[binutils-gdb] aarch64 DWARF: add new CFI directive for PAuth_LR

[Matthieu Longo]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=c4ab4dd7bd96ec20b577619001ba2b50a0b1ce6e

commit c4ab4dd7bd96ec20b577619001ba2b50a0b1ce6e
Author: Matthieu Longo <matthieu.longo@arm.com>
Date:   Mon Nov 25 12:17:56 2024 +0000

    aarch64 DWARF: add new CFI directive for PAuth_LR
    
    This patch adds a new CFI directive (cfi_negate_ra_state_with_pc) which
    set an additional bit in the RA state to inform that RA was signed with
    SP but also PC as an additional diversifier.
    
    RA state | Description
    0b00     | Return address not signed (default if no cfi_negate_ra_state*)
    0b01     | Return address signed with SP (cfi_negate_ra_state)
    0b10     | Invalid state
    0b11     | Return address signed with SP+PC (cfi_negate_ra_state_with_pc)
    
    Approved-by: Indu Bhagat <indu.bhagat@oracle.com>
    Approved-by: Jan Beulich <jbeulich@suse.com>

Diff:
---
 bfd/elf-eh-frame.c |  1 +
 binutils/dwarf.c   |  5 +++++
 gas/dw2gencfi.c    | 14 +++++++++++++-
 gas/scfidw2gen.c   |  1 +
 include/dwarf2.def |  2 ++
 5 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/bfd/elf-eh-frame.c b/bfd/elf-eh-frame.c
index d903e27a676..b6f5078bb33 100644
--- a/bfd/elf-eh-frame.c
+++ b/bfd/elf-eh-frame.c
@@ -359,6 +359,7 @@ skip_cfa_op (bfd_byte **iter, bfd_byte *end, unsigned int encoded_ptr_width)
     case DW_CFA_remember_state:
     case DW_CFA_restore_state:
     case DW_CFA_GNU_window_save:
+    case DW_CFA_AARCH64_negate_ra_state_with_pc:
       /* No arguments.  */
       return true;
 
diff --git a/binutils/dwarf.c b/binutils/dwarf.c
index 626efb2eb9a..8e004cea839 100644
--- a/binutils/dwarf.c
+++ b/binutils/dwarf.c
@@ -10408,6 +10408,11 @@ display_debug_frames (struct dwarf_section *section,
 	      fc->pc_begin += ofs;
 	      break;
 
+	    case DW_CFA_AARCH64_negate_ra_state_with_pc:
+	      if (! do_debug_frames_interp)
+		printf ("  DW_CFA_AARCH64_negate_ra_state_with_pc\n");
+	      break;
+
 	    case DW_CFA_GNU_window_save:
 	      if (! do_debug_frames_interp)
 		printf ("  %s\n", DW_CFA_GNU_window_save_name[is_aarch64]);
diff --git a/gas/dw2gencfi.c b/gas/dw2gencfi.c
index fbeb697af09..012af0ff33e 100644
--- a/gas/dw2gencfi.c
+++ b/gas/dw2gencfi.c
@@ -714,6 +714,7 @@ const pseudo_typeS cfi_pseudo_table[] =
     { "cfi_restore_state", dot_cfi, DW_CFA_restore_state },
     { "cfi_window_save", dot_cfi, DW_CFA_GNU_window_save },
     { "cfi_negate_ra_state", dot_cfi, DW_CFA_AARCH64_negate_ra_state },
+    { "cfi_negate_ra_state_with_pc", dot_cfi, DW_CFA_AARCH64_negate_ra_state_with_pc },
     { "cfi_escape", dot_cfi_escape, 0 },
     { "cfi_signal_frame", dot_cfi, CFI_signal_frame },
     { "cfi_personality", dot_cfi_personality, 0 },
@@ -914,6 +915,10 @@ dot_cfi (int arg)
       cfi_add_CFA_insn (DW_CFA_GNU_window_save);
       break;
 
+    case DW_CFA_AARCH64_negate_ra_state_with_pc:
+      cfi_add_CFA_insn (DW_CFA_AARCH64_negate_ra_state_with_pc);
+      break;
+
     case CFI_signal_frame:
       frchain_now->frch_cfi_data->cur_fde_data->signal_frame = 1;
       break;
@@ -1754,6 +1759,10 @@ output_cfi_insn (struct cfi_insn_data *insn)
       out_one (DW_CFA_GNU_window_save);
       break;
 
+    case DW_CFA_AARCH64_negate_ra_state_with_pc:
+      out_one (DW_CFA_AARCH64_negate_ra_state_with_pc);
+      break;
+
     case CFI_escape:
       {
 	struct cfi_escape_data *e;
@@ -2212,6 +2221,7 @@ cfi_change_reg_numbers (struct cfi_insn_data *insn, segT ccseg)
 	case DW_CFA_remember_state:
 	case DW_CFA_restore_state:
 	case DW_CFA_GNU_window_save:
+	case DW_CFA_AARCH64_negate_ra_state_with_pc:
 	case CFI_escape:
 	case CFI_label:
 	  break;
@@ -2619,14 +2629,16 @@ const pseudo_typeS cfi_pseudo_table[] =
     { "cfi_remember_state", dot_cfi_dummy, 0 },
     { "cfi_restore_state", dot_cfi_dummy, 0 },
     { "cfi_window_save", dot_cfi_dummy, 0 },
+    { "cfi_negate_ra_state", dot_cfi_dummy, 0 },
+    { "cfi_negate_ra_state_with_pc", dot_cfi_dummy, 0 },
     { "cfi_escape", dot_cfi_dummy, 0 },
     { "cfi_signal_frame", dot_cfi_dummy, 0 },
     { "cfi_personality", dot_cfi_dummy, 0 },
     { "cfi_personality_id", dot_cfi_dummy, 0 },
     { "cfi_lsda", dot_cfi_dummy, 0 },
     { "cfi_val_encoded_addr", dot_cfi_dummy, 0 },
-    { "cfi_label", dot_cfi_dummy, 0 },
     { "cfi_inline_lsda", dot_cfi_dummy, 0 },
+    { "cfi_label", dot_cfi_dummy, 0 },
     { "cfi_val_offset", dot_cfi_dummy, 0 },
     { NULL, NULL, 0 }
   };
diff --git a/gas/scfidw2gen.c b/gas/scfidw2gen.c
index 7463207e170..9b3ad4b13e0 100644
--- a/gas/scfidw2gen.c
+++ b/gas/scfidw2gen.c
@@ -113,6 +113,7 @@ const pseudo_typeS scfi_pseudo_table[] =
     { "cfi_restore_state", dot_scfi_ignore, 0 },
     { "cfi_window_save", dot_scfi_ignore, 0 },
     { "cfi_negate_ra_state", dot_scfi_ignore, 0 },
+    { "cfi_negate_ra_state_with_pc", dot_scfi_ignore, 0 },
     { "cfi_escape", dot_scfi_ignore, 0 },
     { "cfi_personality", dot_scfi_ignore, 0 },
     { "cfi_personality_id", dot_scfi_ignore, 0 },
diff --git a/include/dwarf2.def b/include/dwarf2.def
index 63cb35560e7..6d6c0e0cc39 100644
--- a/include/dwarf2.def
+++ b/include/dwarf2.def
@@ -785,6 +785,8 @@ DW_CFA (DW_CFA_hi_user, 0x3f)
 
 /* SGI/MIPS specific.  */
 DW_CFA (DW_CFA_MIPS_advance_loc8, 0x1d)
+/* AArch64 extensions.  */
+DW_CFA (DW_CFA_AARCH64_negate_ra_state_with_pc, 0x2c)
 /* GNU extensions.
    NOTE: DW_CFA_GNU_window_save is multiplexed on Sparc and AArch64.  */
 DW_CFA (DW_CFA_GNU_window_save, 0x2d)