Hi, On Fri, Jun 14, 2024 at 03:47:16PM +0100, Steve Capper wrote: > From: German Gomez <german.go...@arm.com> > > Implement DW_CFA_AARCH64_negate_ra_state in accordance with the DWARF > AARCH64 ABI [1]. > > Followup commits will use the value of this register to remove the PAC > from return addresses.
Looks correct. > [1] > https://github.com/ARM-software/abi-aa/blob/main/aadwarf64/aadwarf64.rst#44call-frame-instructions > > Signed-off-by: German Gomez <german.go...@arm.com> > Signed-off-by: Steve Capper <steve.cap...@arm.com> > --- > libdw/cfi.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > diff --git a/libdw/cfi.c b/libdw/cfi.c > index a7174405..743bfc07 100644 > --- a/libdw/cfi.c > +++ b/libdw/cfi.c > @@ -125,6 +125,15 @@ execute_cfi (Dwarf_CFI *cache, > fs->regs[regno].value = (r_value); \ > } while (0) > > + /* The AARCH64 DWARF ABI states that register 34 (ra_sign_state) must > + be initialized to 0. So do it before executing the CFI. */ > + if (cache->e_machine == EM_AARCH64) > + { > + if (unlikely (! enough_registers (DW_AARCH64_RA_SIGN_STATE, &fs, > &result))) > + goto out; > + fs->regs[DW_AARCH64_RA_SIGN_STATE].value = 0; > + } > + > while (program < end) > { > uint8_t opcode = *program++; OK. > @@ -357,7 +366,10 @@ execute_cfi (Dwarf_CFI *cache, > { > /* Toggles the return address state, indicating whether > the return address is encrypted or not on > - aarch64. XXX not handled yet. */ > + aarch64. */ > + if (unlikely (! enough_registers (DW_AARCH64_RA_SIGN_STATE, &fs, > &result))) > + goto out; > + fs->regs[DW_AARCH64_RA_SIGN_STATE].value ^= 0x1; > } > else > { Funny we already had some code here to handle DW_CFA_AARCH64_negate_ra_state (and how unfortunate it overlaps with DW_CFA_GNU_window_save, but there is already an em check). Also looks good. Thanks, Mark
