[PATCH RFC 28/28] ARM: entry: Convert to generic entry

From: Linus Walleij
Date: Thu Oct 10 2024 - 07:38:51 EST

This rewrites ARM to use the generic entry.

All of the irqentry_* callbacks are renamed to arm_irqentry_*
and made to call into the generic entry code.

The state for IRQ and NMI for usermode and kernelmode is
stored into a static local variable as interrupts are
not reentrant.

The syscall_enter_from_user_mode(), syscall_exit_to_user_mode(),
do_work_pending() constructs are replaced with generic code.

The syscall invocation now enables syscall tracing "work" using
the generic callbacks and no extra actions are needed to
enable/disable syscall tracing.

The old context tracking with user_exit_callable()
user_enter_callable() is no longer used. Only CSKY and Xtensa
use this deprecated mechanism now.

Like with the ARM64 proposed patch for generic entry, it is
necessary to create a small call "arm_exit_to_user_mode()"
that is used for things such as ret_from_fork, i.e. when
we create a completely new execution context with a botched
return from interrupt.

Open questions:

- I had to add defines for PTRACE_SYSEMU and
PTRACE_SYSEMU_SINGLESTEP and I have no idea what those
are or why they are required. Sorry for my ignorance,
I need help to figure out how we deal with this.

Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
arch/arm/Kconfig | 1 +
arch/arm/include/asm/entry-common.h | 66 +++++++++++++++++++++++++++
arch/arm/include/asm/entry.h | 23 ++++------
arch/arm/include/asm/ptrace.h | 3 --
arch/arm/include/asm/signal.h | 2 -
arch/arm/include/asm/syscall.h | 7 ++-
arch/arm/include/asm/thread_info.h | 17 +------
arch/arm/include/uapi/asm/ptrace.h | 2 +
arch/arm/kernel/entry-armv.S | 8 ++--
arch/arm/kernel/entry-common.S | 34 +++++---------
arch/arm/kernel/entry-header.S | 8 ++--
arch/arm/kernel/entry.c | 80 +++++++++++----------------------
arch/arm/kernel/process.c | 2 -
arch/arm/kernel/ptrace.c | 90 -------------------------------------
arch/arm/kernel/signal.c | 31 +------------
arch/arm/kernel/syscall.c | 27 +++--------
16 files changed, 137 insertions(+), 264 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 749179a1d162..8155a4be7c9b 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -66,6 +66,7 @@ config ARM
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_DEVICES
select GENERIC_EARLY_IOREMAP
+ select GENERIC_ENTRY
select GENERIC_IDLE_POLL_SETUP
select GENERIC_IRQ_MULTI_HANDLER
select GENERIC_IRQ_PROBE
diff --git a/arch/arm/include/asm/entry-common.h b/arch/arm/include/asm/entry-common.h
new file mode 100644
index 000000000000..7b1f108512db
--- /dev/null
+++ b/arch/arm/include/asm/entry-common.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _ASM_ARM_ENTRY_COMMON_H
+#define _ASM_ARM_ENTRY_COMMON_H
+
+#include <linux/thread_info.h>
+
+#include <asm/stacktrace.h>
+
+enum ptrace_syscall_dir {
+ PTRACE_SYSCALL_ENTER = 0,
+ PTRACE_SYSCALL_EXIT,
+};
+
+static inline unsigned long
+arch_prepare_report_syscall_entry(struct pt_regs *regs)
+{
+ unsigned long ip;
+
+ /*
+ * IP is used to denote syscall entry/exit:
+ * IP = 0 -> entry
+ */
+ ip = regs->ARM_ip;
+ regs->ARM_ip = PTRACE_SYSCALL_ENTER;
+
+ return ip;
+}
+#define arch_prepare_report_syscall_entry arch_prepare_report_syscall_entry
+
+static inline void
+arch_post_report_syscall_entry(struct pt_regs *regs,
+ unsigned long saved_reg, long ret)
+{
+ regs->ARM_ip = saved_reg;
+}
+#define arch_post_report_syscall_entry arch_post_report_syscall_entry
+
+
+static inline unsigned long
+arch_prepare_report_syscall_exit(struct pt_regs *regs,
+ unsigned long work)
+{
+ unsigned long ip;
+
+ /*
+ * IP is used to denote syscall entry/exit:
+ * IP = 1 -> exit
+ */
+ ip = regs->ARM_ip;
+ regs->ARM_ip = PTRACE_SYSCALL_EXIT;
+
+ return ip;
+}
+#define arch_prepare_report_syscall_exit arch_prepare_report_syscall_exit
+
+static inline void
+arch_post_report_syscall_exit(struct pt_regs *regs,
+ unsigned long saved_reg,
+ unsigned long work)
+{
+ regs->ARM_ip = saved_reg;
+}
+#define arch_post_report_syscall_exit arch_post_report_syscall_exit
+
+#endif /* _ASM_ARM_ENTRY_COMMON_H */
diff --git a/arch/arm/include/asm/entry.h b/arch/arm/include/asm/entry.h
index 2e7ccd87f0eb..dadf0064c65b 100644
--- a/arch/arm/include/asm/entry.h
+++ b/arch/arm/include/asm/entry.h
@@ -4,19 +4,14 @@

struct pt_regs;

-/*
- * These are copies of generic entry headers so we can transition
- * to generic entry once they are semantically equivalent.
- */
-long syscall_enter_from_user_mode(struct pt_regs *regs, long);
-void syscall_exit_to_user_mode(struct pt_regs *regs);
-void irqentry_enter_from_user_mode(struct pt_regs *regs);
-void irqentry_exit_to_user_mode(struct pt_regs *regs);
-void irqentry_enter_from_kernel_mode(struct pt_regs *regs);
-void irqentry_exit_to_kernel_mode(struct pt_regs *regs);
-void irqentry_nmi_enter_from_user_mode(struct pt_regs *regs);
-void irqentry_nmi_exit_to_user_mode(struct pt_regs *regs);
-void irqentry_nmi_enter_from_kernel_mode(struct pt_regs *regs);
-void irqentry_nmi_exit_to_kernel_mode(struct pt_regs *regs);
+void arm_irqentry_enter_from_user_mode(struct pt_regs *regs);
+void arm_irqentry_exit_to_user_mode(struct pt_regs *regs);
+void arm_irqentry_enter_from_kernel_mode(struct pt_regs *regs);
+void arm_irqentry_exit_to_kernel_mode(struct pt_regs *regs);
+void arm_irqentry_nmi_enter_from_user_mode(struct pt_regs *regs);
+void arm_irqentry_nmi_exit_to_user_mode(struct pt_regs *regs);
+void arm_irqentry_nmi_enter_from_kernel_mode(struct pt_regs *regs);
+void arm_irqentry_nmi_exit_to_kernel_mode(struct pt_regs *regs);
+void arm_exit_to_user_mode(struct pt_regs *regs);

#endif /* __ASM_ENTRY_H__ */
diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h
index a01c66f0ad90..8a7de4020cbc 100644
--- a/arch/arm/include/asm/ptrace.h
+++ b/arch/arm/include/asm/ptrace.h
@@ -200,8 +200,5 @@ static inline unsigned long it_advance(unsigned long cpsr)
return cpsr;
}

-int syscall_trace_enter(struct pt_regs *regs);
-void syscall_trace_exit(struct pt_regs *regs);
-
#endif /* __ASSEMBLY__ */
#endif
diff --git a/arch/arm/include/asm/signal.h b/arch/arm/include/asm/signal.h
index bb753cd3e29f..45885383646c 100644
--- a/arch/arm/include/asm/signal.h
+++ b/arch/arm/include/asm/signal.h
@@ -23,6 +23,4 @@ typedef struct {

#include <asm/sigcontext.h>

-void do_work_pending(struct pt_regs *regs, unsigned int thread_flags);
-
#endif
diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h
index b94fd7ce17f8..a6c8f0e799bb 100644
--- a/arch/arm/include/asm/syscall.h
+++ b/arch/arm/include/asm/syscall.h
@@ -19,7 +19,12 @@

extern const unsigned long sys_call_table[];

-int invoke_syscall(void *table, struct pt_regs *regs, int scno);
+void invoke_syscall(void *table, struct pt_regs *regs, int scno);
+
+static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
+{
+ return false;
+}

static inline int syscall_get_nr(struct task_struct *task,
struct pt_regs *regs)
diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index d8a45c5a1049..84e58a9cdab6 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -74,6 +74,7 @@ struct thread_info {
#ifdef CONFIG_ARM_THUMBEE
unsigned long thumbee_state; /* ThumbEE Handler Base register */
#endif
+ unsigned long syscall_work; /* SYSCALL_WORK_ flags */
};

#define INIT_THREAD_INFO(tsk) \
@@ -149,30 +150,14 @@ extern int vfp_restore_user_hwstate(struct user_vfp *,
#define TIF_USING_IWMMXT 17
#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 19
-#define TIF_SYSCALL_TRACE 20 /* syscall trace active */
-#define TIF_SYSCALL_AUDIT 21 /* syscall auditing active */
-#define TIF_SYSCALL_TRACEPOINT 22 /* syscall tracepoint instrumentation */
-#define TIF_SECCOMP 23 /* seccomp syscall filtering active */
-

#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_UPROBE (1 << TIF_UPROBE)
-#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
-#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
-#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
-#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
#define _TIF_USING_IWMMXT (1 << TIF_USING_IWMMXT)

-/* Checks for any syscall work in entry-common.S */
-#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
- _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP)
-
-/*
- * Change these and you break ASM code in entry-common.S
- */
#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
_TIF_NOTIFY_RESUME | _TIF_UPROBE | \
_TIF_NOTIFY_SIGNAL)
diff --git a/arch/arm/include/uapi/asm/ptrace.h b/arch/arm/include/uapi/asm/ptrace.h
index 8896c23ccba7..336a5beb282f 100644
--- a/arch/arm/include/uapi/asm/ptrace.h
+++ b/arch/arm/include/uapi/asm/ptrace.h
@@ -33,6 +33,8 @@
#define PTRACE_GETHBPREGS 29
#define PTRACE_SETHBPREGS 30
#define PTRACE_GETFDPIC 31
+#define PTRACE_SYSEMU 32
+#define PTRACE_SYSEMU_SINGLESTEP 33

#define PTRACE_GETFDPIC_EXEC 0
#define PTRACE_GETFDPIC_INTERP 1
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 839f3ebe7228..1bbadf13136e 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -206,9 +206,9 @@ ENDPROC(__und_invalid)

mov r0, sp @ 'regs'
.if \nmi
- bl irqentry_nmi_enter_from_kernel_mode
+ bl arm_irqentry_nmi_enter_from_kernel_mode
.else
- bl irqentry_enter_from_kernel_mode
+ bl arm_irqentry_enter_from_kernel_mode
.endif

.endm
@@ -495,12 +495,12 @@ ENDPROC(ret_from_exception)
__fiq_usr:
usr_entry
mov r0, sp
- bl irqentry_nmi_enter_from_user_mode
+ bl arm_irqentry_nmi_enter_from_user_mode
kuser_cmpxchg_check
mov r0, sp @ struct pt_regs *regs
bl handle_fiq_as_nmi
mov r0, sp
- bl irqentry_nmi_exit_to_user_mode
+ bl arm_irqentry_nmi_exit_to_user_mode
get_thread_info tsk
restore_user_regs
UNWIND(.fnend )
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 6b0f86786a7d..b3b2455ab0a1 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -39,10 +39,6 @@ ret_fast_syscall:
UNWIND(.fnstart )
UNWIND(.cantunwind )
add sp, sp, #(S_R0 + S_OFF)
- /* do_rseq_syscall needs interrupts enabled. */
- mov r0, sp @ 'regs'
- bl syscall_exit_to_user_mode
-
#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
bl stackleak_erase_on_task_stack
#endif
@@ -60,7 +56,7 @@ ENTRY(ret_to_user)
/* do_rseq_syscall needs interrupts enabled. */
enable_irq_notrace @ enable interrupts
mov r0, sp @ 'regs'
- bl syscall_exit_to_user_mode
+ bl arm_exit_to_user_mode

#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
bl stackleak_erase_on_task_stack
@@ -94,7 +90,14 @@ SYM_TYPED_FUNC_START(ret_from_fork_asm)
bl ret_from_fork
mov r0, #0
1: get_thread_info tsk
- b ret_to_user
+ enable_irq_notrace @ enable interrupts
+ mov r0, sp @ 'regs'
+ bl syscall_exit_to_user_mode
+
+#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
+ bl stackleak_erase_on_task_stack
+#endif
+ restore_user_regs
SYM_FUNC_END(ret_from_fork_asm)

/*=============================================================================
@@ -210,29 +213,12 @@ ENTRY(vector_swi)
#else
str scno, [tsk, #TI_ABI_SYSCALL]
#endif
-
- /*
- * Calling out to C to be careful to save and restore registers.
- * This call could modify the syscall number. scno is r7 so we
- * do not save and restore r7.
- */
- mov r0, sp @ regs
- mov r1, scno
- push {r4 - r6, r8 - r10, lr}
- bl syscall_enter_from_user_mode
- pop {r4 - r6, r8 - r10, lr}
- mov scno, r0
-
mov r1, sp @ put regs into r1
stmdb sp!, {r4, r5} @ push fifth and sixth args
mov r0, tbl
mov r2, scno @ syscall number from r7
bl invoke_syscall
- cmp r0, #0
- beq ret_fast_syscall
- /* This path taken when tracing */
- add sp, sp, #(S_R0 + S_OFF)
- b ret_to_user
+ b ret_fast_syscall

#if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI)
/*
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S
index ec8a6e193802..b5d61b871dec 100644
--- a/arch/arm/kernel/entry-header.S
+++ b/arch/arm/kernel/entry-header.S
@@ -205,7 +205,7 @@
disable_irq_notrace

mov r0, sp @ 'regs'
- bl irqentry_exit_to_kernel_mode
+ bl arm_irqentry_exit_to_kernel_mode

uaccess_exit tsk, r0, r1

@@ -253,7 +253,7 @@
.macro svc_exit_via_fiq
uaccess_exit tsk, r0, r1
mov r0, sp
- bl irqentry_nmi_exit_to_kernel_mode
+ bl arm_irqentry_nmi_exit_to_kernel_mode
#ifndef CONFIG_THUMB2_KERNEL
@ ARM mode restore
mov r0, sp
@@ -348,12 +348,12 @@ ALT_UP_B(.L1_\@)
*/
.macro asm_irqentry_enter_from_user_mode
mov r0, sp @ regs
- bl irqentry_enter_from_user_mode
+ bl arm_irqentry_enter_from_user_mode
.endm

.macro asm_irqentry_exit_to_user_mode
mov r0, sp @ regs
- bl irqentry_exit_to_user_mode
+ bl arm_irqentry_exit_to_user_mode
.endm

/*
diff --git a/arch/arm/kernel/entry.c b/arch/arm/kernel/entry.c
index 09109215dfdf..7302ed8025a9 100644
--- a/arch/arm/kernel/entry.c
+++ b/arch/arm/kernel/entry.c
@@ -1,87 +1,59 @@
// SPDX-License-Identifier: GPL-2.0
#include <asm/entry.h>
-#include <asm/ptrace.h>
-#include <asm/signal.h>
#include <linux/context_tracking.h>
+#include <linux/entry-common.h>
#include <linux/irqflags.h>
#include <linux/rseq.h>

-long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
-{
- trace_hardirqs_on();
- local_irq_enable();
- /* This context tracking call has inverse naming */
- user_exit_callable();
-
- /* This will optionally be modified later */
- return syscall;
-}
+static irqentry_state_t user_irq_state;
+static irqentry_state_t kernel_irq_state;
+static irqentry_state_t user_nmi_state;
+static irqentry_state_t kernel_nmi_state;

-void syscall_exit_to_user_mode(struct pt_regs *regs)
+noinstr void arm_irqentry_enter_from_user_mode(struct pt_regs *regs)
{
- unsigned long flags = read_thread_flags();
-
- rseq_syscall(regs);
- local_irq_disable();
- /*
- * It really matters that we check for flags != 0 and not
- * just for pending work here!
- */
- if (flags)
- do_work_pending(regs, flags);
-
- trace_hardirqs_on();
- /* This context tracking call has inverse naming */
- user_enter_callable();
+ user_irq_state = irqentry_enter(regs);
}

-noinstr void irqentry_enter_from_user_mode(struct pt_regs *regs)
+noinstr void arm_irqentry_exit_to_user_mode(struct pt_regs *regs)
{
- trace_hardirqs_off();
- /* This context tracking call has inverse naming */
- user_exit_callable();
+ irqentry_exit(regs, user_irq_state);
}

-noinstr void irqentry_exit_to_user_mode(struct pt_regs *regs)
+noinstr void arm_irqentry_enter_from_kernel_mode(struct pt_regs *regs)
{
- unsigned long flags = read_thread_flags();
-
- /*
- * It really matters that we check for flags != 0 and not
- * just for pending work here!
- */
- if (flags)
- do_work_pending(regs, flags);
- trace_hardirqs_on();
- /* This context tracking call has inverse naming */
- user_enter_callable();
+ kernel_irq_state = irqentry_enter(regs);
}

-noinstr void irqentry_enter_from_kernel_mode(struct pt_regs *regs)
+noinstr void arm_irqentry_exit_to_kernel_mode(struct pt_regs *regs)
{
- trace_hardirqs_off();
+ irqentry_exit(regs, kernel_irq_state);
}

-noinstr void irqentry_exit_to_kernel_mode(struct pt_regs *regs)
+noinstr void arm_irqentry_nmi_enter_from_user_mode(struct pt_regs *regs)
{
- if (interrupts_enabled(regs))
- trace_hardirqs_on();
- else
- trace_hardirqs_off();
+ irqentry_enter_from_user_mode(regs);
+ user_nmi_state = irqentry_nmi_enter(regs);
}

-noinstr void irqentry_nmi_enter_from_user_mode(struct pt_regs *regs)
+noinstr void arm_irqentry_nmi_exit_to_user_mode(struct pt_regs *regs)
{
+ irqentry_nmi_exit(regs, user_nmi_state);
+ irqentry_exit_to_user_mode(regs);
}

-noinstr void irqentry_nmi_exit_to_user_mode(struct pt_regs *regs)
+noinstr void arm_irqentry_nmi_enter_from_kernel_mode(struct pt_regs *regs)
{
+ kernel_nmi_state = irqentry_nmi_enter(regs);
}

-noinstr void irqentry_nmi_enter_from_kernel_mode(struct pt_regs *regs)
+noinstr void arm_irqentry_nmi_exit_to_kernel_mode(struct pt_regs *regs)
{
+ irqentry_nmi_exit(regs, kernel_nmi_state);
}

-noinstr void irqentry_nmi_exit_to_kernel_mode(struct pt_regs *regs)
+asmlinkage void arm_exit_to_user_mode(struct pt_regs *regs)
{
+ local_irq_disable();
+ irqentry_exit_to_user_mode(regs);
}
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 81c1c3f98834..6c525a33fa6d 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -248,8 +248,6 @@ __visible void ret_from_fork(struct task_struct *prev, struct pt_regs *regs,
* execve() syscall.
*/
}
-
- /* syscall_exit_to_user_mode(regs); here once we switch to generic entry */
}

int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index ac7b98ae4724..89afe714cedc 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -27,9 +27,6 @@
#include <asm/syscall.h>
#include <asm/traps.h>

-#define CREATE_TRACE_POINTS
-#include <trace/events/syscalls.h>
-
#define REG_PC 15
#define REG_PSR 16
/*
@@ -821,90 +818,3 @@ long arch_ptrace(struct task_struct *child, long request,

return ret;
}
-
-enum ptrace_syscall_dir {
- PTRACE_SYSCALL_ENTER = 0,
- PTRACE_SYSCALL_EXIT,
-};
-
-static void report_syscall_enter(struct pt_regs *regs)
-{
- unsigned long ip;
-
- /*
- * IP is used to denote syscall entry/exit:
- * IP = 0 -> entry
- */
- ip = regs->ARM_ip;
- regs->ARM_ip = PTRACE_SYSCALL_ENTER;
-
- if (ptrace_report_syscall_entry(regs))
- current_thread_info()->abi_syscall = -1;
-
- regs->ARM_ip = ip;
-}
-
-static void report_syscall_exit(struct pt_regs *regs)
-{
- unsigned long ip;
-
- /*
- * IP is used to denote syscall entry/exit:
- * IP = 1 -> exit
- */
- ip = regs->ARM_ip;
- regs->ARM_ip = PTRACE_SYSCALL_EXIT;
-
- ptrace_report_syscall_exit(regs, 0);
-
- regs->ARM_ip = ip;
-}
-
-asmlinkage int syscall_trace_enter(struct pt_regs *regs)
-{
- int scno;
-
- if (test_thread_flag(TIF_SYSCALL_TRACE))
- report_syscall_enter(regs);
-
- /* Do seccomp after ptrace; syscall may have changed. */
-#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
- if (secure_computing() == -1)
- return -1;
-#else
- /* XXX: remove this once OABI gets fixed */
- secure_computing_strict(syscall_get_nr(current, regs));
-#endif
-
- /* Tracer or seccomp may have changed syscall. */
- scno = syscall_get_nr(current, regs);
-
- if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
- trace_sys_enter(regs, scno);
-
- audit_syscall_entry(scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
- regs->ARM_r3);
-
- return scno;
-}
-
-void syscall_trace_exit(struct pt_regs *regs)
-{
- /*
- * Audit the syscall before anything else, as a debugger may
- * come in and change the current registers.
- */
- audit_syscall_exit(regs);
-
- /*
- * Note that we haven't updated the ->syscall field for the
- * current thread. This isn't a problem because it will have
- * been set on syscall entry and there hasn't been an opportunity
- * for a PTRACE_SET_SYSCALL since then.
- */
- if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
- trace_sys_exit(regs, regs_return_value(regs));
-
- if (test_thread_flag(TIF_SYSCALL_TRACE))
- report_syscall_exit(regs);
-}
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index a39ee14ec5b7..35d2bb3cd2b4 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -4,6 +4,7 @@
*
* Copyright (C) 1995-2009 Russell King
*/
+#include <linux/entry-common.h>
#include <linux/errno.h>
#include <linux/random.h>
#include <linux/signal.h>
@@ -535,7 +536,7 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
* the kernel can handle, and then we build all the user-level signal handling
* stack-frames in one go after that.
*/
-static void arch_do_signal_or_restart(struct pt_regs *regs)
+void arch_do_signal_or_restart(struct pt_regs *regs)
{
unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
bool syscall = (syscall_get_nr(current, regs) != -1);
@@ -598,34 +599,6 @@ static void arch_do_signal_or_restart(struct pt_regs *regs)
return;
}

-void do_work_pending(struct pt_regs *regs, unsigned int thread_flags)
-{
- /*
- * The assembly code enters us with IRQs off, but it hasn't
- * informed the tracing code of that for efficiency reasons.
- * Update the trace code with the current status.
- */
- trace_hardirqs_off();
- do {
- if (likely(thread_flags & _TIF_NEED_RESCHED)) {
- schedule();
- } else {
- if (unlikely(!user_mode(regs)))
- return;
- local_irq_enable();
- if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
- arch_do_signal_or_restart(regs);
- } else if (thread_flags & _TIF_UPROBE) {
- uprobe_notify_resume(regs);
- } else {
- resume_user_mode_work(regs);
- }
- }
- local_irq_disable();
- thread_flags = read_thread_flags();
- } while (thread_flags & _TIF_WORK_MASK);
-}
-
struct page *get_signal_page(void)
{
unsigned long ptr;
diff --git a/arch/arm/kernel/syscall.c b/arch/arm/kernel/syscall.c
index 968cec945a7e..26ec3a151652 100644
--- a/arch/arm/kernel/syscall.c
+++ b/arch/arm/kernel/syscall.c
@@ -1,25 +1,16 @@
// SPDX-License-Identifier: GPL-2.0

+#include <linux/entry-common.h>
#include <linux/syscalls.h>
#include <asm/syscall.h>

-static inline bool has_syscall_work(unsigned long flags)
-{
- return unlikely(flags & _TIF_SYSCALL_WORK);
-}
-
int invoke_syscall_asm(void *table, struct pt_regs *regs, int scno);

-__visible int invoke_syscall(void *table, struct pt_regs *regs, int scno)
+__visible void invoke_syscall(void *table, struct pt_regs *regs, int scno)
{
- unsigned long flags = read_thread_flags();
int ret;

- if (has_syscall_work(flags)) {
- scno = syscall_trace_enter(regs);
- if (scno == -1)
- goto trace_exit_nosave;
- }
+ scno = syscall_enter_from_user_mode(regs, scno);

if (scno < NR_syscalls) {
ret = invoke_syscall_asm(table, regs, scno);
@@ -34,13 +25,7 @@ __visible int invoke_syscall(void *table, struct pt_regs *regs, int scno)
ret = sys_ni_syscall();

exit_save:
- /* Save return value from syscall */
- regs->ARM_r0 = ret;
- if (!has_syscall_work(flags))
- return 0;
-
-trace_exit_nosave:
- local_irq_enable();
- syscall_trace_exit(regs);
- return 1;
+ syscall_set_return_value(current, regs, 0, ret);
+
+ syscall_exit_to_user_mode(regs);
}

--
2.46.2