__attribute__ ((__unused__, section(".ctors"), \
aligned(sizeof(func_ptr)))) \
= { (func_ptr) (-1) }
+
+/* Do code reading to identify a signal frame, and set the frame
+ state data appropriately. See unwind-dw2.c for the structs. */
+
+#ifdef IN_LIBGCC2
+#include <signal.h>
+#include <sys/ucontext.h>
+
+/* Unfortunately, because of various bugs and changes to the kernel,
+ we have several cases to deal with.
+
+ In 2.4, the signal trampoline is 4 words, and (CONTEXT)->ra should
+ point directly at the beginning of the trampoline and struct rt_sigframe.
+
+ In <= 2.6.5-rc2-pa3, the signal trampoline is 9 words, and
+ (CONTEXT)->ra points at the 4th word in the trampoline structure. This
+ is wrong, it should point at the 5th word. This is fixed in 2.6.5-rc2-pa4.
+
+ To detect these cases, we first take (CONTEXT)->ra, align it to 64-bytes
+ to get the beginning of the signal frame, and then check offsets 0, 4
+ and 5 to see if we found the beginning of the trampoline. This will
+ tell us how to locate the sigcontext structure.
+
+ Note that with a 2.4 64-bit kernel, the signal context is not properly
+ passed back to userspace so the unwind will not work correctly. */
+#define MD_FALLBACK_FRAME_STATE_FOR(CONTEXT, FS, SUCCESS) \
+ do { \
+ unsigned long sp = (unsigned long)(CONTEXT)->ra & ~63; \
+ unsigned int *pc = (unsigned int *)sp; \
+ unsigned long off; \
+ _Unwind_Ptr new_cfa; \
+ int i; \
+ struct sigcontext *sc; \
+ struct rt_sigframe { \
+ struct siginfo info; \
+ struct ucontext uc; \
+ } *frame; \
+ \
+ /* rt_sigreturn trampoline: \
+ 3419000x ldi 0, %r25 or ldi 1, %r25 (x = 0 or 2) \
+ 3414015a ldi __NR_rt_sigreturn, %r20 \
+ e4008200 be,l 0x100(%sr2, %r0), %sr0, %r31 \
+ 08000240 nop */ \
+ \
+ if (pc[0] == 0x34190000 || pc[0] == 0x34190002) \
+ off = 4*4; \
+ else if (pc[4] == 0x34190000 || pc[4] == 0x34190002) \
+ { \
+ pc += 4; \
+ off = 10 * 4; \
+ } \
+ else if (pc[5] == 0x34190000 || pc[5] == 0x34190002) \
+ { \
+ pc += 5; \
+ off = 10 * 4; \
+ } \
+ else \
+ break; \
+ if (pc[1] != 0x3414015a \
+ || pc[2] != 0xe4008200 \
+ || pc[3] != 0x08000240) \
+ break; \
+ \
+ frame = (struct rt_sigframe *)(sp + off); \
+ sc = &frame->uc.uc_mcontext; \
+ \
+ new_cfa = sc->sc_gr[30]; \
+ (FS)->cfa_how = CFA_REG_OFFSET; \
+ (FS)->cfa_reg = 30; \
+ (FS)->cfa_offset = new_cfa - (long) (CONTEXT)->cfa; \
+ for (i = 1; i <= 31; i++) \
+ { \
+ (FS)->regs.reg[i].how = REG_SAVED_OFFSET; \
+ (FS)->regs.reg[i].loc.offset = (long)&sc->sc_gr[i] - new_cfa; \
+ } \
+ for (i = 4; i <= 31; i++) \
+ { \
+ /* FP regs have left and right halves */ \
+ (FS)->regs.reg[2*i+24].how = REG_SAVED_OFFSET; \
+ (FS)->regs.reg[2*i+24].loc.offset \
+ = (long)&sc->sc_fr[i] - new_cfa; \
+ (FS)->regs.reg[2*i+24+1].how = REG_SAVED_OFFSET; \
+ (FS)->regs.reg[2*i+24+1].loc.offset \
+ = (long)&sc->sc_fr[i] + 4 - new_cfa; \
+ } \
+ (FS)->regs.reg[88].how = REG_SAVED_OFFSET; \
+ (FS)->regs.reg[88].loc.offset = (long) &sc->sc_sar - new_cfa; \
+ (FS)->regs.reg[2].how = REG_SAVED_OFFSET; \
+ (FS)->regs.reg[2].loc.offset = (long) &sc->sc_iaoq[0] - new_cfa; \
+ (FS)->retaddr_column = 2; \
+ goto SUCCESS; \
+ } while (0)
+
+#endif /* IN_LIBGCC2 */
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