Optimize x86 and x86-64 ____longjmp_chk for Linux.

diff --git a/ChangeLog b/ChangeLog
index fb046fe..6d2a62b 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2009-07-31  Ulrich Drepper  <drepper@redhat.com>
 
+       * sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S (longjmp_msg): Yet
+       another rewrite.  Much smaller and faster.
+       * sysdeps/unix/sysv/linux/i386/____longjmp_chk.S: Likewise.
+
        * sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S (longjmp_msg): Get
        ss_flags from the correct location.
 

diff --git a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
index b07e972..65c7bae 100644 (file)
--- a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
+++ b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
@@ -58,8 +58,6 @@ ENTRY (____longjmp_chk)
        PTR_DEMANGLE (%edx)
        PTR_DEMANGLE (%edi)
 
-       pushl   $0
-       cfi_adjust_cfa_offset(4)
        cmpl    %edi, %esp
        jbe     .Lok
 
@@ -69,15 +67,25 @@ ENTRY (____longjmp_chk)
        movl    %esp, %ecx
        movl    $__NR_sigaltstack, %eax
        ENTER_KERNEL
-       movl    4(%esp), %ebx
-       addl    $12, %esp
+       /* Without working sigaltstack we cannot perform the test.  */
+       test    %eax, %eax
+       jne     .Lok2
+       testl   $1, 4(%esp)
+       jz      .Lfail
+
+       movl    (%esp), %eax
+       addl    8(%esp), %eax
+       subl    %edi, %eax
+       cmpl    8(%esp), %eax
+       jae     .Lok2
+
+.Lfail:        CALL_FAIL
+
+.Lok2: addl    $12, %esp
        cfi_adjust_cfa_offset(-12)
-       movl    8(%esp), %ecx
-       testl   %eax, %eax
-       jne     .Lok
-       andl    $1, %ebx
-       movl    %ebx, (%esp)
-.Lok:
+       movl    4(%esp), %ecx
+
+.Lok:  /* We add unwind information for the target here.  */
        cfi_def_cfa(%ecx, 0)
        cfi_register(%eip, %edx)
        cfi_register(%esp, %edi)
@@ -86,15 +94,11 @@ ENTRY (____longjmp_chk)
        cfi_offset(%edi, JB_DI*4)
        cfi_offset(%ebp, JB_BP*4)
 
-       movl    12(%esp), %eax  /* Second argument is return value.  */
-       xchgl   %edi, %esp
-       cfi_restore(%edi)
-
-       cmpl    %esp, %edi
-       jnbe    .Lcheck
+       movl    8(%esp), %eax   /* Second argument is return value.  */
+       movl    %edi, %esp
 
        /* Restore registers.  */
-.Lout: movl    (JB_BX*4)(%ecx), %ebx
+       movl    (JB_BX*4)(%ecx), %ebx
        movl    (JB_SI*4)(%ecx), %esi
        movl    (JB_DI*4)(%ecx), %edi
        movl    (JB_BP*4)(%ecx), %ebp
@@ -105,39 +109,4 @@ ENTRY (____longjmp_chk)
 
        /* Jump to saved PC.  */
        jmp     *%edx
-
-       cfi_def_cfa(%ecx, 0)
-       cfi_register(%eip, %edx)
-       cfi_offset(%ebx, JB_BX*4)
-       cfi_offset(%esi, JB_SI*4)
-       cfi_offset(%edi, JB_DI*4)
-       cfi_offset(%ebp, JB_BP*4)
-
-.Lcheck:
-       cmpl    $0, (%edi)
-       je      .Lfail
-
-       subl    $12, %esp
-       cfi_adjust_cfa_offset(12)
-       xorl    %ebx, %ebx
-       movl    %esp, %ecx
-       movl    $__NR_sigaltstack, %eax
-       ENTER_KERNEL
-       testl   $1, 4(%esp)
-       leal    12(%esp), %esp
-       movl    8(%edi), %ecx
-       movl    12(%edi), %eax
-       cfi_adjust_cfa_offset(-12)
-       je      .Lout
-
-.Lfail:        xchgl   %edi, %esp
-       cfi_def_cfa(%esp, 8)
-       cfi_restore(%esp)
-       cfi_restore(%ebx)
-       cfi_restore(%esi)
-       cfi_undefined(%edi)
-       cfi_restore(%ebp)
-
-       CALL_FAIL
-       hlt
 END (____longjmp_chk)

diff --git a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
index 4e53ea6..87c728d 100644 (file)
--- a/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
+++ b/sysdeps/unix/sysv/linux/x86_64/____longjmp_chk.S
@@ -58,31 +58,36 @@ ENTRY(____longjmp_chk)
        PTR_DEMANGLE (%rdx)
 #endif
 
+       cmpq    %r8, %rsp
+       jbe     .Lok
+
        /* Save function parameters.  */
        movq    %rdi, %r10
        movl    %esi, %ecx
 
-       xorl    %eax, %eax
-       cmpq    %r8, %rsp
-       jbe     .Lok
-
-       subq    $24, %rsp
-       cfi_adjust_cfa_offset(24)
        xorl    %edi, %edi
-       movq    %rsp, %rsi
+       leaq    -24(%rsp), %rsi
        movl    $__NR_sigaltstack, %eax
        syscall
+       /* Without working sigaltstack we cannot perform the test.  */
        testl   %eax, %eax
-       movl    $0, %eax
-       leaq    24(%rsp), %rsp
-       cfi_adjust_cfa_offset(-24)
-       jne     .Lok
-       movl    -16(%rsp), %eax
-       andl    $1, %eax
+       jne     .Lok2
+       testl   $1, -16(%rsp)
+       jz      .Lfail
 
-.Lok:
-       /* We add unwind information for the target here.  */
-       cfi_def_cfa(%r10, 0)
+       movq    -24(%rsp), %rax
+       addq    -8(%rsp), %rax
+       subq    %r8, %rax
+       cmpq    -8(%rsp), %rax
+       jae     .Lok2
+
+.Lfail:        CALL_FAIL
+
+.Lok2: movq    %r10, %rdi
+       movl    %ecx, %esi
+
+.Lok:  /* We add unwind information for the target here.  */
+       cfi_def_cfa(%rdi, 0)
        cfi_register(%rsp,%r8)
        cfi_register(%rbp,%r9)
        cfi_register(%rip,%rdx)
@@ -91,55 +96,14 @@ ENTRY(____longjmp_chk)
        cfi_offset(%r13,JB_R13*8)
        cfi_offset(%r14,JB_R14*8)
        cfi_offset(%r15,JB_R15*8)
-
-       xchgq   %r8, %rsp
-       cfi_restore(%rsp)
-       xchgq   %r9, %rbp
-       cfi_restore(%rbp)
-
-       movq    (JB_RBX*8)(%r10),%rbx
-       movq    (JB_R12*8)(%r10),%r12
-       movq    (JB_R13*8)(%r10),%r13
-       movq    (JB_R14*8)(%r10),%r14
-       movq    (JB_R15*8)(%r10),%r15
-
-       cmpq    %rsp, %r8
-       jnbe    .Lcheck
-
+       movq    (JB_RBX*8)(%rdi),%rbx
+       movq    (JB_R12*8)(%rdi),%r12
+       movq    (JB_R13*8)(%rdi),%r13
+       movq    (JB_R14*8)(%rdi),%r14
+       movq    (JB_R15*8)(%rdi),%r15
        /* Set return value for setjmp.  */
-.Lout: movl    %ecx, %eax
+       movl    %esi, %eax
+       movq    %r8,%rsp
+       movq    %r9,%rbp
        jmpq    *%rdx
-
-.Lcheck:
-       testl   %eax, %eax
-       je      .Lfail
-
-       subq    $24, %rsp
-       cfi_adjust_cfa_offset(24)
-       xorl    %edi, %edi
-       movq    %rsp, %rsi
-       movl    $__NR_sigaltstack, %eax
-       syscall
-       addq    $24, %rsp
-       cfi_adjust_cfa_offset(-24)
-       testl   $1, -16(%rsp)
-       je      .Lout
-
-.Lfail:        xchgq   %r8, %rsp
-       /* We want the stack trace to show that of the caller.  */
-       cfi_def_cfa(%rsp, 8)
-       cfi_restore(%rsp)
-       cfi_register(%rbp, %r9)
-       cfi_restore(%rip)
-       cfi_restore(%rbx)
-       cfi_restore(%r12)
-       cfi_restore(%r13)
-       cfi_restore(%r14)
-       cfi_restore(%r15)
-
-       xchgq   %r9, %rbp
-       cfi_restore(%rbp)
-
-       CALL_FAIL
-       hlt
 END (BP_SYM (____longjmp_chk))