aarch64: Fix pac-ret with unusual dwarf in libgcc unwinder [PR104689]
The RA_SIGN_STATE dwarf pseudo-register is normally only set using the DW_CFA_AARCH64_negate_ra_state (== DW_CFA_window_save) operation which toggles the return address signedness state (the default state is 0). (It may be set by remember/restore_state CFI too, those save/restore the state of all registers.) However RA_SIGN_STATE can be set directly via DW_CFA_val_expression too. GCC does not generate such CFI but some other compilers reportedly do. Note: the toggle operation must not be mixed with other dwarf register rule CFI within the same CIE and FDE. In libgcc we assume REG_UNSAVED means the RA_STATE is set using toggle operations, otherwise we assume its value is set by other CFI. libgcc/ChangeLog: PR target/104689 * config/aarch64/aarch64-unwind.h (aarch64_frob_update_context): Handle the !REG_UNSAVED case. * unwind-dw2.c (execute_cfa_program): Fail toggle if !REG_UNSAVED. gcc/testsuite/ChangeLog: PR target/104689 * gcc.target/aarch64/pr104689.c: New test.
This commit is contained in:
Szabolcs Nagy
parent
768f49a20f
commit
0d344b5576
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/* PR target/104689. Unwind across pac-ret frames with unusual dwarf. */
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/* { dg-do run } */
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/* { dg-require-effective-target lp64 } */
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/* { dg-options "-fexceptions -O2" } */
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#include <unwind.h>
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#include <stdlib.h>
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#include <stdio.h>
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#define die() \
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do { \
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printf ("%s:%d: reached unexpectedly.\n", __FILE__, __LINE__); \
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fflush (stdout); \
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abort (); \
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} while (0)
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/* Code to invoke unwinding with a logging callback. */
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static struct _Unwind_Exception exc;
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static _Unwind_Reason_Code
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force_unwind_stop (int version, _Unwind_Action actions,
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_Unwind_Exception_Class exc_class,
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struct _Unwind_Exception *exc_obj,
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struct _Unwind_Context *context,
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void *stop_parameter)
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{
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printf ("%s: CFA: %p PC: %p actions: %d\n",
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__func__,
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(void *)_Unwind_GetCFA (context),
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(void *)_Unwind_GetIP (context),
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(int)actions);
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if (actions & _UA_END_OF_STACK)
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die ();
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return _URC_NO_REASON;
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}
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static void force_unwind (void)
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{
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#ifndef __USING_SJLJ_EXCEPTIONS__
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_Unwind_ForcedUnwind (&exc, force_unwind_stop, 0);
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#else
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_Unwind_SjLj_ForcedUnwind (&exc, force_unwind_stop, 0);
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#endif
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}
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/* Define functions with unusual pac-ret dwarf via top level asm. */
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#define STR(x) #x
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#define DW_CFA_val_expression 0x16
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#define RA_SIGN_STATE 34
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#define DW_OP_lit0 0x30
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#define DW_OP_lit1 0x31
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#define cfi_escape(a1, a2, a3, a4) \
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".cfi_escape " STR(a1) ", " STR(a2) ", " STR(a3) ", " STR(a4)
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/* Bytes: 0x16 0x22 0x01 0x30 */
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#define SET_RA_STATE_0 \
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cfi_escape (DW_CFA_val_expression, RA_SIGN_STATE, 1, DW_OP_lit0)
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/* Bytes: 0x16 0x22 0x01 0x31 */
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#define SET_RA_STATE_1 \
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cfi_escape (DW_CFA_val_expression, RA_SIGN_STATE, 1, DW_OP_lit1)
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/* These function call their argument. */
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void unusual_pac_ret (void *);
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void unusual_no_pac_ret (void *);
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asm(""
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".global unusual_pac_ret\n"
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".type unusual_pac_ret, %function\n"
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"unusual_pac_ret:\n"
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" .cfi_startproc\n"
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" " SET_RA_STATE_0 "\n"
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" hint 25 // paciasp\n"
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" " SET_RA_STATE_1 "\n"
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" stp x29, x30, [sp, -16]!\n"
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" .cfi_def_cfa_offset 16\n"
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" .cfi_offset 29, -16\n"
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" .cfi_offset 30, -8\n"
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" mov x29, sp\n"
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" blr x0\n"
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" ldp x29, x30, [sp], 16\n"
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" .cfi_restore 30\n"
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" .cfi_restore 29\n"
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" .cfi_def_cfa_offset 0\n"
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" hint 29 // autiasp\n"
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" " SET_RA_STATE_0 "\n"
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" ret\n"
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" .cfi_endproc\n");
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asm(""
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".global unusual_no_pac_ret\n"
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".type unusual_no_pac_ret, %function\n"
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"unusual_no_pac_ret:\n"
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" .cfi_startproc\n"
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" " SET_RA_STATE_0 "\n"
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" stp x29, x30, [sp, -16]!\n"
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" .cfi_def_cfa_offset 16\n"
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" .cfi_offset 29, -16\n"
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" .cfi_offset 30, -8\n"
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" mov x29, sp\n"
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" blr x0\n"
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" ldp x29, x30, [sp], 16\n"
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" .cfi_restore 30\n"
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" .cfi_restore 29\n"
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" .cfi_def_cfa_offset 0\n"
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" ret\n"
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" .cfi_endproc\n");
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/* Functions to create a call chain with mixed pac-ret dwarf. */
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__attribute__((target("branch-protection=pac-ret")))
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static void f2_pac_ret (void)
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{
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force_unwind ();
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die ();
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}
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__attribute__((target("branch-protection=none")))
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static void f1_no_pac_ret (void)
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{
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unusual_pac_ret (f2_pac_ret);
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die ();
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}
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__attribute__((noinline, target("branch-protection=pac-ret")))
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static void f0_pac_ret (void)
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{
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unusual_no_pac_ret (f1_no_pac_ret);
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die ();
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}
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static void cleanup_handler (void *p)
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{
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printf ("%s: Success.\n", __func__);
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exit (0);
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}
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int main ()
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{
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char dummy __attribute__((cleanup (cleanup_handler)));
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f0_pac_ret ();
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die ();
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}
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@ -78,7 +78,13 @@ static inline void
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aarch64_frob_update_context (struct _Unwind_Context *context,
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_Unwind_FrameState *fs)
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{
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if (fs->regs.reg[DWARF_REGNUM_AARCH64_RA_STATE].loc.offset & 0x1)
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const int reg = DWARF_REGNUM_AARCH64_RA_STATE;
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int ra_signed;
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if (fs->regs.reg[reg].how == REG_UNSAVED)
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ra_signed = fs->regs.reg[reg].loc.offset & 0x1;
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else
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ra_signed = _Unwind_GetGR (context, reg) & 0x1;
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if (ra_signed)
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/* The flag is used for re-authenticating EH handler's address. */
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context->flags |= RA_SIGNED_BIT;
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else
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@ -1204,7 +1204,9 @@ execute_cfa_program (const unsigned char *insn_ptr,
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#if defined (__aarch64__) && !defined (__ILP32__)
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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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reg = DWARF_REGNUM_AARCH64_RA_STATE;
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gcc_assert (fs->regs.reg[reg].how == REG_UNSAVED);
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fs->regs.reg[reg].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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