Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 553 insertions, 0 deletions

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
new file mode 100644
index 000000000..1945b8096
--- /dev/null
+++ b/arch/arm64/kernel/process.c
@@ -0,0 +1,553 @@
+/*
+ * Based on arch/arm/kernel/process.c
+ *
+ * Original Copyright (C) 1995  Linus Torvalds
+ * Copyright (C) 1996-2000 Russell King - Converted to ARM.
+ * Copyright (C) 2012 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * 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/>.
+ */
+
+#include <stdarg.h>
+
+#include <linux/compat.h>
+#include <linux/efi.h>
+#include <linux/export.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/stddef.h>
+#include <linux/unistd.h>
+#include <linux/user.h>
+#include <linux/delay.h>
+#include <linux/reboot.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/cpu.h>
+#include <linux/elfcore.h>
+#include <linux/pm.h>
+#include <linux/tick.h>
+#include <linux/utsname.h>
+#include <linux/uaccess.h>
+#include <linux/random.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/personality.h>
+#include <linux/notifier.h>
+#include <trace/events/power.h>
+#include <linux/percpu.h>
+#include <linux/thread_info.h>
+
+#include <asm/alternative.h>
+#include <asm/compat.h>
+#include <asm/cacheflush.h>
+#include <asm/exec.h>
+#include <asm/fpsimd.h>
+#include <asm/mmu_context.h>
+#include <asm/processor.h>
+#include <asm/stacktrace.h>
+
+#ifdef CONFIG_STACKPROTECTOR
+#include <linux/stackprotector.h>
+unsigned long __stack_chk_guard __ro_after_init;
+EXPORT_SYMBOL(__stack_chk_guard);
+#endif
+
+/*
+ * Function pointers to optional machine specific functions
+ */
+void (*pm_power_off)(void);
+EXPORT_SYMBOL_GPL(pm_power_off);
+
+void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
+
+/*
+ * This is our default idle handler.
+ */
+void arch_cpu_idle(void)
+{
+	/*
+	 * This should do all the clock switching and wait for interrupt
+	 * tricks
+	 */
+	trace_cpu_idle_rcuidle(1, smp_processor_id());
+	cpu_do_idle();
+	local_irq_enable();
+	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+void arch_cpu_idle_dead(void)
+{
+       cpu_die();
+}
+#endif
+
+/*
+ * Called by kexec, immediately prior to machine_kexec().
+ *
+ * This must completely disable all secondary CPUs; simply causing those CPUs
+ * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
+ * kexec'd kernel to use any and all RAM as it sees fit, without having to
+ * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
+ * functionality embodied in disable_nonboot_cpus() to achieve this.
+ */
+void machine_shutdown(void)
+{
+	disable_nonboot_cpus();
+}
+
+/*
+ * Halting simply requires that the secondary CPUs stop performing any
+ * activity (executing tasks, handling interrupts). smp_send_stop()
+ * achieves this.
+ */
+void machine_halt(void)
+{
+	local_irq_disable();
+	smp_send_stop();
+	while (1);
+}
+
+/*
+ * Power-off simply requires that the secondary CPUs stop performing any
+ * activity (executing tasks, handling interrupts). smp_send_stop()
+ * achieves this. When the system power is turned off, it will take all CPUs
+ * with it.
+ */
+void machine_power_off(void)
+{
+	local_irq_disable();
+	smp_send_stop();
+	if (pm_power_off)
+		pm_power_off();
+}
+
+/*
+ * Restart requires that the secondary CPUs stop performing any activity
+ * while the primary CPU resets the system. Systems with multiple CPUs must
+ * provide a HW restart implementation, to ensure that all CPUs reset at once.
+ * This is required so that any code running after reset on the primary CPU
+ * doesn't have to co-ordinate with other CPUs to ensure they aren't still
+ * executing pre-reset code, and using RAM that the primary CPU's code wishes
+ * to use. Implementing such co-ordination would be essentially impossible.
+ */
+void machine_restart(char *cmd)
+{
+	/* Disable interrupts first */
+	local_irq_disable();
+	smp_send_stop();
+
+	/*
+	 * UpdateCapsule() depends on the system being reset via
+	 * ResetSystem().
+	 */
+	if (efi_enabled(EFI_RUNTIME_SERVICES))
+		efi_reboot(reboot_mode, NULL);
+
+	/* Now call the architecture specific reboot code. */
+	if (arm_pm_restart)
+		arm_pm_restart(reboot_mode, cmd);
+	else
+		do_kernel_restart(cmd);
+
+	/*
+	 * Whoops - the architecture was unable to reboot.
+	 */
+	printk("Reboot failed -- System halted\n");
+	while (1);
+}
+
+static void print_pstate(struct pt_regs *regs)
+{
+	u64 pstate = regs->pstate;
+
+	if (compat_user_mode(regs)) {
+		printk("pstate: %08llx (%c%c%c%c %c %s %s %c%c%c)\n",
+			pstate,
+			pstate & PSR_AA32_N_BIT ? 'N' : 'n',
+			pstate & PSR_AA32_Z_BIT ? 'Z' : 'z',
+			pstate & PSR_AA32_C_BIT ? 'C' : 'c',
+			pstate & PSR_AA32_V_BIT ? 'V' : 'v',
+			pstate & PSR_AA32_Q_BIT ? 'Q' : 'q',
+			pstate & PSR_AA32_T_BIT ? "T32" : "A32",
+			pstate & PSR_AA32_E_BIT ? "BE" : "LE",
+			pstate & PSR_AA32_A_BIT ? 'A' : 'a',
+			pstate & PSR_AA32_I_BIT ? 'I' : 'i',
+			pstate & PSR_AA32_F_BIT ? 'F' : 'f');
+	} else {
+		printk("pstate: %08llx (%c%c%c%c %c%c%c%c %cPAN %cUAO)\n",
+			pstate,
+			pstate & PSR_N_BIT ? 'N' : 'n',
+			pstate & PSR_Z_BIT ? 'Z' : 'z',
+			pstate & PSR_C_BIT ? 'C' : 'c',
+			pstate & PSR_V_BIT ? 'V' : 'v',
+			pstate & PSR_D_BIT ? 'D' : 'd',
+			pstate & PSR_A_BIT ? 'A' : 'a',
+			pstate & PSR_I_BIT ? 'I' : 'i',
+			pstate & PSR_F_BIT ? 'F' : 'f',
+			pstate & PSR_PAN_BIT ? '+' : '-',
+			pstate & PSR_UAO_BIT ? '+' : '-');
+	}
+}
+
+void __show_regs(struct pt_regs *regs)
+{
+	int i, top_reg;
+	u64 lr, sp;
+
+	if (compat_user_mode(regs)) {
+		lr = regs->compat_lr;
+		sp = regs->compat_sp;
+		top_reg = 12;
+	} else {
+		lr = regs->regs[30];
+		sp = regs->sp;
+		top_reg = 29;
+	}
+
+	show_regs_print_info(KERN_DEFAULT);
+	print_pstate(regs);
+
+	if (!user_mode(regs)) {
+		printk("pc : %pS\n", (void *)regs->pc);
+		printk("lr : %pS\n", (void *)lr);
+	} else {
+		printk("pc : %016llx\n", regs->pc);
+		printk("lr : %016llx\n", lr);
+	}
+
+	printk("sp : %016llx\n", sp);
+
+	i = top_reg;
+
+	while (i >= 0) {
+		printk("x%-2d: %016llx ", i, regs->regs[i]);
+		i--;
+
+		if (i % 2 == 0) {
+			pr_cont("x%-2d: %016llx ", i, regs->regs[i]);
+			i--;
+		}
+
+		pr_cont("\n");
+	}
+}
+
+void show_regs(struct pt_regs * regs)
+{
+	__show_regs(regs);
+	dump_backtrace(regs, NULL);
+}
+
+static void tls_thread_flush(void)
+{
+	write_sysreg(0, tpidr_el0);
+
+	if (is_compat_task()) {
+		current->thread.uw.tp_value = 0;
+
+		/*
+		 * We need to ensure ordering between the shadow state and the
+		 * hardware state, so that we don't corrupt the hardware state
+		 * with a stale shadow state during context switch.
+		 */
+		barrier();
+		write_sysreg(0, tpidrro_el0);
+	}
+}
+
+void flush_thread(void)
+{
+	fpsimd_flush_thread();
+	tls_thread_flush();
+	flush_ptrace_hw_breakpoint(current);
+}
+
+void release_thread(struct task_struct *dead_task)
+{
+}
+
+void arch_release_task_struct(struct task_struct *tsk)
+{
+	fpsimd_release_task(tsk);
+}
+
+int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
+{
+	if (current->mm)
+		fpsimd_preserve_current_state();
+	*dst = *src;
+
+	/* We rely on the above assignment to initialize dst's thread_flags: */
+	BUILD_BUG_ON(!IS_ENABLED(CONFIG_THREAD_INFO_IN_TASK));
+
+	/*
+	 * Detach src's sve_state (if any) from dst so that it does not
+	 * get erroneously used or freed prematurely.  dst's sve_state
+	 * will be allocated on demand later on if dst uses SVE.
+	 * For consistency, also clear TIF_SVE here: this could be done
+	 * later in copy_process(), but to avoid tripping up future
+	 * maintainers it is best not to leave TIF_SVE and sve_state in
+	 * an inconsistent state, even temporarily.
+	 */
+	dst->thread.sve_state = NULL;
+	clear_tsk_thread_flag(dst, TIF_SVE);
+
+	return 0;
+}
+
+asmlinkage void ret_from_fork(void) asm("ret_from_fork");
+
+int copy_thread(unsigned long clone_flags, unsigned long stack_start,
+		unsigned long stk_sz, struct task_struct *p)
+{
+	struct pt_regs *childregs = task_pt_regs(p);
+
+	memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
+
+	/*
+	 * In case p was allocated the same task_struct pointer as some
+	 * other recently-exited task, make sure p is disassociated from
+	 * any cpu that may have run that now-exited task recently.
+	 * Otherwise we could erroneously skip reloading the FPSIMD
+	 * registers for p.
+	 */
+	fpsimd_flush_task_state(p);
+
+	if (likely(!(p->flags & PF_KTHREAD))) {
+		*childregs = *current_pt_regs();
+		childregs->regs[0] = 0;
+
+		/*
+		 * Read the current TLS pointer from tpidr_el0 as it may be
+		 * out-of-sync with the saved value.
+		 */
+		*task_user_tls(p) = read_sysreg(tpidr_el0);
+
+		if (stack_start) {
+			if (is_compat_thread(task_thread_info(p)))
+				childregs->compat_sp = stack_start;
+			else
+				childregs->sp = stack_start;
+		}
+
+		/*
+		 * If a TLS pointer was passed to clone (4th argument), use it
+		 * for the new thread.
+		 */
+		if (clone_flags & CLONE_SETTLS)
+			p->thread.uw.tp_value = childregs->regs[3];
+	} else {
+		memset(childregs, 0, sizeof(struct pt_regs));
+		childregs->pstate = PSR_MODE_EL1h;
+		if (IS_ENABLED(CONFIG_ARM64_UAO) &&
+		    cpus_have_const_cap(ARM64_HAS_UAO))
+			childregs->pstate |= PSR_UAO_BIT;
+
+		if (arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE)
+			set_ssbs_bit(childregs);
+
+		p->thread.cpu_context.x19 = stack_start;
+		p->thread.cpu_context.x20 = stk_sz;
+	}
+	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
+	p->thread.cpu_context.sp = (unsigned long)childregs;
+
+	ptrace_hw_copy_thread(p);
+
+	return 0;
+}
+
+void tls_preserve_current_state(void)
+{
+	*task_user_tls(current) = read_sysreg(tpidr_el0);
+}
+
+static void tls_thread_switch(struct task_struct *next)
+{
+	tls_preserve_current_state();
+
+	if (is_compat_thread(task_thread_info(next)))
+		write_sysreg(next->thread.uw.tp_value, tpidrro_el0);
+	else if (!arm64_kernel_unmapped_at_el0())
+		write_sysreg(0, tpidrro_el0);
+
+	write_sysreg(*task_user_tls(next), tpidr_el0);
+}
+
+/* Restore the UAO state depending on next's addr_limit */
+void uao_thread_switch(struct task_struct *next)
+{
+	if (IS_ENABLED(CONFIG_ARM64_UAO)) {
+		if (task_thread_info(next)->addr_limit == KERNEL_DS)
+			asm(ALTERNATIVE("nop", SET_PSTATE_UAO(1), ARM64_HAS_UAO));
+		else
+			asm(ALTERNATIVE("nop", SET_PSTATE_UAO(0), ARM64_HAS_UAO));
+	}
+}
+
+/*
+ * Force SSBS state on context-switch, since it may be lost after migrating
+ * from a CPU which treats the bit as RES0 in a heterogeneous system.
+ */
+static void ssbs_thread_switch(struct task_struct *next)
+{
+	struct pt_regs *regs = task_pt_regs(next);
+
+	/*
+	 * Nothing to do for kernel threads, but 'regs' may be junk
+	 * (e.g. idle task) so check the flags and bail early.
+	 */
+	if (unlikely(next->flags & PF_KTHREAD))
+		return;
+
+	/*
+	 * If all CPUs implement the SSBS extension, then we just need to
+	 * context-switch the PSTATE field.
+	 */
+	if (cpu_have_feature(cpu_feature(SSBS)))
+		return;
+
+	/* If the mitigation is enabled, then we leave SSBS clear. */
+	if ((arm64_get_ssbd_state() == ARM64_SSBD_FORCE_ENABLE) ||
+	    test_tsk_thread_flag(next, TIF_SSBD))
+		return;
+
+	if (compat_user_mode(regs))
+		set_compat_ssbs_bit(regs);
+	else if (user_mode(regs))
+		set_ssbs_bit(regs);
+}
+
+/*
+ * We store our current task in sp_el0, which is clobbered by userspace. Keep a
+ * shadow copy so that we can restore this upon entry from userspace.
+ *
+ * This is *only* for exception entry from EL0, and is not valid until we
+ * __switch_to() a user task.
+ */
+DEFINE_PER_CPU(struct task_struct *, __entry_task);
+
+static void entry_task_switch(struct task_struct *next)
+{
+	__this_cpu_write(__entry_task, next);
+}
+
+/*
+ * Thread switching.
+ */
+__notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
+				struct task_struct *next)
+{
+	struct task_struct *last;
+
+	fpsimd_thread_switch(next);
+	tls_thread_switch(next);
+	hw_breakpoint_thread_switch(next);
+	contextidr_thread_switch(next);
+	entry_task_switch(next);
+	uao_thread_switch(next);
+	ssbs_thread_switch(next);
+
+	/*
+	 * Complete any pending TLB or cache maintenance on this CPU in case
+	 * the thread migrates to a different CPU.
+	 * This full barrier is also required by the membarrier system
+	 * call.
+	 */
+	dsb(ish);
+
+	/* the actual thread switch */
+	last = cpu_switch_to(prev, next);
+
+	return last;
+}
+
+unsigned long get_wchan(struct task_struct *p)
+{
+	struct stackframe frame;
+	unsigned long stack_page, ret = 0;
+	int count = 0;
+	if (!p || p == current || p->state == TASK_RUNNING)
+		return 0;
+
+	stack_page = (unsigned long)try_get_task_stack(p);
+	if (!stack_page)
+		return 0;
+
+	frame.fp = thread_saved_fp(p);
+	frame.pc = thread_saved_pc(p);
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	frame.graph = p->curr_ret_stack;
+#endif
+	do {
+		if (unwind_frame(p, &frame))
+			goto out;
+		if (!in_sched_functions(frame.pc)) {
+			ret = frame.pc;
+			goto out;
+		}
+	} while (count ++ < 16);
+
+out:
+	put_task_stack(p);
+	return ret;
+}
+
+unsigned long arch_align_stack(unsigned long sp)
+{
+	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
+		sp -= get_random_int() & ~PAGE_MASK;
+	return sp & ~0xf;
+}
+
+unsigned long arch_randomize_brk(struct mm_struct *mm)
+{
+	if (is_compat_task())
+		return randomize_page(mm->brk, SZ_32M);
+	else
+		return randomize_page(mm->brk, SZ_1G);
+}
+
+/*
+ * Called from setup_new_exec() after (COMPAT_)SET_PERSONALITY.
+ */
+void arch_setup_new_exec(void)
+{
+	current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0;
+}
+
+#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
+void __used stackleak_check_alloca(unsigned long size)
+{
+	unsigned long stack_left;
+	unsigned long current_sp = current_stack_pointer;
+	struct stack_info info;
+
+	BUG_ON(!on_accessible_stack(current, current_sp, &info));
+
+	stack_left = current_sp - info.low;
+
+	/*
+	 * There's a good chance we're almost out of stack space if this
+	 * is true. Using panic() over BUG() is more likely to give
+	 * reliable debugging output.
+	 */
+	if (size >= stack_left)
+		panic("alloca() over the kernel stack boundary\n");
+}
+EXPORT_SYMBOL(stackleak_check_alloca);
+#endif