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| author | Vineet Gupta <vgupta@synopsys.com> | 2014-12-15 16:33:39 +0530 |
|---|---|---|
| committer | Vineet Gupta <vgupta@synopsys.com> | 2015-02-02 17:08:37 +0530 |
| commit | 98edfab4c10343bd3ba1ca47d000544b9f964886 (patch) | |
| tree | 7a7199204acacf79b6e5b933926a1bc3f73f5067 /arch/arc | |
| parent | 4c86231c14a8a1e9838dcb013ded07ebd2f2a1a5 (diff) | |
| download | linux-98edfab4c10343bd3ba1ca47d000544b9f964886.tar.bz2 | |
ARC: add some more comments to ret_from_fork
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc')
| -rw-r--r-- | arch/arc/kernel/entry.S | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S index 83a046a7cd06..d868289c5a26 100644 --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -736,16 +736,20 @@ ENTRY(ret_from_fork) ; put last task in scheduler queue bl @schedule_tail - ; If kernel thread, jump to its entry-point ld r9, [sp, PT_status32] brne r9, 0, 1f - jl.d [r14] - mov r0, r13 ; arg to payload + jl.d [r14] ; kernel thread entry point + mov r0, r13 ; (see PF_KTHREAD block in copy_thread) 1: - ; special case of kernel_thread entry point returning back due to - ; kernel_execve() - pretend return from syscall to ret to userland + ; Return to user space + ; 1. Any forked task (Reach here via BRne above) + ; 2. First ever init task (Reach here via return from JL above) + ; This is the historic "kernel_execve" use-case, to return to init + ; user mode, in a round about way since that is always done from + ; a kernel thread which is executed via JL above but always returns + ; out whenever kernel_execve (now inline do_fork()) is involved b ret_from_exception END(ret_from_fork) |