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001b2bc6a5
that addresses a real-world issue around threading and unwinding as files/patch-freebsd-unwind.h . This will become obsolete with the next release of GCC 6, GCC 6.5. Bump PORTREVISION since this is a functional change. On the way fix up the format for files/patch-armv7-support . [1] Reported by: portlint [1]
90 lines
2.8 KiB
C
90 lines
2.8 KiB
C
2017-11-05 Andreas Tobler <andreast@gcc.gnu.org>
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Backport from mainline
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2017-11-04 Andreas Tobler <andreast@gcc.gnu.org>
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PR libgcc/82635
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* config/i386/freebsd-unwind.h (MD_FALLBACK_FRAME_STATE_FOR): Use a
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sysctl to determine whether we're in a trampoline.
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Keep the pattern matching method for systems without
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KERN_PROC_SIGTRAMP sysctl.
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--- UTC
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--- libgcc/config/i386/freebsd-unwind.h 2017/11/05 17:24:37 254430
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+++ libgcc/config/i386/freebsd-unwind.h 2017/11/05 19:30:41 254431
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@@ -28,7 +28,10 @@
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#include <sys/types.h>
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#include <signal.h>
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+#include <unistd.h>
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+#include <sys/sysctl.h>
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#include <sys/ucontext.h>
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+#include <sys/user.h>
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#include <machine/sigframe.h>
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#define REG_NAME(reg) sf_uc.uc_mcontext.mc_## reg
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@@ -36,6 +39,38 @@
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#ifdef __x86_64__
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#define MD_FALLBACK_FRAME_STATE_FOR x86_64_freebsd_fallback_frame_state
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+#ifdef KERN_PROC_SIGTRAMP
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+/* FreeBSD past 9.3 provides a kern.proc.sigtramp.<pid> sysctl that
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+ returns the location of the signal trampoline. Use this to find
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+ out whether we're in a trampoline.
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+*/
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+static int
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+x86_64_outside_sigtramp_range (unsigned char *pc)
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+{
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+ static int sigtramp_range_determined = 0;
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+ static unsigned char *sigtramp_start, *sigtramp_end;
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+
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+ if (sigtramp_range_determined == 0)
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+ {
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+ struct kinfo_sigtramp kst = {0};
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+ size_t len = sizeof (kst);
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+ int mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_SIGTRAMP, getpid() };
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+
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+ sigtramp_range_determined = 1;
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+ if (sysctl (mib, 4, &kst, &len, NULL, 0) == 0)
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+ {
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+ sigtramp_range_determined = 2;
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+ sigtramp_start = kst.ksigtramp_start;
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+ sigtramp_end = kst.ksigtramp_end;
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+ }
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+ }
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+ if (sigtramp_range_determined < 2) /* sysctl failed if < 2 */
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+ return 1;
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+
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+ return (pc < sigtramp_start || pc >= sigtramp_end);
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+}
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+#endif
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+
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static _Unwind_Reason_Code
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x86_64_freebsd_fallback_frame_state
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(struct _Unwind_Context *context, _Unwind_FrameState *fs)
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@@ -43,6 +78,7 @@
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struct sigframe *sf;
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long new_cfa;
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+#ifndef KERN_PROC_SIGTRAMP
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/* Prior to FreeBSD 9, the signal trampoline was located immediately
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before the ps_strings. To support non-executable stacks on AMD64,
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the sigtramp was moved to a shared page for FreeBSD 9. Unfortunately
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@@ -62,12 +98,15 @@
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&& *(unsigned int *)(context->ra + 8) == 0x01a1c0c7
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&& *(unsigned int *)(context->ra + 12) == 0x050f0000 ))
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return _URC_END_OF_STACK;
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+#else
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+ if (x86_64_outside_sigtramp_range(context->ra))
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+ return _URC_END_OF_STACK;
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+#endif
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sf = (struct sigframe *) context->cfa;
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new_cfa = sf->REG_NAME(rsp);
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fs->regs.cfa_how = CFA_REG_OFFSET;
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- /* Register 7 is rsp */
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- fs->regs.cfa_reg = 7;
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+ fs->regs.cfa_reg = __LIBGCC_STACK_POINTER_REGNUM__;
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fs->regs.cfa_offset = new_cfa - (long) context->cfa;
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/* The SVR4 register numbering macros aren't usable in libgcc. */
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