Merge tag 'x86_core_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core x86 updates from Borislav Petkov:

 - Remove all the code around GS switching on 32-bit now that it is not
   needed anymore

 - Other misc improvements

* tag 'x86_core_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  bug: Use normal relative pointers in 'struct bug_entry'
  x86/nmi: Make register_nmi_handler() more robust
  x86/asm: Merge load_gs_index()
  x86/32: Remove lazy GS macros
  ELF: Remove elf_core_copy_kernel_regs()
  x86/32: Simplify ELF_CORE_COPY_REGS

6 files changed, 23 insertions, 23 deletions

diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index e73f7df362f5..cec0bfa3bc04 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -157,7 +157,7 @@ int __register_nmi_handler(unsigned int type, struct nmiaction *action)
 	struct nmi_desc *desc = nmi_to_desc(type);
 	unsigned long flags;
 
-	if (!action->handler)
+	if (WARN_ON_ONCE(!action->handler || !list_empty(&action->list)))
 		return -EINVAL;
 
 	raw_spin_lock_irqsave(&desc->lock, flags);
@@ -177,7 +177,7 @@ int __register_nmi_handler(unsigned int type, struct nmiaction *action)
 		list_add_rcu(&action->list, &desc->head);
 	else
 		list_add_tail_rcu(&action->list, &desc->head);
-	
+
 	raw_spin_unlock_irqrestore(&desc->lock, flags);
 	return 0;
 }
@@ -186,7 +186,7 @@ EXPORT_SYMBOL(__register_nmi_handler);
 void unregister_nmi_handler(unsigned int type, const char *name)
 {
 	struct nmi_desc *desc = nmi_to_desc(type);
-	struct nmiaction *n;
+	struct nmiaction *n, *found = NULL;
 	unsigned long flags;
 
 	raw_spin_lock_irqsave(&desc->lock, flags);
@@ -200,12 +200,16 @@ void unregister_nmi_handler(unsigned int type, const char *name)
 			WARN(in_nmi(),
 				"Trying to free NMI (%s) from NMI context!\n", n->name);
 			list_del_rcu(&n->list);
+			found = n;
 			break;
 		}
 	}
 
 	raw_spin_unlock_irqrestore(&desc->lock, flags);
-	synchronize_rcu();
+	if (found) {
+		synchronize_rcu();
+		INIT_LIST_HEAD(&found->list);
+	}
 }
 EXPORT_SYMBOL_GPL(unregister_nmi_handler);
 
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index d5275ecb1e92..cbe6aa3f649d 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -161,6 +161,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
 	savesegment(ds, p->thread.ds);
 #else
 	p->thread.sp0 = (unsigned long) (childregs + 1);
+	savesegment(gs, p->thread.gs);
 	/*
 	 * Clear all status flags including IF and set fixed bit. 64bit
 	 * does not have this initialization as the frame does not contain
@@ -192,10 +193,6 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
 	if (sp)
 		childregs->sp = sp;
 
-#ifdef CONFIG_X86_32
-	task_user_gs(p) = get_user_gs(current_pt_regs());
-#endif
-
 	if (unlikely(p->flags & PF_IO_WORKER)) {
 		/*
 		 * An IO thread is a user space thread, but it doesn't
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 0faa5e28dd64..2f314b170c9f 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -63,10 +63,7 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode,
 	unsigned long d0, d1, d2, d3, d6, d7;
 	unsigned short gs;
 
-	if (user_mode(regs))
-		gs = get_user_gs(regs);
-	else
-		savesegment(gs, gs);
+	savesegment(gs, gs);
 
 	show_ip(regs, log_lvl);
 
@@ -114,7 +111,7 @@ void release_thread(struct task_struct *dead_task)
 void
 start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 {
-	set_user_gs(regs, 0);
+	loadsegment(gs, 0);
 	regs->fs		= 0;
 	regs->ds		= __USER_DS;
 	regs->es		= __USER_DS;
@@ -177,7 +174,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 	 * used %fs or %gs (it does not today), or if the kernel is
 	 * running inside of a hypervisor layer.
 	 */
-	lazy_save_gs(prev->gs);
+	savesegment(gs, prev->gs);
 
 	/*
 	 * Load the per-thread Thread-Local Storage descriptor.
@@ -208,7 +205,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 	 * Restore %gs if needed (which is common)
 	 */
 	if (prev->gs | next->gs)
-		lazy_load_gs(next->gs);
+		loadsegment(gs, next->gs);
 
 	this_cpu_write(current_task, next_p);
 
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 98d10ef60571..37c12fb92906 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -170,9 +170,9 @@ static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
 		retval = *pt_regs_access(task_pt_regs(task), offset);
 	else {
 		if (task == current)
-			retval = get_user_gs(task_pt_regs(task));
+			savesegment(gs, retval);
 		else
-			retval = task_user_gs(task);
+			retval = task->thread.gs;
 	}
 	return retval;
 }
@@ -210,7 +210,7 @@ static int set_segment_reg(struct task_struct *task,
 		break;
 
 	case offsetof(struct user_regs_struct, gs):
-		task_user_gs(task) = value;
+		task->thread.gs = value;
 	}
 
 	return 0;
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index e439eb14325f..9c7265b524c7 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -93,7 +93,7 @@ static bool restore_sigcontext(struct pt_regs *regs,
 		return false;
 
 #ifdef CONFIG_X86_32
-	set_user_gs(regs, sc.gs);
+	loadsegment(gs, sc.gs);
 	regs->fs = sc.fs;
 	regs->es = sc.es;
 	regs->ds = sc.ds;
@@ -146,8 +146,10 @@ __unsafe_setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 		     struct pt_regs *regs, unsigned long mask)
 {
 #ifdef CONFIG_X86_32
-	unsafe_put_user(get_user_gs(regs),
-				  (unsigned int __user *)&sc->gs, Efault);
+	unsigned int gs;
+	savesegment(gs, gs);
+
+	unsafe_put_user(gs,	  (unsigned int __user *)&sc->gs, Efault);
 	unsafe_put_user(regs->fs, (unsigned int __user *)&sc->fs, Efault);
 	unsafe_put_user(regs->es, (unsigned int __user *)&sc->es, Efault);
 	unsafe_put_user(regs->ds, (unsigned int __user *)&sc->ds, Efault);
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index c21bcd668284..e9e803a4d44c 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -151,7 +151,7 @@ exit_vm86:
 
 	memcpy(&regs->pt, &vm86->regs32, sizeof(struct pt_regs));
 
-	lazy_load_gs(vm86->regs32.gs);
+	loadsegment(gs, vm86->regs32.gs);
 
 	regs->pt.ax = retval;
 	return;
@@ -325,7 +325,7 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
  * Save old state
  */
 	vm86->saved_sp0 = tsk->thread.sp0;
-	lazy_save_gs(vm86->regs32.gs);
+	savesegment(gs, vm86->regs32.gs);
 
 	/* make room for real-mode segments */
 	preempt_disable();