Re: [patch 09/18] entry: Remove syscall_enter_from_user_mode()
From: Jinjie Ruan <hidden>
Date: 2026-07-09 02:49:56
Also in:
linux-alpha, linux-arch, linux-doc, linux-m68k, linux-mips, linux-riscv, linux-s390, linux-sh, linux-um, lkml, loongarch, sparclinux
On 7/8/2026 3:06 AM, Thomas Gleixner wrote:
quoted hunk ↗ jump to hunk
All architecture use either: nr = enter_from_user_mode_randomize_stack(regs, nr); or enter_from_user_mode_randomize_stack(regs); nr = syscall_enter_from_user_mode_work(regs, nr); Remove the now unused function. Signed-off-by: Thomas Gleixner <tglx@kernel.org> --- Documentation/core-api/entry.rst | 17 +++++++++------- include/linux/entry-common.h | 40 +++------------------------------------ include/linux/irq-entry-common.h | 6 ++--- 3 files changed, 17 insertions(+), 46 deletions(-)--- a/Documentation/core-api/entry.rst +++ b/Documentation/core-api/entry.rst@@ -68,7 +68,7 @@ low-level C code must not be instrumente noinstr void syscall(struct pt_regs *regs, int nr) { arch_syscall_enter(regs); - nr = syscall_enter_from_user_mode(regs, nr); + nr = syscall_enter_from_user_mode_randomize_stack(regs, nr); instrumentation_begin(); if (!invoke_syscall(regs, nr) && nr != -1)@@ -78,12 +78,14 @@ low-level C code must not be instrumente syscall_exit_to_user_mode(regs); } -syscall_enter_from_user_mode() first invokes enter_from_user_mode() which -establishes state in the following order: +syscall_enter_from_user_mode_randomize_stack() first invokes +enter_from_user_mode_randomize_stack() which establishes state in the +following order: * Lockdep * RCU / Context tracking * Tracing + * Apply stack randomization and then invokes the various entry work functions like ptrace, seccomp, audit, syscall tracing, etc. After all that is done, the instrumentable invoke_syscall@@ -99,10 +101,11 @@ that it invokes exit_to_user_mode() whic * RCU / Context tracking * Lockdep -syscall_enter_from_user_mode() and syscall_exit_to_user_mode() are also -available as fine grained subfunctions in cases where the architecture code -has to do extra work between the various steps. In such cases it has to -ensure that enter_from_user_mode() is called first on entry and +syscall_enter_from_user_mode_randomize_stack() and +syscall_exit_to_user_mode() are also available as fine grained subfunctions +in cases where the architecture code has to do extra work between the +various steps. In such cases it has to ensure that +enter_from_user_mode_randomize_stack() is called first on entry and exit_to_user_mode() is called last on exit. Do not nest syscalls. Nested syscalls will cause RCU and/or context tracking --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h@@ -19,7 +19,7 @@ #endif /* - * SYSCALL_WORK flags handled in syscall_enter_from_user_mode() + * SYSCALL_WORK flags handled in syscall_enter_from_user_mode_work() */ #define SYSCALL_WORK_ENTER (SYSCALL_WORK_SECCOMP | \ SYSCALL_WORK_SYSCALL_TRACEPOINT | \@@ -205,42 +205,10 @@ do { \ _ret; \ }) -/** - * syscall_enter_from_user_mode - Establish state and check and handle work - * before invoking a syscall - * @regs: Pointer to currents pt_regs - * @syscall: The syscall number - * - * Invoked from architecture specific syscall entry code with interrupts - * disabled. The calling code has to be non-instrumentable. When the - * function returns all state is correct, interrupts are enabled and the - * subsequent functions can be instrumented. - * - * This is the combination of enter_from_user_mode() and - * syscall_enter_from_user_mode_work() to be used when there is no - * architecture specific work to be done between the two. - * - * Returns: The original or a modified syscall number. See - * syscall_enter_from_user_mode_work() for further explanation. - */ -static __always_inline long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall) -{ - long ret; - - enter_from_user_mode(regs); - - instrumentation_begin(); - local_irq_enable(); - ret = syscall_enter_from_user_mode_work(regs, syscall); - instrumentation_end(); - - return ret; -} - /* - * 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(). + * 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_work(). */ static __always_inline bool report_single_step(unsigned long work) { --- a/include/linux/irq-entry-common.h +++ b/include/linux/irq-entry-common.h@@ -49,9 +49,9 @@ * Defaults to an empty implementation. Can be replaced by architecture * specific code. * - * Invoked from syscall_enter_from_user_mode() in the non-instrumentable - * section. Use __always_inline so the compiler cannot push it out of line - * and make it instrumentable. + * Invoked from enter_from_user_mode_syscall_and_randomize_stack() in the + * non-instrumentable section. Use __always_inline so the compiler cannot push + * it out of line and make it instrumentable.
Reviewed-by: Jinjie Ruan <redacted>
*/ static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs);