Fix x86-64 ____longjmp_chk to handle signal stacks.

The simple test previously used might trigger if the longjmp jumps
from the signal stack to the normal stack.  We now explicitly test
for this case.

diff --git a/ChangeLog b/ChangeLog
index 9e78199..2492d49 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2009-07-30  Ulrich Drepper  <drepper@redhat.com>
 
+       * sysdeps/x86_64/__longjmp.S: Remove CHECK_RSP handling.  Fix CFI.
+       Remove incorrect use of BP_SYM.
+       * sysdeps/x86_64/____longjmp_chk.S: Rewrite.  Complete implementation
+       here now since it is more complex than just a simple check.
+
        * sysdeps/ia64/backtrace.c (backtrace_helper): Stop backtrace when
        we make no more progress.
 

diff --git a/sysdeps/x86_64/____longjmp_chk.S b/sysdeps/x86_64/____longjmp_chk.S
index 030a0dc..50d2fca 100644 (file)
--- a/sysdeps/x86_64/____longjmp_chk.S
+++ b/sysdeps/x86_64/____longjmp_chk.S
@@ -16,6 +16,10 @@
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */
 
+#include <sysdep.h>
+#include <jmpbuf-offsets.h>
+#include <asm-syntax.h>
+
        .section .rodata.str1.1,"aMS",@progbits,1
        .type   longjmp_msg,@object
 longjmp_msg:
@@ -23,7 +27,7 @@ longjmp_msg:
        .size   longjmp_msg, .-longjmp_msg
 
 
-#define __longjmp ____longjmp_chk
+//#define __longjmp ____longjmp_chk
 
 #ifdef PIC
 # define CALL_FAIL     leaq    longjmp_msg(%rip), %rdi;                      \
@@ -39,4 +43,103 @@ longjmp_msg:
        CALL_FAIL;                                                            \
 .Lok:
 
-#include "__longjmp.S"
+/* Jump to the position specified by ENV, causing the
+   setjmp call there to return VAL, or 1 if VAL is 0.
+   void __longjmp (__jmp_buf env, int val).  */
+       .text
+ENTRY(____longjmp_chk)
+       /* Restore registers.  */
+       movq    (JB_RSP*8)(%rdi),%r8
+       movq    (JB_RBP*8)(%rdi),%r9
+       movq    (JB_PC*8)(%rdi),%rdx
+#ifdef PTR_DEMANGLE
+       PTR_DEMANGLE (%r8)
+       PTR_DEMANGLE (%r9)
+       PTR_DEMANGLE (%rdx)
+#endif
+
+       /* Save function parameters.  */
+       movq    %rdi, %r10
+       movl    %esi, %ecx
+
+       xorl    %eax, %eax
+       cmpq    %r8, %rsp
+       jbe     .Lok
+
+       subq    $32, %rsp
+       cfi_adjust_cfa_offset(32)
+       movq    %r10, 24(%rsp)
+       xorl    %edi, %edi
+       movq    %rsp, %rsi
+       movl    $__NR_sigaltstack, %eax
+       syscall
+       movq    24(%rsp), %r10
+       testl   %eax, %eax
+       movl    $0, %eax
+       jne     .Lok
+       movl    8(%rsp), %eax
+       andl    $1, %eax
+
+.Lok:
+       /* We add unwind information for the target here.  */
+       cfi_def_cfa(%r10, 0)
+       cfi_register(%rsp,%r8)
+       cfi_register(%rbp,%r9)
+       cfi_register(%rip,%rdx)
+       cfi_offset(%rbx,JB_RBX*8)
+       cfi_offset(%r12,JB_R12*8)
+       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
+
+       /* Set return value for setjmp.  */
+.Lout: movl    %ecx, %eax
+       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, 8(%rsp)
+       je      .Lout
+
+.Lfail:        xchgq   %r8, %rsp
+       /* We want the stack trace to show that of the caller.  */
+       cfi_def_cfa(%rsp, 40)
+       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))

diff --git a/sysdeps/x86_64/__longjmp.S b/sysdeps/x86_64/__longjmp.S
index 24552ec..b045c04 100644 (file)
--- a/sysdeps/x86_64/__longjmp.S
+++ b/sysdeps/x86_64/__longjmp.S
@@ -34,16 +34,12 @@ ENTRY(__longjmp)
        PTR_DEMANGLE (%r9)
        PTR_DEMANGLE (%rdx)
 #endif
-#ifdef CHECK_RSP
-       CHECK_RSP (%r8)
-#endif
        /* 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)
        cfi_offset(%rbx,JB_RBX*8)
-       cfi_offset(%rbp,JB_RBP*8)
        cfi_offset(%r12,JB_R12*8)
        cfi_offset(%r13,JB_R13*8)
        cfi_offset(%r14,JB_R14*8)
@@ -58,4 +54,4 @@ ENTRY(__longjmp)
        movq %r8,%rsp
        movq %r9,%rbp
        jmpq *%rdx
-END (BP_SYM (__longjmp))
+END (__longjmp)