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ptrace: Migrate TIF_SYSCALL_EMU to use SYSCALL_WORK flag

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On architectures using the generic syscall entry code the architecture
independent syscall work is moved to flags in thread_info::syscall_work.
This removes architecture dependencies and frees up TIF bits.

Define SYSCALL_WORK_SYSCALL_EMU, use it in the generic entry code and
convert the code which uses the TIF specific helper functions to use the
new *_syscall_work() helpers which either resolve to the new mode for users
of the generic entry code or to the TIF based functions for the other
architectures.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20201116174206.2639648-8-krisman@collabora.com
This commit is contained in:
Gabriel Krisman Bertazi 2020-11-16 12:42:03 -05:00 • committed by Thomas Gleixner
parent 64c19ba29b
commit 64eb35f701
6 changed files with 22 additions and 23 deletions
Download patch file Download diff file Expand all files Collapse all files

8
include/linux/entry-common.h
View file

@ -13,10 +13,6 @@
* Define dummy _TIF work flags if not defined by the architecture or for * Define dummy _TIF work flags if not defined by the architecture or for
* disabled functionality. * disabled functionality.
*/ */
#ifndef _TIF_SYSCALL_EMU
# define _TIF_SYSCALL_EMU (0)
#endif
#ifndef _TIF_SYSCALL_AUDIT #ifndef _TIF_SYSCALL_AUDIT
# define _TIF_SYSCALL_AUDIT (0) # define _TIF_SYSCALL_AUDIT (0)
#endif #endif
@ -42,7 +38,6 @@
#define SYSCALL_ENTER_WORK \ #define SYSCALL_ENTER_WORK \
(_TIF_SYSCALL_AUDIT | \ (_TIF_SYSCALL_AUDIT | \
_TIF_SYSCALL_EMU | \
ARCH_SYSCALL_ENTER_WORK) ARCH_SYSCALL_ENTER_WORK)
/* /*
@ -58,7 +53,8 @@
#define SYSCALL_WORK_ENTER (SYSCALL_WORK_SECCOMP | \ #define SYSCALL_WORK_ENTER (SYSCALL_WORK_SECCOMP | \
SYSCALL_WORK_SYSCALL_TRACEPOINT | \ SYSCALL_WORK_SYSCALL_TRACEPOINT | \
SYSCALL_WORK_SYSCALL_TRACE) SYSCALL_WORK_SYSCALL_TRACE | \
SYSCALL_WORK_SYSCALL_EMU)
#define SYSCALL_WORK_EXIT (SYSCALL_WORK_SYSCALL_TRACEPOINT | \ #define SYSCALL_WORK_EXIT (SYSCALL_WORK_SYSCALL_TRACEPOINT | \
SYSCALL_WORK_SYSCALL_TRACE) SYSCALL_WORK_SYSCALL_TRACE)

2
include/linux/thread_info.h
View file

@ -39,11 +39,13 @@ enum syscall_work_bit {
SYSCALL_WORK_BIT_SECCOMP, SYSCALL_WORK_BIT_SECCOMP,
SYSCALL_WORK_BIT_SYSCALL_TRACEPOINT, SYSCALL_WORK_BIT_SYSCALL_TRACEPOINT,
SYSCALL_WORK_BIT_SYSCALL_TRACE, SYSCALL_WORK_BIT_SYSCALL_TRACE,
SYSCALL_WORK_BIT_SYSCALL_EMU,
}; };
#define SYSCALL_WORK_SECCOMP BIT(SYSCALL_WORK_BIT_SECCOMP) #define SYSCALL_WORK_SECCOMP BIT(SYSCALL_WORK_BIT_SECCOMP)
#define SYSCALL_WORK_SYSCALL_TRACEPOINT BIT(SYSCALL_WORK_BIT_SYSCALL_TRACEPOINT) #define SYSCALL_WORK_SYSCALL_TRACEPOINT BIT(SYSCALL_WORK_BIT_SYSCALL_TRACEPOINT)
#define SYSCALL_WORK_SYSCALL_TRACE BIT(SYSCALL_WORK_BIT_SYSCALL_TRACE) #define SYSCALL_WORK_SYSCALL_TRACE BIT(SYSCALL_WORK_BIT_SYSCALL_TRACE)
#define SYSCALL_WORK_SYSCALL_EMU BIT(SYSCALL_WORK_BIT_SYSCALL_EMU)
#include <asm/thread_info.h> #include <asm/thread_info.h>

2
include/linux/tracehook.h
View file

@ -84,7 +84,7 @@ static inline int ptrace_report_syscall(struct pt_regs *regs,
* @regs: user register state of current task * @regs: user register state of current task
* *
* This will be called if %SYSCALL_WORK_SYSCALL_TRACE or * This will be called if %SYSCALL_WORK_SYSCALL_TRACE or
* %TIF_SYSCALL_EMU have been set, when the current task has just * %SYSCALL_WORK_SYSCALL_EMU have been set, when the current task has just
* entered the kernel for a system call. Full user register state is * entered the kernel for a system call. Full user register state is
* available here. Changing the values in @regs can affect the system * available here. Changing the values in @regs can affect the system
* call number and arguments to be tried. It is safe to block here, * call number and arguments to be tried. It is safe to block here,

19
kernel/entry/common.c
View file

@ -47,9 +47,9 @@ static long syscall_trace_enter(struct pt_regs *regs, long syscall,
long ret = 0; long ret = 0;
/* Handle ptrace */ /* Handle ptrace */
if (work & SYSCALL_WORK_SYSCALL_TRACE || ti_work & _TIF_SYSCALL_EMU) { if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
ret = arch_syscall_enter_tracehook(regs); ret = arch_syscall_enter_tracehook(regs);
if (ret || (ti_work & _TIF_SYSCALL_EMU)) if (ret || (work & SYSCALL_WORK_SYSCALL_EMU))
return -1L; return -1L;
} }
@ -208,21 +208,22 @@ static void exit_to_user_mode_prepare(struct pt_regs *regs)
} }
#ifndef _TIF_SINGLESTEP #ifndef _TIF_SINGLESTEP
static inline bool report_single_step(unsigned long ti_work) static inline bool report_single_step(unsigned long work)
{ {
return false; return false;
} }
#else #else
/* /*
* If TIF_SYSCALL_EMU is set, then the only reason to report is when * If SYSCALL_EMU is set, then the only reason to report is when
* TIF_SINGLESTEP is set (i.e. PTRACE_SYSEMU_SINGLESTEP). This syscall * TIF_SINGLESTEP is set (i.e. PTRACE_SYSEMU_SINGLESTEP). This syscall
* instruction has been already reported in syscall_enter_from_user_mode(). * instruction has been already reported in syscall_enter_from_user_mode().
*/ */
#define SYSEMU_STEP (_TIF_SINGLESTEP | _TIF_SYSCALL_EMU) static inline bool report_single_step(unsigned long work)
static inline bool report_single_step(unsigned long ti_work)
{ {
return (ti_work & SYSEMU_STEP) == _TIF_SINGLESTEP; if (!(work & SYSCALL_WORK_SYSCALL_EMU))
return false;
return !!(current_thread_info()->flags & _TIF_SINGLESTEP);
} }
#endif #endif
@ -236,7 +237,7 @@ static void syscall_exit_work(struct pt_regs *regs, unsigned long ti_work,
if (work & SYSCALL_WORK_SYSCALL_TRACEPOINT) if (work & SYSCALL_WORK_SYSCALL_TRACEPOINT)
trace_sys_exit(regs, syscall_get_return_value(current, regs)); trace_sys_exit(regs, syscall_get_return_value(current, regs));
step = report_single_step(ti_work); step = report_single_step(work);
if (step || work & SYSCALL_WORK_SYSCALL_TRACE) if (step || work & SYSCALL_WORK_SYSCALL_TRACE)
arch_syscall_exit_tracehook(regs, step); arch_syscall_exit_tracehook(regs, step);
} }

4
kernel/fork.c
View file

@ -2159,8 +2159,8 @@ static __latent_entropy struct task_struct *copy_process(
*/ */
user_disable_single_step(p); user_disable_single_step(p);
clear_task_syscall_work(p, SYSCALL_TRACE); clear_task_syscall_work(p, SYSCALL_TRACE);
#ifdef TIF_SYSCALL_EMU #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); clear_task_syscall_work(p, SYSCALL_EMU);
#endif #endif
clear_tsk_latency_tracing(p); clear_tsk_latency_tracing(p);

10
kernel/ptrace.c
View file

@ -118,8 +118,8 @@ void __ptrace_unlink(struct task_struct *child)
BUG_ON(!child->ptrace); BUG_ON(!child->ptrace);
clear_task_syscall_work(child, SYSCALL_TRACE); clear_task_syscall_work(child, SYSCALL_TRACE);
#ifdef TIF_SYSCALL_EMU #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); clear_task_syscall_work(child, SYSCALL_EMU);
#endif #endif
child->parent = child->real_parent; child->parent = child->real_parent;
@ -816,11 +816,11 @@ static int ptrace_resume(struct task_struct *child, long request,
else else
clear_task_syscall_work(child, SYSCALL_TRACE); clear_task_syscall_work(child, SYSCALL_TRACE);
#ifdef TIF_SYSCALL_EMU #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
set_tsk_thread_flag(child, TIF_SYSCALL_EMU); set_task_syscall_work(child, SYSCALL_EMU);
else else
clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); clear_task_syscall_work(child, SYSCALL_EMU);
#endif #endif
if (is_singleblock(request)) { if (is_singleblock(request)) {