[AArch64][4/4] libgcc unwinder support for return address signing
libgcc/ * config/aarch64/aarch64-unwind.h: New file. (DWARF_REGNUM_AARCH64_RA_STATE): Define. (MD_POST_EXTRACT_ROOT_ADDR): New target marcro and define it on AArch64. (MD_POST_EXTRACT_FRAME_ADDR): Likewise. (MD_POST_FROB_EH_HANDLER_ADDR): Likewise. (MD_FROB_UPDATE_CONTEXT): Define it on AArch64. (aarch64_post_extract_frame_addr): New function. (aarch64_post_frob_eh_handler_addr): New function. (aarch64_frob_update_context): New function. * config/aarch64/linux-unwind.h: Include aarch64-unwind.h * config.host (aarch64*-*-elf, aarch64*-*-rtems*, aarch64*-*-freebsd*): Initialize md_unwind_header to include aarch64-unwind.h. * unwind-dw2.c (struct _Unwind_Context): Define "RA_A_SIGNED_BIT". (execute_cfa_program): Multiplex DW_CFA_GNU_window_save for __aarch64__. (uw_update_context): Honor MD_POST_EXTRACT_FRAME_ADDR. (uw_init_context_1): Honor MD_POST_EXTRACT_ROOT_ADDR. (uw_frob_return_addr): New function. (uw_install_context): Use uw_frob_return_addr. From-SVN: r244673
This commit is contained in:
Jiong Wang
Jiong Wang
parent
1d9a762962
commit
5636faf2bc
@ -1,3 +1,26 @@
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2017-01-19 Jiong Wang <jiong.wang@arm.com>
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* config/aarch64/aarch64-unwind.h: New file.
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(DWARF_REGNUM_AARCH64_RA_STATE): Define.
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(MD_POST_EXTRACT_ROOT_ADDR): New target marcro and define it on AArch64.
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(MD_POST_EXTRACT_FRAME_ADDR): Likewise.
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(MD_POST_FROB_EH_HANDLER_ADDR): Likewise.
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(MD_FROB_UPDATE_CONTEXT): Define it on AArch64.
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(aarch64_post_extract_frame_addr): New function.
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(aarch64_post_frob_eh_handler_addr): New function.
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(aarch64_frob_update_context): New function.
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* config/aarch64/linux-unwind.h: Include aarch64-unwind.h
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* config.host (aarch64*-*-elf, aarch64*-*-rtems*,
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aarch64*-*-freebsd*):
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Initialize md_unwind_header to include aarch64-unwind.h.
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* unwind-dw2.c (struct _Unwind_Context): Define "RA_A_SIGNED_BIT".
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(execute_cfa_program): Multiplex DW_CFA_GNU_window_save for
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__aarch64__.
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(uw_update_context): Honor MD_POST_EXTRACT_FRAME_ADDR.
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(uw_init_context_1): Honor MD_POST_EXTRACT_ROOT_ADDR.
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(uw_frob_return_addr): New function.
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(uw_install_context): Use uw_frob_return_addr.
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2017-01-17 Jakub Jelinek <jakub@redhat.com>
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PR other/79046
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@ -331,11 +331,13 @@ aarch64*-*-elf | aarch64*-*-rtems*)
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extra_parts="$extra_parts crtfastmath.o"
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tmake_file="${tmake_file} ${cpu_type}/t-aarch64"
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tmake_file="${tmake_file} ${cpu_type}/t-softfp t-softfp t-crtfm"
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md_unwind_header=aarch64/aarch64-unwind.h
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;;
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aarch64*-*-freebsd*)
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extra_parts="$extra_parts crtfastmath.o"
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tmake_file="${tmake_file} ${cpu_type}/t-aarch64"
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tmake_file="${tmake_file} ${cpu_type}/t-softfp t-softfp t-crtfm"
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md_unwind_header=aarch64/aarch64-unwind.h
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;;
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aarch64*-*-linux*)
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extra_parts="$extra_parts crtfastmath.o"
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@ -24,6 +24,7 @@
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#include <signal.h>
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#include <sys/ucontext.h>
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#include "config/aarch64/aarch64-unwind.h"
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/* Since insns are always stored LE, on a BE system the opcodes will
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@ -136,6 +136,8 @@ struct _Unwind_Context
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#define SIGNAL_FRAME_BIT ((~(_Unwind_Word) 0 >> 1) + 1)
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/* Context which has version/args_size/by_value fields. */
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#define EXTENDED_CONTEXT_BIT ((~(_Unwind_Word) 0 >> 2) + 1)
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/* Bit reserved on AArch64, return address has been signed with A key. */
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#define RA_A_SIGNED_BIT ((~(_Unwind_Word) 0 >> 3) + 1)
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_Unwind_Word flags;
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/* 0 for now, can be increased when further fields are added to
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struct _Unwind_Context. */
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@ -1185,6 +1187,11 @@ execute_cfa_program (const unsigned char *insn_ptr,
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break;
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case DW_CFA_GNU_window_save:
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#ifdef __aarch64__
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/* This CFA is multiplexed with Sparc. On AArch64 it's used to toggle
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return address signing status. */
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fs->regs.reg[DWARF_REGNUM_AARCH64_RA_STATE].loc.offset ^= 1;
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#else
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/* ??? Hardcoded for SPARC register window configuration. */
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if (__LIBGCC_DWARF_FRAME_REGISTERS__ >= 32)
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for (reg = 16; reg < 32; ++reg)
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@ -1192,6 +1199,7 @@ execute_cfa_program (const unsigned char *insn_ptr,
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fs->regs.reg[reg].how = REG_SAVED_OFFSET;
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fs->regs.reg[reg].loc.offset = (reg - 16) * sizeof (void *);
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}
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#endif
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break;
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case DW_CFA_GNU_args_size:
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@ -1513,10 +1521,15 @@ uw_update_context (struct _Unwind_Context *context, _Unwind_FrameState *fs)
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stack frame. */
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context->ra = 0;
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else
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/* Compute the return address now, since the return address column
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can change from frame to frame. */
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context->ra = __builtin_extract_return_addr
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(_Unwind_GetPtr (context, fs->retaddr_column));
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{
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/* Compute the return address now, since the return address column
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can change from frame to frame. */
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context->ra = __builtin_extract_return_addr
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(_Unwind_GetPtr (context, fs->retaddr_column));
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#ifdef MD_POST_EXTRACT_FRAME_ADDR
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context->ra = MD_POST_EXTRACT_FRAME_ADDR (context, fs, context->ra);
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#endif
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}
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}
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static void
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@ -1550,6 +1563,9 @@ uw_init_context_1 (struct _Unwind_Context *context,
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void *outer_cfa, void *outer_ra)
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{
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void *ra = __builtin_extract_return_addr (__builtin_return_address (0));
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#ifdef MD_POST_EXTRACT_ROOT_ADDR
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ra = MD_POST_EXTRACT_ROOT_ADDR (ra);
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#endif
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_Unwind_FrameState fs;
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_Unwind_SpTmp sp_slot;
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_Unwind_Reason_Code code;
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@ -1586,6 +1602,9 @@ uw_init_context_1 (struct _Unwind_Context *context,
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initialization context, then we can't see it in the given
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call frame data. So have the initialization context tell us. */
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context->ra = __builtin_extract_return_addr (outer_ra);
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#ifdef MD_POST_EXTRACT_ROOT_ADDR
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context->ra = MD_POST_EXTRACT_ROOT_ADDR (context->ra);
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#endif
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}
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static void _Unwind_DebugHook (void *, void *)
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@ -1608,6 +1627,21 @@ _Unwind_DebugHook (void *cfa __attribute__ ((__unused__)),
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#endif
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}
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/* Frob exception handler's address kept in TARGET before installing into
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CURRENT context. */
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static inline void *
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uw_frob_return_addr (struct _Unwind_Context *current
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__attribute__ ((__unused__)),
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struct _Unwind_Context *target)
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{
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void *ret_addr = __builtin_frob_return_addr (target->ra);
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#ifdef MD_POST_FROB_EH_HANDLER_ADDR
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ret_addr = MD_POST_FROB_EH_HANDLER_ADDR (current, target, ret_addr);
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#endif
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return ret_addr;
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}
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/* Install TARGET into CURRENT so that we can return to it. This is a
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macro because __builtin_eh_return must be invoked in the context of
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our caller. */
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@ -1616,7 +1650,7 @@ _Unwind_DebugHook (void *cfa __attribute__ ((__unused__)),
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do \
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{ \
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long offset = uw_install_context_1 ((CURRENT), (TARGET)); \
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void *handler = __builtin_frob_return_addr ((TARGET)->ra); \
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void *handler = uw_frob_return_addr ((CURRENT), (TARGET)); \
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_Unwind_DebugHook ((TARGET)->cfa, handler); \
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__builtin_eh_return (offset, handler); \
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} \
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