From: Sascha Hauer <s.hauer@pengutronix.de>
To: Ahmad Fatoum <a.fatoum@pengutronix.de>
Cc: Ahmad Fatoum <a.fatoum@barebox.org>, barebox@lists.infradead.org
Subject: Re: [PATCH] mmu: explicitly map executable non-SDRAM regions with MAP_CODE
Date: Mon, 23 Jun 2025 14:01:31 +0200 [thread overview]
Message-ID: <aFlCG6YGEmXkNwzA@pengutronix.de> (raw)
In-Reply-To: <0c5b58a4-bc8a-4775-a265-f1bb2b46eea0@pengutronix.de>
On Fri, Jun 20, 2025 at 05:45:45PM +0200, Ahmad Fatoum wrote:
> On 20.06.25 14:45, Sascha Hauer wrote:
> > On Wed, Jun 18, 2025 at 02:36:42PM +0200, Ahmad Fatoum wrote:
> >> So far we have been setting eXecute Never on MAP_UNCACHED regions and
> >> left it out for the default MAP_CACHED region.
> >>
> >> We have at least three places, which depend on this to remap non-SDRAM
> >> regions executable, so ROM code or newly uploaded code can be run.
> >>
> >> Switch them over to use a new MAP_CODE mapping type. For now, this is
> >> equivalent to MAP_CACHED, but with the addition of W^X support in
> >> barebox, this will be required to avoid a prefetch abort when MMU
> >> attributes are used.
> >>
> >> Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
> >> ---
> >> Sascha, I think this should be ordered before your MMU patches to avoid
> >> the known regressions. Let's see what else there is. :)
> >> ---
> >> arch/arm/mach-imx/romapi.c | 3 ++-
> >> drivers/firmware/socfpga.c | 3 ++-
> >> drivers/hab/habv4.c | 2 +-
> >> include/mmu.h | 1 +
> >> 4 files changed, 6 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/arch/arm/mach-imx/romapi.c b/arch/arm/mach-imx/romapi.c
> >> index 10af42f28a76..a4143d372ae8 100644
> >> --- a/arch/arm/mach-imx/romapi.c
> >> +++ b/arch/arm/mach-imx/romapi.c
> >> @@ -299,7 +299,8 @@ void imx93_bootsource(void)
> >> goto out;
> >> }
> >>
> >> - arch_remap_range((void *)rom.start, rom.start, resource_size(&rom), MAP_CACHED);
> >> + /* TODO: restore uncached mapping once we no longer need this? */
> >> + arch_remap_range((void *)rom.start, rom.start, resource_size(&rom), MAP_CODE);
> >>
> >> OPTIMIZER_HIDE_VAR(rom_api);
> >>
> >> diff --git a/drivers/firmware/socfpga.c b/drivers/firmware/socfpga.c
> >> index 0f7d11abb588..4b10ca009798 100644
> >> --- a/drivers/firmware/socfpga.c
> >> +++ b/drivers/firmware/socfpga.c
> >> @@ -353,7 +353,8 @@ static int socfpga_fpgamgr_program_finish(struct firmware_handler *fh)
> >> return status;
> >> }
> >>
> >> - remap_range((void *)CYCLONE5_OCRAM_ADDRESS, PAGE_SIZE, MAP_CACHED);
> >> + /* TODO: restore uncached mapping once we no longer need this? */
> >> + remap_range((void *)CYCLONE5_OCRAM_ADDRESS, PAGE_SIZE, MAP_CODE);
> >
> > This is done before the code is copied to this page. I moved it after
> > the fncpy call to avoid writing to readonly memory.
>
> fncpy calls memcpy internally though, so we should either leave the MAP_CACHED
> as is and add a further MAP_CODE after the fncpy or introduce a fncpy_toio
> that calls memcpy_toio internally.
>
Ok, changed that to:
remap_range((void *)CYCLONE5_OCRAM_ADDRESS, PAGE_SIZE, MAP_CACHED);
fncpy();
remap_range((void *)CYCLONE5_OCRAM_ADDRESS, PAGE_SIZE, MAP_CODE);
ocram_func()
remap_range((void *)CYCLONE5_OCRAM_ADDRESS, PAGE_SIZE, MAP_UNCACHED);
Sascha
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next prev parent reply other threads:[~2025-06-23 14:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-18 12:36 Ahmad Fatoum
2025-06-20 12:45 ` Sascha Hauer
2025-06-20 15:45 ` Ahmad Fatoum
2025-06-23 12:01 ` Sascha Hauer [this message]
2025-06-20 12:46 ` Sascha Hauer
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