@@ -178,4 +178,5 @@ void syscall_exit_to_user_mode_work(struct pt_regs *regs);
*/
void syscall_exit_to_user_mode(struct pt_regs *regs);
+void syscall_exit_work(struct pt_regs *regs, unsigned long work);
#endif
@@ -55,6 +55,19 @@ enum syscall_work_bit {
#define SYSCALL_WORK_SYSCALL_AUDIT BIT(SYSCALL_WORK_BIT_SYSCALL_AUDIT)
#define SYSCALL_WORK_SYSCALL_USER_DISPATCH BIT(SYSCALL_WORK_BIT_SYSCALL_USER_DISPATCH)
#define SYSCALL_WORK_SYSCALL_EXIT_TRAP BIT(SYSCALL_WORK_BIT_SYSCALL_EXIT_TRAP)
+
+/*
+ * 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)
+{
+ if (work & SYSCALL_WORK_SYSCALL_EMU)
+ return false;
+
+ return work & SYSCALL_WORK_SYSCALL_EXIT_TRAP;
+}
#endif
#include <asm/thread_info.h>
@@ -17,6 +17,49 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
}
}
+/**
+ * arch_pre_report_syscall_entry - Architecture specific work before
+ * report_syscall_entry().
+ *
+ * Invoked from syscall_trace_enter() to prepare for ptrace_report_syscall_entry().
+ * Defaults to NOP.
+ *
+ * The main purpose is for saving a general purpose register clobbered
+ * in the tracee.
+ */
+static inline unsigned long arch_pre_report_syscall_entry(struct pt_regs *regs);
+
+#ifndef arch_pre_report_syscall_entry
+static inline unsigned long arch_pre_report_syscall_entry(struct pt_regs *regs)
+{
+ return 0;
+}
+#endif
+
+/**
+ * arch_post_report_syscall_entry - Architecture specific work after
+ * report_syscall_entry().
+ *
+ * Invoked from syscall_trace_enter() after calling ptrace_report_syscall_entry().
+ * Defaults to NOP.
+ *
+ * The main purpose is for restoring a general purpose register clobbered
+ * in the trace saved in arch_pre_report_syscall_entry(), also it can
+ * do something arch-specific according to the return value of
+ * ptrace_report_syscall_entry().
+ */
+static inline void arch_post_report_syscall_entry(struct pt_regs *regs,
+ unsigned long saved_reg,
+ long ret);
+
+#ifndef arch_post_report_syscall_entry
+static inline void arch_post_report_syscall_entry(struct pt_regs *regs,
+ unsigned long saved_reg,
+ long ret)
+{
+}
+#endif
+
long syscall_trace_enter(struct pt_regs *regs, long syscall,
unsigned long work)
{
@@ -34,7 +77,9 @@ long syscall_trace_enter(struct pt_regs *regs, long syscall,
/* Handle ptrace */
if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
+ unsigned long saved_reg = arch_pre_report_syscall_entry(regs);
ret = ptrace_report_syscall_entry(regs);
+ arch_post_report_syscall_entry(regs, saved_reg, ret);
if (ret || (work & SYSCALL_WORK_SYSCALL_EMU))
return -1L;
}
@@ -71,20 +116,50 @@ noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
instrumentation_end();
}
-/*
- * 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().
+/**
+ * arch_pre_report_syscall_exit - Architecture specific work before
+ * report_syscall_exit().
+ *
+ * Invoked from syscall_exit_work() to prepare for ptrace_report_syscall_exit().
+ * Defaults to NOP.
+ *
+ * The main purpose is for saving a general purpose register clobbered
+ * in the trace.
*/
-static inline bool report_single_step(unsigned long work)
-{
- if (work & SYSCALL_WORK_SYSCALL_EMU)
- return false;
+static inline unsigned long arch_pre_report_syscall_exit(struct pt_regs *regs,
+ unsigned long work);
- return work & SYSCALL_WORK_SYSCALL_EXIT_TRAP;
+#ifndef arch_pre_report_syscall_exit
+static inline unsigned long arch_pre_report_syscall_exit(struct pt_regs *regs,
+ unsigned long work)
+{
+ return 0;
}
+#endif
+
+/**
+ * arch_post_report_syscall_exit - Architecture specific work after
+ * report_syscall_exit().
+ *
+ * Invoked from syscall_exit_work() after calling ptrace_report_syscall_exit().
+ * Defaults to NOP.
+ *
+ * The main purpose is for restoring a general purpose register clobbered
+ * in the trace saved in arch_pre_report_syscall_exit().
+ */
+static inline void arch_post_report_syscall_exit(struct pt_regs *regs,
+ unsigned long saved_reg,
+ unsigned long work);
+
+#ifndef arch_post_report_syscall_exit
+static inline void arch_post_report_syscall_exit(struct pt_regs *regs,
+ unsigned long saved_reg,
+ unsigned long work)
+{
+}
+#endif
-static void syscall_exit_work(struct pt_regs *regs, unsigned long work)
+void syscall_exit_work(struct pt_regs *regs, unsigned long work)
{
bool step;
@@ -107,8 +182,11 @@ 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) {
+ unsigned long saved_reg = arch_pre_report_syscall_exit(regs, work);
ptrace_report_syscall_exit(regs, step);
+ arch_post_report_syscall_exit(regs, saved_reg, work);
+ }
}
/*
Add some syscall arch functions to support arm64 to use generic syscall code, which do not affect existing architectures that use generic entry: - arch_pre/post_report_syscall_entry/exit(). Also make syscall_exit_work() not static and move report_single_step() to thread_info.h, which can be used by arm64 later. Suggested-by: Mark Rutland <mark.rutland@arm.com> Suggested-by: Kevin Brodsky <kevin.brodsky@arm.com> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- include/linux/entry-common.h | 1 + include/linux/thread_info.h | 13 +++++ kernel/entry/syscall-common.c | 100 ++++++++++++++++++++++++++++++---- 3 files changed, 103 insertions(+), 11 deletions(-)