aboutsummaryrefslogtreecommitdiffstats
AgeCommit message (Collapse)AuthorFilesLines
2022-04-06net/mlx5: Remove indirection in TLS buildLeon Romanovsky10-197/+84
The dream described in the commit 1ae173228489 ("net/mlx5: Accel, Add TLS tx offload interface") never came true, even an opposite happened when FPGA TLS support was dropped. Such removal revealed the problematic flow in the build process: build of unrelated files in case of TLS or IPsec are enabled. In both cases, the MLX5_ACCEL is enabled, which built both TLS and IPsec. As a solution, simply merge MLX5_TLS and MLX5_EN_TLS options and move TLS related files to the eth part of the mlx5_core. Link: https://lore.kernel.org/r/0d1ea8cdc3a15922640b8b764d2bdb8f587b52c2.1649073691.git.leonro@nvidia.com Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Reviewed-by: Saeed Mahameed <saeedm@nvidia.com> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
2022-04-06net/mlx5: Reliably return TLS device capabilitiesLeon Romanovsky1-2/+1
The capabilities returned from the FW are independent to the compiled kernel and traditionally rely on the relevant CAPs bit only. The mlx5_accel_is_ktls_*() functions are compiled out if CONFIG_MLX5_TLS is not set, which "hides" from the user the information that TLS can be enabled on this device. Link: https://lore.kernel.org/r/a333ce541fb9497d04126b11c4a0052f9807d141.1649073691.git.leonro@nvidia.com Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Reviewed-by: Saeed Mahameed <saeedm@nvidia.com> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
2022-04-06net/mlx5_fpga: Drop INNOVA TLS supportLeon Romanovsky16-1459/+10
Mellanox INNOVA TLS cards are EOL in May, 2018 [1]. As such, the code is unmaintained, untested and not in-use by any upstream/distro oriented customers. In order to reduce code complexity, drop the kernel code. [1] https://network.nvidia.com/related-docs/eol/LCR-000286.pdf Link: https://lore.kernel.org/r/b88add368def721ea9d054cb69def72d9e3f67aa.1649073691.git.leonro@nvidia.com Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Reviewed-by: Saeed Mahameed <saeedm@nvidia.com> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
2022-04-06wfx: get out from the staging areaJérôme Pouiller47-11/+26
The wfx driver is now mature enough to leave the staging area. Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com> Signed-off-by: Kalle Valo <kvalo@kernel.org>
2022-04-06ARM: dts: imx6qdl-victgo: add CAN termination supportDavid Jander1-10/+2
The gpio1 0 pin is controlling CAN termination, not USB H1 VBUS. So, remove wrong regulator and assign this gpio to new DT CAN termination property. Signed-off-by: David Jander <david@protonic.nl> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Signed-off-by: Shawn Guo <shawnguo@kernel.org>
2022-04-06ARM: dts: imx6dl-victgo: The TGO uses a lg,lb070wv8 compatible 7" displayRobin van der Gracht1-1/+1
This series of devices is using lg,lb070wv8 instead of kyo,tcg121xglp. Signed-off-by: Robin van der Gracht <robin@protonic.nl> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Signed-off-by: Shawn Guo <shawnguo@kernel.org>
2022-04-06ARM: dts: imx6dl-victgo: Add interrupt-counter nodesRobin van der Gracht1-1/+40
Interrupt counter is mainlined, now we can add missing counter nodes. Signed-off-by: Robin van der Gracht <robin@protonic.nl> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Signed-off-by: Shawn Guo <shawnguo@kernel.org>
2022-04-06ARM: dts: imx6qdl-vicut1: update gpio-line-names for some GPIOsDavid Jander1-5/+7
countedX lines have different board names (YACO_x). And REV_ and BOARD_ pins have multiple functions. So, use names exposed to the OS. Signed-off-by: David Jander <david@protonic.nl> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Signed-off-by: Shawn Guo <shawnguo@kernel.org>
2022-04-06ARM: dts: imx6qdl-vicut1/vicutgo: Add backlight_led nodeDavid Jander2-25/+32
backlight_led is the dimmable backlight for the rubber border on the case. It is also used to highlight the power- and some other buttons. MX6QDL_PAD_SD4_DAT1__PWM3_OUT is also assigned as output for pwm3. Since we need pwm3 for the backlight, we're forced to disable user space hardware revision detection. The bootloader will have to supply this information (i.e. through device tree). Signed-off-by: David Jander <david@protonic.nl> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Signed-off-by: Shawn Guo <shawnguo@kernel.org>
2022-04-06ARM: dts: imx6qdl-vicut1/vicutgo: Rename backlight to backlight_lcdDavid Jander2-4/+4
We have two backlight sources on this boards. Use more specific name for the LCD backlight to see the difference. Signed-off-by: David Jander <david@protonic.nl> Signed-off-by: Robin van der Gracht <robin@protonic.nl> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Signed-off-by: Shawn Guo <shawnguo@kernel.org>
2022-04-06ARM: dts: imx6qdl-vicut1/vicutgo: Set default backlight brightness to maximumDavid Jander2-2/+2
Recover default behavior of the device and set maximal brightness Signed-off-by: David Jander <david@protonic.nl> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Signed-off-by: Shawn Guo <shawnguo@kernel.org>
2022-04-06ata: ahci: Rename CONFIG_SATA_LPM_POLICY configuration item backMario Limonciello3-4/+6
CONFIG_SATA_LPM_MOBILE_POLICY was renamed to CONFIG_SATA_LPM_POLICY in commit 4dd4d3deb502 ("ata: ahci: Rename CONFIG_SATA_LPM_MOBILE_POLICY configuration item"). This can potentially cause problems as users would invisibly lose configuration policy defaults when they built the new kernel. To avoid such problems, switch back to the old name (even if it's wrong). Suggested-by: Christoph Hellwig <hch@infradead.org> Suggested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
2022-04-06arm64: dts: imx8mm: Add support for Data Modul i.MX8M Mini eDM SBCMarek Vasut2-0/+997
Add support for Data Modul i.MX8M Mini eDM SBC board. This is an evaluation board for various custom display units. Currently supported are serial console, ethernet, eMMC, SD, PCIe, SPI NOR, USB host and USB OTG. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Fabio Estevam <festevam@denx.de> Cc: Peng Fan <peng.fan@nxp.com> Cc: Shawn Guo <shawnguo@kernel.org> Cc: NXP Linux Team <linux-imx@nxp.com> To: linux-arm-kernel@lists.infradead.org Reviewed-by: Peng Fan <peng.fan@nxp.com> Signed-off-by: Shawn Guo <shawnguo@kernel.org>
2022-04-05net: ethernet: mv643xx: Fix over zealous checking of_get_mac_address()Andrew Lunn1-1/+1
There is often not a MAC address available in an EEPROM accessible by Linux with Marvell devices. Instead the bootload has the MAC address and directly programs it into the hardware. So don't consider an error from of_get_mac_address() has fatal. However, the check was added for the case where there is a MAC address in an the EEPROM, but the EEPROM has not probed yet, and -EPROBE_DEFER is returned. In that case the error should be returned. So make the check specific to this error code. Cc: Mauri Sandberg <maukka@ext.kapsi.fi> Reported-by: Thomas Walther <walther-it@gmx.de> Fixes: 42404d8f1c01 ("net: mv643xx_eth: process retval from of_get_mac_address") Signed-off-by: Andrew Lunn <andrew@lunn.ch> Link: https://lore.kernel.org/r/20220405000404.3374734-1-andrew@lunn.ch Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-06arm64: dts: imx8mn-bsh-smm-s2pro: Add tlv320aic31xx audio card nodeAriel D'Alessandro1-0/+90
BSH SystemMaster (SMM) S2 PRO board comes with an audio card based on tlv320aic31xx family codec. The audio card exposes two playback devices, one of them using the EASRC (Enhanced Asynchronous Sample Rate Converter) module. Note that this would require SDMA and EASRC firmware in order to work. Signed-off-by: Ariel D'Alessandro <ariel.dalessandro@collabora.com> Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com> Reviewed-by: Fabio Estevam <festevam@gmail.com> Signed-off-by: Shawn Guo <shawnguo@kernel.org>
2022-04-05net: openvswitch: don't send internal clone attribute to the userspace.Ilya Maximets2-2/+4
'OVS_CLONE_ATTR_EXEC' is an internal attribute that is used for performance optimization inside the kernel. It's added by the kernel while parsing user-provided actions and should not be sent during the flow dump as it's not part of the uAPI. The issue doesn't cause any significant problems to the ovs-vswitchd process, because reported actions are not really used in the application lifecycle and only supposed to be shown to a human via ovs-dpctl flow dump. However, the action list is still incorrect and causes the following error if the user wants to look at the datapath flows: # ovs-dpctl add-dp system@ovs-system # ovs-dpctl add-flow "<flow match>" "clone(ct(commit),0)" # ovs-dpctl dump-flows <flow match>, packets:0, bytes:0, used:never, actions:clone(bad length 4, expected -1 for: action0(01 00 00 00), ct(commit),0) With the fix: # ovs-dpctl dump-flows <flow match>, packets:0, bytes:0, used:never, actions:clone(ct(commit),0) Additionally fixed an incorrect attribute name in the comment. Fixes: b233504033db ("openvswitch: kernel datapath clone action") Signed-off-by: Ilya Maximets <i.maximets@ovn.org> Acked-by: Aaron Conole <aconole@redhat.com> Link: https://lore.kernel.org/r/20220404104150.2865736-1-i.maximets@ovn.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-05net: micrel: Fix KS8851 KconfigHoratiu Vultur1-0/+1
KS8851 selects MICREL_PHY, which depends on PTP_1588_CLOCK_OPTIONAL, so make KS8851 also depend on PTP_1588_CLOCK_OPTIONAL. Fixes kconfig warning and build errors: WARNING: unmet direct dependencies detected for MICREL_PHY Depends on [m]: NETDEVICES [=y] && PHYLIB [=y] && PTP_1588_CLOCK_OPTIONAL [=m] Selected by [y]: - KS8851 [=y] && NETDEVICES [=y] && ETHERNET [=y] && NET_VENDOR_MICREL [=y] && SPI [=y] ld.lld: error: undefined symbol: ptp_clock_register referenced by micrel.c net/phy/micrel.o:(lan8814_probe) in archive drivers/built-in.a ld.lld: error: undefined symbol: ptp_clock_index referenced by micrel.c net/phy/micrel.o:(lan8814_ts_info) in archive drivers/built-in.a Reported-by: kernel test robot <lkp@intel.com> Fixes: ece19502834d ("net: phy: micrel: 1588 support for LAN8814 phy") Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com> Tested-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/r/20220405065936.4105272-1-horatiu.vultur@microchip.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-06media: platform: imx-mipi-csis: Add dependency on VIDEO_DEVLaurent Pinchart1-0/+1
The imx-mipi-csis driver (VIDEO_IMX_MIPI_CSIS) lost its dependency on VIDEO_DEV in commit 63fe3d27b226 ("media: platform/*/Kconfig: make manufacturer menus more uniform"). This causes build failures with configurations that don't have VIDEO_DEV set. Fix it by restoring the dependency. Link: https://lore.kernel.org/linux-media/20220331123151.1953-1-laurent.pinchart@ideasonboard.com Fixes: 63fe3d27b226 ("media: platform/*/Kconfig: make manufacturer menus more uniform") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
2022-04-05selftests/bpf: Fix file descriptor leak in load_kallsyms()Yuntao Wang1-4/+5
Currently, if sym_cnt > 0, it just returns and does not close file, fix it. Signed-off-by: Yuntao Wang <ytcoode@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220405145711.49543-1-ytcoode@gmail.com
2022-04-06drm/mediatek: Fix DPI component detection for MT8192Chen-Yu Tsai1-0/+2
When support for MT8192 was added, the DPI device was not added to the list of components to look for. This causes the secondary display pipeline to not be able to fully bind, and the DRM driver subsequently defers probing. Add the DPI device compatible to list of DPI components to fix this. Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20220225032754.140168-1-wenst@chromium.org/ Fixes: 01365f549c88 ("drm/mediatek: Add support for Mediatek SoC MT8192") Signed-off-by: Chen-Yu Tsai <wenst@chromium.org> Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
2022-04-06drm: bridge: icn6211: Fix DSI-to-DPI PLL configurationMarek Vasut1-20/+27
The datasheet for this bridge is not available, the PLL behavior has been inferred from [1] and [2] and by analyzing the DPI pixel clock with scope. After further testing with other displays and different DSI data lane count, it turns out the P-factor is not 1/2^N divider, but rather only 1/N divider. It also turns out the input into the PLL seem to be ByteClock instead of DSI HS clock. Rework the P-factor calculation such that the PLL calculation code handles P-factor from 1..32 with P-factors above 16 must be even. In case P-factor is even, enable built-in 1:2 divider and program P-factor/2 to PLL_REF_DIV, otherwise configure only the P-factor into PLL_REF_DIV register. Switch the PLL factor calculation from kHz to Hz to maintain precision. [1] https://github.com/rockchip-linux/kernel/blob/develop-4.19/drivers/gpu/drm/bridge/icn6211.c [2] https://github.com/tdjastrzebski/ICN6211-Configurator Fixes: f30cf0ece691 ("drm: bridge: icn6211: Add generic DSI-to-DPI PLL configuration") Signed-off-by: Marek Vasut <marex@denx.de> Cc: Jagan Teki <jagan@amarulasolutions.com> Cc: Maxime Ripard <maxime@cerno.tech> Cc: Robert Foss <robert.foss@linaro.org> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Thomas Zimmermann <tzimmermann@suse.de> To: dri-devel@lists.freedesktop.org Acked-by: Maxime Ripard <maxime@cerno.tech> Link: https://patchwork.freedesktop.org/patch/msgid/20220402004118.897014-1-marex@denx.de
2022-04-06drm/mediatek: Add vblank register/unregister callback functionsRex-BC Chen6-25/+80
We encountered a kernel panic issue that callback data will be NULL when it's using in ovl irq handler. There is a timing issue between mtk_disp_ovl_irq_handler() and mtk_ovl_disable_vblank(). To resolve this issue, we use the flow to register/unregister vblank cb: - Register callback function and callback data when crtc creates. - Unregister callback function and callback data when crtc destroies. With this solution, we can assure callback data will not be NULL when vblank is disable. Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20220321072320.15019-1-rex-bc.chen@mediatek.com/ Fixes: 9b0704988b15 ("drm/mediatek: Register vblank callback function") Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com> Reviewed-by: jason-jh.lin <jason-jh.lin@mediatek.com> Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
2022-04-06ARM: config: Refresh U8500 defconfigLinus Walleij1-4/+6
This just updates the U8500 defconfig to reflect what has happened in the Kconfig: DRM_PANEL_SONY_ACX424AKP is now handled by DRM_PANEL_NOVATEK_NT35560, all ST sensors have SPI version drivers that we don't use, and some debug options moved around. Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2022-04-06btrfs: fix btrfs_submit_compressed_write cgroup attributionDennis Zhou1-0/+8
This restores the logic from commit 46bcff2bfc5e ("btrfs: fix compressed write bio blkcg attribution") which added cgroup attribution to btrfs writeback. It also adds back the REQ_CGROUP_PUNT flag for these ios. Fixes: 91507240482e ("btrfs: determine stripe boundary at bio allocation time in btrfs_submit_compressed_write") CC: stable@vger.kernel.org # 5.16+ Signed-off-by: Dennis Zhou <dennis@kernel.org> Signed-off-by: David Sterba <dsterba@suse.com>
2022-04-06btrfs: fix root ref counts in error handling in btrfs_get_root_refJia-Ju Bai1-2/+3
In btrfs_get_root_ref(), when btrfs_insert_fs_root() fails, btrfs_put_root() can happen for two reasons: - the root already exists in the tree, in that case it returns the reference obtained in btrfs_lookup_fs_root() - another error so the cleanup is done in the fail label Calling btrfs_put_root() unconditionally would lead to double decrement of the root reference possibly freeing it in the second case. Reported-by: TOTE Robot <oslab@tsinghua.edu.cn> Fixes: bc44d7c4b2b1 ("btrfs: push btrfs_grab_fs_root into btrfs_get_fs_root") CC: stable@vger.kernel.org # 5.10+ Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2022-04-06ARM: dts: ux500: Add GPS to Skomer device treeLinus Walleij1-1/+30
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2022-04-06btrfs: zoned: activate block group only for extent allocationNaohiro Aota3-9/+21
In btrfs_make_block_group(), we activate the allocated block group, expecting that the block group is soon used for allocation. However, the chunk allocation from flush_space() context broke the assumption. There can be a large time gap between the chunk allocation time and the extent allocation time from the chunk. Activating the empty block groups pre-allocated from flush_space() context can exhaust the active zone counter of a device. Once we use all the active zone counts for empty pre-allocated block groups, we cannot activate new block group for the other things: metadata, tree-log, or data relocation block group. That failure results in a fake -ENOSPC. This patch introduces CHUNK_ALLOC_FORCE_FOR_EXTENT to distinguish the chunk allocation from find_free_extent(). Now, the new block group is activated only in that context. Fixes: eb66a010d518 ("btrfs: zoned: activate new block group") CC: stable@vger.kernel.org # 5.16+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2022-04-06btrfs: return allocated block group from do_chunk_alloc()Naohiro Aota1-3/+13
Return the allocated block group from do_chunk_alloc(). This is a preparation patch for the next patch. CC: stable@vger.kernel.org # 5.16+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2022-04-06btrfs: mark resumed async balance as writingNaohiro Aota1-0/+2
When btrfs balance is interrupted with umount, the background balance resumes on the next mount. There is a potential deadlock with FS freezing here like as described in commit 26559780b953 ("btrfs: zoned: mark relocation as writing"). Mark the process as sb_writing to avoid it. Reviewed-by: Filipe Manana <fdmanana@suse.com> CC: stable@vger.kernel.org # 4.9+ Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2022-04-06ARM: dts: ux500: Add GPS to Janice device treeLinus Walleij1-1/+39
This adds the CSR GSD4t GPS to the Janice device tree. Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2022-04-06btrfs: remove support of balance v1 ioctlNikolay Borisov1-2/+0
It was scheduled for removal in kernel v5.18 commit 6c405b24097c ("btrfs: deprecate BTRFS_IOC_BALANCE ioctl") thus its time has come. Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2022-04-06btrfs: release correct delalloc amount in direct IO write pathNaohiro Aota1-3/+3
Running generic/406 causes the following WARNING in btrfs_destroy_inode() which tells there are outstanding extents left. In btrfs_get_blocks_direct_write(), we reserve a temporary outstanding extents with btrfs_delalloc_reserve_metadata() (or indirectly from btrfs_delalloc_reserve_space(()). We then release the outstanding extents with btrfs_delalloc_release_extents(). However, the "len" can be modified in the COW case, which releases fewer outstanding extents than expected. Fix it by calling btrfs_delalloc_release_extents() for the original length. To reproduce the warning, the filesystem should be 1 GiB. It's triggering a short-write, due to not being able to allocate a large extent and instead allocating a smaller one. WARNING: CPU: 0 PID: 757 at fs/btrfs/inode.c:8848 btrfs_destroy_inode+0x1e6/0x210 [btrfs] Modules linked in: btrfs blake2b_generic xor lzo_compress lzo_decompress raid6_pq zstd zstd_decompress zstd_compress xxhash zram zsmalloc CPU: 0 PID: 757 Comm: umount Not tainted 5.17.0-rc8+ #101 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS d55cb5a 04/01/2014 RIP: 0010:btrfs_destroy_inode+0x1e6/0x210 [btrfs] RSP: 0018:ffffc9000327bda8 EFLAGS: 00010206 RAX: 0000000000000000 RBX: ffff888100548b78 RCX: 0000000000000000 RDX: 0000000000026900 RSI: 0000000000000000 RDI: ffff888100548b78 RBP: ffff888100548940 R08: 0000000000000000 R09: ffff88810b48aba8 R10: 0000000000000001 R11: ffff8881004eb240 R12: ffff88810b48a800 R13: ffff88810b48ec08 R14: ffff88810b48ed00 R15: ffff888100490c68 FS: 00007f8549ea0b80(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f854a09e733 CR3: 000000010a2e9003 CR4: 0000000000370eb0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> destroy_inode+0x33/0x70 dispose_list+0x43/0x60 evict_inodes+0x161/0x1b0 generic_shutdown_super+0x2d/0x110 kill_anon_super+0xf/0x20 btrfs_kill_super+0xd/0x20 [btrfs] deactivate_locked_super+0x27/0x90 cleanup_mnt+0x12c/0x180 task_work_run+0x54/0x80 exit_to_user_mode_prepare+0x152/0x160 syscall_exit_to_user_mode+0x12/0x30 do_syscall_64+0x42/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f854a000fb7 Fixes: f0bfa76a11e9 ("btrfs: fix ENOSPC failure when attempting direct IO write into NOCOW range") CC: stable@vger.kernel.org # 5.17 Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2022-04-06btrfs: remove unused variable in btrfs_{start,write}_dirty_block_groups()Nathan Chancellor1-4/+0
Clang's version of -Wunused-but-set-variable recently gained support for unary operations, which reveals two unused variables: fs/btrfs/block-group.c:2949:6: error: variable 'num_started' set but not used [-Werror,-Wunused-but-set-variable] int num_started = 0; ^ fs/btrfs/block-group.c:3116:6: error: variable 'num_started' set but not used [-Werror,-Wunused-but-set-variable] int num_started = 0; ^ 2 errors generated. These variables appear to be unused from their introduction, so just remove them to silence the warnings. Fixes: c9dc4c657850 ("Btrfs: two stage dirty block group writeout") Fixes: 1bbc621ef284 ("Btrfs: allow block group cache writeout outside critical section in commit") CC: stable@vger.kernel.org # 5.4+ Link: https://github.com/ClangBuiltLinux/linux/issues/1614 Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: David Sterba <dsterba@suse.com>
2022-04-06btrfs: zoned: remove redundant condition in btrfs_run_delalloc_rangeHaowen Bai1-2/+1
The logic !A || A && B is equivalent to !A || B. so we can make code clear. Note: though it's preferred to be in the more human readable form, there have been repeated reports and patches as the expression is detected by tools so apply it to reduce the load. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Haowen Bai <baihaowen@meizu.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add note ] Signed-off-by: David Sterba <dsterba@suse.com>
2022-04-06drm/mediatek: mtk_drm_crtc: Use kmalloc in mtk_drm_crtc_duplicate_stateAngeloGioacchino Del Regno1-1/+2
Optimize mtk_drm_crtc_duplicate_state() by switching from kzalloc() to kmalloc(): the only variable of this struct that gets checked in other functions is `pending_config`, but if that's set to false, then all of the remaining variables will only ever be set, but not read - so, also set `pending_config` to false. This saves us some small overhead. Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20220118133759.112458-2-angelogioacchino.delregno@collabora.com/ Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
2022-04-06drm/mediatek: mtk_drm_plane: Use kmalloc in mtk_plane_duplicate_stateAngeloGioacchino Del Regno1-1/+1
There is no need to zero out the newly allocated memory because we are duplicating all members of struct mtk_plane_state: switch to kmalloc to save some overhead. Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20220118133759.112458-1-angelogioacchino.delregno@collabora.com/ Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
2022-04-06bpf, arm64: Sign return address for JITed codeXu Kuohai2-2/+13
Sign return address for JITed code when the kernel is built with pointer authentication enabled: 1. Sign LR with paciasp instruction before LR is pushed to stack. Since paciasp acts like landing pads for function entry, no need to insert bti instruction before paciasp. 2. Authenticate LR with autiasp instruction after LR is popped from stack. For BPF tail call, the stack frame constructed by the caller is reused by the callee. That is, the stack frame is constructed by the caller and destructed by the callee. Thus LR is signed and pushed to the stack in the caller's prologue, and poped from the stack and authenticated in the callee's epilogue. For BPF2BPF call, the caller and callee construct their own stack frames, and sign and authenticate their own LRs. Signed-off-by: Xu Kuohai <xukuohai@huawei.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://events.static.linuxfound.org/sites/events/files/slides/slides_23.pdf Link: https://lore.kernel.org/bpf/20220402073942.3782529-1-xukuohai@huawei.com
2022-04-05net: ensure net_todo_list is processed quicklyJohannes Berg3-2/+36
In [1], Will raised a potential issue that the cfg80211 code, which does (from a locking perspective) rtnl_lock() wiphy_lock() rtnl_unlock() might be suspectible to ABBA deadlocks, because rtnl_unlock() calls netdev_run_todo(), which might end up calling rtnl_lock() again, which could then deadlock (see the comment in the code added here for the scenario). Some back and forth and thinking ensued, but clearly this can't happen if the net_todo_list is empty at the rtnl_unlock() here. Clearly, the code here cannot actually put an entry on it, and all other users of rtnl_unlock() will empty it since that will always go through netdev_run_todo(), emptying the list. So the only other way to get there would be to add to the list and then unlock the RTNL without going through rtnl_unlock(), which is only possible through __rtnl_unlock(). However, this isn't exported and not used in many places, and none of them seem to be able to unregister before using it. Therefore, add a WARN_ON() in the code to ensure this invariant won't be broken, so that the cfg80211 (or any similar) code stays safe. [1] https://lore.kernel.org/r/Yjzpo3TfZxtKPMAG@google.com Signed-off-by: Johannes Berg <johannes.berg@intel.com> Link: https://lore.kernel.org/r/20220404113847.0ee02e4a70da.Ic73d206e217db20fd22dcec14fe5442ca732804b@changeid Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-05drm/panel: innolux-ej030na and abt-y030xx067a: add .enable and .disableChristophe Branchereau2-7/+54
Following the introduction of bridge_atomic_enable in the ingenic drm driver, the crtc is enabled between .prepare and .enable, if it exists. Add it so the backlight is only enabled after the crtc is, to avoid graphical issues. As we're moving the "sleep out" command out of the init sequence into .enable for the ABT, we need to switch the regmap cache to REGCACHE_FLAT to be able to use regmap_set_bits, given this panel registers are write-ony and read as 0. Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com> Signed-off-by: Paul Cercueil <paul@crapouillou.net> [pcercuei: Remove empty line after opening brace] Acked-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20220321133651.291592-4-cbranchereau@gmail.com
2022-04-05drm/panel: Add panel driver for NewVision NV3052C based LCDsChristophe Branchereau3-0/+494
This driver supports the NewVision NV3052C based LCDs. Right now, it only supports the LeadTek LTK035C5444T 2.4" 640x480 TFT LCD panel, which can be found in the Anbernic RG-350M handheld console. Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com> Signed-off-by: Paul Cercueil <paul@crapouillou.net> [pcercuei: Change msleep(5) to usleep_range(5000, 20000)] Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20220321133651.291592-3-cbranchereau@gmail.com
2022-04-05drm/ingenic: Add ingenic_drm_bridge_atomic_enable and disableChristophe Branchereau1-11/+23
ingenic_drm_bridge_atomic_enable allows the CRTC to be enabled after panels have slept out, and before their display is turned on, solving a graphical bug on the newvision nv3502c. Also add ingenic_drm_bridge_atomic_disable to balance it out. Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com> Signed-off-by: Paul Cercueil <paul@crapouillou.net> Acked-by: Artur Rojek <contact@artur-rojek.eu> Link: https://patchwork.freedesktop.org/patch/msgid/20220321133651.291592-2-cbranchereau@gmail.com
2022-04-05mlxsw: spectrum_router: simplify list unwindingTom Rix1-12/+8
The setting of i here err_nexthop6_group_get: i = nrt6; Is redundant, i is already nrt6. So remove this statement. The for loop for the unwinding err_rt6_create: for (i--; i >= 0; i--) { Is equivelent to for (; i > 0; i--) { Two consecutive labels can be reduced to one. Signed-off-by: Tom Rix <trix@redhat.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Link: https://lore.kernel.org/r/20220402121516.2750284-1-trix@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-05Merge branch 'Add libbpf support for USDTs'Alexei Starovoitov19-25/+2938
Andrii Nakryiko says: ==================== Add libbpf support for USDT (User Statically-Defined Tracing) probes. USDTs is important part of tracing, and BPF, ecosystem, widely used in mission-critical production applications for observability, performance analysis, and debugging. And while USDTs themselves are pretty complicated abstraction built on top of uprobes, for end-users USDT is as natural a primitive as uprobes themselves. And thus it's important for libbpf to provide best possible user experience when it comes to build tracing applications relying on USDTs. USDTs historically presented a lot of challenges for libbpf's no compilation-on-the-fly general approach to BPF tracing. BCC utilizes power of on-the-fly source code generation and compilation using its embedded Clang toolchain, which was impractical for more lightweight and thus more rigid libbpf-based approach. But still, with enough diligence and BPF cookies it's possible to implement USDT support that feels as natural as tracing any uprobe. This patch set is the culmination of such effort to add libbpf USDT support following the spirit and philosophy of BPF CO-RE (even though it's not inherently relying on BPF CO-RE much, see patch #1 for some notes regarding this). Each respective patch has enough details and explanations, so I won't go into details here. In the end, I think the overall usability of libbpf's USDT support *exceeds* the status quo set by BCC due to the elimination of awkward runtime USDT supporting code generation. It also exceeds BCC's capabilities due to the use of BPF cookie. This eliminates the need to determine a USDT call site (and thus specifics about how exactly to fetch arguments) based on its *absolute IP address*, which is impossible with shared libraries if no PID is specified (as we then just *can't* know absolute IP at which shared library is loaded, because it might be different for each process). With BPF cookie this is not a problem as we record "call site ID" directly in a BPF cookie value. This makes it possible to do a system-wide tracing of a USDT defined in a shared library. Think about tracing some USDT in libc across any process in the system, both running at the time of attachment and all the new processes started *afterwards*. This is a very powerful capability that allows more efficient observability and tracing tooling. Once this functionality lands, the plan is to extend libbpf-bootstrap ([0]) with an USDT example. It will also become possible to start converting BCC tools that rely on USDTs to their libbpf-based counterparts ([1]). It's worth noting that preliminary version of this code was currently used and tested in production code running fleet-wide observability toolkit. Libbpf functionality is broken down into 5 mostly logically independent parts, for ease of reviewing: - patch #1 adds BPF-side implementation; - patch #2 adds user-space APIs and wires bpf_link for USDTs; - patch #3 adds the most mundate pieces: handling ELF, parsing USDT notes, dealing with memory segments, relative vs absolute addresses, etc; - patch #4 adds internal ID allocation and setting up/tearing down of BPF-side state (spec and IP-to-ID mapping); - patch #5 implements x86/x86-64-specific logic of parsing USDT argument specifications; - patch #6 adds testing of various basic aspects of handling of USDT; - patch #7 extends the set of tests with more combinations of semaphore, executable vs shared library, and PID filter options. [0] https://github.com/libbpf/libbpf-bootstrap [1] https://github.com/iovisor/bcc/tree/master/libbpf-tools v2->v3: - fix typos, leave link to systemtap doc, acks, etc (Dave); - include sys/sdt.h to avoid extra system-wide package dependencies; v1->v2: - huge high-level comment describing how all the moving parts fit together (Alan, Alexei); - switched from `__hidden __weak` to `static inline __noinline` for now, as there is a bug in BPF linker breaking final BPF object file due to invalid .BTF.ext data; I want to fix it separately at which point I'll switch back to __hidden __weak again. The fix isn't trivial, so I don't want to block on that. Same for __weak variable lookup bug that Henqi reported. - various fixes and improvements, addressing other feedback (Alan, Hengqi); Cc: Alan Maguire <alan.maguire@oracle.com> Cc: Dave Marchevsky <davemarchevsky@fb.com> Cc: Hengqi Chen <hengqi.chen@gmail.com> ==================== Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-04-05selftests/bpf: Add urandom_read shared lib and USDTsAndrii Nakryiko8-9/+275
Extend urandom_read helper binary to include USDTs of 4 combinations: semaphore/semaphoreless (refcounted and non-refcounted) and based in executable or shared library. We also extend urandom_read with ability to report it's own PID to parent process and wait for parent process to ready itself up for tracing urandom_read. We utilize popen() and underlying pipe properties for proper signaling. Once urandom_read is ready, we add few tests to validate that libbpf's USDT attachment handles all the above combinations of semaphore (or lack of it) and static or shared library USDTs. Also, we validate that libbpf handles shared libraries both with PID filter and without one (i.e., -1 for PID argument). Having the shared library case tested with and without PID is important because internal logic differs on kernels that don't support BPF cookies. On such older kernels, attaching to USDTs in shared libraries without specifying concrete PID doesn't work in principle, because it's impossible to determine shared library's load address to derive absolute IPs for uprobe attachments. Without absolute IPs, it's impossible to perform correct look up of USDT spec based on uprobe's absolute IP (the only kind available from BPF at runtime). This is not the problem on newer kernels with BPF cookie as we don't need IP-to-ID lookup because BPF cookie value *is* spec ID. So having those two situations as separate subtests is good because libbpf CI is able to test latest selftests against old kernels (e.g., 4.9 and 5.5), so we'll be able to disable PID-less shared lib attachment for old kernels, but will still leave PID-specific one enabled to validate this legacy logic is working correctly. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Dave Marchevsky <davemarchevsky@fb.com> Link: https://lore.kernel.org/bpf/20220404234202.331384-8-andrii@kernel.org
2022-04-05selftests/bpf: Add basic USDT selftestsAndrii Nakryiko6-6/+970
Add semaphore-based USDT to test_progs itself and write basic tests to valicate both auto-attachment and manual attachment logic, as well as BPF-side functionality. Also add subtests to validate that libbpf properly deduplicates USDT specs and handles spec overflow situations correctly, as well as proper "rollback" of partially-attached multi-spec USDT. BPF-side of selftest intentionally consists of two files to validate that usdt.bpf.h header can be included from multiple source code files that are subsequently linked into final BPF object file without causing any symbol duplication or other issues. We are validating that __weak maps and bpf_usdt_xxx() API functions defined in usdt.bpf.h do work as intended. USDT selftests utilize sys/sdt.h header that on Ubuntu systems comes from systemtap-sdt-devel package. But to simplify everyone's life, including CI but especially casual contributors to bpf/bpf-next that are trying to build selftests, I've checked in sys/sdt.h header from [0] directly. This way it will work on all architectures and distros without having to figure it out for every relevant combination and adding any extra implicit package dependencies. [0] https://sourceware.org/git?p=systemtap.git;a=blob_plain;f=includes/sys/sdt.h;h=ca0162b4dc57520b96638c8ae79ad547eb1dd3a1;hb=HEAD Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Acked-by: Dave Marchevsky <davemarchevsky@fb.com> Link: https://lore.kernel.org/bpf/20220404234202.331384-7-andrii@kernel.org
2022-04-05libbpf: Add x86-specific USDT arg spec parsing logicAndrii Nakryiko1-0/+105
Add x86/x86_64-specific USDT argument specification parsing. Each architecture will require their own logic, as all this is arch-specific assembly-based notation. Architectures that libbpf doesn't support for USDTs will pr_warn() with specific error and return -ENOTSUP. We use sscanf() as a very powerful and easy to use string parser. Those spaces in sscanf's format string mean "skip any whitespaces", which is pretty nifty (and somewhat little known) feature. All this was tested on little-endian architecture, so bit shifts are probably off on big-endian, which our CI will hopefully prove. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Reviewed-by: Dave Marchevsky <davemarchevsky@fb.com> Link: https://lore.kernel.org/bpf/20220404234202.331384-6-andrii@kernel.org
2022-04-05libbpf: Wire up spec management and other arch-independent USDT logicAndrii Nakryiko1-1/+167
Last part of architecture-agnostic user-space USDT handling logic is to set up BPF spec and, optionally, IP-to-ID maps from user-space. usdt_manager performs a compact spec ID allocation to utilize fixed-sized BPF maps as efficiently as possible. We also use hashmap to deduplicate USDT arg spec strings and map identical strings to single USDT spec, minimizing the necessary BPF map size. usdt_manager supports arbitrary sequences of attachment and detachment, both of the same USDT and multiple different USDTs and internally maintains a free list of unused spec IDs. bpf_link_usdt's logic is extended with proper setup and teardown of this spec ID free list and supporting BPF maps. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Reviewed-by: Dave Marchevsky <davemarchevsky@fb.com> Link: https://lore.kernel.org/bpf/20220404234202.331384-5-andrii@kernel.org
2022-04-05libbpf: Add USDT notes parsing and resolution logicAndrii Nakryiko1-1/+581
Implement architecture-agnostic parts of USDT parsing logic. The code is the documentation in this case, it's futile to try to succinctly describe how USDT parsing is done in any sort of concreteness. But still, USDTs are recorded in special ELF notes section (.note.stapsdt), where each USDT call site is described separately. Along with USDT provider and USDT name, each such note contains USDT argument specification, which uses assembly-like syntax to describe how to fetch value of USDT argument. USDT arg spec could be just a constant, or a register, or a register dereference (most common cases in x86_64), but it technically can be much more complicated cases, like offset relative to global symbol and stuff like that. One of the later patches will implement most common subset of this for x86 and x86-64 architectures, which seems to handle a lot of real-world production application. USDT arg spec contains a compact encoding allowing usdt.bpf.h from previous patch to handle the above 3 cases. Instead of recording which register might be needed, we encode register's offset within struct pt_regs to simplify BPF-side implementation. USDT argument can be of different byte sizes (1, 2, 4, and 8) and signed or unsigned. To handle this, libbpf pre-calculates necessary bit shifts to do proper casting and sign-extension in a short sequences of left and right shifts. The rest is in the code with sometimes extensive comments and references to external "documentation" for USDTs. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Reviewed-by: Dave Marchevsky <davemarchevsky@fb.com> Link: https://lore.kernel.org/bpf/20220404234202.331384-4-andrii@kernel.org
2022-04-05libbpf: Wire up USDT API and bpf_link integrationAndrii Nakryiko6-11/+587
Wire up libbpf USDT support APIs without yet implementing all the nitty-gritty details of USDT discovery, spec parsing, and BPF map initialization. User-visible user-space API is simple and is conceptually very similar to uprobe API. bpf_program__attach_usdt() API allows to programmatically attach given BPF program to a USDT, specified through binary path (executable or shared lib), USDT provider and name. Also, just like in uprobe case, PID filter is specified (0 - self, -1 - any process, or specific PID). Optionally, USDT cookie value can be specified. Such single API invocation will try to discover given USDT in specified binary and will use (potentially many) BPF uprobes to attach this program in correct locations. Just like any bpf_program__attach_xxx() APIs, bpf_link is returned that represents this attachment. It is a virtual BPF link that doesn't have direct kernel object, as it can consist of multiple underlying BPF uprobe links. As such, attachment is not atomic operation and there can be brief moment when some USDT call sites are attached while others are still in the process of attaching. This should be taken into consideration by user. But bpf_program__attach_usdt() guarantees that in the case of success all USDT call sites are successfully attached, or all the successfuly attachments will be detached as soon as some USDT call sites failed to be attached. So, in theory, there could be cases of failed bpf_program__attach_usdt() call which did trigger few USDT program invocations. This is unavoidable due to multi-uprobe nature of USDT and has to be handled by user, if it's important to create an illusion of atomicity. USDT BPF programs themselves are marked in BPF source code as either SEC("usdt"), in which case they won't be auto-attached through skeleton's <skel>__attach() method, or it can have a full definition, which follows the spirit of fully-specified uprobes: SEC("usdt/<path>:<provider>:<name>"). In the latter case skeleton's attach method will attempt auto-attachment. Similarly, generic bpf_program__attach() will have enought information to go off of for parameterless attachment. USDT BPF programs are actually uprobes, and as such for kernel they are marked as BPF_PROG_TYPE_KPROBE. Another part of this patch is USDT-related feature probing: - BPF cookie support detection from user-space; - detection of kernel support for auto-refcounting of USDT semaphore. The latter is optional. If kernel doesn't support such feature and USDT doesn't rely on USDT semaphores, no error is returned. But if libbpf detects that USDT requires setting semaphores and kernel doesn't support this, libbpf errors out with explicit pr_warn() message. Libbpf doesn't support poking process's memory directly to increment semaphore value, like BCC does on legacy kernels, due to inherent raciness and danger of such process memory manipulation. Libbpf let's kernel take care of this properly or gives up. Logistically, all the extra USDT-related infrastructure of libbpf is put into a separate usdt.c file and abstracted behind struct usdt_manager. Each bpf_object has lazily-initialized usdt_manager pointer, which is only instantiated if USDT programs are attempted to be attached. Closing BPF object frees up usdt_manager resources. usdt_manager keeps track of USDT spec ID assignment and few other small things. Subsequent patches will fill out remaining missing pieces of USDT initialization and setup logic. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/bpf/20220404234202.331384-3-andrii@kernel.org
2022-04-05libbpf: Add BPF-side of USDT supportAndrii Nakryiko2-1/+257
Add BPF-side implementation of libbpf-provided USDT support. This consists of single header library, usdt.bpf.h, which is meant to be used from user's BPF-side source code. This header is added to the list of installed libbpf header, along bpf_helpers.h and others. BPF-side implementation consists of two BPF maps: - spec map, which contains "a USDT spec" which encodes information necessary to be able to fetch USDT arguments and other information (argument count, user-provided cookie value, etc) at runtime; - IP-to-spec-ID map, which is only used on kernels that don't support BPF cookie feature. It allows to lookup spec ID based on the place in user application that triggers USDT program. These maps have default sizes, 256 and 1024, which are chosen conservatively to not waste a lot of space, but handling a lot of common cases. But there could be cases when user application needs to either trace a lot of different USDTs, or USDTs are heavily inlined and their arguments are located in a lot of differing locations. For such cases it might be necessary to size those maps up, which libbpf allows to do by overriding BPF_USDT_MAX_SPEC_CNT and BPF_USDT_MAX_IP_CNT macros. It is an important aspect to keep in mind. Single USDT (user-space equivalent of kernel tracepoint) can have multiple USDT "call sites". That is, single logical USDT is triggered from multiple places in user application. This can happen due to function inlining. Each such inlined instance of USDT invocation can have its own unique USDT argument specification (instructions about the location of the value of each of USDT arguments). So while USDT looks very similar to usual uprobe or kernel tracepoint, under the hood it's actually a collection of uprobes, each potentially needing different spec to know how to fetch arguments. User-visible API consists of three helper functions: - bpf_usdt_arg_cnt(), which returns number of arguments of current USDT; - bpf_usdt_arg(), which reads value of specified USDT argument (by it's zero-indexed position) and returns it as 64-bit value; - bpf_usdt_cookie(), which functions like BPF cookie for USDT programs; this is necessary as libbpf doesn't allow specifying actual BPF cookie and utilizes it internally for USDT support implementation. Each bpf_usdt_xxx() APIs expect struct pt_regs * context, passed into BPF program. On kernels that don't support BPF cookie it is used to fetch absolute IP address of the underlying uprobe. usdt.bpf.h also provides BPF_USDT() macro, which functions like BPF_PROG() and BPF_KPROBE() and allows much more user-friendly way to get access to USDT arguments, if USDT definition is static and known to the user. It is expected that majority of use cases won't have to use bpf_usdt_arg_cnt() and bpf_usdt_arg() directly and BPF_USDT() will cover all their needs. Last, usdt.bpf.h is utilizing BPF CO-RE for one single purpose: to detect kernel support for BPF cookie. If BPF CO-RE dependency is undesirable, user application can redefine BPF_USDT_HAS_BPF_COOKIE to either a boolean constant (or equivalently zero and non-zero), or even point it to its own .rodata variable that can be specified from user's application user-space code. It is important that BPF_USDT_HAS_BPF_COOKIE is known to BPF verifier as static value (thus .rodata and not just .data), as otherwise BPF code will still contain bpf_get_attach_cookie() BPF helper call and will fail validation at runtime, if not dead-code eliminated. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/bpf/20220404234202.331384-2-andrii@kernel.org