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x86: Add support for frame pointer less mcount
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Andi Kleen authored and Ulrich Drepper committed Aug 8, 2010
1 parent 805bc17 commit d22e4cc
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7 changes: 7 additions & 0 deletions ChangeLog
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@@ -1,3 +1,10 @@
2010-07-17 Andi Kleen <ak@linux.intel.com>

* sysdeps/i386/i386-mcount.S (__fentry__): Define.
* sysdeps/x86_64/_mcount.S (__fentry__): Define.
* stdlib/Versions (__fentry__): Add for GLIBC 2.13
* Versions.def [GLIBC_2.13]: Add.

2010-08-06 Ulrich Drepper <drepper@redhat.com>

* sysdeps/unix/sysv/linux/getlogin_r.c (__getlogin_r_loginuid):
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1 change: 1 addition & 0 deletions Versions.def
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Expand Up @@ -29,6 +29,7 @@ libc {
GLIBC_2.10
GLIBC_2.11
GLIBC_2.12
GLIBC_2.13
%ifdef USE_IN_LIBIO
HURD_CTHREADS_0.3
%endif
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3 changes: 3 additions & 0 deletions stdlib/Versions
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Expand Up @@ -100,6 +100,9 @@ libc {
GLIBC_2.10 {
quick_exit; __cxa_at_quick_exit;
}
GLIBC_2.13 {
__fentry__;
}
GLIBC_PRIVATE {
# functions which have an additional interface since they are
# are cancelable.
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25 changes: 25 additions & 0 deletions sysdeps/i386/i386-mcount.S
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Expand Up @@ -53,3 +53,28 @@ C_LABEL(_mcount)

#undef mcount
weak_alias (_mcount, mcount)

/* Same as above, but doesn't require a frame pointer */
ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(__fentry__)
ASM_TYPE_DIRECTIVE(C_SYMBOL_NAME(__fentry__), @function)
.align ALIGNARG(4)
C_LABEL(__fentry__)
/* Save the caller-clobbered registers. */
pushl %eax
pushl %ecx
pushl %edx

movl 12(%esp), %edx
movl 16(%esp), %eax

/* No need to access the PLT or GOT, __mcount_internal is an
internal function and we can make a relative call. */
call C_SYMBOL_NAME(__mcount_internal)

/* Pop the saved registers. Please note that `__fentry__' has no
return value. */
popl %edx
popl %ecx
popl %eax
ret
ASM_SIZE_DIRECTIVE(C_SYMBOL_NAME(__fentry__))
38 changes: 38 additions & 0 deletions sysdeps/x86_64/_mcount.S
Original file line number Diff line number Diff line change
Expand Up @@ -65,3 +65,41 @@ C_LABEL(_mcount)

#undef mcount
weak_alias (_mcount, mcount)

ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(__fentry__)
ASM_TYPE_DIRECTIVE(C_SYMBOL_NAME(__fentry__), @function)
.align ALIGNARG(4)
C_LABEL(__fentry__)
/* Allocate space for 7 registers. */
subq $64,%rsp
movq %rax,(%rsp)
movq %rcx,8(%rsp)
movq %rdx,16(%rsp)
movq %rsi,24(%rsp)
movq %rdi,32(%rsp)
movq %r8,40(%rsp)
movq %r9,48(%rsp)

/* Setup parameter for __mcount_internal. */
/* selfpc is the return address on the stack. */
movq 64(%rsp),%rsi
/* caller is the return address above it */
movq 72(%rsp),%rdi
#ifdef PIC
call C_SYMBOL_NAME(__mcount_internal)@PLT
#else
call C_SYMBOL_NAME(__mcount_internal)
#endif
/* Pop the saved registers. Please note that `__fentry__' has no
return value. */
movq 48(%rsp),%r9
movq 40(%rsp),%r8
movq 32(%rsp),%rdi
movq 24(%rsp),%rsi
movq 16(%rsp),%rdx
movq 8(%rsp),%rcx
movq (%rsp),%rax
addq $64,%rsp
ret

ASM_SIZE_DIRECTIVE(C_SYMBOL_NAME(__fentry__))

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