libgcc: fix the handling of return address mangling [PR94891]
Mangling, currently only used on AArch64 for return address signing,
is an internal representation that should not be exposed via
__builtin_return_address return value,
__builtin_eh_return handler argument,
_Unwind_DebugHook handler argument.
Note that a mangled address might not even fit into a void *, e.g.
with AArch64 ilp32 ABI the return address is stored as 64bit, so
the mangled return address cannot be accessed via _Unwind_GetPtr.
This patch changes the unwinder hooks as follows:
MD_POST_EXTRACT_ROOT_ADDR is removed: root address comes from
__builtin_return_address which is not mangled.
MD_POST_EXTRACT_FRAME_ADDR is renamed to MD_DEMANGLE_RETURN_ADDR,
it now operates on _Unwind_Word instead of void *, so the hook
should work when return address signing is enabled on AArch64 ilp32.
(But for that __builtin_aarch64_autia1716 should be fixed to operate
on 64bit input instead of a void *.)
MD_POST_FROB_EH_HANDLER_ADDR is removed: it is the responsibility of
__builtin_eh_return to do the mangling if necessary.
2020-07-13 Szabolcs Nagy <szabolcs.nagy@arm.com>
libgcc/ChangeLog:
PR target/94891
* config/aarch64/aarch64-unwind.h (MD_POST_EXTRACT_ROOT_ADDR): Remove.
(MD_POST_FROB_EH_HANDLER_ADDR): Remove.
(MD_POST_EXTRACT_FRAME_ADDR): Rename to ...
(MD_DEMANGLE_RETURN_ADDR): This.
(aarch64_post_extract_frame_addr): Rename to ...
(aarch64_demangle_return_addr): This.
(aarch64_post_frob_eh_handler_addr): Remove.
* unwind-dw2.c (uw_update_context): Demangle return address.
(uw_frob_return_addr): Remove.
(cherry picked from commit b097c7a27f)
This commit is contained in:
Szabolcs Nagy
parent
a0ae6c7652
commit
f5cab58621
|
|
@ -27,22 +27,20 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|||
|
||||
#define DWARF_REGNUM_AARCH64_RA_STATE 34
|
||||
|
||||
#define MD_POST_EXTRACT_ROOT_ADDR(addr) __builtin_aarch64_xpaclri (addr)
|
||||
#define MD_POST_EXTRACT_FRAME_ADDR(context, fs, addr) \
|
||||
aarch64_post_extract_frame_addr (context, fs, addr)
|
||||
#define MD_POST_FROB_EH_HANDLER_ADDR(current, target, addr) \
|
||||
aarch64_post_frob_eh_handler_addr (current, target, addr)
|
||||
#define MD_DEMANGLE_RETURN_ADDR(context, fs, addr) \
|
||||
aarch64_demangle_return_addr (context, fs, addr)
|
||||
#define MD_FROB_UPDATE_CONTEXT(context, fs) \
|
||||
aarch64_frob_update_context (context, fs)
|
||||
|
||||
/* Do AArch64 private extraction on ADDR based on context info CONTEXT and
|
||||
unwind frame info FS. If ADDR is signed, we do address authentication on it
|
||||
using CFA of current frame. */
|
||||
/* Do AArch64 private extraction on ADDR_WORD based on context info CONTEXT and
|
||||
unwind frame info FS. If ADDR_WORD is signed, we do address authentication
|
||||
on it using CFA of current frame. */
|
||||
|
||||
static inline void *
|
||||
aarch64_post_extract_frame_addr (struct _Unwind_Context *context,
|
||||
_Unwind_FrameState *fs, void *addr)
|
||||
aarch64_demangle_return_addr (struct _Unwind_Context *context,
|
||||
_Unwind_FrameState *fs, _Unwind_Word addr_word)
|
||||
{
|
||||
void *addr = (void *)addr_word;
|
||||
if (fs->regs.reg[DWARF_REGNUM_AARCH64_RA_STATE].loc.offset & 0x1)
|
||||
{
|
||||
_Unwind_Word salt = (_Unwind_Word) context->cfa;
|
||||
|
|
@ -52,23 +50,6 @@ aarch64_post_extract_frame_addr (struct _Unwind_Context *context,
|
|||
return addr;
|
||||
}
|
||||
|
||||
/* Do AArch64 private frob on exception handler's address HANDLER_ADDR before
|
||||
installing it into current context CURRENT. TARGET is currently not used.
|
||||
We need to sign exception handler's address if CURRENT itself is signed. */
|
||||
|
||||
static inline void *
|
||||
aarch64_post_frob_eh_handler_addr (struct _Unwind_Context *current,
|
||||
struct _Unwind_Context *target
|
||||
ATTRIBUTE_UNUSED,
|
||||
void *handler_addr)
|
||||
{
|
||||
if (current->flags & RA_A_SIGNED_BIT)
|
||||
return __builtin_aarch64_pacia1716 (handler_addr,
|
||||
(_Unwind_Word) current->cfa);
|
||||
else
|
||||
return handler_addr;
|
||||
}
|
||||
|
||||
/* Do AArch64 private initialization on CONTEXT based on frame info FS. Mark
|
||||
CONTEXT as return address signed if bit 0 of DWARF_REGNUM_AARCH64_RA_STATE is
|
||||
set. */
|
||||
|
|
|
|||
|
|
@ -1532,11 +1532,14 @@ uw_update_context (struct _Unwind_Context *context, _Unwind_FrameState *fs)
|
|||
{
|
||||
/* Compute the return address now, since the return address column
|
||||
can change from frame to frame. */
|
||||
context->ra = __builtin_extract_return_addr
|
||||
(_Unwind_GetPtr (context, fs->retaddr_column));
|
||||
#ifdef MD_POST_EXTRACT_FRAME_ADDR
|
||||
context->ra = MD_POST_EXTRACT_FRAME_ADDR (context, fs, context->ra);
|
||||
void *ret_addr;
|
||||
#ifdef MD_DEMANGLE_RETURN_ADDR
|
||||
_Unwind_Word ra = _Unwind_GetGR (context, fs->retaddr_column);
|
||||
ret_addr = MD_DEMANGLE_RETURN_ADDR (context, fs, ra);
|
||||
#else
|
||||
ret_addr = _Unwind_GetPtr (context, fs->retaddr_column);
|
||||
#endif
|
||||
context->ra = __builtin_extract_return_addr (ret_addr);
|
||||
}
|
||||
}
|
||||
|
||||
|
|
@ -1571,9 +1574,6 @@ uw_init_context_1 (struct _Unwind_Context *context,
|
|||
void *outer_cfa, void *outer_ra)
|
||||
{
|
||||
void *ra = __builtin_extract_return_addr (__builtin_return_address (0));
|
||||
#ifdef MD_POST_EXTRACT_ROOT_ADDR
|
||||
ra = MD_POST_EXTRACT_ROOT_ADDR (ra);
|
||||
#endif
|
||||
_Unwind_FrameState fs;
|
||||
_Unwind_SpTmp sp_slot;
|
||||
_Unwind_Reason_Code code;
|
||||
|
|
@ -1610,9 +1610,6 @@ uw_init_context_1 (struct _Unwind_Context *context,
|
|||
initialization context, then we can't see it in the given
|
||||
call frame data. So have the initialization context tell us. */
|
||||
context->ra = __builtin_extract_return_addr (outer_ra);
|
||||
#ifdef MD_POST_EXTRACT_ROOT_ADDR
|
||||
context->ra = MD_POST_EXTRACT_ROOT_ADDR (context->ra);
|
||||
#endif
|
||||
}
|
||||
|
||||
static void _Unwind_DebugHook (void *, void *)
|
||||
|
|
@ -1635,21 +1632,6 @@ _Unwind_DebugHook (void *cfa __attribute__ ((__unused__)),
|
|||
#endif
|
||||
}
|
||||
|
||||
/* Frob exception handler's address kept in TARGET before installing into
|
||||
CURRENT context. */
|
||||
|
||||
static inline void *
|
||||
uw_frob_return_addr (struct _Unwind_Context *current
|
||||
__attribute__ ((__unused__)),
|
||||
struct _Unwind_Context *target)
|
||||
{
|
||||
void *ret_addr = __builtin_frob_return_addr (target->ra);
|
||||
#ifdef MD_POST_FROB_EH_HANDLER_ADDR
|
||||
ret_addr = MD_POST_FROB_EH_HANDLER_ADDR (current, target, ret_addr);
|
||||
#endif
|
||||
return ret_addr;
|
||||
}
|
||||
|
||||
/* Install TARGET into CURRENT so that we can return to it. This is a
|
||||
macro because __builtin_eh_return must be invoked in the context of
|
||||
our caller. FRAMES is a number of frames to be unwind.
|
||||
|
|
@ -1661,7 +1643,7 @@ uw_frob_return_addr (struct _Unwind_Context *current
|
|||
do \
|
||||
{ \
|
||||
long offset = uw_install_context_1 ((CURRENT), (TARGET)); \
|
||||
void *handler = uw_frob_return_addr ((CURRENT), (TARGET)); \
|
||||
void *handler = __builtin_frob_return_addr ((TARGET)->ra); \
|
||||
_Unwind_DebugHook ((TARGET)->cfa, handler); \
|
||||
_Unwind_Frames_Extra (FRAMES); \
|
||||
__builtin_eh_return (offset, handler); \
|
||||
|
|
|
|||
Loading…
Reference in New Issue