prctl: rename branch landing pad implementation functions to be more explicit

Per Linus' comments about the unreadability of abbreviations such as
"indir_br_lp", rename the three prctl() implementation functions to be more
explicit.  This involves renaming "indir_br_lp_status" in the function
names to "branch_landing_pad_state".

While here, add _prctl_ into the function names, following the
speculation control prctl implementation functions.

Link: https://lore.kernel.org/linux-riscv/CAHk-=whhSLGZAx3N5jJpb4GLFDqH_QvS07D+6BnkPWmCEzTAgw@mail.gmail.com/
Cc: Deepak Gupta <debug@rivosinc.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Paul Walmsley <pjw@kernel.org>

Author: Paul Walmsley

arch/riscv/kernel/usercfi.c

@@ -457,7 +457,8 @@ int arch_lock_shadow_stack_status(struct task_struct *task,
 	return 0;
 }
 
-int arch_get_indir_br_lp_status(struct task_struct *t, unsigned long __user *status)
+int arch_prctl_get_branch_landing_pad_state(struct task_struct *t,
+					    unsigned long __user *state)
 {
 	unsigned long fcfi_status = 0;
 
@@ -467,10 +468,10 @@ int arch_get_indir_br_lp_status(struct task_struct *t, unsigned long __user *sta
 	/* indirect branch tracking is enabled on the task or not */
 	fcfi_status |= (is_indir_lp_enabled(t) ? PR_INDIR_BR_LP_ENABLE : 0);
 
-	return copy_to_user(status, &fcfi_status, sizeof(fcfi_status)) ? -EFAULT : 0;
+	return copy_to_user(state, &fcfi_status, sizeof(fcfi_status)) ? -EFAULT : 0;
 }
 
-int arch_set_indir_br_lp_status(struct task_struct *t, unsigned long status)
+int arch_prctl_set_branch_landing_pad_state(struct task_struct *t, unsigned long state)
 {
 	bool enable_indir_lp = false;
 
@@ -482,24 +483,23 @@ int arch_set_indir_br_lp_status(struct task_struct *t, unsigned long status)
 		return -EINVAL;
 
 	/* Reject unknown flags */
-	if (status & ~PR_INDIR_BR_LP_ENABLE)
+	if (state & ~PR_INDIR_BR_LP_ENABLE)
 		return -EINVAL;
 
-	enable_indir_lp = (status & PR_INDIR_BR_LP_ENABLE);
+	enable_indir_lp = (state & PR_INDIR_BR_LP_ENABLE);
 	set_indir_lp_status(t, enable_indir_lp);
 
 	return 0;
 }
 
-int arch_lock_indir_br_lp_status(struct task_struct *task,
-				 unsigned long arg)
+int arch_prctl_lock_branch_landing_pad_state(struct task_struct *task)
 {
 	/*
 	 * If indirect branch tracking is not supported or not enabled on task,
 	 * nothing to lock here
 	 */
 	if (!is_user_lpad_enabled() ||
-	    !is_indir_lp_enabled(task) || arg != 0)
+	    !is_indir_lp_enabled(task))
 		return -EINVAL;
 
 	set_indir_lp_lock(task, true);

include/linux/cpu.h

@@ -229,8 +229,8 @@ static inline bool cpu_attack_vector_mitigated(enum cpu_attack_vectors v)
 #define smt_mitigations SMT_MITIGATIONS_OFF
 #endif
 
-int arch_get_indir_br_lp_status(struct task_struct *t, unsigned long __user *status);
-int arch_set_indir_br_lp_status(struct task_struct *t, unsigned long status);
-int arch_lock_indir_br_lp_status(struct task_struct *t, unsigned long status);
+int arch_prctl_get_branch_landing_pad_state(struct task_struct *t, unsigned long __user *state);
+int arch_prctl_set_branch_landing_pad_state(struct task_struct *t, unsigned long state);
+int arch_prctl_lock_branch_landing_pad_state(struct task_struct *t);
 
 #endif /* _LINUX_CPU_H_ */

kernel/sys.c

@@ -2388,17 +2388,18 @@ int __weak arch_lock_shadow_stack_status(struct task_struct *t, unsigned long st
 	return -EINVAL;
 }
 
-int __weak arch_get_indir_br_lp_status(struct task_struct *t, unsigned long __user *status)
+int __weak arch_prctl_get_branch_landing_pad_state(struct task_struct *t,
+						   unsigned long __user *state)
 {
 	return -EINVAL;
 }
 
-int __weak arch_set_indir_br_lp_status(struct task_struct *t, unsigned long status)
+int __weak arch_prctl_set_branch_landing_pad_state(struct task_struct *t, unsigned long state)
 {
 	return -EINVAL;
 }
 
-int __weak arch_lock_indir_br_lp_status(struct task_struct *t, unsigned long status)
+int __weak arch_prctl_lock_branch_landing_pad_state(struct task_struct *t)
 {
 	return -EINVAL;
 }
@@ -2891,17 +2892,17 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
 	case PR_GET_INDIR_BR_LP_STATUS:
 		if (arg3 || arg4 || arg5)
 			return -EINVAL;
-		error = arch_get_indir_br_lp_status(me, (unsigned long __user *)arg2);
+		error = arch_prctl_get_branch_landing_pad_state(me, (unsigned long __user *)arg2);
 		break;
 	case PR_SET_INDIR_BR_LP_STATUS:
 		if (arg3 || arg4 || arg5)
 			return -EINVAL;
-		error = arch_set_indir_br_lp_status(me, arg2);
+		error = arch_prctl_set_branch_landing_pad_state(me, arg2);
 		break;
 	case PR_LOCK_INDIR_BR_LP_STATUS:
-		if (arg3 || arg4 || arg5)
+		if (arg2 || arg3 || arg4 || arg5)
 			return -EINVAL;
-		error = arch_lock_indir_br_lp_status(me, arg2);
+		error = arch_prctl_lock_branch_landing_pad_state(me);
 		break;
 	default:
 		trace_task_prctl_unknown(option, arg2, arg3, arg4, arg5);