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/* DWARF2 EH unwinding support for AIX.
Copyright (C) 2011-2022 Free Software Foundation, Inc.
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/>. */
/* Useful register numbers. */
#define R_LR 65
#define R_CR2 70
#define R_XER 76
#define R_FIRST_ALTIVEC 77
#define R_VRSAVE 109
#define R_VSCR 110
/* If the current unwind info (FS) does not contain explicit info
saving R2, then we have to do a minor amount of code reading to
figure out if it was saved. The big problem here is that the
code that does the save/restore is generated by the linker, so
we have no good way to determine at compile time what to do. */
#ifdef __64BIT__
#define MD_FROB_UPDATE_CONTEXT(CTX, FS) \
do { \
if ((FS)->regs.reg[2].how == REG_UNSAVED) \
{ \
unsigned int *insn \
= (unsigned int *) \
_Unwind_GetGR ((CTX), R_LR); \
if (*insn == 0xE8410028) \
_Unwind_SetGRPtr ((CTX), 2, (CTX)->cfa + 40); \
} \
} while (0)
#else
#define MD_FROB_UPDATE_CONTEXT(CTX, FS) \
do { \
if ((FS)->regs.reg[2].how == REG_UNSAVED) \
{ \
unsigned int *insn \
= (unsigned int *) \
_Unwind_GetGR ((CTX), R_LR); \
if (*insn == 0x80410014) \
_Unwind_SetGRPtr ((CTX), 2, (CTX)->cfa + 20); \
} \
} while (0)
#endif
/* Now on to MD_FALLBACK_FRAME_STATE_FOR.
32bit AIX 5.2, 5.3, 6.1, 7.X and
64bit AIX 6.1, 7.X only at this stage. */
#include <stdlib.h>
#include <stddef.h>
#include <signal.h>
#include <sys/machine.h>
#ifdef __64BIT__
typedef struct __context64 mstate_t;
#else
typedef struct mstsave mstate_t;
#endif
#define MD_FALLBACK_FRAME_STATE_FOR ppc_aix_fallback_frame_state
/* If we are compiling on AIX < 5.3, the VMX related datastructs are not
defined and we take measures to obtain proper runtime behavior if the
compiled code happens to run on a later version with VMX enabled. */
#ifndef MSR_VMX
#define MSR_VMX 0x2000000
#endif
typedef unsigned int uint;
typedef struct { uint v[4]; } vreg_t;
typedef struct {
vreg_t regs[32];
uint pad1 [3];
uint vscr;
uint vrsave;
uint pad2 [3];
} vstate_t;
#define EXT_CONTEXT_MARK 0x45435458
#define EXT_CONTEXT_SIZE 4096
#define BUMPER_SIZE (EXT_CONTEXT_SIZE - sizeof(vstate_t) - (5 * sizeof(int)))
typedef struct {
uint pad1 [4];
vstate_t vstate;
char bumper [BUMPER_SIZE];
int mark;
} extended_context_t;
typedef struct {
char bumper [offsetof (ucontext_t, uc_stack) + sizeof (stack_t)];
extended_context_t * ectx;
int mark;
} vmx_ucontext_t;
/* Determine whether CONTEXT designates a signal handler, and return the
associated ucontext_t address if so. Return NULL otherwise. */
static ucontext_t *
ucontext_for (struct _Unwind_Context *context)
{
const unsigned int * ra = context->ra;
/* AIX 5.2, 5.3, 6.1 and 7.X, threaded or not, share common patterns
and feature variants depending on the configured kernel (unix_mp
or unix_64). */
#ifdef __64BIT__
if (*(ra - 5) == 0x4c00012c /* isync */
&& *(ra - 4) == 0xe8ec0000 /* ld r7,0(r12) */
&& *(ra - 3) == 0xe84c0008 /* ld r2,8(r12) */
&& *(ra - 2) == 0x7ce903a6 /* mtctr r7 */
&& *(ra - 1) == 0x4e800421 /* bctrl */
&& *(ra - 0) == 0x7de27b78) /* mr r2,r15 <-- context->ra */
{
/* unix_64 */
if (*(ra - 6) == 0x7d000164) /* mtmsrd r8 */
{
/* AIX 6.1, 7.1 and 7.2 */
return (ucontext_t *)(context->cfa + 0x70);
}
}
#else
if (*(ra - 5) == 0x4c00012c /* isync */
&& *(ra - 4) == 0x80ec0000 /* lwz r7,0(r12) */
&& *(ra - 3) == 0x804c0004 /* lwz r2,4(r12) */
&& *(ra - 2) == 0x7ce903a6 /* mtctr r7 */
&& *(ra - 1) == 0x4e800421 /* bctrl */
&& *(ra - 0) == 0x7dc37378) /* mr r3,r14 <-- context->ra */
{
/* unix_64 */
if (*(ra - 6) == 0x7d000164) /* mtmsrd r8 */
{
switch (*(ra + 18))
{
/* AIX 5.2 */
case 0x835a0520: /* lwz r26,1312(r26) */
return (ucontext_t *)(context->cfa + 0x70);
/* AIX 5.3 */
case 0x835a0570: /* lwz r26,1392(r26) */
return (ucontext_t *)(context->cfa + 0x40);
/* AIX 6.1 and 7.1 */
case 0x2c1a0000: /* cmpwi r26,0 */
return (ucontext_t *)(context->cfa + 0x40);
/* AIX 7.2 */
case 0x3800000a: /* li r0,A */
return (ucontext_t *)(context->cfa + 0x40);
default:
return 0;
}
}
/* unix_mp */
if (*(ra - 6) == 0x7d000124) /* mtmsr r8 */
{
typedef struct {
char pad[56];
ucontext_t ucontext;
siginfo_t siginfo;
} aix52_stack_t;
aix52_stack_t * frame = (aix52_stack_t *) context->cfa;
return &frame->ucontext;
}
}
#endif
return 0;
}
/* The fallback proper. */
#ifdef __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__
#define RETURN_COLUMN __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__
#else
#define RETURN_COLUMN ARG_POINTER_REGNUM
#endif
#define REGISTER_CFA_OFFSET_FOR(FS,REGNO,ADDR,CFA)\
do { \
(FS)->regs.reg[REGNO].how = REG_SAVED_OFFSET; \
(FS)->regs.reg[REGNO].loc.offset = (long) (ADDR) - (CFA); \
} while (0)
static _Unwind_Reason_Code
ppc_aix_fallback_frame_state (struct _Unwind_Context *context,
_Unwind_FrameState *fs)
{
ucontext_t * uctx = ucontext_for (context);
mstate_t * mctx;
long new_cfa;
int i;
if (uctx == NULL)
return _URC_END_OF_STACK;
mctx = &uctx->uc_mcontext.jmp_context;
/* The "kernel" frame cfa is the stack pointer at the signal occurrence
point. */
new_cfa = mctx->gpr[__LIBGCC_STACK_POINTER_REGNUM__];
fs->regs.cfa_how = CFA_REG_OFFSET;
fs->regs.cfa_reg = __LIBGCC_STACK_POINTER_REGNUM__;
fs->regs.cfa_offset = new_cfa - (long) context->cfa;
/* And we state how to find the various registers it has saved with
relative offset rules from there. */
for (i = 0; i < 32; i++)
if (i != __LIBGCC_STACK_POINTER_REGNUM__)
REGISTER_CFA_OFFSET_FOR (fs, i, &mctx->gpr[i], new_cfa);
REGISTER_CFA_OFFSET_FOR (fs, R_CR2, &mctx->cr, new_cfa);
REGISTER_CFA_OFFSET_FOR (fs, R_XER, &mctx->xer, new_cfa);
REGISTER_CFA_OFFSET_FOR (fs, R_LR, &mctx->lr, new_cfa);
fs->retaddr_column = RETURN_COLUMN;
REGISTER_CFA_OFFSET_FOR (fs, RETURN_COLUMN, &mctx->iar, new_cfa);
fs->signal_frame = 1;
/* Honor FP Ever Used ... */
if (mctx->fpeu)
{
for (i = 0; i < 32; i++)
REGISTER_CFA_OFFSET_FOR (fs, i+32, &mctx->fpr[i], new_cfa);
}
/* Honor VMX context, if any. We expect the msr bit never to be set in
environments where there is no VMX support, e.g. on AIX < 5.3. */
if (mctx->msr & MSR_VMX)
{
vmx_ucontext_t * uc = (vmx_ucontext_t *) uctx;
if (uc->mark == EXT_CONTEXT_MARK && uc->ectx->mark == EXT_CONTEXT_MARK)
{
vstate_t * vstate = &uc->ectx->vstate;
for (i = 0; i < 32; i++)
REGISTER_CFA_OFFSET_FOR
(fs, i+R_FIRST_ALTIVEC, &vstate->regs[i], new_cfa);
REGISTER_CFA_OFFSET_FOR (fs, R_VSCR, &vstate->vscr, new_cfa);
REGISTER_CFA_OFFSET_FOR (fs, R_VRSAVE, &vstate->vrsave, new_cfa);
}
}
return _URC_NO_REASON;
}
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