From: Peter Bergner Date: Mon, 15 Jul 2024 21:57:32 +0000 (-0500) Subject: rs6000: Error on CPUs and ABIs that don't support the ROP protection insns [PR114759] X-Git-Tag: basepoints/gcc-16~7472 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6f2bab9b5d1ce1914c748b7dcd8638dafaa98df7;p=thirdparty%2Fgcc.git rs6000: Error on CPUs and ABIs that don't support the ROP protection insns [PR114759] We currently silently ignore the -mrop-protect option for old CPUs we don't support with the ROP hash insns, but we throw an error for unsupported ABIs. This patch treats unsupported CPUs and ABIs similarly by throwing an error both both. This matches clang behavior and allows us to simplify our tests in the code that generates our prologue and epilogue code. 2024-06-26 Peter Bergner gcc/ PR target/114759 * config/rs6000/rs6000.cc (rs6000_option_override_internal): Disallow CPUs and ABIs that do no support the ROP protection insns. * config/rs6000/rs6000-logue.cc (rs6000_stack_info): Remove now unneeded tests. (rs6000_emit_prologue): Likewise. Remove unneeded gcc_assert. (rs6000_emit_epilogue): Likewise. * config/rs6000/rs6000.md: Likewise. gcc/testsuite/ PR target/114759 * gcc.target/powerpc/pr114759-3.c: New test. --- diff --git a/gcc/config/rs6000/rs6000-logue.cc b/gcc/config/rs6000/rs6000-logue.cc index 48f40633071..edc0d6c8f52 100644 --- a/gcc/config/rs6000/rs6000-logue.cc +++ b/gcc/config/rs6000/rs6000-logue.cc @@ -716,17 +716,11 @@ rs6000_stack_info (void) info->calls_p = (!crtl->is_leaf || cfun->machine->ra_needs_full_frame); info->rop_hash_size = 0; - if (TARGET_POWER8 - && info->calls_p - && DEFAULT_ABI == ABI_ELFv2 - && rs6000_rop_protect) + /* If we want ROP protection and this function makes a call, indicate + we need to create a stack slot to save the hashed return address in. */ + if (rs6000_rop_protect + && info->calls_p) info->rop_hash_size = 8; - else if (rs6000_rop_protect && DEFAULT_ABI != ABI_ELFv2) - { - /* We can't check this in rs6000_option_override_internal since - DEFAULT_ABI isn't established yet. */ - error ("%qs requires the ELFv2 ABI", "-mrop-protect"); - } /* Determine if we need to save the condition code registers. */ if (save_reg_p (CR2_REGNO) @@ -3272,9 +3266,8 @@ rs6000_emit_prologue (void) /* NOTE: The hashst isn't needed if we're going to do a sibcall, but there's no way to know that here. Harmless except for performance, of course. */ - if (TARGET_POWER8 && rs6000_rop_protect && info->rop_hash_size != 0) + if (info->rop_hash_size) { - gcc_assert (DEFAULT_ABI == ABI_ELFv2); rtx stack_ptr = gen_rtx_REG (Pmode, STACK_POINTER_REGNUM); rtx addr = gen_rtx_PLUS (Pmode, stack_ptr, GEN_INT (info->rop_hash_save_offset)); @@ -5051,12 +5044,9 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type) /* The ROP hash check must occur after the stack pointer is restored (since the hash involves r1), and is not performed for a sibcall. */ - if (TARGET_POWER8 - && rs6000_rop_protect - && info->rop_hash_size != 0 + if (info->rop_hash_size && epilogue_type != EPILOGUE_TYPE_SIBCALL) { - gcc_assert (DEFAULT_ABI == ABI_ELFv2); rtx stack_ptr = gen_rtx_REG (Pmode, STACK_POINTER_REGNUM); rtx addr = gen_rtx_PLUS (Pmode, stack_ptr, GEN_INT (info->rop_hash_save_offset)); diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc index 195f2af9062..d4eec5c472f 100644 --- a/gcc/config/rs6000/rs6000.cc +++ b/gcc/config/rs6000/rs6000.cc @@ -4844,6 +4844,18 @@ rs6000_option_override_internal (bool global_init_p) } } + /* We only support ROP protection on certain targets. */ + if (rs6000_rop_protect) + { + /* Disallow CPU targets we don't support. */ + if (!TARGET_POWER8) + error ("%<-mrop-protect%> requires %<-mcpu=power8%> or later"); + + /* Disallow ABI targets we don't support. */ + if (DEFAULT_ABI != ABI_ELFv2) + error ("%<-mrop-protect%> requires the ELFv2 ABI"); + } + /* Initialize all of the registers. */ rs6000_init_hard_regno_mode_ok (global_init_p); diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md index 679aac5a10d..45a4a8cfb90 100644 --- a/gcc/config/rs6000/rs6000.md +++ b/gcc/config/rs6000/rs6000.md @@ -15810,7 +15810,7 @@ [(set (match_operand:DI 0 "simple_offsettable_mem_operand" "=m") (unspec_volatile:DI [(match_operand:DI 1 "int_reg_operand" "r")] UNSPEC_HASHST))] - "TARGET_POWER8 && rs6000_rop_protect" + "rs6000_rop_protect" { static char templ[32]; const char *p = rs6000_privileged ? "p" : ""; @@ -15823,7 +15823,7 @@ [(unspec_volatile [(match_operand:DI 0 "int_reg_operand" "r") (match_operand:DI 1 "simple_offsettable_mem_operand" "m")] UNSPEC_HASHCHK)] - "TARGET_POWER8 && rs6000_rop_protect" + "rs6000_rop_protect" { static char templ[32]; const char *p = rs6000_privileged ? "p" : ""; diff --git a/gcc/testsuite/gcc.target/powerpc/pr114759-3.c b/gcc/testsuite/gcc.target/powerpc/pr114759-3.c new file mode 100644 index 00000000000..6770a9aec3b --- /dev/null +++ b/gcc/testsuite/gcc.target/powerpc/pr114759-3.c @@ -0,0 +1,19 @@ +/* PR target/114759 */ +/* { dg-do compile } */ +/* { dg-options "-O2 -mdejagnu-cpu=power7 -mrop-protect" } */ + +/* Verify we emit an error if we use -mrop-protect with an unsupported cpu. */ + +extern void foo (void); + +int +bar (void) +{ + foo (); + return 5; +} + +/* The correct line number is in the preamble to the error message, not + in the final line (which is all that dg-error inspects). Hence, we have + to tell dg-error to ignore the line number. */ +/* { dg-error "'-mrop-protect' requires '-mcpu=power8'" "PR114759" { target *-*-* } 0 } */