[PATCH 1/3] entry: Add some arch funcs to support arm64 to use generic entry
Jinjie Ruan
ruanjinjie at huawei.com
Tue Jun 25 02:27:57 PDT 2024
Add some arch functions to support arm64 to use generic entry:
- Add arch_prepare/post_report_syscall_entry/exit(),
arch_enter_from_kernel_mode(), arch_exit_to_kernel_mode_prepare(),
arch_irqentry_exit_need_resched() arch function to support
architecture-related action, which do not affect existing architectures
that use generic entry.
- Make report_single_step() and syscall_exit_work() not static.
Signed-off-by: Jinjie Ruan <ruanjinjie at huawei.com>
---
include/linux/entry-common.h | 51 ++++++++++++++++++++++++++++++++++++
kernel/entry/common.c | 49 +++++++++++++++++++++++++++++-----
2 files changed, 94 insertions(+), 6 deletions(-)
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index b0fb775a600d..1be4c3d91995 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -84,6 +84,18 @@ static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs);
static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs) {}
#endif
+static __always_inline void arch_enter_from_kernel_mode(struct pt_regs *regs);
+
+#ifndef arch_enter_from_kernel_mode
+static __always_inline void arch_enter_from_kernel_mode(struct pt_regs *regs) {}
+#endif
+
+static __always_inline void arch_exit_to_kernel_mode_prepare(struct pt_regs *regs);
+
+#ifndef arch_exit_to_kernel_mode_prepare
+static __always_inline void arch_exit_to_kernel_mode_prepare(struct pt_regs *regs) {}
+#endif
+
/**
* enter_from_user_mode - Establish state when coming from user mode
*
@@ -298,6 +310,42 @@ static __always_inline void arch_exit_to_user_mode(void) { }
*/
void arch_do_signal_or_restart(struct pt_regs *regs);
+/**
+ * arch_irqentry_exit_need_resched - Architecture specific need resched function
+ */
+bool arch_irqentry_exit_need_resched(void);
+
+/**
+ * arch_prepare_report_syscall_entry - Architecture specific report_syscall_entry()
+ * prepare function
+ */
+unsigned long arch_prepare_report_syscall_entry(struct pt_regs *regs);
+
+/**
+ * arch_post_report_syscall_entry - Architecture specific report_syscall_entry()
+ * post function
+ */
+void arch_post_report_syscall_entry(struct pt_regs *regs, unsigned long saved_reg);
+
+/**
+ * arch_prepare_report_syscall_exit - Architecture specific report_syscall_exit()
+ * prepare function
+ */
+unsigned long arch_prepare_report_syscall_exit(struct pt_regs *regs, unsigned long work);
+
+/**
+ * arch_post_report_syscall_exit - Architecture specific report_syscall_exit()
+ * post function
+ */
+void arch_post_report_syscall_exit(struct pt_regs *regs, unsigned long saved_reg,
+ unsigned long work);
+
+/**
+ * arch_forget_syscall - Architecture specific function called if
+ * ptrace_report_syscall_entry() return nonzero
+ */
+void arch_forget_syscall(struct pt_regs *regs);
+
/**
* exit_to_user_mode_loop - do any pending work before leaving to user space
*/
@@ -552,4 +600,7 @@ irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs);
*/
void noinstr irqentry_nmi_exit(struct pt_regs *regs, irqentry_state_t irq_state);
+bool report_single_step(unsigned long work);
+void syscall_exit_work(struct pt_regs *regs, unsigned long work);
+
#endif
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index 90843cc38588..c524cf7f86f8 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -25,9 +25,14 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
}
}
+unsigned long __weak arch_prepare_report_syscall_entry(struct pt_regs *regs) { return 0; }
+void __weak arch_post_report_syscall_entry(struct pt_regs *regs, unsigned long saved_reg) { }
+void __weak arch_forget_syscall(struct pt_regs *regs) { };
+
long syscall_trace_enter(struct pt_regs *regs, long syscall,
unsigned long work)
{
+ unsigned long saved_reg;
long ret = 0;
/*
@@ -42,8 +47,14 @@ long syscall_trace_enter(struct pt_regs *regs, long syscall,
/* Handle ptrace */
if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
+ saved_reg = arch_prepare_report_syscall_entry(regs);
ret = ptrace_report_syscall_entry(regs);
- if (ret || (work & SYSCALL_WORK_SYSCALL_EMU))
+ if (ret) {
+ arch_forget_syscall(regs);
+ return -1L;
+ }
+ arch_post_report_syscall_entry(regs, saved_reg);
+ if (work & SYSCALL_WORK_SYSCALL_EMU)
return -1L;
}
@@ -138,7 +149,7 @@ __always_inline unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
* 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)
+inline bool report_single_step(unsigned long work)
{
if (work & SYSCALL_WORK_SYSCALL_EMU)
return false;
@@ -146,8 +157,22 @@ static inline bool report_single_step(unsigned long work)
return work & SYSCALL_WORK_SYSCALL_EXIT_TRAP;
}
-static void syscall_exit_work(struct pt_regs *regs, unsigned long work)
+unsigned long __weak arch_prepare_report_syscall_exit(struct pt_regs *regs,
+ unsigned long work)
{
+ return 0;
+}
+
+void __weak arch_post_report_syscall_exit(struct pt_regs *regs,
+ unsigned long saved_reg,
+ unsigned long work)
+{
+
+}
+
+void syscall_exit_work(struct pt_regs *regs, unsigned long work)
+{
+ unsigned long saved_reg;
bool step;
/*
@@ -169,8 +194,11 @@ static void syscall_exit_work(struct pt_regs *regs, unsigned long work)
trace_sys_exit(regs, syscall_get_return_value(current, regs));
step = report_single_step(work);
- if (step || work & SYSCALL_WORK_SYSCALL_TRACE)
+ if (step || work & SYSCALL_WORK_SYSCALL_TRACE) {
+ saved_reg = arch_prepare_report_syscall_exit(regs, work);
ptrace_report_syscall_exit(regs, step);
+ arch_post_report_syscall_exit(regs, saved_reg, work);
+ }
}
/*
@@ -244,6 +272,8 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)
return ret;
}
+ arch_enter_from_kernel_mode(regs);
+
/*
* If this entry hit the idle task invoke ct_irq_enter() whether
* RCU is watching or not.
@@ -300,6 +330,8 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)
return ret;
}
+bool __weak arch_irqentry_exit_need_resched(void) { return true; }
+
void raw_irqentry_exit_cond_resched(void)
{
if (!preempt_count()) {
@@ -307,7 +339,7 @@ void raw_irqentry_exit_cond_resched(void)
rcu_irq_exit_check_preempt();
if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
WARN_ON_ONCE(!on_thread_stack());
- if (need_resched())
+ if (need_resched() && arch_irqentry_exit_need_resched())
preempt_schedule_irq();
}
}
@@ -332,7 +364,12 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state)
/* Check whether this returns to user mode */
if (user_mode(regs)) {
irqentry_exit_to_user_mode(regs);
- } else if (!regs_irqs_disabled(regs)) {
+ return;
+ }
+
+ arch_exit_to_kernel_mode_prepare(regs);
+
+ if (!regs_irqs_disabled(regs)) {
/*
* If RCU was not watching on entry this needs to be done
* carefully and needs the same ordering of lockdep/tracing
--
2.34.1
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