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ARC: entry.S: move some code around for cache locality in return path 

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
hifive-unleashed-5.1
Vineet Gupta 2015-03-10 19:13:07 +05:30
parent 6d1a20b1d2
commit c7e6d79204
2 changed files with 52 additions and 48 deletions
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2
arch/arc/kernel/entry-compact.S
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@ -391,3 +391,5 @@ not_level1_interrupt:
EXCEPTION_EPILOGUE
debug_marker_syscall:
rtie
END(ret_from_exception)

98
arch/arc/kernel/entry.S
View File

@ -24,6 +24,55 @@
*------------------------------------------------------------------
*/
;################### Special Sys Call Wrappers ##########################
ENTRY(sys_clone_wrapper)
SAVE_CALLEE_SAVED_USER
bl @sys_clone
DISCARD_CALLEE_SAVED_USER
GET_CURR_THR_INFO_FLAGS r10
btst r10, TIF_SYSCALL_TRACE
bnz tracesys_exit
b ret_from_system_call
END(sys_clone_wrapper)
ENTRY(ret_from_fork)
; when the forked child comes here from the __switch_to function
; r0 has the last task pointer.
; put last task in scheduler queue
bl @schedule_tail
ld r9, [sp, PT_status32]
brne r9, 0, 1f
jl.d [r14] ; kernel thread entry point
mov r0, r13 ; (see PF_KTHREAD block in copy_thread)
1:
; 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)
#ifdef CONFIG_ARC_DW2_UNWIND
; Workaround for bug 94179 (STAR ):
; Despite -fasynchronous-unwind-tables, linker is not making dwarf2 unwinder
; section (.debug_frame) as loadable. So we force it here.
; This also fixes STAR 9000487933 where the prev-workaround (objcopy --setflag)
; would not work after a clean build due to kernel build system dependencies.
.section .debug_frame, "wa",@progbits
; Reset to .text as this file is included in entry-<isa>.S
.section .text, "ax",@progbits
#endif
;################### Non TLB Exception Handling #############################
; ---------------------------------------------
@ -338,53 +387,6 @@ resume_kernel_mode:
#endif
b .Lrestore_regs
END(ret_from_exception)
ENTRY(ret_from_fork)
; when the forked child comes here from the __switch_to function
; r0 has the last task pointer.
; put last task in scheduler queue
bl @schedule_tail
##### DONT ADD CODE HERE - .Lrestore_regs actually follows in entry-<isa>.S
ld r9, [sp, PT_status32]
brne r9, 0, 1f
jl.d [r14] ; kernel thread entry point
mov r0, r13 ; (see PF_KTHREAD block in copy_thread)
1:
; 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)
;################### Special Sys Call Wrappers ##########################
ENTRY(sys_clone_wrapper)
SAVE_CALLEE_SAVED_USER
bl @sys_clone
DISCARD_CALLEE_SAVED_USER
GET_CURR_THR_INFO_FLAGS r10
btst r10, TIF_SYSCALL_TRACE
bnz tracesys_exit
b ret_from_system_call
END(sys_clone_wrapper)
#ifdef CONFIG_ARC_DW2_UNWIND
; Workaround for bug 94179 (STAR ):
; Despite -fasynchronous-unwind-tables, linker is not making dwarf2 unwinder
; section (.debug_frame) as loadable. So we force it here.
; This also fixes STAR 9000487933 where the prev-workaround (objcopy --setflag)
; would not work after a clean build due to kernel build system dependencies.
.section .debug_frame, "wa",@progbits
; Reset to .text as this file is included in entry-<isa>.S
.section .text, "ax",@progbits
#endif