Support Solaris 9, 11/x86 in MD_FALLBACK_FRAME_STATE_FOR
Rainer Orth
ro@CeBiTec.Uni-Bielefeld.DE
Mon Jul 12 16:18:00 GMT 2010
This is a considerably reworked version of my earlier patch
PATCH: Fix Solaris 11/x86 MD_FALLBACK_FRAME_STATE_FOR
http://gcc.gnu.org/ml/gcc-patches/2010-02/msg00994.html
The problem is that a couple of ACATS and libjava tests were failing on
Solaris 9 and 11 because MD_FALLBACK_FRAME_STATE_FOR returned
_URC_END_OF_STACK. There were several problems:
* There were no 32-bit sigacthandler patterns for Solaris 9
(single-threaded only, multi-threaded is identical to Solaris 10) nor
__sighndlr patterns for Solaris 11. Solaris 11 actually needs two
different ones, as learned by inspection of the OpenSolaris libc
sources
http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/lib/libc/i386/threads/asm_subr.s#94
The change occured in build 125, but I haven't yet tried that part of
the code.
* The 64-bit case is more involved. While my original patch worked on
Solaris 11, it caused Solaris 10 to regress. I started several
attempts to work out the offset from the signal handler frame to the
ucontext_t structure in the kernel frame, but unfortunately the
offsets vary even between different Solaris 10 updates and the whole
procedure is incredibly fragile. Finally, I gave up and decided to
walk the stack instead.
The layout of the kernel frame can be confirmed from the OpenSolaris
sources:
http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/intel/ia32/os/sendsig.c#105
I'd have liked to use the unwinder routines for the stack walking
(e.g. some new _Unwind_BacktraceFrom function that takes a context to
start from (i.e. the context argument to MD_FALLBACK_FRAME_STATE_FOR
instead of the current context), but couldn't get this to work, so I'm
doing the walking myself.
The patch was tested on Solaris 8 to 11 and fixed all EH problems found
there. One problem is that the 64-bit stack unwinding relies on the
frame pointer now, which doesn't work with libjava out of the box since
that is built with -fomit-frame-pointer by default. I'll post an
updated patch for that soon.
Will soon commit to mainline and backport to the 4.4 and 4.5 branches.
Rainer
2010-02-17 Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
* config/i386/sol2-unwind.h (x86_64_fallback_frame_state): Correct
explanation.
Find ucontext_t * on Solaris 11.
(x86_fallback_frame_state): Handle Solaris 9 multi-threaded pattern.
Handle new Solaris 11 __sighndlr patterns.
diff -r 927eaa7fb82d gcc/config/i386/sol2-unwind.h
--- a/gcc/config/i386/sol2-unwind.h Fri Jul 09 22:53:24 2010 +0200
+++ b/gcc/config/i386/sol2-unwind.h Mon Jul 12 09:29:23 2010 +0200
@@ -1,5 +1,5 @@
/* DWARF2 EH unwinding support for AMD x86-64 and x86.
- Copyright (C) 2009 Free Software Foundation, Inc.
+ Copyright (C) 2009, 2010 Free Software Foundation, Inc.
This file is part of GCC.
@@ -26,6 +26,7 @@
state data appropriately. See unwind-dw2.c for the structs. */
#include <ucontext.h>
+#include <sys/frame.h>
#ifdef __x86_64__
@@ -39,7 +40,7 @@
mcontext_t *mctx;
long new_cfa;
- if (/* Solaris 2.10
+ if (/* Solaris 10+
------------
<__sighndlr+0>: push %rbp
<__sighndlr+1>: mov %rsp,%rbp
@@ -47,15 +48,41 @@
<__sighndlr+6>: leaveq <--- PC
<__sighndlr+7>: retq */
*(unsigned long *)(pc - 6) == 0xc3c9d1ffe5894855)
- /* We need to move up four frames (the kernel frame, the signal frame,
- the call_user_handler frame and the __sighndlr frame). Two of them
- have the minimum stack frame size (kernel and __sighndlr frames),
- the signal frame has a stack frame size of 32 and there is another
- with a stack frame size of 112 bytes (the call_user_handler frame).
- The ucontext_t structure is after this offset. */
+
+ /* We need to move up three frames:
+
+ <signal handler> <-- context->cfa
+ __sighndlr
+ call_user_handler
+ sigacthandler
+ <kernel>
+
+ context->cfa points into the frame after the saved frame pointer and
+ saved pc (struct frame).
+
+ The ucontext_t structure is in the kernel frame after the signal
+ number and a siginfo_t *. Since the frame sizes vary even within
+ Solaris 10 updates, we need to walk the stack to get there. */
{
- int off = 16 + 16 + 32 + 112;
- mctx = &((ucontext_t *) (context->cfa + off))->uc_mcontext;
+ struct frame *fp = (struct frame *) context->cfa - 1;
+ struct handler_args {
+ int signo;
+ siginfo_t *sip;
+ ucontext_t ucontext;
+ } *handler_args;
+ ucontext_t *ucp;
+
+ /* Next frame: __sighndlr frame pointer. */
+ fp = (struct frame *) fp->fr_savfp;
+ /* call_user_handler frame pointer. */
+ fp = (struct frame *) fp->fr_savfp;
+ /* sigacthandler frame pointer. */
+ fp = (struct frame *) fp->fr_savfp;
+
+ /* The argument area precedes the struct frame. */
+ handler_args = (struct handler_args *) (fp + 1);
+ ucp = &handler_args->ucontext;
+ mctx = &ucp->uc_mcontext;
}
else
return _URC_END_OF_STACK;
@@ -117,8 +144,8 @@
mcontext_t *mctx;
long new_cfa;
- if (/* Solaris 2.8 - single thread
- -------------------------
+ if (/* Solaris 8 - single-threaded
+ ----------------------------
<sigacthandler+17>: mov 0x10(%ebp),%esi
<sigacthandler+20>: push %esi
<sigacthandler+21>: pushl 0xc(%ebp)
@@ -135,7 +162,7 @@
&& *(unsigned long *)(pc - 4) == 0x8814ff00
&& *(unsigned long *)(pc - 0) == 0x560cc483)
- || /* Solaris 2.8 - multi thread
+ || /* Solaris 8 - multi-threaded
---------------------------
<__sighndlr+0>: push %ebp
<__sighndlr+1>: mov %esp,%ebp
@@ -149,8 +176,26 @@
&& *(unsigned long *)(pc - 7) == 0x0875ff0c
&& *(unsigned long *)(pc - 3) == 0xc91455ff)
- || /* Solaris 2.10
- ------------
+ || /* Solaris 9 - single-threaded
+ ----------------------------
+ <sigacthandler+16>: mov 0x244(%ebx),%ecx
+ <sigacthandler+22>: mov 0x8(%ebp),%eax
+ <sigacthandler+25>: mov (%ecx,%eax,4),%ecx
+ <sigacthandler+28>: pushl 0x10(%ebp)
+ <sigacthandler+31>: pushl 0xc(%ebp)
+ <sigacthandler+34>: push %eax
+ <sigacthandler+35>: call *%ecx
+ <sigacthandler+37>: add $0xc,%esp <--- PC
+ <sigacthandler+40>: pushl 0x10(%ebp) */
+ (*(unsigned long *)(pc - 21) == 0x2448b8b
+ && *(unsigned long *)(pc - 17) == 0x458b0000
+ && *(unsigned long *)(pc - 13) == 0x810c8b08
+ && *(unsigned long *)(pc - 9) == 0xff1075ff
+ && *(unsigned long *)(pc - 5) == 0xff500c75
+ && *(unsigned long *)(pc - 1) == 0xcc483d1)
+
+ || /* Solaris 9 - multi-threaded, Solaris 10
+ ---------------------------------------
<__sighndlr+0>: push %ebp
<__sighndlr+1>: mov %esp,%ebp
<__sighndlr+3>: pushl 0x10(%ebp)
@@ -164,7 +209,43 @@
&& *(unsigned long *)(pc - 11) == 0x75ff1075
&& *(unsigned long *)(pc - 7) == 0x0875ff0c
&& *(unsigned long *)(pc - 3) == 0x831455ff
- && *(unsigned long *)(pc + 1) == 0xc3c90cc4))
+ && *(unsigned long *)(pc + 1) == 0xc3c90cc4)
+
+ || /* Solaris 11 before snv_125
+ --------------------------
+ <__sighndlr+0> push %ebp
+ <__sighndlr+1> mov %esp,%ebp
+ <__sighndlr+4> pushl 0x10(%ebp)
+ <__sighndlr+6> pushl 0xc(%ebp)
+ <__sighndlr+9> pushl 0x8(%ebp)
+ <__sighndlr+12> call *0x14(%ebp)
+ <__sighndlr+15> add $0xc,%esp
+ <__sighndlr+18> leave <--- PC
+ <__sighndlr+19> ret */
+ (*(unsigned long *)(pc - 18) == 0xffec8b55
+ && *(unsigned long *)(pc - 14) == 0x7fff107f
+ && *(unsigned long *)(pc - 10) == 0x0875ff0c
+ && *(unsigned long *)(pc - 6) == 0x83145fff
+ && *(unsigned long *)(pc - 1) == 0xc3c90cc4)
+
+ || /* Solaris 11 since snv_125
+ -------------------------
+ <__sighndlr+0> push %ebp
+ <__sighndlr+1> mov %esp,%ebp
+ <__sighndlr+3> and $0xfffffff0,%esp
+ <__sighndlr+6> sub $0x4,%esp
+ <__sighndlr+9> pushl 0x10(%ebp)
+ <__sighndlr+12> pushl 0xc(%ebp)
+ <__sighndlr+15> pushl 0x8(%ebp)
+ <__sighndlr+18> call *0x14(%ebp)
+ <__sighndlr+21> leave <--- PC
+ <__sighndlr+22> ret */
+ (*(unsigned long *)(pc - 21) == 0x83ec8b55
+ && *(unsigned long *)(pc - 17) == 0xec83f0e4
+ && *(unsigned long *)(pc - 13) == 0x1075ff04
+ && *(unsigned long *)(pc - 9) == 0xff0c75ff
+ && *(unsigned long *)(pc - 5) == 0x55ff0875
+ && (*(unsigned long *)(pc - 1) & 0x00ffffff) == 0x00c3c914))
{
struct handler_args {
int signo;
--
-----------------------------------------------------------------------------
Rainer Orth, Center for Biotechnology, Bielefeld University
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