Merge tag 'powerpc-6.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:

 - Add support for building the kernel using PC-relative addressing on
   Power10.

 - Allow HV KVM guests on Power10 to use prefixed instructions.

 - Unify support for the P2020 CPU (85xx) into a single machine
   description.

 - Always build the 64-bit kernel with 128-bit long double.

 - Drop support for several obsolete 2000's era development boards as
   identified by Paul Gortmaker.

 - A series fixing VFIO on Power since some generic changes.

 - Various other small features and fixes.

Thanks to Alexey Kardashevskiy, Andrew Donnellan, Benjamin Gray, Bo Liu,
Christophe Leroy, Dan Carpenter, David Binderman, Ira Weiny, Joel
Stanley, Kajol Jain, Kautuk Consul, Liang He, Luis Chamberlain, Masahiro
Yamada, Michael Neuling, Nathan Chancellor, Nathan Lynch, Nicholas
Miehlbradt, Nicholas Piggin, Nick Desaulniers, Nysal Jan K.A, Pali
Rohár, Paul Gortmaker, Paul Mackerras, Petr Vaněk, Randy Dunlap, Rob
Herring, Sachin Sant, Sean Christopherson, Segher Boessenkool, and
Timothy Pearson.

* tag 'powerpc-6.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (156 commits)
  powerpc/64s: Disable pcrel code model on Clang
  powerpc: Fix merge conflict between pcrel and copy_thread changes
  powerpc/configs/powernv: Add IGB=y
  powerpc/configs/64s: Drop JFS Filesystem
  powerpc/configs/64s: Use EXT4 to mount EXT2 filesystems
  powerpc/configs: Make pseries_defconfig an alias for ppc64le_guest
  powerpc/configs: Make pseries_le an alias for ppc64le_guest
  powerpc/configs: Incorporate generic kvm_guest.config into guest configs
  powerpc/configs: Add IBMVETH=y and IBMVNIC=y to guest configs
  powerpc/configs/64s: Enable Device Mapper options
  powerpc/configs/64s: Enable PSTORE
  powerpc/configs/64s: Enable VLAN support
  powerpc/configs/64s: Enable BLK_DEV_NVME
  powerpc/configs/64s: Drop REISERFS
  powerpc/configs/64s: Use SHA512 for module signatures
  powerpc/configs/64s: Enable IO_STRICT_DEVMEM
  powerpc/configs/64s: Enable SCHEDSTATS
  powerpc/configs/64s: Enable DEBUG_VM & other options
  powerpc/configs/64s: Enable EMULATED_STATS
  powerpc/configs/64s: Enable KUNIT and most tests
  ...

1 files changed, 69 insertions, 57 deletions

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 4b29ac5ddac6..1fefafb2b29b 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1630,7 +1630,7 @@ void arch_setup_new_exec(void)
 }
 
 #ifdef CONFIG_PPC64
-/**
+/*
  * Assign a TIDR (thread ID) for task @t and set it in the thread
  * structure. For now, we only support setting TIDR for 'current' task.
  *
@@ -1738,68 +1738,83 @@ static void setup_ksp_vsid(struct task_struct *p, unsigned long sp)
  */
 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
-	unsigned long clone_flags = args->flags;
-	unsigned long usp = args->stack;
-	unsigned long tls = args->tls;
-	struct pt_regs *childregs, *kregs;
+	struct pt_regs *kregs; /* Switch frame regs */
 	extern void ret_from_fork(void);
 	extern void ret_from_fork_scv(void);
-	extern void ret_from_kernel_thread(void);
+	extern void ret_from_kernel_user_thread(void);
+	extern void start_kernel_thread(void);
 	void (*f)(void);
 	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
-	struct thread_info *ti = task_thread_info(p);
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 	int i;
 #endif
 
 	klp_init_thread_info(p);
 
-	/* Create initial stack frame. */
-	sp -= STACK_USER_INT_FRAME_SIZE;
-	*(unsigned long *)(sp + STACK_INT_FRAME_MARKER) = STACK_FRAME_REGS_MARKER;
-
-	/* Copy registers */
-	childregs = (struct pt_regs *)(sp + STACK_INT_FRAME_REGS);
-	if (unlikely(args->fn)) {
+	if (unlikely(p->flags & PF_KTHREAD)) {
 		/* kernel thread */
+
+		/* Create initial minimum stack frame. */
+		sp -= STACK_FRAME_MIN_SIZE;
 		((unsigned long *)sp)[0] = 0;
-		memset(childregs, 0, sizeof(struct pt_regs));
-		childregs->gpr[1] = sp + STACK_USER_INT_FRAME_SIZE;
-		/* function */
-		if (args->fn)
-			childregs->gpr[14] = ppc_function_entry((void *)args->fn);
-#ifdef CONFIG_PPC64
-		clear_tsk_thread_flag(p, TIF_32BIT);
-		childregs->softe = IRQS_ENABLED;
-#endif
-		childregs->gpr[15] = (unsigned long)args->fn_arg;
+
+		f = start_kernel_thread;
 		p->thread.regs = NULL;	/* no user register state */
-		ti->flags |= _TIF_RESTOREALL;
-		f = ret_from_kernel_thread;
+		clear_tsk_compat_task(p);
 	} else {
 		/* user thread */
-		struct pt_regs *regs = current_pt_regs();
-		*childregs = *regs;
-		if (usp)
-			childregs->gpr[1] = usp;
-		((unsigned long *)sp)[0] = childregs->gpr[1];
-		p->thread.regs = childregs;
-		/* 64s sets this in ret_from_fork */
-		if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64))
-			childregs->gpr[3] = 0;  /* Result from fork() */
-		if (clone_flags & CLONE_SETTLS) {
-			if (!is_32bit_task())
-				childregs->gpr[13] = tls;
+		struct pt_regs *childregs;
+
+		/* Create initial user return stack frame. */
+		sp -= STACK_USER_INT_FRAME_SIZE;
+		*(unsigned long *)(sp + STACK_INT_FRAME_MARKER) = STACK_FRAME_REGS_MARKER;
+
+		childregs = (struct pt_regs *)(sp + STACK_INT_FRAME_REGS);
+
+		if (unlikely(args->fn)) {
+			/*
+			 * A user space thread, but it first runs a kernel
+			 * thread, and then returns as though it had called
+			 * execve rather than fork, so user regs will be
+			 * filled in (e.g., by kernel_execve()).
+			 */
+			((unsigned long *)sp)[0] = 0;
+			memset(childregs, 0, sizeof(struct pt_regs));
+#ifdef CONFIG_PPC64
+			childregs->softe = IRQS_ENABLED;
+#endif
+			f = ret_from_kernel_user_thread;
+		} else {
+			struct pt_regs *regs = current_pt_regs();
+			unsigned long clone_flags = args->flags;
+			unsigned long usp = args->stack;
+
+			/* Copy registers */
+			*childregs = *regs;
+			if (usp)
+				childregs->gpr[1] = usp;
+			((unsigned long *)sp)[0] = childregs->gpr[1];
+#ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
+			WARN_ON_ONCE(childregs->softe != IRQS_ENABLED);
+#endif
+			if (clone_flags & CLONE_SETTLS) {
+				unsigned long tls = args->tls;
+
+				if (!is_32bit_task())
+					childregs->gpr[13] = tls;
+				else
+					childregs->gpr[2] = tls;
+			}
+
+			if (trap_is_scv(regs))
+				f = ret_from_fork_scv;
 			else
-				childregs->gpr[2] = tls;
+				f = ret_from_fork;
 		}
 
-		if (trap_is_scv(regs))
-			f = ret_from_fork_scv;
-		else
-			f = ret_from_fork;
+		childregs->msr &= ~(MSR_FP|MSR_VEC|MSR_VSX);
+		p->thread.regs = childregs;
 	}
-	childregs->msr &= ~(MSR_FP|MSR_VEC|MSR_VSX);
 
 	/*
 	 * The way this works is that at some point in the future
@@ -1813,6 +1828,16 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 	sp -= STACK_SWITCH_FRAME_SIZE;
 	((unsigned long *)sp)[0] = sp + STACK_SWITCH_FRAME_SIZE;
 	kregs = (struct pt_regs *)(sp + STACK_SWITCH_FRAME_REGS);
+	kregs->nip = ppc_function_entry(f);
+	if (unlikely(args->fn)) {
+		/*
+		 * Put kthread fn, arg parameters in non-volatile GPRs in the
+		 * switch frame so they are loaded by _switch before it returns
+		 * to ret_from_kernel_thread.
+		 */
+		kregs->gpr[14] = ppc_function_entry((void *)args->fn);
+		kregs->gpr[15] = (unsigned long)args->fn_arg;
+	}
 	p->thread.ksp = sp;
 
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
@@ -1840,22 +1865,9 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 		p->thread.dscr_inherit = current->thread.dscr_inherit;
 		p->thread.dscr = mfspr(SPRN_DSCR);
 	}
-	if (cpu_has_feature(CPU_FTR_HAS_PPR))
-		childregs->ppr = DEFAULT_PPR;
 
 	p->thread.tidr = 0;
 #endif
-	/*
-	 * Run with the current AMR value of the kernel
-	 */
-#ifdef CONFIG_PPC_PKEY
-	if (mmu_has_feature(MMU_FTR_BOOK3S_KUAP))
-		kregs->amr = AMR_KUAP_BLOCKED;
-
-	if (mmu_has_feature(MMU_FTR_BOOK3S_KUEP))
-		kregs->iamr = AMR_KUEP_BLOCKED;
-#endif
-	kregs->nip = ppc_function_entry(f);
 	return 0;
 }