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    Subject[PATCH v2 09/10] entry: Drop usage of TIF flags in the generic syscall code
    Date
    Now that the flags migration in the common syscall entry is complete and
    the code relies exclusively on syscall_work, clean up the
    accesses to TI flags in that path.

    Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>

    ---
    Changes since v2:
    - Fix subsystem prefix (tglx)
    ---
    include/linux/entry-common.h | 20 +++++++++-----------
    kernel/entry/common.c | 17 +++++++----------
    2 files changed, 16 insertions(+), 21 deletions(-)

    diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
    index afeb927e8545..cffd8bf1e085 100644
    --- a/include/linux/entry-common.h
    +++ b/include/linux/entry-common.h
    @@ -26,31 +26,29 @@
    #endif

    /*
    - * TIF flags handled in syscall_enter_from_user_mode()
    + * SYSCALL_WORK flags handled in syscall_enter_from_user_mode()
    */
    -#ifndef ARCH_SYSCALL_ENTER_WORK
    -# define ARCH_SYSCALL_ENTER_WORK (0)
    +#ifndef ARCH_SYSCALL_WORK_ENTER
    +# define ARCH_SYSCALL_WORK_ENTER (0)
    #endif

    -#define SYSCALL_ENTER_WORK ARCH_SYSCALL_ENTER_WORK
    -
    /*
    * TIF flags handled in syscall_exit_to_user_mode()
    */
    -#ifndef ARCH_SYSCALL_EXIT_WORK
    -# define ARCH_SYSCALL_EXIT_WORK (0)
    +#ifndef ARCH_SYSCALL_WORK_EXIT
    +# define ARCH_SYSCALL_WORK_EXIT (0)
    #endif

    -#define SYSCALL_EXIT_WORK ARCH_SYSCALL_EXIT_WORK
    -
    #define SYSCALL_WORK_ENTER (SYSCALL_WORK_SECCOMP | \
    SYSCALL_WORK_SYSCALL_TRACEPOINT | \
    SYSCALL_WORK_SYSCALL_TRACE | \
    SYSCALL_WORK_SYSCALL_EMU | \
    - SYSCALL_WORK_SYSCALL_AUDIT)
    + SYSCALL_WORK_SYSCALL_AUDIT | \
    + ARCH_SYSCALL_WORK_ENTER)
    #define SYSCALL_WORK_EXIT (SYSCALL_WORK_SYSCALL_TRACEPOINT | \
    SYSCALL_WORK_SYSCALL_TRACE | \
    - SYSCALL_WORK_SYSCALL_AUDIT)
    + SYSCALL_WORK_SYSCALL_AUDIT | \
    + ARCH_SYSCALL_WORK_EXIT)

    /*
    * TIF flags handled in exit_to_user_mode_loop()
    diff --git a/kernel/entry/common.c b/kernel/entry/common.c
    index a7233cca01ba..61b6936a0623 100644
    --- a/kernel/entry/common.c
    +++ b/kernel/entry/common.c
    @@ -42,7 +42,7 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
    }

    static long syscall_trace_enter(struct pt_regs *regs, long syscall,
    - unsigned long ti_work, unsigned long work)
    + unsigned long work)
    {
    long ret = 0;

    @@ -75,11 +75,9 @@ static __always_inline long
    __syscall_enter_from_user_work(struct pt_regs *regs, long syscall)
    {
    unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
    - unsigned long ti_work;

    - ti_work = READ_ONCE(current_thread_info()->flags);
    - if (work & SYSCALL_WORK_ENTER || ti_work & SYSCALL_ENTER_WORK)
    - syscall = syscall_trace_enter(regs, syscall, ti_work, work);
    + if (work & SYSCALL_WORK_ENTER)
    + syscall = syscall_trace_enter(regs, syscall, work);

    return syscall;
    }
    @@ -227,8 +225,8 @@ static inline bool report_single_step(unsigned long work)
    }
    #endif

    -static void syscall_exit_work(struct pt_regs *regs, unsigned long ti_work,
    - unsigned long work)
    +
    +static void syscall_exit_work(struct pt_regs *regs, unsigned long work)
    {
    bool step;

    @@ -249,7 +247,6 @@ static void syscall_exit_work(struct pt_regs *regs, unsigned long ti_work,
    static void syscall_exit_to_user_mode_prepare(struct pt_regs *regs)
    {
    unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
    - u32 cached_flags = READ_ONCE(current_thread_info()->flags);
    unsigned long nr = syscall_get_nr(current, regs);

    CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
    @@ -266,8 +263,8 @@ static void syscall_exit_to_user_mode_prepare(struct pt_regs *regs)
    * enabled, we want to run them exactly once per syscall exit with
    * interrupts enabled.
    */
    - if (unlikely(work & SYSCALL_WORK_EXIT || cached_flags & SYSCALL_EXIT_WORK))
    - syscall_exit_work(regs, cached_flags, work);
    + if (unlikely(work & SYSCALL_WORK_EXIT))
    + syscall_exit_work(regs, work);
    }

    __visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs)
    --
    2.29.2
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