From: Luis Machado <luis.machado@arm.com>
To: Yvan Roux <yvan.roux@foss.st.com>, gdb-patches@sourceware.org
Cc: Torbjorn SVENSSON <torbjorn.svensson@foss.st.com>
Subject: Re: [PATCH 2/3] gdb/arm: Track msp and psp
Date: Wed, 15 Jun 2022 09:57:22 +0100 [thread overview]
Message-ID: <65771da9-0ff9-170c-f682-337ae0296884@arm.com> (raw)
In-Reply-To: <20220614150032.GD12000@gnbcxd0114.gnb.st.com>
On 6/14/22 16:00, Yvan Roux wrote:
> For Arm Cortex-M33 with security extensions, there are 4 different
> stack pointers (msp_s, msp_ns, psp_s, psp_ns). To be compatible
> with earlier Cortex-M derivates, the msp and psp registers are
> aliases for one of the 4 real stack pointer registers.
>
> These are the combinations that exist:
> sp -> msp -> msp_s
> sp -> msp -> msp_ns
> sp -> psp -> psp_s
> sp -> psp -> psp_ns
>
> This means that when the GDB client is to show the value of "msp",
> the value should always be equal to either "msp_s" or "msp_ns".
> Same goes for "psp".
>
> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29121
>
> Signed-off-by: Torbj�rn SVENSSON <torbjorn.svensson@foss.st.com>
> Signed-off-by: Yvan Roux <yvan.roux@foss.st.com>
> ---
> gdb/arm-tdep.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
> index 1df57f5b5c8..e497dd1b3b8 100644
> --- a/gdb/arm-tdep.c
> +++ b/gdb/arm-tdep.c
> @@ -288,6 +288,8 @@ struct arm_prologue_cache
>
> /* Active stack pointer. */
> int active_sp_regnum;
> + int active_msp_regnum;
> + int active_psp_regnum;
>
> /* The frame base for this frame is just prev_sp - frame size.
> FRAMESIZE is the distance from the frame pointer to the
> @@ -345,11 +347,23 @@ arm_cache_init (struct arm_prologue_cache *cache, struct frame_info *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);
>
> + 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;
> + 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;
> +
> /* 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;
> @@ -384,6 +398,10 @@ arm_cache_get_sp_register (struct arm_prologue_cache *cache,
> return cache->psp_s;
> if (regnum == tdep->m_profile_psp_ns_regnum)
> return cache->psp_ns;
> + if (regnum == tdep->m_profile_msp_regnum)
> + return arm_cache_get_sp_register (cache, tdep, cache->active_msp_regnum);
> + if (regnum == tdep->m_profile_psp_regnum)
> + return arm_cache_get_sp_register (cache, tdep, cache->active_psp_regnum);
> }
> else if (tdep->is_m)
> {
Just so I understand this correctly, the problem is that we're not keeping the aliases in sync
all the time, so sp/msp/psp and the 4 other registers are going out-of-sync.
Also, although SP will be either msp or psp, we can have distinct and valid msp/psp values, right?
next prev parent reply other threads:[~2022-06-15 8:57 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-14 14:56 [PATCH 0/3] gdb/arm: ARMv8-M Secure/Non-Secure stack support fixes Yvan Roux
2022-06-14 14:59 ` [PATCH 1/3] gdb/arm: Fetch initial sp value prior to compare Yvan Roux
2022-06-15 8:39 ` Luis Machado
2022-06-15 9:20 ` Yvan Roux
2022-06-14 15:00 ` [PATCH 2/3] gdb/arm: Track msp and psp Yvan Roux
2022-06-15 8:57 ` Luis Machado [this message]
2022-06-15 9:28 ` Yvan Roux
2022-06-15 9:46 ` Torbjorn SVENSSON
2022-06-15 10:15 ` Luis Machado
2022-06-15 10:46 ` Yvan Roux
2022-06-14 15:01 ` [PATCH 3/3] gdb/arm: Make sp alias for one of the other stack pointers Yvan Roux
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