@ ret_from_exception:
 	and	r10, r9
 	cmpnei	r10, 0
 	bt	exit_work
+#ifdef CONFIG_CONTEXT_TRACKING
+	jbsr	context_tracking_user_enter
+#endif
 1:
 #ifdef CONFIG_PREEMPTION
 	mov	r9, sp
@@ -274,6 +300,7 @@ work_resched:
 ENTRY(csky_trap)
 	SAVE_ALL 0
 	zero_fp
+	context_tracking
 	psrset	ee
 	mov	a0, sp                 /* Push Stack pointer arg */
 	jbsr	trap_c                 /* Call C-level trap handler */
@@ -308,6 +335,7 @@ ENTRY(csky_get_tls)
 ENTRY(csky_irq)
 	SAVE_ALL 0
 	zero_fp
+	context_tracking
 	psrset	ee
 
 #ifdef CONFIG_TRACE_IRQFLAGS