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    Subject[RFC PATCH v1 30/31] ARC: switch to generic kernel_execve() and sys_execve()
    Date
    Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
    ---
    arch/arc/include/asm/ptrace.h | 8 +++++++
    arch/arc/include/asm/unistd.h | 2 +
    arch/arc/kernel/entry.S | 17 ++++++++-------
    arch/arc/kernel/process.c | 44 -----------------------------------------
    arch/arc/kernel/sys.c | 1 -
    5 files changed, 19 insertions(+), 53 deletions(-)

    diff --git a/arch/arc/include/asm/ptrace.h b/arch/arc/include/asm/ptrace.h
    index ee31d8a..bc2229f 100644
    --- a/arch/arc/include/asm/ptrace.h
    +++ b/arch/arc/include/asm/ptrace.h
    @@ -120,6 +120,14 @@ struct user_regs_struct {
    #define in_syscall(regs) (((regs->orig_r8) >= 0 && \
    (regs->orig_r8 <= NR_syscalls)) ? 1 : 0)

    +#define current_pt_regs() \
    +({ \
    + /* open-coded current_thread_info() */ \
    + register unsigned long sp asm ("sp"); \
    + unsigned long pg_start = (sp & ~(THREAD_SIZE - 1)); \
    + (struct pt_regs *)(pg_start + THREAD_SIZE - 4) - 1; \
    +})
    +
    #endif /* __ASSEMBLY__ */

    #endif /* __ASM_PTRACE_H */
    diff --git a/arch/arc/include/asm/unistd.h b/arch/arc/include/asm/unistd.h
    index 754d588..09144a8 100644
    --- a/arch/arc/include/asm/unistd.h
    +++ b/arch/arc/include/asm/unistd.h
    @@ -22,6 +22,8 @@
    #define __ARCH_WANT_SYSCALL_NO_FLAGS
    #define __ARCH_WANT_SYSCALL_OFF_T
    #define __ARCH_WANT_SYSCALL_DEPRECATED
    +#define __ARCH_WANT_KERNEL_EXECVE
    +#define __ARCH_WANT_SYS_EXECVE

    #define sys_mmap2 sys_mmap_pgoff

    diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S
    index 46d0280..deb2652 100644
    --- a/arch/arc/kernel/entry.S
    +++ b/arch/arc/kernel/entry.S
    @@ -588,15 +588,16 @@ ARC_ENTRY ret_from_kernel_thread
    j @sys_exit
    ARC_EXIT ret_from_kernel_thread

    -;################### Special Sys Call Wrappers ##########################
    -
    -ARC_ENTRY sys_execve_wrapper
    - ; copy pointer to pt_regs as a parameter
    - mov r3, sp
    - bl @sys_execve
    +; When we land here, pt_regs have already been updated in-place correctly
    +; A pointer to them is also passed by kernel_execve, we just need to make sure
    +; that SP is set to point to them.
    +ARC_ENTRY ret_from_kernel_execve
    + ; Force SP to "normal" pt_regs just populated.
    + b.d ret_from_system_call
    + mov sp, r0
    +ARC_EXIT ret_from_kernel_execve

    - b ret_from_system_call
    -ARC_EXIT sys_execve_wrapper
    +;################### Special Sys Call Wrappers ##########################

    ; TBD: call do_fork directly from here
    ARC_ENTRY sys_fork_wrapper
    diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c
    index d2bb27f..65dfa89 100644
    --- a/arch/arc/kernel/process.c
    +++ b/arch/arc/kernel/process.c
    @@ -53,50 +53,6 @@ asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
    child_tidptr);
    }

    -int sys_execve(const char __user *filenamei, const char __user *__user *argv,
    - const char __user *__user *envp, struct pt_regs *regs)
    -{
    - long error;
    - struct filename *filename;
    -
    - filename = getname(filenamei);
    - error = PTR_ERR(filename);
    - if (IS_ERR(filename))
    - goto out;
    -
    - error = do_execve(filename->name, argv, envp, regs);
    - putname(filename);
    -out:
    - return error;
    -}
    -
    -int kernel_execve(const char *filename, const char *const argv[],
    - const char *const envp[])
    -{
    - /*
    - * Although the arguments (order, number) to this function are
    - * same as sys call, we don't need to setup args in regs again.
    - * However in case mainline kernel changes the order of args to
    - * kernel_execve, that assumtion will break.
    - * So to be safe, let gcc know the args for sys call.
    - * If they match no extra code will be generated
    - */
    - register int arg2 asm("r1") = (int)argv;
    - register int arg3 asm("r2") = (int)envp;
    -
    - register int filenm_n_ret asm("r0") = (int)filename;
    -
    - __asm__ __volatile__(
    - "mov r8, %1 \n\t"
    - "trap0 \n\t"
    - : "+r"(filenm_n_ret)
    - : "i"(__NR_execve), "r"(arg2), "r"(arg3)
    - : "r8", "memory");
    -
    - return filenm_n_ret;
    -}
    -EXPORT_SYMBOL(kernel_execve);
    -
    SYSCALL_DEFINE1(arc_settls, void *, user_tls_data_ptr)
    {
    task_thread_info(current)->thr_ptr = (unsigned int)user_tls_data_ptr;
    diff --git a/arch/arc/kernel/sys.c b/arch/arc/kernel/sys.c
    index 4c30345..f6bdd07 100644
    --- a/arch/arc/kernel/sys.c
    +++ b/arch/arc/kernel/sys.c
    @@ -5,7 +5,6 @@

    #include <asm/syscalls.h>

    -#define sys_execve sys_execve_wrapper
    #define sys_clone sys_clone_wrapper
    #define sys_fork sys_fork_wrapper
    #define sys_vfork sys_vfork_wrapper
    --
    1.7.4.1


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