From 03150a9f84b328f5c724b8ed9ff8600c2d7e2d7b Mon Sep 17 00:00:00 2001 From: Jinjie Ruan Date: Wed, 28 Jan 2026 11:19:21 +0800 Subject: entry: Remove unused syscall argument from syscall_trace_enter() The 'syscall' argument of syscall_trace_enter() is immediately overwritten before any real use and serves only as a local variable, so drop the parameter. No functional change intended. Signed-off-by: Jinjie Ruan Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20260128031934.3906955-2-ruanjinjie@huawei.com --- kernel/entry/syscall-common.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/entry/syscall-common.c b/kernel/entry/syscall-common.c index 940a597ded40..e6237b536d8b 100644 --- a/kernel/entry/syscall-common.c +++ b/kernel/entry/syscall-common.c @@ -17,10 +17,9 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall) } } -long syscall_trace_enter(struct pt_regs *regs, long syscall, - unsigned long work) +long syscall_trace_enter(struct pt_regs *regs, unsigned long work) { - long ret = 0; + long syscall, ret = 0; /* * Handle Syscall User Dispatch. This must comes first, since -- cgit v1.2.3 From 578b21fd3ab2d9901ce40ed802e428a41a40610d Mon Sep 17 00:00:00 2001 From: Jinjie Ruan Date: Wed, 28 Jan 2026 11:19:30 +0800 Subject: entry: Add arch_ptrace_report_syscall_entry/exit() ARM64 requires a architecture specific ptrace wrapper as it needs to save and restore scratch registers. Provide arch_ptrace_report_syscall_entry/exit() wrappers which fall back to ptrace_report_syscall_entry/exit() if the architecture does not provide them. No functional change intended. [ tglx: Massaged changelog and comments ] Suggested-by: Mark Rutland Suggested-by: Thomas Gleixner Signed-off-by: Jinjie Ruan Signed-off-by: Thomas Gleixner Reviewed-by: Kevin Brodsky Link: https://patch.msgid.link/20260128031934.3906955-11-ruanjinjie@huawei.com --- kernel/entry/syscall-common.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/entry/syscall-common.c b/kernel/entry/syscall-common.c index e6237b536d8b..bb5f61f5629d 100644 --- a/kernel/entry/syscall-common.c +++ b/kernel/entry/syscall-common.c @@ -33,7 +33,7 @@ long syscall_trace_enter(struct pt_regs *regs, unsigned long work) /* Handle ptrace */ if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) { - ret = ptrace_report_syscall_entry(regs); + ret = arch_ptrace_report_syscall_entry(regs); if (ret || (work & SYSCALL_WORK_SYSCALL_EMU)) return -1L; } @@ -99,5 +99,5 @@ void syscall_exit_work(struct pt_regs *regs, unsigned long work) step = report_single_step(work); if (step || work & SYSCALL_WORK_SYSCALL_TRACE) - ptrace_report_syscall_exit(regs, step); + arch_ptrace_report_syscall_exit(regs, step); } -- cgit v1.2.3 From 31c9387d0d84bc1d643a0c30155b6d92d05c92fc Mon Sep 17 00:00:00 2001 From: Jinjie Ruan Date: Wed, 28 Jan 2026 11:19:33 +0800 Subject: entry: Inline syscall_exit_work() and syscall_trace_enter() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit After switching ARM64 to the generic entry code, a syscall_exit_work() appeared as a profiling hotspot because it is not inlined. Inlining both syscall_trace_enter() and syscall_exit_work() provides a performance gain when any of the work items is enabled. With audit enabled this results in a ~4% performance gain for perf bench basic syscall on a kunpeng920 system: | Metric | Baseline | Inlined | Change | | ---------- | ----------- | ----------- | ------ | | Total time | 2.353 [sec] | 2.264 [sec] | ↓3.8% | | usecs/op | 0.235374 | 0.226472 | ↓3.8% | | ops/sec | 4,248,588 | 4,415,554 | ↑3.9% | Small gains can be observed on x86 as well, though the generated code optimizes for the work case, which is counterproductive for high performance scenarios where such entry/exit work is usually avoided. Avoid this by marking the work check in syscall_enter_from_user_mode_work() unlikely, which is what the corresponding check in the exit path does already. [ tglx: Massage changelog and add the unlikely() ] Signed-off-by: Jinjie Ruan Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20260128031934.3906955-14-ruanjinjie@huawei.com --- kernel/entry/common.h | 7 --- kernel/entry/syscall-common.c | 96 +++--------------------------------- kernel/entry/syscall_user_dispatch.c | 4 +- 3 files changed, 10 insertions(+), 97 deletions(-) delete mode 100644 kernel/entry/common.h (limited to 'kernel') diff --git a/kernel/entry/common.h b/kernel/entry/common.h deleted file mode 100644 index f6e6d02f07fe..000000000000 --- a/kernel/entry/common.h +++ /dev/null @@ -1,7 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _COMMON_H -#define _COMMON_H - -bool syscall_user_dispatch(struct pt_regs *regs); - -#endif diff --git a/kernel/entry/syscall-common.c b/kernel/entry/syscall-common.c index bb5f61f5629d..cd4967a9c53e 100644 --- a/kernel/entry/syscall-common.c +++ b/kernel/entry/syscall-common.c @@ -1,103 +1,23 @@ // SPDX-License-Identifier: GPL-2.0 -#include #include -#include "common.h" #define CREATE_TRACE_POINTS #include -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]); - } -} +/* Out of line to prevent tracepoint code duplication */ -long syscall_trace_enter(struct pt_regs *regs, unsigned long work) +long trace_syscall_enter(struct pt_regs *regs, long syscall) { - long syscall, ret = 0; - + trace_sys_enter(regs, syscall); /* - * 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. + * Probes or BPF hooks in the tracepoint may have changed the + * system call number. Reread it. */ - 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 = arch_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; + return syscall_get_nr(current, regs); } -/* - * 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) +void trace_syscall_exit(struct pt_regs *regs, long ret) { - 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) - arch_ptrace_report_syscall_exit(regs, step); + trace_sys_exit(regs, ret); } diff --git a/kernel/entry/syscall_user_dispatch.c b/kernel/entry/syscall_user_dispatch.c index a9055eccb27e..d89dffcc2d64 100644 --- a/kernel/entry/syscall_user_dispatch.c +++ b/kernel/entry/syscall_user_dispatch.c @@ -2,6 +2,8 @@ /* * Copyright (C) 2020 Collabora Ltd. */ + +#include #include #include #include @@ -15,8 +17,6 @@ #include -#include "common.h" - static void trigger_sigsys(struct pt_regs *regs) { struct kernel_siginfo info; -- cgit v1.2.3