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Subject[RFC patch 04/15] arm64/entry: Use generic syscall entry function
Replace the syscall entry work handling with the generic version, Provide
the necessary helper inlines to handle the real architecture specific
parts, e.g. audit and seccomp invocations.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/arm64/Kconfig | 1
arch/arm64/include/asm/entry-common.h | 39 ++++++++++++++++++++++++++++++++++
arch/arm64/kernel/ptrace.c | 29 -------------------------
arch/arm64/kernel/syscall.c | 15 +++++--------
4 files changed, 47 insertions(+), 37 deletions(-)

--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -99,6 +99,7 @@ config ARM64
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_VULNERABILITIES
select GENERIC_EARLY_IOREMAP
+ select GENERIC_ENTRY
select GENERIC_IDLE_POLL_SETUP
select GENERIC_IRQ_MULTI_HANDLER
select GENERIC_IRQ_PROBE
--- /dev/null
+++ b/arch/arm64/include/asm/entry-common.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2017 ARM Ltd.
+ */
+#ifndef __ASM_ENTRY_COMMON_H
+#define __ASM_ENTRY_COMMON_H
+
+enum ptrace_syscall_dir {
+ PTRACE_SYSCALL_ENTER = 0,
+ PTRACE_SYSCALL_EXIT,
+};
+
+/*
+ * A scratch register (ip(r12) on AArch32, x7 on AArch64) is
+ * used to denote syscall entry/exit for the tracehooks
+ */
+static inline __must_check int arch_syscall_enter_tracehook(struct pt_regs *regs)
+{
+ int regno = (is_compat_task() ? 12 : 7);
+ unsigned long reg = regs->regs[regno];
+ long ret;
+
+ regs->regs[regno] = PTRACE_SYSCALL_ENTER;
+ ret = tracehook_report_syscall_entry(regs);
+ if (ret)
+ forget_syscall(regs);
+ regs->regs[regno] = reg;
+ return ret;
+}
+#define arch_syscall_enter_tracehook arch_syscall_enter_tracehook
+
+static inline void arch_syscall_enter_audit(struct pt_regs *regs)
+{
+ audit_syscall_entry(regs->syscallno, regs->orig_x0, regs->regs[1],
+ regs->regs[2], regs->regs[3]);
+}
+#define arch_syscall_enter_audit arch_syscall_enter_audit
+
+#endif
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -13,6 +13,7 @@
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/sched/task_stack.h>
+#include <linux/entry-common.h>
#include <linux/mm.h>
#include <linux/nospec.h>
#include <linux/smp.h>
@@ -41,7 +42,6 @@
#include <asm/traps.h>
#include <asm/system_misc.h>

-#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>

struct pt_regs_offset {
@@ -1779,11 +1779,6 @@ long arch_ptrace(struct task_struct *chi
return ptrace_request(child, request, addr, data);
}

-enum ptrace_syscall_dir {
- PTRACE_SYSCALL_ENTER = 0,
- PTRACE_SYSCALL_EXIT,
-};
-
static void tracehook_report_syscall(struct pt_regs *regs,
enum ptrace_syscall_dir dir)
{
@@ -1806,28 +1801,6 @@ static void tracehook_report_syscall(str
regs->regs[regno] = saved_reg;
}

-int syscall_trace_enter(struct pt_regs *regs)
-{
- if (test_thread_flag(TIF_SYSCALL_TRACE) ||
- test_thread_flag(TIF_SYSCALL_EMU)) {
- tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
- if (!in_syscall(regs) || test_thread_flag(TIF_SYSCALL_EMU))
- return -1;
- }
-
- /* Do the secure computing after ptrace; failures should be fast. */
- if (secure_computing(NULL) == -1)
- return -1;
-
- if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
- trace_sys_enter(regs, regs->syscallno);
-
- audit_syscall_entry(regs->syscallno, regs->orig_x0, regs->regs[1],
- regs->regs[2], regs->regs[3]);
-
- return regs->syscallno;
-}
-
void syscall_trace_exit(struct pt_regs *regs)
{
audit_syscall_exit(regs);
--- a/arch/arm64/kernel/syscall.c
+++ b/arch/arm64/kernel/syscall.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0

#include <linux/compiler.h>
+#include <linux/entry-common.h>
#include <linux/context_tracking.h>
#include <linux/errno.h>
#include <linux/nospec.h>
@@ -58,7 +59,6 @@ static inline bool has_syscall_work(unsi
return unlikely(flags & _TIF_SYSCALL_WORK);
}

-int syscall_trace_enter(struct pt_regs *regs);
void syscall_trace_exit(struct pt_regs *regs);

#ifdef CONFIG_ARM64_ERRATUM_1463225
@@ -97,19 +97,16 @@ static void el0_svc_common(struct pt_reg

regs->orig_x0 = regs->regs[0];
regs->syscallno = scno;
+ /* Set default error number */
+ regs->regs[0] = -ENOSYS;

cortex_a76_erratum_1463225_svc_handler();
local_daif_restore(DAIF_PROCCTX);
user_exit();

- if (has_syscall_work(flags)) {
- /* set default errno for user-issued syscall(-1) */
- if (scno == NO_SYSCALL)
- regs->regs[0] = -ENOSYS;
- scno = syscall_trace_enter(regs);
- if (scno == NO_SYSCALL)
- goto trace_exit;
- }
+ scno = syscall_enter_from_usermode(regs, scno);
+ if (scno == NO_SYSCALL)
+ goto trace_exit;

invoke_syscall(regs, scno, sc_nr, syscall_table);


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