diff options
Diffstat (limited to 'gcc/config/aarch64/aarch64.c')
| -rw-r--r-- | gcc/config/aarch64/aarch64.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c index 4432cae6b8d..62baf584994 100644 --- a/gcc/config/aarch64/aarch64.c +++ b/gcc/config/aarch64/aarch64.c @@ -3123,6 +3123,22 @@ aarch64_gen_load_pair (machine_mode mode, rtx reg1, rtx mem1, rtx reg2, } } +/* Return TRUE if return address signing should be enabled for the current + function, otherwise return FALSE. */ + +bool +aarch64_return_address_signing_enabled (void) +{ + /* This function should only be called after frame laid out. */ + gcc_assert (cfun->machine->frame.laid_out); + + /* If signing scope is AARCH64_FUNCTION_NON_LEAF, we only sign a leaf function + if it's LR is pushed onto stack. */ + return (aarch64_ra_sign_scope == AARCH64_FUNCTION_ALL + || (aarch64_ra_sign_scope == AARCH64_FUNCTION_NON_LEAF + && cfun->machine->frame.reg_offset[LR_REGNUM] >= 0)); +} + /* Emit code to save the callee-saved registers from register number START to LIMIT to the stack at the location starting at offset START_OFFSET, skipping any write-back candidates if SKIP_WB is true. */ @@ -3541,6 +3557,10 @@ aarch64_expand_prologue (void) unsigned reg2 = cfun->machine->frame.wb_candidate2; rtx_insn *insn; + /* Sign return address for functions. */ + if (aarch64_return_address_signing_enabled ()) + emit_insn (gen_pacisp ()); + if (flag_stack_usage_info) current_function_static_stack_size = frame_size; @@ -3677,6 +3697,25 @@ aarch64_expand_epilogue (bool for_sibcall) RTX_FRAME_RELATED_P (insn) = 1; } + /* We prefer to emit the combined return/authenticate instruction RETAA, + however there are three cases in which we must instead emit an explicit + authentication instruction. + + 1) Sibcalls don't return in a normal way, so if we're about to call one + we must authenticate. + + 2) The RETAA instruction is not available before ARMv8.3-A, so if we are + generating code for !TARGET_ARMV8_3 we can't use it and must + explicitly authenticate. + + 3) On an eh_return path we make extra stack adjustments to update the + canonical frame address to be the exception handler's CFA. We want + to authenticate using the CFA of the function which calls eh_return. + */ + if (aarch64_return_address_signing_enabled () + && (for_sibcall || !TARGET_ARMV8_3 || crtl->calls_eh_return)) + emit_insn (gen_autisp ()); + /* Stack adjustment for exception handler. */ if (crtl->calls_eh_return) { @@ -8889,6 +8928,9 @@ aarch64_override_options (void) error ("Assembler does not support -mabi=ilp32"); #endif + if (aarch64_ra_sign_scope != AARCH64_FUNCTION_NONE && TARGET_ILP32) + sorry ("Return address signing is only supported for -mabi=lp64"); + /* Make sure we properly set up the explicit options. */ if ((aarch64_cpu_string && valid_cpu) || (aarch64_tune_string && valid_tune)) @@ -9272,6 +9314,8 @@ static const struct aarch64_attribute_info aarch64_attributes[] = { "cpu", aarch64_attr_custom, false, aarch64_handle_attr_cpu, OPT_mcpu_ }, { "tune", aarch64_attr_custom, false, aarch64_handle_attr_tune, OPT_mtune_ }, + { "sign-return-address", aarch64_attr_enum, false, NULL, + OPT_msign_return_address_ }, { NULL, aarch64_attr_custom, false, NULL, OPT____ } }; |