1 files changed, 129 insertions, 155 deletions

diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 2bc3eddae34a..0df95dcb2101 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * This file handles the architecture dependent parts of process handling.
  *
@@ -7,9 +8,13 @@
  *		 Denis Joseph Barrow,
  */
 
+#include <linux/elf-randomize.h>
 #include <linux/compiler.h>
 #include <linux/cpu.h>
 #include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/task.h>
+#include <linux/sched/task_stack.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/elfcore.h>
@@ -19,93 +24,90 @@
 #include <linux/tick.h>
 #include <linux/personality.h>
 #include <linux/syscalls.h>
-#include <linux/compat.h>
 #include <linux/kprobes.h>
 #include <linux/random.h>
-#include <linux/module.h>
-#include <asm/io.h>
+#include <linux/init_task.h>
+#include <linux/entry-common.h>
+#include <linux/io.h>
+#include <asm/guarded_storage.h>
+#include <asm/access-regs.h>
+#include <asm/switch_to.h>
+#include <asm/cpu_mf.h>
 #include <asm/processor.h>
+#include <asm/ptrace.h>
 #include <asm/vtimer.h>
 #include <asm/exec.h>
+#include <asm/fpu.h>
 #include <asm/irq.h>
 #include <asm/nmi.h>
 #include <asm/smp.h>
-#include <asm/switch_to.h>
+#include <asm/stacktrace.h>
 #include <asm/runtime_instr.h>
+#include <asm/unwind.h>
 #include "entry.h"
 
-asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
+void ret_from_fork(void) asm("ret_from_fork");
 
-/*
- * Return saved PC of a blocked thread. used in kernel/sched.
- * resume in entry.S does not create a new stack frame, it
- * just stores the registers %r6-%r15 to the frame given by
- * schedule. We want to return the address of the caller of
- * schedule, so we have to walk the backchain one time to
- * find the frame schedule() store its return address.
- */
-unsigned long thread_saved_pc(struct task_struct *tsk)
+void __ret_from_fork(struct task_struct *prev, struct pt_regs *regs)
 {
-	struct stack_frame *sf, *low, *high;
+	void (*func)(void *arg);
 
-	if (!tsk || !task_stack_page(tsk))
-		return 0;
-	low = task_stack_page(tsk);
-	high = (struct stack_frame *) task_pt_regs(tsk);
-	sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
-	if (sf <= low || sf > high)
-		return 0;
-	sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
-	if (sf <= low || sf > high)
-		return 0;
-	return sf->gprs[8];
-}
+	schedule_tail(prev);
 
-void arch_cpu_idle(void)
-{
-	local_mcck_disable();
-	if (test_thread_flag(TIF_MCCK_PENDING)) {
-		local_mcck_enable();
-		local_irq_enable();
-		return;
+	if (!user_mode(regs)) {
+		/* Kernel thread */
+		func = (void *)regs->gprs[9];
+		func((void *)regs->gprs[10]);
 	}
-	/* Halt the cpu and keep track of cpu time accounting. */
-	vtime_stop_cpu();
+	clear_pt_regs_flag(regs, PIF_SYSCALL);
+	syscall_exit_to_user_mode(regs);
 }
 
-void arch_cpu_idle_exit(void)
+void flush_thread(void)
 {
-	if (test_thread_flag(TIF_MCCK_PENDING))
-		s390_handle_mcck();
 }
 
-void arch_cpu_idle_dead(void)
+void arch_setup_new_exec(void)
 {
-	cpu_die();
+	if (get_lowcore()->current_pid != current->pid) {
+		get_lowcore()->current_pid = current->pid;
+		if (test_facility(40))
+			lpp(&get_lowcore()->lpp);
+	}
 }
 
-extern void __kprobes kernel_thread_starter(void);
-
-/*
- * Free current thread data structures etc..
- */
-void exit_thread(void)
+void arch_release_task_struct(struct task_struct *tsk)
 {
-	exit_thread_runtime_instr();
+	runtime_instr_release(tsk);
+	guarded_storage_release(tsk);
 }
 
-void flush_thread(void)
+int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 {
-}
+	save_user_fpu_regs();
 
-void release_thread(struct task_struct *dead_task)
-{
+	*dst = *src;
+	dst->thread.kfpu_flags = 0;
+
+	/*
+	 * Don't transfer over the runtime instrumentation or the guarded
+	 * storage control block pointers. These fields are cleared here instead
+	 * of in copy_thread() to avoid premature freeing of associated memory
+	 * on fork() failure. Wait to clear the RI flag because ->stack still
+	 * refers to the source thread.
+	 */
+	dst->thread.ri_cb = NULL;
+	dst->thread.gs_cb = NULL;
+	dst->thread.gs_bc_cb = NULL;
+
+	return 0;
 }
 
-int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
-		unsigned long arg, struct task_struct *p)
+int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
-	struct thread_info *ti;
+	u64 clone_flags = args->flags;
+	unsigned long new_stackp = args->stack;
+	unsigned long tls = args->tls;
 	struct fake_frame
 	{
 		struct stack_frame sf;
@@ -117,158 +119,130 @@ int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
 	/* Save access registers to new thread structure. */
 	save_access_regs(&p->thread.acrs[0]);
 	/* start new process with ar4 pointing to the correct address space */
-	p->thread.mm_segment = get_fs();
 	/* Don't copy debug registers */
 	memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
 	memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
 	clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
-	clear_tsk_thread_flag(p, TIF_PER_TRAP);
+	p->thread.per_flags = 0;
 	/* Initialize per thread user and system timer values */
-	ti = task_thread_info(p);
-	ti->user_timer = 0;
-	ti->system_timer = 0;
+	p->thread.user_timer = 0;
+	p->thread.guest_timer = 0;
+	p->thread.system_timer = 0;
+	p->thread.hardirq_timer = 0;
+	p->thread.softirq_timer = 0;
+	p->thread.last_break = 1;
 
 	frame->sf.back_chain = 0;
+	frame->sf.gprs[11 - 6] = (unsigned long)&frame->childregs;
+	frame->sf.gprs[12 - 6] = (unsigned long)p;
 	/* new return point is ret_from_fork */
-	frame->sf.gprs[8] = (unsigned long) ret_from_fork;
+	frame->sf.gprs[14 - 6] = (unsigned long)ret_from_fork;
 	/* fake return stack for resume(), don't go back to schedule */
-	frame->sf.gprs[9] = (unsigned long) frame;
+	frame->sf.gprs[15 - 6] = (unsigned long)frame;
 
 	/* Store access registers to kernel stack of new process. */
-	if (unlikely(p->flags & PF_KTHREAD)) {
+	if (unlikely(args->fn)) {
 		/* kernel thread */
 		memset(&frame->childregs, 0, sizeof(struct pt_regs));
-		frame->childregs.psw.mask = psw_kernel_bits | PSW_MASK_DAT |
-				PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
-		frame->childregs.psw.addr = PSW_ADDR_AMODE |
-				(unsigned long) kernel_thread_starter;
-		frame->childregs.gprs[9] = new_stackp; /* function */
-		frame->childregs.gprs[10] = arg;
-		frame->childregs.gprs[11] = (unsigned long) do_exit;
+		frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO |
+					    PSW_MASK_EXT | PSW_MASK_MCHECK;
+		frame->childregs.gprs[9] = (unsigned long)args->fn;
+		frame->childregs.gprs[10] = (unsigned long)args->fn_arg;
 		frame->childregs.orig_gpr2 = -1;
-
+		frame->childregs.last_break = 1;
 		return 0;
 	}
 	frame->childregs = *current_pt_regs();
 	frame->childregs.gprs[2] = 0;	/* child returns 0 on fork. */
+	frame->childregs.flags = 0;
 	if (new_stackp)
 		frame->childregs.gprs[15] = new_stackp;
-
-	/* Don't copy runtime instrumentation info */
-	p->thread.ri_cb = NULL;
-	p->thread.ri_signum = 0;
-	frame->childregs.psw.mask &= ~PSW_MASK_RI;
-
-#ifndef CONFIG_64BIT
 	/*
-	 * save fprs to current->thread.fp_regs to merge them with
-	 * the emulated registers and then copy the result to the child.
+	 * Clear the runtime instrumentation flag after the above childregs
+	 * copy. The CB pointer was already cleared in arch_dup_task_struct().
 	 */
-	save_fp_regs(&current->thread.fp_regs);
-	memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
-	       sizeof(s390_fp_regs));
-	/* Set a new TLS ?  */
-	if (clone_flags & CLONE_SETTLS)
-		p->thread.acrs[0] = frame->childregs.gprs[6];
-#else /* CONFIG_64BIT */
-	/* Save the fpu registers to new thread structure. */
-	save_fp_regs(&p->thread.fp_regs);
+	frame->childregs.psw.mask &= ~PSW_MASK_RI;
+
 	/* Set a new TLS ?  */
 	if (clone_flags & CLONE_SETTLS) {
-		unsigned long tls = frame->childregs.gprs[6];
-		if (is_compat_task()) {
-			p->thread.acrs[0] = (unsigned int)tls;
-		} else {
-			p->thread.acrs[0] = (unsigned int)(tls >> 32);
-			p->thread.acrs[1] = (unsigned int)tls;
-		}
+		p->thread.acrs[0] = (unsigned int)(tls >> 32);
+		p->thread.acrs[1] = (unsigned int)tls;
 	}
-#endif /* CONFIG_64BIT */
+	/*
+	 * s390 stores the svc return address in arch_data when calling
+	 * sigreturn()/restart_syscall() via vdso. 1 means no valid address
+	 * stored.
+	 */
+	p->restart_block.arch_data = 1;
 	return 0;
 }
 
-asmlinkage void execve_tail(void)
+void execve_tail(void)
 {
-	current->thread.fp_regs.fpc = 0;
-	if (MACHINE_HAS_IEEE)
-		asm volatile("sfpc %0,%0" : : "d" (0));
+	current->thread.ufpu.fpc = 0;
+	fpu_sfpc(0);
 }
 
-/*
- * fill in the FPU structure for a core dump.
- */
-int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
+struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *next)
 {
-#ifndef CONFIG_64BIT
-	/*
-	 * save fprs to current->thread.fp_regs to merge them with
-	 * the emulated registers and then copy the result to the dump.
-	 */
-	save_fp_regs(&current->thread.fp_regs);
-	memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));
-#else /* CONFIG_64BIT */
-	save_fp_regs(fpregs);
-#endif /* CONFIG_64BIT */
-	return 1;
+	save_user_fpu_regs();
+	save_kernel_fpu_regs(&prev->thread);
+	save_access_regs(&prev->thread.acrs[0]);
+	save_ri_cb(prev->thread.ri_cb);
+	save_gs_cb(prev->thread.gs_cb);
+	update_cr_regs(next);
+	restore_kernel_fpu_regs(&next->thread);
+	restore_access_regs(&next->thread.acrs[0]);
+	restore_ri_cb(next->thread.ri_cb, prev->thread.ri_cb);
+	restore_gs_cb(next->thread.gs_cb);
+	return __switch_to_asm(prev, next);
 }
-EXPORT_SYMBOL(dump_fpu);
 
-unsigned long get_wchan(struct task_struct *p)
+unsigned long __get_wchan(struct task_struct *p)
 {
-	struct stack_frame *sf, *low, *high;
-	unsigned long return_address;
-	int count;
+	struct unwind_state state;
+	unsigned long ip = 0;
 
-	if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
+	if (!task_stack_page(p))
 		return 0;
-	low = task_stack_page(p);
-	high = (struct stack_frame *) task_pt_regs(p);
-	sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
-	if (sf <= low || sf > high)
+
+	if (!try_get_task_stack(p))
 		return 0;
-	for (count = 0; count < 16; count++) {
-		sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
-		if (sf <= low || sf > high)
-			return 0;
-		return_address = sf->gprs[8] & PSW_ADDR_INSN;
-		if (!in_sched_functions(return_address))
-			return return_address;
+
+	unwind_for_each_frame(&state, p, NULL, 0) {
+		if (state.stack_info.type != STACK_TYPE_TASK) {
+			ip = 0;
+			break;
+		}
+
+		ip = unwind_get_return_address(&state);
+		if (!ip)
+			break;
+
+		if (!in_sched_functions(ip))
+			break;
 	}
-	return 0;
+
+	put_task_stack(p);
+	return ip;
 }
 
 unsigned long arch_align_stack(unsigned long sp)
 {
 	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
-		sp -= get_random_int() & ~PAGE_MASK;
+		sp -= get_random_u32_below(PAGE_SIZE);
 	return sp & ~0xf;
 }
 
 static inline unsigned long brk_rnd(void)
 {
-	/* 8MB for 32bit, 1GB for 64bit */
-	if (is_32bit_task())
-		return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
-	else
-		return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
+	return (get_random_u16() & BRK_RND_MASK) << PAGE_SHIFT;
 }
 
 unsigned long arch_randomize_brk(struct mm_struct *mm)
 {
-	unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
-
-	if (ret < mm->brk)
-		return mm->brk;
-	return ret;
-}
-
-unsigned long randomize_et_dyn(unsigned long base)
-{
-	unsigned long ret = PAGE_ALIGN(base + brk_rnd());
+	unsigned long ret;
 
-	if (!(current->flags & PF_RANDOMIZE))
-		return base;
-	if (ret < base)
-		return base;
-	return ret;
+	ret = PAGE_ALIGN(mm->brk + brk_rnd());
+	return (ret > mm->brk) ? ret : mm->brk;
 }