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re PR libgcc/82635 (std::thread's join broken on FreeBSD with all GCCs >= 5)

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2017-11-04  Andreas Tobler  <andreast@gcc.gnu.org>

    PR libgcc/82635
    * config/i386/freebsd-unwind.h (MD_FALLBACK_FRAME_STATE_FOR): Use a
    sysctl to determine whether we're in a trampoline.
    Keep the pattern matching method for systems without
    KERN_PROC_SIGTRAMP sysctl.

From-SVN: r254411
This commit is contained in:
Andreas Tobler 2017-11-04 20:40:23 +01:00
parent 7c4acac3a0
commit 59fcf6c3ec
2 changed files with 49 additions and 2 deletions
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8
libgcc/ChangeLog
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@ -1,3 +1,11 @@
2017-11-04 Andreas Tobler <andreast@gcc.gnu.org>
PR libgcc/82635
* config/i386/freebsd-unwind.h (MD_FALLBACK_FRAME_STATE_FOR): Use a
sysctl to determine whether we're in a trampoline.
Keep the pattern matching method for systems without
KERN_PROC_SIGTRAMP sysctl.
2017-11-03 Cupertino Miranda <cmiranda@synopsys.com>
Vineet Gupta <vgupta@synopsys.com>

43
libgcc/config/i386/freebsd-unwind.h
View file

@ -28,7 +28,10 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
#include <sys/types.h>
#include <signal.h>
#include <unistd.h>
#include <sys/sysctl.h>
#include <sys/ucontext.h>
#include <sys/user.h>
#include <machine/sigframe.h>
#define REG_NAME(reg) sf_uc.uc_mcontext.mc_## reg
@ -36,6 +39,38 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
#ifdef __x86_64__
#define MD_FALLBACK_FRAME_STATE_FOR x86_64_freebsd_fallback_frame_state
#ifdef KERN_PROC_SIGTRAMP
/* FreeBSD past 9.3 provides a kern.proc.sigtramp.<pid> sysctl that
returns the location of the signal trampoline. Use this to find
out whether we're in a trampoline.
*/
static int
x86_64_outside_sigtramp_range (unsigned char *pc)
{
static int sigtramp_range_determined = 0;
static unsigned char *sigtramp_start, *sigtramp_end;
if (sigtramp_range_determined == 0)
{
struct kinfo_sigtramp kst = {0};
size_t len = sizeof (kst);
int mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_SIGTRAMP, getpid() };
sigtramp_range_determined = 1;
if (sysctl (mib, 4, &kst, &len, NULL, 0) == 0)
{
sigtramp_range_determined = 2;
sigtramp_start = kst.ksigtramp_start;
sigtramp_end = kst.ksigtramp_end;
}
}
if (sigtramp_range_determined < 2) /* sysctl failed if < 2 */
return 1;
return (pc < sigtramp_start || pc >= sigtramp_end);
}
#endif
static _Unwind_Reason_Code
x86_64_freebsd_fallback_frame_state
(struct _Unwind_Context *context, _Unwind_FrameState *fs)
@ -43,6 +78,7 @@ x86_64_freebsd_fallback_frame_state
struct sigframe *sf;
long new_cfa;
#ifndef KERN_PROC_SIGTRAMP
/* Prior to FreeBSD 9, the signal trampoline was located immediately
before the ps_strings. To support non-executable stacks on AMD64,
the sigtramp was moved to a shared page for FreeBSD 9. Unfortunately
@ -62,12 +98,15 @@ x86_64_freebsd_fallback_frame_state
&& *(unsigned int *)(context->ra + 8) == 0x01a1c0c7
&& *(unsigned int *)(context->ra + 12) == 0x050f0000 ))
return _URC_END_OF_STACK;
#else
if (x86_64_outside_sigtramp_range(context->ra))
return _URC_END_OF_STACK;
#endif
sf = (struct sigframe *) context->cfa;
new_cfa = sf->REG_NAME(rsp);
fs->regs.cfa_how = CFA_REG_OFFSET;
/* Register 7 is rsp */
fs->regs.cfa_reg = 7;
fs->regs.cfa_reg = __LIBGCC_STACK_POINTER_REGNUM__;
fs->regs.cfa_offset = new_cfa - (long) context->cfa;
/* The SVR4 register numbering macros aren't usable in libgcc. */