libc/amd64: Do not export .cerror.
For some reason, libc exports the symbol .cerror (HIDENAME(cerror)), albeit in the FBSDprivate_1.0 version. It looks like there is no reason for this since it is not used from other libraries. Given that it cannot be accessed from C and its strange calling convention, it is rather unlikely that other things rely on it. Perhaps it is from a time when symbols could not be hidden. Most of the amd64 assembler code jumps to .cerror using the GOT. It can jump to it directly now, as in non-PIC mode. There are also some minor size optimizations to instructions but they yield virtually no benefit in the size of libc.so.7 due to padding. Reviewed by: kib
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=240178
@ -36,38 +36,20 @@
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#include <sys/syscall.h>
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#include <machine/asm.h>
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#ifdef PIC
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#define RSYSCALL(x) ENTRY(__CONCAT(__sys_,x)); \
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.weak CNAME(x); \
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.set CNAME(x),CNAME(__CONCAT(__sys_,x)); \
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.weak CNAME(__CONCAT(_,x)); \
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.set CNAME(__CONCAT(_,x)),CNAME(__CONCAT(__sys_,x)); \
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mov __CONCAT($SYS_,x),%rax; KERNCALL; jb 2f; ret; \
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2: movq PIC_GOT(HIDENAME(cerror)),%rcx; jmp *%rcx; \
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mov __CONCAT($SYS_,x),%eax; KERNCALL; \
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jb HIDENAME(cerror); ret; \
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END(__CONCAT(__sys_,x))
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#define PSEUDO(x) ENTRY(__CONCAT(__sys_,x)); \
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.weak CNAME(__CONCAT(_,x)); \
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.set CNAME(__CONCAT(_,x)),CNAME(__CONCAT(__sys_,x)); \
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mov __CONCAT($SYS_,x),%rax; KERNCALL; jb 2f; ret ; \
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2: movq PIC_GOT(HIDENAME(cerror)),%rcx; jmp *%rcx; \
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mov __CONCAT($SYS_,x),%eax; KERNCALL; \
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jb HIDENAME(cerror); ret; \
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END(__CONCAT(__sys_,x))
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#else
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#define RSYSCALL(x) ENTRY(__CONCAT(__sys_,x)); \
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.weak CNAME(x); \
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.set CNAME(x),CNAME(__CONCAT(__sys_,x)); \
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.weak CNAME(__CONCAT(_,x)); \
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.set CNAME(__CONCAT(_,x)),CNAME(__CONCAT(__sys_,x)); \
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mov __CONCAT($SYS_,x),%rax; KERNCALL; jb 2f; ret; \
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2: jmp HIDENAME(cerror); \
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END(__CONCAT(__sys_,x))
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#define PSEUDO(x) ENTRY(__CONCAT(__sys_,x)); \
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.weak CNAME(__CONCAT(_,x)); \
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.set CNAME(__CONCAT(_,x)),CNAME(__CONCAT(__sys_,x)); \
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mov __CONCAT($SYS_,x),%rax; KERNCALL; jb 2f; ret; \
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2: jmp HIDENAME(cerror); \
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END(__CONCAT(__sys_,x))
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#endif
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#define KERNCALL movq %rcx, %r10; syscall
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@ -66,7 +66,6 @@ FBSDprivate_1.0 {
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.curbrk;
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.minbrk;
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_brk;
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.cerror;
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_end;
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__sys_vfork;
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_vfork;
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@ -93,12 +93,7 @@ ENTRY(rfork_thread)
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2:
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popq %r12
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popq %rbx
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#ifdef PIC
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movq PIC_GOT(HIDENAME(cerror)), %rdx
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jmp *%rdx
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#else
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jmp HIDENAME(cerror)
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#endif
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END(rfork_thread)
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.section .note.GNU-stack,"",%progbits
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@ -76,12 +76,7 @@ ok:
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ret
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err:
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addq $8, %rsp
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#ifdef PIC
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movq PIC_GOT(HIDENAME(cerror)),%rdx
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jmp *%rdx
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#else
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jmp HIDENAME(cerror)
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#endif
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END(brk)
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.section .note.GNU-stack,"",%progbits
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@ -47,12 +47,7 @@ ENTRY(exect)
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pushq %r8
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popfq
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KERNCALL
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#ifdef PIC
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movq PIC_GOT(HIDENAME(cerror)),%rdx
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jmp *%rdx
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#else
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jmp HIDENAME(cerror)
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#endif
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END(exect)
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.section .note.GNU-stack,"",%progbits
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@ -42,16 +42,9 @@ ENTRY(__sys_getcontext)
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movq (%rsp),%rsi /* save getcontext return address */
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mov $SYS_getcontext,%rax
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KERNCALL
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jb 1f
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jb HIDENAME(cerror)
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addq $8,%rsp /* remove stale (setcontext) return address */
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jmp *%rsi /* restore return address */
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1:
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#ifdef PIC
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movq PIC_GOT(HIDENAME(cerror)),%rdx
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jmp *%rdx
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#else
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jmp HIDENAME(cerror)
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#endif
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END(__sys_getcontext)
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.section .note.GNU-stack,"",%progbits
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@ -45,18 +45,11 @@ __FBSDID("$FreeBSD$");
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ENTRY(__sys_pipe)
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mov $SYS_pipe,%rax
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KERNCALL
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jb 1f
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jb HIDENAME(cerror)
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movl %eax,(%rdi) /* %rdi is preserved by syscall */
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movl %edx,4(%rdi)
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movq $0,%rax
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ret
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1:
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#ifdef PIC
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movq PIC_GOT(HIDENAME(cerror)),%rdx
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jmp *%rdx
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#else
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jmp HIDENAME(cerror)
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#endif
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END(__sys_pipe)
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.section .note.GNU-stack,"",%progbits
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@ -48,15 +48,8 @@ ENTRY(ptrace)
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#endif
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mov $SYS_ptrace,%eax
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KERNCALL
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jb err
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jb HIDENAME(cerror)
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ret
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err:
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#ifdef PIC
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movq PIC_GOT(HIDENAME(cerror)),%rdx
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jmp *%rdx
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#else
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jmp HIDENAME(cerror)
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#endif
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END(ptrace)
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.section .note.GNU-stack,"",%progbits
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@ -45,15 +45,8 @@ __FBSDID("$FreeBSD$");
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ENTRY(__sys_reboot)
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mov $SYS_reboot,%rax
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KERNCALL
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jb 1f
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jb HIDENAME(cerror)
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iretq
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1:
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#ifdef PIC
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movq PIC_GOT(HIDENAME(cerror)),%rdx
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jmp *%rdx
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#else
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jmp HIDENAME(cerror)
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#endif
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END(__sys_reboot)
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.section .note.GNU-stack,"",%progbits
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@ -79,12 +79,7 @@ back:
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ret
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err:
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addq $8, %rsp
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#ifdef PIC
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movq PIC_GOT(HIDENAME(cerror)),%rdx
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jmp *%rdx
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#else
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jmp HIDENAME(cerror)
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#endif
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END(sbrk)
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.section .note.GNU-stack,"",%progbits
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@ -47,7 +47,7 @@ __FBSDID("$FreeBSD$");
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ENTRY(__sys_setlogin)
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mov $SYS_setlogin,%rax
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KERNCALL
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jb 1f
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jb HIDENAME(cerror)
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#ifdef PIC
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movq PIC_GOT(CNAME(_logname_valid)),%rdx
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movl $0,(%rdx)
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@ -55,13 +55,6 @@ ENTRY(__sys_setlogin)
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movl $0,CNAME(_logname_valid)(%rip)
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#endif
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ret /* setlogin(name) */
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1:
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#ifdef PIC
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movq PIC_GOT(HIDENAME(cerror)),%rdx
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jmp *%rdx
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#else
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jmp HIDENAME(cerror)
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#endif
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END(__sys_setlogin)
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.section .note.GNU-stack,"",%progbits
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@ -50,12 +50,7 @@ ENTRY(__sys_vfork)
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jmp *%rsi
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1:
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pushq %rsi
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#ifdef PIC
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movq PIC_GOT(HIDENAME(cerror)),%rdx
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jmp *%rdx
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#else
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jmp HIDENAME(cerror)
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#endif
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END(__sys_vfork)
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.section .note.GNU-stack,"",%progbits
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