Hi Steve, On Fri, Jun 14, 2024 at 03:47:19PM +0100, Steve Capper wrote: > We need to read the PAC mask from a core file when debugging offline > as the information is still needed to demangle return addresses. > > This commit pulls out the NT_ARM_PAC_MASK info from the core and feeds > it through to dwfl_thread_state_aarch64_pauth for each thread.
Sorry, I was on vacation and started reviewing patches posted while I was away. Should have started at the other end of the queue. This patch partially overlaps with: https://patchwork.sourceware.org/project/elfutils/patch/20240814085134.109500-3-kuan-ying....@canonical.com/ Luckily the patches agree on the definition of the the pac_items (modulo the name data_mask/insn_mask vs pauth_dmask/pauth_cmask). This patch doesn't introduce a regset for ARM_PAC_ENABLED_KEYS that the other one does. Is this not necessary? Thanks, Mark > Signed-off-by: Steve Capper <steve.cap...@arm.com> > --- > backends/aarch64_corenote.c | 15 ++++++++++++++- > libdwfl/linux-core-attach.c | 34 ++++++++++++++++++++++++++++++++++ > 2 files changed, 48 insertions(+), 1 deletion(-) > > diff --git a/backends/aarch64_corenote.c b/backends/aarch64_corenote.c > index 905a4b8a..f612d2ce 100644 > --- a/backends/aarch64_corenote.c > +++ b/backends/aarch64_corenote.c > @@ -107,6 +107,18 @@ static const Ebl_Core_Item aarch64_syscall_items [] = > } > }; > > +static const Ebl_Core_Item aarch64_pac_items [] = > + { > + { > + .name = "data_mask", .type = ELF_T_XWORD, .format = 'x', > + .offset = 0, .group = "register" > + }, > + { > + .name = "insn_mask", .type = ELF_T_XWORD, .format = 'x', > + .offset = 8, .group = "register" > + } > + }; > + > #define AARCH64_HWBP_REG(KIND, N) \ > { > \ > .name = "DBG" KIND "VR" #N "_EL1", .type = ELF_T_XWORD, .format = 'x', > \ > @@ -167,6 +179,7 @@ AARCH64_BP_WP_GROUP ("W", aarch64_hw_wp_items); > EXTRA_ITEMS (NT_ARM_TLS, 8, aarch64_tls_items) \ > EXTRA_ITEMS (NT_ARM_HW_BREAK, 264, aarch64_hw_bp_items) \ > EXTRA_ITEMS (NT_ARM_HW_WATCH, 264, aarch64_hw_wp_items) \ > - EXTRA_ITEMS (NT_ARM_SYSTEM_CALL, 4, aarch64_syscall_items) > + EXTRA_ITEMS (NT_ARM_SYSTEM_CALL, 4, aarch64_syscall_items) \ > + EXTRA_ITEMS (NT_ARM_PAC_MASK, 16, aarch64_pac_items) > > #include "linux-core-note.c" > diff --git a/libdwfl/linux-core-attach.c b/libdwfl/linux-core-attach.c > index d6f9e971..91a5461a 100644 > --- a/libdwfl/linux-core-attach.c > +++ b/libdwfl/linux-core-attach.c > @@ -289,6 +289,40 @@ core_set_initial_registers (Dwfl_Thread *thread, void > *thread_arg_voidp) > reg_desc += regloc->pad; > } > } > + > + /* look for any Pointer Authentication code masks on AArch64 machines */ > + GElf_Ehdr ehdr_mem; > + GElf_Ehdr *ehdr = gelf_getehdr(core, &ehdr_mem); > + if (ehdr && ehdr->e_machine == EM_AARCH64) > + { > + while (offset < note_data->d_size > + && (offset = gelf_getnote (note_data, offset, > + &nhdr, &name_offset, &desc_offset)) > 0) > + { > + if (nhdr.n_type != NT_ARM_PAC_MASK) > + continue; > + > + name = (nhdr.n_namesz == 0 ? "" : note_data->d_buf + name_offset); > + desc = note_data->d_buf + desc_offset; > + core_note_err = ebl_core_note (core_arg->ebl, &nhdr, name, desc, > + ®s_offset, &nregloc, ®locs, > + &nitems, &items); > + if (!core_note_err) > + break; > + > + for (item = items; item < items + nitems; item++) > + if (strcmp(item->name, "insn_mask") == 0) > + break; > + > + if (item == items + nitems) > + continue; > + > + uint64_t insn_mask = read_8ubyte_unaligned_noncvt(desc + item->offset); > + dwfl_thread_state_aarch64_pauth(thread, insn_mask); > + break; > + } > + } > + > return true; > } > > -- > 2.39.2 >
