- 07 Mar, 2020 12 commits
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Dmitry Safonov authored
Many embedded boards have a disconnected TTL level serial which can generate some garbage that can lead to spurious false sysrq detects. Currently, sysrq can be either completely disabled for serial console or always disabled (with CONFIG_MAGIC_SYSRQ_SERIAL), since commit 732dbf3a ("serial: do not accept sysrq characters via serial port") At Arista, we have such boards that can generate BREAK and random garbage. While disabling sysrq for serial console would solve the problem with spurious false sysrq triggers, it's also desirable to have a way to enable sysrq back. As a measure of balance between on and off options, add MAGIC_SYSRQ_SERIAL_SEQUENCE which is a string sequence that can enable sysrq if it follows BREAK on a serial line. The longer the string - the less likely it may be in the garbage. Having the way to enable sysrq was beneficial to debug lockups with a manual investigation in field and on the other side preventing false sysrq detections. Based-on-patch-by:
Vasiliy Khoruzhick <vasilykh@arista.com> Signed-off-by:
Dmitry Safonov <dima@arista.com> Link: https://lore.kernel.org/r/20200302175135.269397-3-dima@arista.comSigned-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Dmitry Safonov authored
Many embedded boards have a disconnected TTL level serial which can generate some garbage that can lead to spurious false sysrq detects. Currently, sysrq can be either completely disabled for serial console or always disabled (with CONFIG_MAGIC_SYSRQ_SERIAL), since commit 732dbf3a ("serial: do not accept sysrq characters via serial port") At Arista, we have such boards that can generate BREAK and random garbage. While disabling sysrq for serial console would solve the problem with spurious false sysrq triggers, it's also desirable to have a way to enable sysrq back. Having the way to enable sysrq was beneficial to debug lockups with a manual investigation in field and on the other side preventing false sysrq detections. As a preparation to add sysrq_toggle_support() call into uart, remove a private copy of sysrq_enabled from sysctl - it should reflect the actual status of sysrq. Furthermore, the private copy isn't correct already in case sysrq_always_enabled is true. So, remove __sysrq_enabled and use a getter-helper sysrq_mask() to check sysrq_key_op enabled status. Cc: Iurii Zaikin <yzaikin@google.com> Cc: Jiri Slaby <jslaby@suse.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: linux-fsdevel@vger.kernel.org Signed-off-by:
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Lukas Wunner authored
Commit e490c914 ("tty: Add software emulated RS485 support for 8250") introduced support to use RTS as an rs485 Transmit Enable signal if data is transmitted through the tty layer. Console messages bypass the tty layer and instead are emitted via serial8250_console_write(). Amend that function to drive RTS as well, allowing for a console on rs485 ports. Note that serial8250_console_write() may be called concurrently to the tty layer accessing the port. The two protect their accesses with the port lock, but serial8250_console_write() may find RTS still being asserted by the tty layer, in which case it shouldn't be deasserted after the console message has been printed. Recognize such situations by checking the em485->tx_stopped flag. If a delay_rts_before_send or delay_rts_after_send has been specified, serial8250_console_write() busy-waits for its duration. Optimizations for those wait times are conceivable: E.g. if RTS is already asserted, we could check whether em485->start_tx_timer is active and wait only for the remaining expire time. But this would require calling into the hrtimer infrastructure, which involves acquiring locks and potentially reprogramming timer hardware. Such operations seem too risky in the context of console printout, which needs to work even when the kernel has crashed and emits a BUG splat. So I've gone with a simplistic solution which just always waits for the full delay. Signed-off-by:
Lukas Wunner <lukas@wunner.de> Cc: Matwey V. Kornilov <matwey@sai.msu.ru> Link: https://lore.kernel.org/r/65edffce4670a19e598015c03cbe46f1ffd93e43.1582895077.git.lukas@wunner.deSigned-off-by:
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Lukas Wunner authored
Amend 8250_bcm2835aux.c to support rs485 as introduced for 8250_omap.c by commit e490c914 ("tty: Add software emulated RS485 support for 8250"). The bcm2835aux differs from omap chips by inverting the meaning of RTS in the MCR register: If the bit is clear, RTS is high. With omap, it's apparently the other way round. Moreover, omap achieves half-duplex mode by disabling the UART_IER_RDI interrupt and clearing the RX FIFO when TX stops. This approach doesn't work on bcm2835aux because the UART_LSR_DR bit is set even when UART_IER_RDI is disabled. Consequently, serial8250_handle_irq() invokes serial8250_rx_chars() to empty the FIFO and characters are received even though the user requested half-duplex. Solve by disabling the receiver using the non-standard CNTL register. Cache that register in the driver's private data for performance. Set the private data pointer before calling serial8250_register_8250_port() to prevent a null pointer deref in case one of the rs485 callbacks is invoked immediately after port registration. Signed-off-by:
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Lukas Wunner authored
Commit e490c914 ("tty: Add software emulated RS485 support for 8250") introduced support to use RTS as an rs485 Transmit Enable signal. So far the only drivers taking advantage of it are 8250_omap.c and 8250_of.c. We're about to make use of the feature in 8250_bcm2835aux.c as well. The bcm2835aux differs from omap chips by inverting the meaning of RTS in the MCR register. Moreover, omap achieves half-duplex mode by disabling the RX interrupt and clearing the RX FIFO when TX stops. The bcm2835aux requires disabling the receiver instead. Support these behavioral differences by generalizing the rs485 emulation: Introduce ->rs485_start_tx() and ->rs485_stop_tx() callbacks in struct uart_8250_port, provide generic implementations containing the existing code and use them as callbacks in 8250_omap.c and 8250_of.c. start_tx_rs485() is idempotent in that it recognizes whether RTS is already asserted. Achieve the same by introducing a tx_stopped flag in struct uart_8250_em485. This may even perform a little better on arches where memory access is faster than mmio access. Signed-off-by:
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Lukas Wunner authored
When rs485 transmission over an 8250 port stops, __stop_tx() assigns active_timer = NULL before calling __stop_tx_rs485(). That function in turn either assigns active_timer = stop_tx_timer and rearms the timer (in case a delay_rts_after_send needs to be observed) or directly calls __do_stop_tx_rs485(). Move the assignment active_timer = NULL to __stop_tx_rs485() into the branch which directly calls __do_stop_tx_rs485(), thereby avoiding a duplicate assignment and simplifying the code. Signed-off-by:
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Lukas Wunner authored
Amend the generic ->rs485_config() callback to sanitize RTS polarity and zero-fill the padding (in addition to the existing sanitization of the RTS delays). Signed-off-by:
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Lukas Wunner authored
Commit e490c914 ("tty: Add software emulated RS485 support for 8250") introduced support to use RTS as an rs485 Transmit Enable signal. Drivers opt in to the feature by calling serial8250_em485_init() from their ->rs485_config() callback. So far there are two drivers doing that, 8250_omap.c and 8250_of.c. Both use an identical callback. We're about to add a third user of that callback, therefore deduplicate it and move it to 8250_port.c. Drivers now opt in to rs485 software emulation by assigning the generic serial8250_rs485_config() callback introduced herein to their .rs485_config struct member. This change allows unexporting serial8250_em485_init() and declaring it static. Signed-off-by:
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Lukas Wunner authored
Retrieve rs485 devicetree properties on registration of 8250 ports in case they are attached to an rs485 transceiver. If the property "linux,rs485-enabled-at-boot-time" is present, invoke the ->rs485_config() callback to immediately deassert RTS, thereby ceasing control of the bus. Signed-off-by:
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Lukas Wunner authored
serial8250_do_set_mctrl() currently allows modifying the RTS modem control line even when RTS is used as an rs485 Transmit Enable signal. It is thus possible for user space to interfere with rs485 communication by invoking a TIOCMSET ioctl(). Ignore such change requests and retain the current RTS polarity when in rs485 mode. Note that serial8250_set_mctrl() is always called with port->lock held, so there's no risk that RTS is changed concurrently. Signed-off-by:
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Michael Walle authored
If a driver exposes early consoles with EARLYCON_DECLARE() and OF_EARLYCON_DECLARE(), pefer the non-OF variant if the user specifies it by earlycon=<driver>,<options> The rationale behind this is that some drivers register multiple setup functions under the same driver name. Eg. OF_EARLYCON_DECLARE(lpuart, "fsl,vf610-lpuart", lpuart_early_console_setup); OF_EARLYCON_DECLARE(lpuart32, "fsl,ls1021a-lpuart", lpuart32_early_console_setup); OF_EARLYCON_DECLARE(lpuart32, "fsl,imx7ulp-lpuart", lpuart32_imx_early_console_setup); EARLYCON_DECLARE(lpuart, lpuart_early_console_setup); EARLYCON_DECLARE(lpuart32, lpuart32_early_console_setup); It depends on the order of the entries which console_setup() actually gets called. To make things worse, I guess it also depends on the compiler how these are ordered. Thus always prefer the EARLYCON_DECLARE() ones. Signed-off-by:
Michael Walle <michael@walle.cc> Link: https://lore.kernel.org/r/20200220174607.24285-1-michael@walle.ccSigned-off-by:
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Nishad Kamdar authored
This patch corrects the SPDX License Identifier style in header files related to tty serial drivers. For C header files Documentation/process/license-rules.rst mandates C-like comments (opposed to C source files where C++ style should be used). Changes made by using a script provided by Joe Perches here: https://lkml.org/lkml/2019/2/7/46. Suggested-by:
Joe Perches <joe@perches.com> Signed-off-by:
Nishad Kamdar <nishadkamdar@gmail.com> Link: https://lore.kernel.org/r/20200301204517.GA10368@nishadSigned-off-by:
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- 06 Mar, 2020 18 commits
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Chunyan Zhang authored
Remove the dependency with ARCH_SPRD from sprd serial/console Kconfig-s, since we want them can be built-in when ARCH_SPRD is set as 'm'. Signed-off-by:
Chunyan Zhang <chunyan.zhang@unisoc.com> Link: https://lore.kernel.org/r/20200305103228.9686-2-zhang.lyra@gmail.comSigned-off-by:
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Chunyan Zhang authored
The default value of Kconfig for almost all sprd drivers are the same with ARCH_SPRD, making these drivers built as modules as default would be easier if we can set ARCH_SPRD as 'm', so this patch change ARCH_SPRD to tristate. Signed-off-by:
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Andy Shevchenko authored
The ->setup() callback is mandatory for the devices. Provide it for Elkhart Lake UART ports. Note, for time being it's empty, but in the future it might require an additional configuration such as DMA. Reported-by:
Raymond Tan <raymond.tan@intel.com> Signed-off-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200305130822.36850-1-andriy.shevchenko@linux.intel.comSigned-off-by:
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Changqi Hu authored
MTK uart design no need to control uart clock, so we just control bus clock in runtime function. Add uart clock used count to avoid repeatedly switching the clock. Signed-off-by:
Changqi Hu <changqi.hu@mediatek.com> Link: https://lore.kernel.org/r/1582707225-26815-1-git-send-email-changqi.hu@mediatek.comSigned-off-by:
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George Hilliard authored
The peripheral has support for inverting its input and/or output signals. This is useful if the hardware flips polarity of the peripheral's signal, such as swapped +/- pins on an RS-422 transceiver, or an inverting level shifter. Add support for these control registers via the device tree binding. As part of this change, make the writes of the various registers more uniform by moving the UCR3 block up near the other registers' blocks, since the INVT bit must be set before enabling the peripheral. Signed-off-by:
George Hilliard <ghilliard@kopismobile.com> Acked-by:
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20200226222319.18383-3-ghilliard@kopismobile.comSigned-off-by:
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George Hilliard authored
Add a description for the new fsl,inverted-tx and fsl,inverted-rx options for the i.MX UART peripheral. Signed-off-by:
Rob Herring <robh@kernel.org> Link: https://lore.kernel.org/r/20200226222319.18383-2-ghilliard@kopismobile.comSigned-off-by:
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Daniel Golle authored
Emulate half-duplex operation and use mctrl_gpio to add support for RS485 tranceiver with transmit/receive switch hooked to RTS GPIO line. This is needed to make use of the RS485 port found on Teltonika RUT955. Signed-off-by:
Daniel Golle <daniel@makrotopia.org> Link: https://lore.kernel.org/r/20200221212331.GA21467@makrotopia.orgSigned-off-by:
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Roja Rani Yarubandi authored
Add capability to support RX-TX, CTS-RTS pins swap in HW. Configure UART_IO_MACRO_CTRL register accordingly if RX-TX pair or CTS-RTS pair or both pairs swapped. Signed-off-by:
Roja Rani Yarubandi <rojay@codeaurora.org> Reviewed-by:
Stephen Boyd <swboyd@chromium.org> Tested-by:
Matthias Kaehlcke <mka@chromium.org> Reviewed-by:
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Linus Walleij authored
The CPM UART (PowerPC) has an open coded GPIO modem control handling. Since I can't test this I can't just migrate it to the serial mctrl GPIO helper library though I wish I could. I do second best and convert it to GPIO descriptors at least. Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by:
Linus Walleij <linus.walleij@linaro.org> Link: https://lore.kernel.org/r/20200229231842.247563-1-linus.walleij@linaro.orgSigned-off-by:
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Linus Walleij authored
Nothing in this driver uses the symbols from <linux/gpio.h> so drop this include. Cc: Rahul Tanwar <rahul.tanwar@linux.intel.com> Cc: Songjun Wu <songjun.wu@linux.intel.com> Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Cc: John Crispin <john@phrozen.org> Signed-off-by:
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Linus Walleij authored
Nothing in this driver uses the symbols from these GPIO includes so drop them. These are probably just historical artifacts from befor mctrl_gpio was used. Cc: Ludovic Desroches <ludovic.desroches@microchip.com> Cc: Razvan Stefanescu <razvan.stefanescu@microchip.com> Signed-off-by:
Ludovic Desroches <ludovic.desroches@microchip.com> Link: https://lore.kernel.org/r/20200229220941.205599-1-linus.walleij@linaro.orgSigned-off-by:
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Jiri Slaby authored
Shift the cases one level left as this is how we are supposed to write the switch-case code according to the CodingStyle. Signed-off-by:
Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20200219073951.16151-9-jslaby@suse.czSigned-off-by:
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Jiri Slaby authored
It is declared in vt_kern.h, so no need to declare it in selection.c which includes the header. Signed-off-by:
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Jiri Slaby authored
Unify the declarations of functions in vt_kern.h: some are with extern, some are not. Remove extern from the former as it is not needed for functions. Signed-off-by:
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Jiri Slaby authored
vt_dont_switch is pure boolean, no need for whole char. Signed-off-by:
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Jiri Slaby authored
Move all the selection global variables to a structure vc_selection, instantiated as vc_sel. This helps to group all the variables together and see what should be protected by the embedded lock too. It might be used later also for per-console selection support. Signed-off-by:
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Jiri Slaby authored
use_unicode needs not be global. It is used only in set_selection_kernel and sel_pos (a callee). It is also always set there prior calling sel_pos. So make use_unicode local and rename it to plain shorter "unicode". Finally, propagate it to sel_pos via parameter. Signed-off-by:
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Jiri Slaby authored
multiplier and mode are not actually needed: * multiplier is used only in kmalloc_array, so use "use_unicode ? 4 : 1" directly * mode is used only to assign a bool in this manner: if (cond) x = true; else x = false; So do "x = cond" directly. Signed-off-by:
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- 24 Feb, 2020 2 commits
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Greg Kroah-Hartman authored
We want the tty fixes in here as well. Signed-off-by: -
Linus Torvalds authored
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- 23 Feb, 2020 8 commits
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Kees Cook authored
Variables declared in a switch statement before any case statements cannot be automatically initialized with compiler instrumentation (as they are not part of any execution flow). With GCC's proposed automatic stack variable initialization feature, this triggers a warning (and they don't get initialized). Clang's automatic stack variable initialization (via CONFIG_INIT_STACK_ALL=y) doesn't throw a warning, but it also doesn't initialize such variables[1]. Note that these warnings (or silent skipping) happen before the dead-store elimination optimization phase, so even when the automatic initializations are later elided in favor of direct initializations, the warnings remain. To avoid these problems, move such variables into the "case" where they're used or lift them up into the main function body. drivers/tty/n_tty.c: In function ‘__process_echoes’: drivers/tty/n_tty.c:657:18: warning: statement will never be executed [-Wswitch-unreachable] 657 | unsigned int num_chars, num_bs; | ^~~~~~~~~ [1] https://bugs.llvm.org/show_bug.cgi?id=44916Reviewed-by:Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200220062313.69209-1-keescook@chromium.orgSigned-off-by:
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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linuxLinus Torvalds authored
Pull btrfs fixes from David Sterba: "These are fixes that were found during testing with help of error injection, plus some other stable material. There's a fixup to patch added to rc1 causing locking in wrong context warnings, tests found one more deadlock scenario. The patches are tagged for stable, two of them now in the queue but we'd like all three released at the same time. I'm not happy about fixes to fixes in such a fast succession during rcs, but I hope we found all the fallouts of commit 28553fa9 ('Btrfs: fix race between shrinking truncate and fiemap')" * tag 'for-5.6-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: Btrfs: fix deadlock during fast fsync when logging prealloc extents beyond eof Btrfs: fix btrfs_wait_ordered_range() so that it waits for all ordered extents btrfs: fix bytes_may_use underflow in prealloc error condtition btrfs: handle logged extent failure properly btrfs: do not check delayed items are empty for single transaction cleanup btrfs: reset fs_root to NULL on error in open_ctree btrfs: destroy qgroup extent records on transaction abort
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git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4Linus Torvalds authored
Pull ext4 fixes from Ted Ts'o: "More miscellaneous ext4 bug fixes (all stable fodder)" * tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: ext4: fix mount failure with quota configured as module jbd2: fix ocfs2 corrupt when clearing block group bits ext4: fix race between writepages and enabling EXT4_EXTENTS_FL ext4: rename s_journal_flag_rwsem to s_writepages_rwsem ext4: fix potential race between s_flex_groups online resizing and access ext4: fix potential race between s_group_info online resizing and access ext4: fix potential race between online resizing and write operations ext4: add cond_resched() to __ext4_find_entry() ext4: fix a data race in EXT4_I(inode)->i_disksize
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git://github.com/c-sky/csky-linuxLinus Torvalds authored
Pull csky updates from Guo Ren: "Sorry, I missed 5.6-rc1 merge window, but in this pull request the most are the fixes and the rests are between fixes and features. The only outside modification is the MAINTAINERS file update with our mailing list. - cache flush implementation fixes - ftrace modify panic fix - CONFIG_SMP boot problem fix - fix pt_regs saving for atomic.S - fix fixaddr_init without highmem. - fix stack protector support - fix fake Tightly-Coupled Memory code compile and use - fix some typos and coding convention" * tag 'csky-for-linus-5.6-rc3' of git://github.com/c-sky/csky-linux: (23 commits) csky: Replace <linux/clk-provider.h> by <linux/of_clk.h> csky: Implement copy_thread_tls csky: Add PCI support csky: Minimize defconfig to support buildroot config.fragment csky: Add setup_initrd check code csky: Cleanup old Kconfig options arch/csky: fix some Kconfig typos csky: Fixup compile warning for three unimplemented syscalls csky: Remove unused cache implementation csky: Fixup ftrace modify panic csky: Add flush_icache_mm to defer flush icache all csky: Optimize abiv2 copy_to_user_page with VM_EXEC csky: Enable defer flush_dcache_page for abiv2 cpus (807/810/860) csky: Remove unnecessary flush_icache_* implementation csky: Support icache flush without specific instructions csky/Kconfig: Add Kconfig.platforms to support some drivers csky/smp: Fixup boot failed when CONFIG_SMP csky: Set regs->usp to kernel sp, when the exception is from kernel csky/mm: Fixup export invalid_pte_table symbol csky: Separate fixaddr_init from highmem ...
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Geert Uytterhoeven authored
The C-Sky platform code is not a clock provider, and just needs to call of_clk_init(). Hence it can include <linux/of_clk.h> instead of <linux/clk-provider.h>. Signed-off-by:
Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by:
Guo Ren <guoren@linux.alibaba.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull RAS fixes from Thomas Gleixner: "Two fixes for the AMD MCE driver: - Populate the per CPU MCA bank descriptor pointer only after it has been completely set up to prevent a use-after-free in case that one of the subsequent initialization step fails - Implement a proper release function for the sysfs entries of MCA threshold controls instead of freeing the memory right in the CPU teardown code, which leads to another use-after-free when the associated sysfs file is opened and accessed" * tag 'ras-urgent-2020-02-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mce/amd: Fix kobject lifetime x86/mce/amd: Publish the bank pointer only after setup has succeeded -
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull irq fixes from Thomas Gleixner: "Two fixes for the irq core code which are follow ups to the recent MSI fixes: - The WARN_ON which was put into the MSI setaffinity callback for paranoia reasons actually triggered via a callchain which escaped when all the possible ways to reach that code were analyzed. The proc/irq/$N/*affinity interfaces have a quirk which came in when ALPHA moved to the generic interface: In case that the written affinity mask does not contain any online CPU it calls into ALPHAs magic auto affinity setting code. A few years later this mechanism was also made available to x86 for no good reasons and in a way which circumvents all sanity checks for interrupts which cannot have their affinity set from process context on X86 due to the way the X86 interrupt delivery works. It would be possible to make this work properly, but there is no point in doing so. If the interrupt is not yet started then the affinity setting has no effect and if it is started already then it is already assigned to an online CPU so there is no point to randomly move it to some other CPU. Just return EINVAL as the code has done before that change forever. - The new MSI quirk bit in the irq domain flags turned out to be already occupied, which escaped the author and the reviewers because the already in use bits were 0,6,2,3,4,5 listed in that order. That bit 6 was simply overlooked because the ordering was straight forward linear otherwise. So the new bit ended up being a duplicate. Fix it up by switching the oddball 6 to the obvious 1" * tag 'irq-urgent-2020-02-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq/irqdomain: Make sure all irq domain flags are distinct genirq/proc: Reject invalid affinity masks (again) -
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 fixes from Thomas Gleixner: "Two fixes for x86: - Remove the __force_oder definiton from the kaslr boot code as it is already defined in the page table code which makes GCC 10 builds fail because it changed the default to -fno-common. - Address the AMD erratum 1054 concerning the IRPERF capability and enable the Instructions Retired fixed counter on machines which are not affected by the erratum" * tag 'x86-urgent-2020-02-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/cpu/amd: Enable the fixed Instructions Retired counter IRPERF x86/boot/compressed: Don't declare __force_order in kaslr_64.c
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