drm/meson: improve encoder probe / initialization error handling

Rename meson_encoder_{cvbs,dsi,hdmi}_init() to
meson_encoder_{cvbs,dsi,hdmi}_probe() so it's clear that these functions
are used at probe time during driver initialization. Also switch all
error prints inside those functions to use dev_err_probe() for
consistency.

This makes the code more straight forward to read and makes the error
prints within those functions consistent (by logging all -EPROBE_DEFER
with dev_dbg(), while actual errors are logged with dev_err() and get
the error value printed).

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240218175035.1948165-1-martin.blumenstingl@googlemail.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240218175035.1948165-1-martin.blumenstingl@googlemail.com

drm/meson: Don't remove bridges which are created by other drivers

Stop calling drm_bridge_remove() for bridges allocated/managed by other
drivers in the remove paths of meson_encoder_{cvbs,dsi,hdmi}.
drm_bridge_remove() unregisters the bridge so it cannot be used
anymore. Doing so for bridges we don't own can lead to the video
pipeline not being able to come up after -EPROBE_DEFER of the VPU
because we're unregistering a bridge that's managed by another driver.
The other driver doesn't know that we have unregistered it's bridge
and on subsequent .probe() we're not able to find those bridges anymore
(since nobody re-creates them).

This fixes probe errors on Meson8b boards with the CVBS outputs enabled.

Fixes: 09847723c12f ("drm/meson: remove drm bridges at aggregate driver unbind time")
Fixes: 42dcf15f901c ("drm/meson: add DSI encoder")
Cc: <stable@vger.kernel.org>
Reported-by: Steve Morvai <stevemorvai@hotmail.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Tested-by: Steve Morvai <stevemorvai@hotmail.com>
Link: https://lore.kernel.org/r/20240215220442.1343152-1-martin.blumenstingl@googlemail.com
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240215220442.1343152-1-martin.blumenstingl@googlemail.com

drm/meson: Fix return type of meson_encoder_cvbs_mode_valid()

With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
indirect call targets are validated against the expected function
pointer prototype to make sure the call target is valid to help mitigate
ROP attacks. If they are not identical, there is a failure at run time,
which manifests as either a kernel panic or thread getting killed. A
proposed warning in clang aims to catch these at compile time, which
reveals:

drivers/gpu/drm/meson/meson_encoder_cvbs.c:211:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' with an expression of type 'int (struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict]
.mode_valid = meson_encoder_cvbs_mode_valid,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.

->mode_valid() in 'struct drm_bridge_funcs' expects a return type of
'enum drm_mode_status', not 'int'. Adjust the return type of
meson_encoder_cvbs_mode_valid() to match the prototype's to resolve the
warning and CFI failure.

Link: https://github.com/ClangBuiltLinux/linux/issues/1750
Reported-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221102155242.1927166-1-nathan@kernel.org

drm/meson: remove drm bridges at aggregate driver unbind time

drm bridges added by meson_encoder_hdmi_init and meson_encoder_cvbs_init
were not manually removed at module unload time, which caused dangling
references to freed memory to remain linked in the global bridge_list.

When loading the driver modules back in, the same functions would again
call drm_bridge_add, and when traversing the global bridge_list, would
end up peeking into freed memory.

Once again KASAN revealed the problem:

[ +0.000095] =============================================================
[ +0.000008] BUG: KASAN: use-after-free in __list_add_valid+0x9c/0x120
[ +0.000018] Read of size 8 at addr ffff00003da291f0 by task modprobe/2483

[ +0.000018] CPU: 3 PID: 2483 Comm: modprobe Tainted: G C O 5.19.0-rc6-lrmbkasan+ #1
[ +0.000011] Hardware name: Hardkernel ODROID-N2Plus (DT)
[ +0.000008] Call trace:
[ +0.000006] dump_backtrace+0x1ec/0x280
[ +0.000012] show_stack+0x24/0x80
[ +0.000008] dump_stack_lvl+0x98/0xd4
[ +0.000011] print_address_description.constprop.0+0x80/0x520
[ +0.000011] print_report+0x128/0x260
[ +0.000008] kasan_report+0xb8/0xfc
[ +0.000008] __asan_report_load8_noabort+0x3c/0x50
[ +0.000009] __list_add_valid+0x9c/0x120
[ +0.000009] drm_bridge_add+0x6c/0x104 [drm]
[ +0.000165] dw_hdmi_probe+0x1900/0x2360 [dw_hdmi]
[ +0.000022] meson_dw_hdmi_bind+0x520/0x814 [meson_dw_hdmi]
[ +0.000014] component_bind+0x174/0x520
[ +0.000012] component_bind_all+0x1a8/0x38c
[ +0.000010] meson_drv_bind_master+0x5e8/0xb74 [meson_drm]
[ +0.000032] meson_drv_bind+0x20/0x2c [meson_drm]
[ +0.000027] try_to_bring_up_aggregate_device+0x19c/0x390
[ +0.000010] component_master_add_with_match+0x1c8/0x284
[ +0.000009] meson_drv_probe+0x274/0x280 [meson_drm]
[ +0.000026] platform_probe+0xd0/0x220
[ +0.000009] really_probe+0x3ac/0xa80
[ +0.000009] __driver_probe_device+0x1f8/0x400
[ +0.000009] driver_probe_device+0x68/0x1b0
[ +0.000009] __driver_attach+0x20c/0x480
[ +0.000008] bus_for_each_dev+0x114/0x1b0
[ +0.000009] driver_attach+0x48/0x64
[ +0.000008] bus_add_driver+0x390/0x564
[ +0.000009] driver_register+0x1a8/0x3e4
[ +0.000009] __platform_driver_register+0x6c/0x94
[ +0.000008] meson_drm_platform_driver_init+0x3c/0x1000 [meson_drm]
[ +0.000027] do_one_initcall+0xc4/0x2b0
[ +0.000011] do_init_module+0x154/0x570
[ +0.000011] load_module+0x1a78/0x1ea4
[ +0.000008] __do_sys_init_module+0x184/0x1cc
[ +0.000009] __arm64_sys_init_module+0x78/0xb0
[ +0.000009] invoke_syscall+0x74/0x260
[ +0.000009] el0_svc_common.constprop.0+0xcc/0x260
[ +0.000008] do_el0_svc+0x50/0x70
[ +0.000007] el0_svc+0x68/0x1a0
[ +0.000012] el0t_64_sync_handler+0x11c/0x150
[ +0.000008] el0t_64_sync+0x18c/0x190

[ +0.000016] Allocated by task 879:
[ +0.000008] kasan_save_stack+0x2c/0x5c
[ +0.000011] __kasan_kmalloc+0x90/0xd0
[ +0.000007] __kmalloc+0x278/0x4a0
[ +0.000011] mpi_resize+0x13c/0x1d0
[ +0.000011] mpi_powm+0xd24/0x1570
[ +0.000009] rsa_enc+0x1a4/0x30c
[ +0.000009] pkcs1pad_verify+0x3f0/0x580
[ +0.000009] public_key_verify_signature+0x7a8/0xba4
[ +0.000010] public_key_verify_signature_2+0x40/0x60
[ +0.000008] verify_signature+0xb4/0x114
[ +0.000008] pkcs7_validate_trust_one.constprop.0+0x3b8/0x574
[ +0.000009] pkcs7_validate_trust+0xb8/0x15c
[ +0.000008] verify_pkcs7_message_sig+0xec/0x1b0
[ +0.000012] verify_pkcs7_signature+0x78/0xac
[ +0.000007] mod_verify_sig+0x110/0x190
[ +0.000009] module_sig_check+0x114/0x1e0
[ +0.000009] load_module+0xa0/0x1ea4
[ +0.000008] __do_sys_init_module+0x184/0x1cc
[ +0.000008] __arm64_sys_init_module+0x78/0xb0
[ +0.000008] invoke_syscall+0x74/0x260
[ +0.000009] el0_svc_common.constprop.0+0x1a8/0x260
[ +0.000008] do_el0_svc+0x50/0x70
[ +0.000007] el0_svc+0x68/0x1a0
[ +0.000009] el0t_64_sync_handler+0x11c/0x150
[ +0.000009] el0t_64_sync+0x18c/0x190

[ +0.000013] Freed by task 2422:
[ +0.000008] kasan_save_stack+0x2c/0x5c
[ +0.000009] kasan_set_track+0x2c/0x40
[ +0.000007] kasan_set_free_info+0x28/0x50
[ +0.000009] ____kasan_slab_free+0x128/0x1d4
[ +0.000008] __kasan_slab_free+0x18/0x24
[ +0.000007] slab_free_freelist_hook+0x108/0x230
[ +0.000010] kfree+0x110/0x35c
[ +0.000008] release_nodes+0xf0/0x16c
[ +0.000009] devres_release_group+0x180/0x270
[ +0.000008] take_down_aggregate_device+0xcc/0x160
[ +0.000010] component_del+0x18c/0x360
[ +0.000009] meson_dw_hdmi_remove+0x28/0x40 [meson_dw_hdmi]
[ +0.000013] platform_remove+0x64/0xb0
[ +0.000008] device_remove+0xb8/0x154
[ +0.000009] device_release_driver_internal+0x398/0x5b0
[ +0.000009] driver_detach+0xac/0x1b0
[ +0.000009] bus_remove_driver+0x158/0x29c
[ +0.000008] driver_unregister+0x70/0xb0
[ +0.000009] platform_driver_unregister+0x20/0x2c
[ +0.000007] meson_dw_hdmi_platform_driver_exit+0x1c/0x30 [meson_dw_hdmi]
[ +0.000012] __do_sys_delete_module+0x288/0x400
[ +0.000009] __arm64_sys_delete_module+0x5c/0x80
[ +0.000009] invoke_syscall+0x74/0x260
[ +0.000008] el0_svc_common.constprop.0+0xcc/0x260
[ +0.000008] do_el0_svc+0x50/0x70
[ +0.000007] el0_svc+0x68/0x1a0
[ +0.000008] el0t_64_sync_handler+0x11c/0x150
[ +0.000009] el0t_64_sync+0x18c/0x190

[ +0.000013] The buggy address belongs to the object at ffff00003da29000
which belongs to the cache kmalloc-1k of size 1024
[ +0.000008] The buggy address is located 496 bytes inside of
1024-byte region [ffff00003da29000, ffff00003da29400)

[ +0.000015] The buggy address belongs to the physical page:
[ +0.000009] page:fffffc0000f68a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3da28
[ +0.000012] head:fffffc0000f68a00 order:3 compound_mapcount:0 compound_pincount:0
[ +0.000009] flags: 0xffff00000010200(slab|head|node=0|zone=0|lastcpupid=0xffff)
[ +0.000019] raw: 0ffff00000010200 fffffc0000eb5c08 fffffc0000d96608 ffff000000002a80
[ +0.000008] raw: 0000000000000000 00000000000a000a 00000001ffffffff 0000000000000000
[ +0.000008] page dumped because: kasan: bad access detected

[ +0.000011] Memory state around the buggy address:
[ +0.000009] ffff00003da29080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ +0.000007] ffff00003da29100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ +0.000007] >ffff00003da29180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ +0.000007] ^
[ +0.000008] ffff00003da29200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ +0.000006] ffff00003da29280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ +0.000007] ==================================================================

Fix by keeping track of which encoders were initialised in the meson_drm
structure and manually removing their bridges at aggregate driver's unbind
time.

Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220920222842.1053234-1-adrian.larumbe@collabora.com

drm/meson: encoder_cvbs: Fix refcount leak in meson_encoder_cvbs_init

of_graph_get_remote_node() returns remote device nodepointer with
refcount incremented, we should use of_node_put() on it when done.
Add missing of_node_put() to avoid refcount leak.

Fixes: 318ba02cd8a8 ("drm/meson: encoder_cvbs: switch to bridge with ATTACH_NO_CONNECTOR")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220601033927.47814-2-linmq006@gmail.com

drm/meson: encoder_cvbs: switch to bridge with ATTACH_NO_CONNECTOR

Drop the local connector and move all callback to bridge funcs in order
to leverage the generic CVBS display connector.

This will also permit adding custom cvbs connectors for ADC based HPD
detection on some Amlogic SoC based boards.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
[narmstrong: fixed diplay typo in commit log]
Link: https://patchwork.freedesktop.org/patch/msgid/20211020123947.2585572-7-narmstrong@baylibre.com

drm/meson: rename venc_cvbs to encoder_cvbs

Rename the cvbs encoder to match the newly introduced meson_encoder_hdmi.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211020123947.2585572-6-narmstrong@baylibre.com