entry: Split generic entry into generic exception and syscall entry

Currently CONFIG_GENERIC_ENTRY enables both the generic exception
entry logic and the generic syscall entry logic, which are otherwise
loosely coupled.

Introduce separate config options for these so that architectures can
select the two independently. This will make it easier for
architectures to migrate to generic entry code.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/20250213130007.1418890-2-ruanjinjie@huawei.com
Link: https://lore.kernel.org/all/20250624-generic-entry-split-v1-1-53d5ef4f94df@linaro.org

[Linus Walleij: rebase onto v6.16-rc1]

1 files changed, 1 insertions, 112 deletions

diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index a8dd1f27417c..b82032777310 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -1,84 +1,13 @@
 // SPDX-License-Identifier: GPL-2.0
 
-#include <linux/context_tracking.h>
-#include <linux/entry-common.h>
+#include <linux/irq-entry-common.h>
 #include <linux/resume_user_mode.h>
 #include <linux/highmem.h>
 #include <linux/jump_label.h>
 #include <linux/kmsan.h>
 #include <linux/livepatch.h>
-#include <linux/audit.h>
 #include <linux/tick.h>
 
-#include "common.h"
-
-#define CREATE_TRACE_POINTS
-#include <trace/events/syscalls.h>
-
-static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
-{
-	if (unlikely(audit_context())) {
-		unsigned long args[6];
-
-		syscall_get_arguments(current, regs, args);
-		audit_syscall_entry(syscall, args[0], args[1], args[2], args[3]);
-	}
-}
-
-long syscall_trace_enter(struct pt_regs *regs, long syscall,
-				unsigned long work)
-{
-	long ret = 0;
-
-	/*
-	 * Handle Syscall User Dispatch.  This must comes first, since
-	 * the ABI here can be something that doesn't make sense for
-	 * other syscall_work features.
-	 */
-	if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) {
-		if (syscall_user_dispatch(regs))
-			return -1L;
-	}
-
-	/* Handle ptrace */
-	if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
-		ret = ptrace_report_syscall_entry(regs);
-		if (ret || (work & SYSCALL_WORK_SYSCALL_EMU))
-			return -1L;
-	}
-
-	/* Do seccomp after ptrace, to catch any tracer changes. */
-	if (work & SYSCALL_WORK_SECCOMP) {
-		ret = __secure_computing();
-		if (ret == -1L)
-			return ret;
-	}
-
-	/* Either of the above might have changed the syscall number */
-	syscall = syscall_get_nr(current, regs);
-
-	if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT)) {
-		trace_sys_enter(regs, syscall);
-		/*
-		 * Probes or BPF hooks in the tracepoint may have changed the
-		 * system call number as well.
-		 */
-		syscall = syscall_get_nr(current, regs);
-	}
-
-	syscall_enter_audit(regs, syscall);
-
-	return ret ? : syscall;
-}
-
-noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
-{
-	enter_from_user_mode(regs);
-	instrumentation_begin();
-	local_irq_enable();
-	instrumentation_end();
-}
-
 /* Workaround to allow gradual conversion of architecture code */
 void __weak arch_do_signal_or_restart(struct pt_regs *regs) { }
 
@@ -133,46 +62,6 @@ __always_inline unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
 	return ti_work;
 }
 
-/*
- * If SYSCALL_EMU is set, then the only reason to report is when
- * SINGLESTEP is set (i.e. PTRACE_SYSEMU_SINGLESTEP).  This syscall
- * instruction has been already reported in syscall_enter_from_user_mode().
- */
-static inline bool report_single_step(unsigned long work)
-{
-	if (work & SYSCALL_WORK_SYSCALL_EMU)
-		return false;
-
-	return work & SYSCALL_WORK_SYSCALL_EXIT_TRAP;
-}
-
-void syscall_exit_work(struct pt_regs *regs, unsigned long work)
-{
-	bool step;
-
-	/*
-	 * If the syscall was rolled back due to syscall user dispatching,
-	 * then the tracers below are not invoked for the same reason as
-	 * the entry side was not invoked in syscall_trace_enter(): The ABI
-	 * of these syscalls is unknown.
-	 */
-	if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) {
-		if (unlikely(current->syscall_dispatch.on_dispatch)) {
-			current->syscall_dispatch.on_dispatch = false;
-			return;
-		}
-	}
-
-	audit_syscall_exit(regs);
-
-	if (work & SYSCALL_WORK_SYSCALL_TRACEPOINT)
-		trace_sys_exit(regs, syscall_get_return_value(current, regs));
-
-	step = report_single_step(work);
-	if (step || work & SYSCALL_WORK_SYSCALL_TRACE)
-		ptrace_report_syscall_exit(regs, step);
-}
-
 noinstr void irqentry_enter_from_user_mode(struct pt_regs *regs)
 {
 	enter_from_user_mode(regs);