[thirdparty/gcc.git] / libgcc / config / i386 / freebsd-unwind.h

/* DWARF2 EH unwinding support for FreeBSD: AMD x86-64 and x86.
   Copyright (C) 2015-2022 Free Software Foundation, Inc.
   Contributed by John Marino <gnugcc@marino.st>

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

/* Do code reading to identify a signal frame, and set the frame
   state data appropriately.  See unwind-dw2.c for the structs. */

#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

#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)
{
  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
     this means looking frame patterns again (sys/amd64/amd64/sigtramp.S)
     rather than using the robust and convenient KERN_PS_STRINGS trick.

     <pc + 00>:  lea     0x10(%rsp),%rdi
     <pc + 05>:  pushq   $0x0
     <pc + 17>:  mov     $0x1a1,%rax
     <pc + 14>:  syscall

     If we can't find this pattern, we're at the end of the stack.
  */

  if (!(   *(unsigned int *)(context->ra)      == 0x247c8d48
        && *(unsigned int *)(context->ra +  4) == 0x48006a10
        && *(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;
  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.  */
  fs->regs.reg[0].how = REG_SAVED_OFFSET;
  fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(rax) - new_cfa;
  fs->regs.reg[1].how = REG_SAVED_OFFSET;
  fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(rdx) - new_cfa;
  fs->regs.reg[2].how = REG_SAVED_OFFSET;
  fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(rcx) - new_cfa;
  fs->regs.reg[3].how = REG_SAVED_OFFSET;
  fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(rbx) - new_cfa;
  fs->regs.reg[4].how = REG_SAVED_OFFSET;
  fs->regs.reg[4].loc.offset = (long)&sf->REG_NAME(rsi) - new_cfa;
  fs->regs.reg[5].how = REG_SAVED_OFFSET;
  fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(rdi) - new_cfa;
  fs->regs.reg[6].how = REG_SAVED_OFFSET;
  fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(rbp) - new_cfa;
  fs->regs.reg[8].how = REG_SAVED_OFFSET;
  fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(r8) - new_cfa;
  fs->regs.reg[9].how = REG_SAVED_OFFSET;
  fs->regs.reg[9].loc.offset = (long)&sf->REG_NAME(r9) - new_cfa;
  fs->regs.reg[10].how = REG_SAVED_OFFSET;
  fs->regs.reg[10].loc.offset = (long)&sf->REG_NAME(r10) - new_cfa;
  fs->regs.reg[11].how = REG_SAVED_OFFSET;
  fs->regs.reg[11].loc.offset = (long)&sf->REG_NAME(r11) - new_cfa;
  fs->regs.reg[12].how = REG_SAVED_OFFSET;
  fs->regs.reg[12].loc.offset = (long)&sf->REG_NAME(r12) - new_cfa;
  fs->regs.reg[13].how = REG_SAVED_OFFSET;
  fs->regs.reg[13].loc.offset = (long)&sf->REG_NAME(r13) - new_cfa;
  fs->regs.reg[14].how = REG_SAVED_OFFSET;
  fs->regs.reg[14].loc.offset = (long)&sf->REG_NAME(r14) - new_cfa;
  fs->regs.reg[15].how = REG_SAVED_OFFSET;
  fs->regs.reg[15].loc.offset = (long)&sf->REG_NAME(r15) - new_cfa;
  fs->regs.reg[16].how = REG_SAVED_OFFSET;
  fs->regs.reg[16].loc.offset = (long)&sf->REG_NAME(rip) - new_cfa;
  fs->retaddr_column = 16;
  fs->signal_frame = 1;
  return _URC_NO_REASON;
}

#else /* Next section is for i386  */

#define MD_FALLBACK_FRAME_STATE_FOR x86_freebsd_fallback_frame_state

/*
 * We can't use KERN_PS_STRINGS anymore if we want to support FreeBSD32
 * compat on AMD64.  The sigtramp is in a shared page in that case so the
 * x86_sigtramp_range only works on a true i386 system.  We have to
 * search for the sigtramp frame if we want it working everywhere.
 */

static _Unwind_Reason_Code
x86_freebsd_fallback_frame_state
(struct _Unwind_Context *context, _Unwind_FrameState *fs)
{
  struct sigframe *sf;
  long new_cfa;

/*
 * i386 sigtramp frame we are looking for follows.
 * Apparently PSL_VM is variable, so we can't look past context->ra + 4
 * <sigcode>:
 *   0:	ff 54 24 10          	call   *0x10(%esp)          *SIGF_HANDLER
 *   4:	8d 44 24 20          	lea    0x20(%esp),%eax       SIGF_UC
 *   8:	50                   	push   %eax
 *   9:	f7 40 54 00 00 02 00 	testl  $0x20000,0x54(%eax)  $PSL_VM
 *  10:	75 03                	jne    15 <sigcode+0x15>
 *  12:	8e 68 14             	mov    0x14(%eax),%gs        UC_GS
 *  15:	b8 a1 01 00 00       	mov    0x1a1,%eax           $SYS_sigreturn
 */

  if (!(   *(unsigned int *)(context->ra - 4) == 0x102454ff
        && *(unsigned int *)(context->ra)     == 0x2024448d ))
    return _URC_END_OF_STACK;

  sf = (struct sigframe *) context->cfa;
  new_cfa = sf->REG_NAME(esp);
  fs->regs.cfa_how = CFA_REG_OFFSET;
  fs->regs.cfa_reg = 4;
  fs->regs.cfa_offset = new_cfa - (long) context->cfa;

  /* The SVR4 register numbering macros aren't usable in libgcc.  */
  fs->regs.reg[0].how = REG_SAVED_OFFSET;
  fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(eax) - new_cfa;
  fs->regs.reg[3].how = REG_SAVED_OFFSET;
  fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(ebx) - new_cfa;
  fs->regs.reg[1].how = REG_SAVED_OFFSET;
  fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(ecx) - new_cfa;
  fs->regs.reg[2].how = REG_SAVED_OFFSET;
  fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(edx) - new_cfa;
  fs->regs.reg[6].how = REG_SAVED_OFFSET;
  fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(esi) - new_cfa;
  fs->regs.reg[7].how = REG_SAVED_OFFSET;
  fs->regs.reg[7].loc.offset = (long)&sf->REG_NAME(edi) - new_cfa;
  fs->regs.reg[5].how = REG_SAVED_OFFSET;
  fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(ebp) - new_cfa;
  fs->regs.reg[8].how = REG_SAVED_OFFSET;
  fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(eip) - new_cfa;
  fs->retaddr_column = 8;
  fs->signal_frame = 1;
  return _URC_NO_REASON;
}
#endif /* ifdef __x86_64__  */
Commit	Line	Data
89c54dd3	1	/* DWARF2 EH unwinding support for FreeBSD: AMD x86-64 and x86.
7adcbafe	2	Copyright (C) 2015-2022 Free Software Foundation, Inc.
89c54dd3 JM	3	Contributed by John Marino <gnugcc@marino.st>
	4
	5	This file is part of GCC.
	6
	7	GCC is free software; you can redistribute it and/or modify
	8	it under the terms of the GNU General Public License as published by
	9	the Free Software Foundation; either version 3, or (at your option)
	10	any later version.
	11
	12	GCC is distributed in the hope that it will be useful,
	13	but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	GNU General Public License for more details.
	16
	17	Under Section 7 of GPL version 3, you are granted additional
	18	permissions described in the GCC Runtime Library Exception, version
	19	3.1, as published by the Free Software Foundation.
	20
	21	You should have received a copy of the GNU General Public License and
	22	a copy of the GCC Runtime Library Exception along with this program;
	23	see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
	24	<http://www.gnu.org/licenses/>. */
	25
	26	/* Do code reading to identify a signal frame, and set the frame
	27	state data appropriately. See unwind-dw2.c for the structs. */
	28
	29	#include <sys/types.h>
	30	#include <signal.h>
59fcf6c3 AT	31	#include <unistd.h>
59fcf6c3 AT	32	#include <sys/sysctl.h>
89c54dd3	33	#include <sys/ucontext.h>
59fcf6c3	34	#include <sys/user.h>
89c54dd3 JM	35	#include <machine/sigframe.h>
	36
	37	#define REG_NAME(reg) sf_uc.uc_mcontext.mc_## reg
	38
	39	#ifdef __x86_64__
	40	#define MD_FALLBACK_FRAME_STATE_FOR x86_64_freebsd_fallback_frame_state
	41
59fcf6c3 AT	42	#ifdef KERN_PROC_SIGTRAMP
	43	/* FreeBSD past 9.3 provides a kern.proc.sigtramp.<pid> sysctl that
	44	returns the location of the signal trampoline. Use this to find
	45	out whether we're in a trampoline.
	46	*/
	47	static int
	48	x86_64_outside_sigtramp_range (unsigned char *pc)
	49	{
	50	static int sigtramp_range_determined = 0;
	51	static unsigned char sigtramp_start, sigtramp_end;
	52
	53	if (sigtramp_range_determined == 0)
	54	{
	55	struct kinfo_sigtramp kst = {0};
	56	size_t len = sizeof (kst);
	57	int mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_SIGTRAMP, getpid() };
	58
	59	sigtramp_range_determined = 1;
	60	if (sysctl (mib, 4, &kst, &len, NULL, 0) == 0)
	61	{
	62	sigtramp_range_determined = 2;
	63	sigtramp_start = kst.ksigtramp_start;
	64	sigtramp_end = kst.ksigtramp_end;
	65	}
	66	}
	67	if (sigtramp_range_determined < 2) /* sysctl failed if < 2 */
	68	return 1;
	69
	70	return (pc < sigtramp_start \|\| pc >= sigtramp_end);
	71	}
	72	#endif
	73
89c54dd3 JM	74	static _Unwind_Reason_Code
	75	x86_64_freebsd_fallback_frame_state
	76	(struct _Unwind_Context context, _Unwind_FrameState fs)
	77	{
	78	struct sigframe *sf;
	79	long new_cfa;
	80
59fcf6c3	81	#ifndef KERN_PROC_SIGTRAMP
89c54dd3 JM	82	/* Prior to FreeBSD 9, the signal trampoline was located immediately
	83	before the ps_strings. To support non-executable stacks on AMD64,
	84	the sigtramp was moved to a shared page for FreeBSD 9. Unfortunately
	85	this means looking frame patterns again (sys/amd64/amd64/sigtramp.S)
	86	rather than using the robust and convenient KERN_PS_STRINGS trick.
	87
	88	<pc + 00>: lea 0x10(%rsp),%rdi
	89	<pc + 05>: pushq $0x0
	90	<pc + 17>: mov $0x1a1,%rax
	91	<pc + 14>: syscall
	92
	93	If we can't find this pattern, we're at the end of the stack.
	94	*/
	95
	96	if (!( (unsigned int )(context->ra) == 0x247c8d48
	97	&& (unsigned int )(context->ra + 4) == 0x48006a10
	98	&& (unsigned int )(context->ra + 8) == 0x01a1c0c7
	99	&& (unsigned int )(context->ra + 12) == 0x050f0000 ))
	100	return _URC_END_OF_STACK;
59fcf6c3 AT	101	#else
	102	if (x86_64_outside_sigtramp_range(context->ra))
	103	return _URC_END_OF_STACK;
	104	#endif
89c54dd3 JM	105
	106	sf = (struct sigframe *) context->cfa;
	107	new_cfa = sf->REG_NAME(rsp);
	108	fs->regs.cfa_how = CFA_REG_OFFSET;
59fcf6c3	109	fs->regs.cfa_reg = __LIBGCC_STACK_POINTER_REGNUM__;
89c54dd3 JM	110	fs->regs.cfa_offset = new_cfa - (long) context->cfa;
	111
	112	/* The SVR4 register numbering macros aren't usable in libgcc. */
	113	fs->regs.reg[0].how = REG_SAVED_OFFSET;
	114	fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(rax) - new_cfa;
	115	fs->regs.reg[1].how = REG_SAVED_OFFSET;
	116	fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(rdx) - new_cfa;
	117	fs->regs.reg[2].how = REG_SAVED_OFFSET;
	118	fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(rcx) - new_cfa;
	119	fs->regs.reg[3].how = REG_SAVED_OFFSET;
	120	fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(rbx) - new_cfa;
	121	fs->regs.reg[4].how = REG_SAVED_OFFSET;
	122	fs->regs.reg[4].loc.offset = (long)&sf->REG_NAME(rsi) - new_cfa;
	123	fs->regs.reg[5].how = REG_SAVED_OFFSET;
	124	fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(rdi) - new_cfa;
	125	fs->regs.reg[6].how = REG_SAVED_OFFSET;
	126	fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(rbp) - new_cfa;
	127	fs->regs.reg[8].how = REG_SAVED_OFFSET;
	128	fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(r8) - new_cfa;
	129	fs->regs.reg[9].how = REG_SAVED_OFFSET;
	130	fs->regs.reg[9].loc.offset = (long)&sf->REG_NAME(r9) - new_cfa;
	131	fs->regs.reg[10].how = REG_SAVED_OFFSET;
	132	fs->regs.reg[10].loc.offset = (long)&sf->REG_NAME(r10) - new_cfa;
	133	fs->regs.reg[11].how = REG_SAVED_OFFSET;
	134	fs->regs.reg[11].loc.offset = (long)&sf->REG_NAME(r11) - new_cfa;
	135	fs->regs.reg[12].how = REG_SAVED_OFFSET;
	136	fs->regs.reg[12].loc.offset = (long)&sf->REG_NAME(r12) - new_cfa;
	137	fs->regs.reg[13].how = REG_SAVED_OFFSET;
	138	fs->regs.reg[13].loc.offset = (long)&sf->REG_NAME(r13) - new_cfa;
	139	fs->regs.reg[14].how = REG_SAVED_OFFSET;
	140	fs->regs.reg[14].loc.offset = (long)&sf->REG_NAME(r14) - new_cfa;
	141	fs->regs.reg[15].how = REG_SAVED_OFFSET;
	142	fs->regs.reg[15].loc.offset = (long)&sf->REG_NAME(r15) - new_cfa;
	143	fs->regs.reg[16].how = REG_SAVED_OFFSET;
	144	fs->regs.reg[16].loc.offset = (long)&sf->REG_NAME(rip) - new_cfa;
	145	fs->retaddr_column = 16;
	146	fs->signal_frame = 1;
	147	return _URC_NO_REASON;
	148	}
	149
	150	#else /* Next section is for i386 */
	151
	152	#define MD_FALLBACK_FRAME_STATE_FOR x86_freebsd_fallback_frame_state
	153
	154	/*
	155	* We can't use KERN_PS_STRINGS anymore if we want to support FreeBSD32
	156	* compat on AMD64. The sigtramp is in a shared page in that case so the
	157	* x86_sigtramp_range only works on a true i386 system. We have to
	158	* search for the sigtramp frame if we want it working everywhere.
	159	*/
	160
	161	static _Unwind_Reason_Code
	162	x86_freebsd_fallback_frame_state
	163	(struct _Unwind_Context context, _Unwind_FrameState fs)
	164	{
	165	struct sigframe *sf;
	166	long new_cfa;
	167
	168	/*
	169	* i386 sigtramp frame we are looking for follows.
	170	* Apparently PSL_VM is variable, so we can't look past context->ra + 4
	171	* <sigcode>:
	172	* 0: ff 54 24 10 call 0x10(%esp) SIGF_HANDLER
	173	* 4: 8d 44 24 20 lea 0x20(%esp),%eax SIGF_UC
174	* 8: 50 push %eax
175	* 9: f7 40 54 00 00 02 00 testl $0x20000,0x54(%eax) $PSL_VM
176	* 10: 75 03 jne 15 <sigcode+0x15>
177	* 12: 8e 68 14 mov 0x14(%eax),%gs UC_GS
178	* 15: b8 a1 01 00 00 mov 0x1a1,%eax $SYS_sigreturn
179	*/
180
181	if (!( (unsigned int )(context->ra - 4) == 0x102454ff
182	&& (unsigned int )(context->ra) == 0x2024448d ))
183	return _URC_END_OF_STACK;
184
185	sf = (struct sigframe *) context->cfa;
186	new_cfa = sf->REG_NAME(esp);
187	fs->regs.cfa_how = CFA_REG_OFFSET;
188	fs->regs.cfa_reg = 4;
189	fs->regs.cfa_offset = new_cfa - (long) context->cfa;
190
191	/* The SVR4 register numbering macros aren't usable in libgcc. */
192	fs->regs.reg[0].how = REG_SAVED_OFFSET;
193	fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(eax) - new_cfa;
194	fs->regs.reg[3].how = REG_SAVED_OFFSET;
195	fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(ebx) - new_cfa;
196	fs->regs.reg[1].how = REG_SAVED_OFFSET;
197	fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(ecx) - new_cfa;
198	fs->regs.reg[2].how = REG_SAVED_OFFSET;
199	fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(edx) - new_cfa;
200	fs->regs.reg[6].how = REG_SAVED_OFFSET;
201	fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(esi) - new_cfa;
202	fs->regs.reg[7].how = REG_SAVED_OFFSET;
203	fs->regs.reg[7].loc.offset = (long)&sf->REG_NAME(edi) - new_cfa;
204	fs->regs.reg[5].how = REG_SAVED_OFFSET;
205	fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(ebp) - new_cfa;
206	fs->regs.reg[8].how = REG_SAVED_OFFSET;
207	fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(eip) - new_cfa;
208	fs->retaddr_column = 8;
209	fs->signal_frame = 1;
210	return _URC_NO_REASON;
211	}
212	#endif /* ifdef __x86_64__ */