Hi Javier
Am 12.06.24 um 09:49 schrieb Javier Martinez Canillas:
Thomas Zimmermann <tzimmermann@xxxxxxx> writes:
Hello Thomas,
Hi
Am 10.06.24 um 10:47 schrieb Thomas Zimmermann:
Hi
Am 04.06.24 um 10:03 schrieb Peng Fan (OSS):
From: Peng Fan <peng.fan@xxxxxxx>
If 'info->screen_buffer' locates in vmalloc address space, virt_to_page
will not be able to get correct results. With CONFIG_DEBUG_VM and
CONFIG_DEBUG_VIRTUAL enabled on ARM64, there is dump below:
Which graphics driver triggers this bug?
[ 3.536043] ------------[ cut here ]------------
[ 3.540716] virt_to_phys used for non-linear address:
000000007fc4f540 (0xffff800086001000)
[ 3.552628] WARNING: CPU: 4 PID: 61 at arch/arm64/mm/physaddr.c:12
__virt_to_phys+0x68/0x98
[ 3.565455] Modules linked in:
[ 3.568525] CPU: 4 PID: 61 Comm: kworker/u12:5 Not tainted
6.6.23-06226-g4986cc3e1b75-dirty #250
[ 3.577310] Hardware name: NXP i.MX95 19X19 board (DT)
[ 3.582452] Workqueue: events_unbound deferred_probe_work_func
[ 3.588291] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS
BTYPE=--)
[ 3.595233] pc : __virt_to_phys+0x68/0x98
[ 3.599246] lr : __virt_to_phys+0x68/0x98
[ 3.603276] sp : ffff800083603990
[ 3.677939] Call trace:
[ 3.680393] __virt_to_phys+0x68/0x98
[ 3.684067] drm_fbdev_dma_helper_fb_probe+0x138/0x238
[ 3.689214] __drm_fb_helper_initial_config_and_unlock+0x2b0/0x4c0
[ 3.695385] drm_fb_helper_initial_config+0x4c/0x68
[ 3.700264] drm_fbdev_dma_client_hotplug+0x8c/0xe0
[ 3.705161] drm_client_register+0x60/0xb0
[ 3.709269] drm_fbdev_dma_setup+0x94/0x148
So add a check 'is_vmalloc_addr'.
Fixes: b79fe9abd58b ("drm/fbdev-dma: Implement fbdev emulation for
GEM DMA helpers")
Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
Reviewed-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
I'm taking back my r-b. The memory is expected to by be physically
contiguous and vmalloc() won't guarantee that.
Agreed.
These smem_ fields are clearly designed for PCI BARs of traditional
graphics cards. So can we even assume contiguous memory for DMA? That
was my assumption, but with IOMMUs it might not be the case. Fbdev-dma
only sets smem_start to support a single old userspace driver. Maybe we
should further restrict usage of this field by making it opt-in for each
driver. Best regards Thomas
Best regards
Thomas
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
