[PATCH v2 2/4] gdb/arm: Ensure that stack pointers are in sync

Torbjörn SVENSSON via Gdb-patches
2022-11-18T15:54:13Z

Without this patch, sp might be secure, but msp or psp is non-secure
(this state can not happen in the hardware).

Signed-off-by: Torbjörn SVENSSON <torbjorn.svensson@foss.st.com>
---
gdb/arm-tdep.c | 86 ++++++++++++++++++++++++++++++++++----------------
1 file changed, 58 insertions(+), 28 deletions(-)

diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 124a94dc87d..c011b2aa973 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -324,20 +324,6 @@ reconstruct_t_bit(struct gdbarch *gdbarch, CORE_ADDR lr, ULONGEST psr)
return psr;
}

-/* Initialize stack pointers, and flag the active one. */
-
-static inline void
-arm_cache_init_sp (int regnum, CORE_ADDR* member,
- struct arm_prologue_cache *cache,
- frame_info_ptr frame)
-{
- CORE_ADDR val = get_frame_register_unsigned (frame, regnum);
- if (val == cache->sp)
- cache->active_sp_regnum = regnum;
-
- *member = val;
-}
-
/* Initialize CACHE fields for which zero is not adequate (CACHE is
expected to have been ZALLOC'ed before calling this function). */

@@ -362,34 +348,78 @@ arm_cache_init (struct arm_prologue_cache *cache, frame_info_ptr frame)

if (tdep->have_sec_ext)
{
- CORE_ADDR msp_val = get_frame_register_unsigned (frame, tdep->m_profile_msp_regnum);
- CORE_ADDR psp_val = get_frame_register_unsigned (frame, tdep->m_profile_psp_regnum);
-
- arm_cache_init_sp (tdep->m_profile_msp_s_regnum, &cache->msp_s, cache, frame);
- arm_cache_init_sp (tdep->m_profile_psp_s_regnum, &cache->psp_s, cache, frame);
- arm_cache_init_sp (tdep->m_profile_msp_ns_regnum, &cache->msp_ns, cache, frame);
- arm_cache_init_sp (tdep->m_profile_psp_ns_regnum, &cache->psp_ns, cache, frame);
-
+ const CORE_ADDR msp_val
+ = get_frame_register_unsigned (frame, tdep->m_profile_msp_regnum);
+ const CORE_ADDR psp_val
+ = get_frame_register_unsigned (frame, tdep->m_profile_psp_regnum);
+
+ cache->msp_s
+ = get_frame_register_unsigned (frame, tdep->m_profile_msp_s_regnum);
+ cache->msp_ns
+ = get_frame_register_unsigned (frame, tdep->m_profile_msp_ns_regnum);
+ cache->psp_s
+ = get_frame_register_unsigned (frame, tdep->m_profile_psp_s_regnum);
+ cache->psp_ns
+ = get_frame_register_unsigned (frame, tdep->m_profile_psp_ns_regnum);
+
+ /* Identify what msp is alias for (msp_s or msp_ns). */
if (msp_val == cache->msp_s)
cache->active_msp_regnum = tdep->m_profile_msp_s_regnum;
else if (msp_val == cache->msp_ns)
cache->active_msp_regnum = tdep->m_profile_msp_ns_regnum;
+ else
+ {
+ warning (_("Invalid state, unable to determine msp alias."));
+ cache->active_msp_regnum = tdep->m_profile_msp_s_regnum;
+ }
+
+ /* Identify what psp is alias for (psp_s or psp_ns). */
if (psp_val == cache->psp_s)
cache->active_psp_regnum = tdep->m_profile_psp_s_regnum;
else if (psp_val == cache->psp_ns)
cache->active_psp_regnum = tdep->m_profile_psp_ns_regnum;
+ else
+ {
+ warning (_("Invalid state, unable to determine psp alias."));
+ cache->active_psp_regnum = tdep->m_profile_psp_s_regnum;
+ }

- /* Use MSP_S as default stack pointer. */
- if (cache->active_sp_regnum == ARM_SP_REGNUM)
- cache->active_sp_regnum = tdep->m_profile_msp_s_regnum;
+ /* Identify what sp is alias for (msp_s, msp_ns, psp_s or psp_ns). */
+ if (msp_val == cache->sp)
+ cache->active_sp_regnum = cache->active_msp_regnum;
+ else if (psp_val == cache->sp)
+ cache->active_sp_regnum = cache->active_psp_regnum;
+ else
+ {
+ warning (_("Invalid state, unable to determine sp alias."));
+ cache->active_sp_regnum = cache->active_msp_regnum;
+ }
}
else if (tdep->is_m)
{
- arm_cache_init_sp (tdep->m_profile_msp_regnum, &cache->msp_s, cache, frame);
- arm_cache_init_sp (tdep->m_profile_psp_regnum, &cache->psp_s, cache, frame);
+ cache->msp_s
+ = get_frame_register_unsigned (frame, tdep->m_profile_msp_s_regnum);
+ cache->psp_s
+ = get_frame_register_unsigned (frame, tdep->m_profile_psp_s_regnum);
+
+ /* Identify what sp is alias for (msp or psp). */
+ if (cache->msp_s == cache->sp)
+ cache->active_sp_regnum = tdep->m_profile_msp_regnum;
+ else if (cache->psp_s == cache->sp)
+ cache->active_sp_regnum = tdep->m_profile_psp_regnum;
+ else
+ {
+ warning (_("Invalid state, unable to determine sp alias."));
+ cache->active_sp_regnum = tdep->m_profile_msp_regnum;
+ }
}
else
- arm_cache_init_sp (ARM_SP_REGNUM, &cache->msp_s, cache, frame);
+ {
+ cache->msp_s
+ = get_frame_register_unsigned (frame, ARM_SP_REGNUM);
+
+ cache->active_sp_regnum = ARM_SP_REGNUM;
+ }
}

/* Return the requested stack pointer value (in REGNUM), taking into
--
2.25.1