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    Subject[PATCH V6 19/49] x86/entry: move PUSH_AND_CLEAR_REGS out of error_entry
    Date
    From: Lai Jiangshan <laijs@linux.alibaba.com>

    Moving PUSH_AND_CLEAR_REGS out of error_entry doesn't change any
    functionality. It will enlarge the size:

    size arch/x86/entry/entry_64.o.before:
    text data bss dec hex filename
    17916 384 0 18300 477c arch/x86/entry/entry_64.o

    size --format=SysV arch/x86/entry/entry_64.o.before:
    .entry.text 5528 0
    .orc_unwind 6456 0
    .orc_unwind_ip 4304 0

    size arch/x86/entry/entry_64.o.after:
    text data bss dec hex filename
    26868 384 0 27252 6a74 arch/x86/entry/entry_64.o

    size --format=SysV arch/x86/entry/entry_64.o.after:
    .entry.text 8200 0
    .orc_unwind 10224 0
    .orc_unwind_ip 6816 0

    But .entry.text in x86_64 is 2M aligned, enlarging it to 8.2k doesn't
    enlarge the final text size.

    The tables .orc_unwind[_ip] are enlarged due to it adds many pushes.

    It is prepared for converting the whole error_entry into C code.

    Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
    ---
    arch/x86/entry/entry_64.S | 5 +++--
    1 file changed, 3 insertions(+), 2 deletions(-)

    diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
    index e5d69604322d..4781ffbe39ba 100644
    --- a/arch/x86/entry/entry_64.S
    +++ b/arch/x86/entry/entry_64.S
    @@ -322,6 +322,9 @@ SYM_CODE_END(ret_from_fork)
    */
    .macro idtentry_body cfunc has_error_code:req

    + PUSH_AND_CLEAR_REGS
    + ENCODE_FRAME_POINTER
    +
    call error_entry
    movq %rax, %rsp /* switch stack settled by sync_regs() */
    ENCODE_FRAME_POINTER
    @@ -973,8 +976,6 @@ SYM_CODE_END(paranoid_exit)
    SYM_CODE_START_LOCAL(error_entry)
    UNWIND_HINT_FUNC
    cld
    - PUSH_AND_CLEAR_REGS save_ret=1
    - ENCODE_FRAME_POINTER 8
    testb $3, CS+8(%rsp)
    jz .Lerror_kernelspace

    --
    2.19.1.6.gb485710b
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