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* x86/intel/quark: Fix simple_return.cocci warningsFengguang Wu2015-02-19
| | | | | | | | | | | | | | | | | arch/x86/platform/intel-quark/imr.c:129:1-4: WARNING: end returns can be simpified Simplify a trivial if-return sequence. Possibly combine with a preceding function call. Generated by: scripts/coccinelle/misc/simple_return.cocci Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Cc: Andy Shevchenko <andy.schevchenko@gmail.com> Cc: Ong, Boon Leong <boon.leong.ong@intel.com> Cc: Bryan O'Donoghue <pure.logic@nexus-software.ie> Cc: Darren Hart <dvhart@linux.intel.com> Cc: kbuild-all@01.org Link: http://lkml.kernel.org/r/20150219081432.GA21996@waimea Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/intel/quark: Fix ptr_ret.cocci warningsFengguang Wu2015-02-19
| | | | | | | | | | | | | | | | | arch/x86/platform/intel-quark/imr.c:280:1-3: WARNING: PTR_ERR_OR_ZERO can be used Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR Generated by: scripts/coccinelle/api/ptr_ret.cocci Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Cc: Andy Shevchenko <andy.schevchenko@gmail.com> Cc: Ong, Boon Leong <boon.leong.ong@intel.com> Cc: Bryan O'Donoghue <pure.logic@nexus-software.ie> Cc: Darren Hart <dvhart@linux.intel.com> Cc: kbuild-all@01.org Link: http://lkml.kernel.org/r/20150219081432.GA21983@waimea Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/intel/quark: Add Intel Quark platform supportBryan O'Donoghue2015-02-18
| | | | | | | | | | | | | | | | | | | | Add Intel Quark platform support. Quark needs to pull down all unlocked IMRs to ensure agreement with the EFI memory map post boot. This patch adds an entry in Kconfig for Quark as a platform and makes IMR support mandatory if selected. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Tested-by: Ong, Boon Leong <boon.leong.ong@intel.com> Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie> Reviewed-by: Andy Shevchenko <andy.schevchenko@gmail.com> Reviewed-by: Darren Hart <dvhart@linux.intel.com> Reviewed-by: Ong, Boon Leong <boon.leong.ong@intel.com> Cc: dvhart@infradead.org Link: http://lkml.kernel.org/r/1422635379-12476-3-git-send-email-pure.logic@nexus-software.ie Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/intel/quark: Add Isolated Memory Regions for Quark X1000Bryan O'Donoghue2015-02-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Intel's Quark X1000 SoC contains a set of registers called Isolated Memory Regions. IMRs are accessed over the IOSF mailbox interface. IMRs are areas carved out of memory that define read/write access rights to the various system agents within the Quark system. For a given agent in the system it is possible to specify if that agent may read or write an area of memory defined by an IMR with a granularity of 1 KiB. Quark_SecureBootPRM_330234_001.pdf section 4.5 details the concept of IMRs quark-x1000-datasheet.pdf section 12.7.4 details the implementation of IMRs in silicon. eSRAM flush, CPU Snoop write-only, CPU SMM Mode, CPU non-SMM mode, RMU and PCIe Virtual Channels (VC0 and VC1) can have individual read/write access masks applied to them for a given memory region in Quark X1000. This enables IMRs to treat each memory transaction type listed above on an individual basis and to filter appropriately based on the IMR access mask for the memory region. Quark supports eight IMRs. Since all of the DMA capable SoC components in the X1000 are mapped to VC0 it is possible to define sections of memory as invalid for DMA write operations originating from Ethernet, USB, SD and any other DMA capable south-cluster component on VC0. Similarly it is possible to mark kernel memory as non-SMM mode read/write only or to mark BIOS runtime memory as SMM mode accessible only depending on the particular memory footprint on a given system. On an IMR violation Quark SoC X1000 systems are configured to reset the system, so ensuring that the IMR memory map is consistent with the EFI provided memory map is critical to ensure no IMR violations reset the system. The API for accessing IMRs is based on MTRR code but doesn't provide a /proc or /sys interface to manipulate IMRs. Defining the size and extent of IMRs is exclusively the domain of in-kernel code. Quark firmware sets up a series of locked IMRs around pieces of memory that firmware owns such as ACPI runtime data. During boot a series of unlocked IMRs are placed around items in memory to guarantee no DMA modification of those items can take place. Grub also places an unlocked IMR around the kernel boot params data structure and compressed kernel image. It is necessary for the kernel to tear down all unlocked IMRs in order to ensure that the kernel's view of memory passed via the EFI memory map is consistent with the IMR memory map. Without tearing down all unlocked IMRs on boot transitory IMRs such as those used to protect the compressed kernel image will cause IMR violations and system reboots. The IMR init code tears down all unlocked IMRs and sets a protective IMR around the kernel .text and .rodata as one contiguous block. This sanitizes the IMR memory map with respect to the EFI memory map and protects the read-only portions of the kernel from unwarranted DMA access. Tested-by: Ong, Boon Leong <boon.leong.ong@intel.com> Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie> Reviewed-by: Andy Shevchenko <andy.schevchenko@gmail.com> Reviewed-by: Darren Hart <dvhart@linux.intel.com> Reviewed-by: Ong, Boon Leong <boon.leong.ong@intel.com> Cc: andy.shevchenko@gmail.com Cc: dvhart@infradead.org Link: http://lkml.kernel.org/r/1422635379-12476-2-git-send-email-pure.logic@nexus-software.ie Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'x86-ras-for-linus' of ↵Linus Torvalds2015-02-09
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 RAS update from Ingo Molnar: "The changes in this cycle were: - allow mmcfg access to APEI error injection handlers - improve MCE error messages - smaller cleanups" * 'x86-ras-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, mce: Fix sparse errors x86, mce: Improve timeout error messages ACPI, EINJ: Enhance error injection tolerance level
| * Merge tag 'please-pull-einj-mmcfg' of ↵Ingo Molnar2015-01-15
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras into x86/ras Pull RAS update from Tony Luck: "When checking addresses in APEI action entries for validity, allow access to the mmcfg space - some error injection functions need to do this." Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * ACPI, EINJ: Enhance error injection tolerance levelChen, Gong2014-12-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some BIOSes utilize PCI MMCFG space read/write opertion to trigger specific errors. EINJ will report errors as below when hitting such cases: APEI: Can not request [mem 0x83f990a0-0x83f990a3] for APEI EINJ Trigger registers It is because on x86 platform ACPI based PCI MMCFG logic has reserved all MMCFG spaces so that EINJ can't reserve it again. We already trust the ACPI/APEI code when using the EINJ interface so it is not a big leap to also trust it to access the right MMCFG addresses. Skip address checking to allow the access. Signed-off-by: Chen, Gong <gong.chen@linux.intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
| * | Merge tag 'ras_for_3.20' of ↵Ingo Molnar2015-01-15
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp into x86/ras Pull RAS updates from Borislav Petkov: "Nothing special this time, just an error messages improvement from Andy and a cleanup from me." Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | x86, mce: Fix sparse errorsBorislav Petkov2014-12-22
| | | | | | | | | | | | | | | | | | | | | | | | Make stuff used in mce.c only, static. Signed-off-by: Borislav Petkov <bp@suse.de>
| | * | x86, mce: Improve timeout error messagesAndy Lutomirski2014-12-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are four different possible types of timeouts. Distinguish them in the logs to help debug them. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/0fa6d2653a54a01c48b43a3583caf950ea99606e.1419178397.git.luto@amacapital.net Signed-off-by: Borislav Petkov <bp@suse.de>
* | | | Merge branch 'x86-mm-for-linus' of ↵Linus Torvalds2015-02-09
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 mm cleanups from Ingo Molnar: "Two cleanups: simplify parse_setup_data() and sanitize_e820_map() usage" * 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, e820: Clean up sanitize_e820_map() users x86, setup: Let early_memremap() handle page alignment
| * | | | x86, e820: Clean up sanitize_e820_map() usersWANG Chao2015-01-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The argument 3 of sanitize_e820_map() will only be updated upon a successful sanitization. Some of the callers have extra conditionals for the same purpose. Clean them up. default_machine_specific_memory_setup() must keep the extra conditional because boot_params.e820_entries is an u8 and not an u32, so the direct update would overwrite other fields in boot_params. [ tglx: Massaged changelog ] Signed-off-by: WANG Chao <chaowang@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Grygorii Strashko <grygorii.strashko@ti.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Lee Chun-Yi <joeyli.kernel@gmail.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Link: http://lkml.kernel.org/r/1420601859-18439-1-git-send-email-chaowang@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | x86, setup: Let early_memremap() handle page alignmentWANG Chao2015-01-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | early_memremap() takes care of page alignment and map size, so we can just remap the required data size and get rid of the adjustments in the setup code. [tglx: Massaged changelog ] Signed-off-by: WANG Chao <chaowang@redhat.com> Cc: Matt Fleming <matt.fleming@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: Bryan O'Donoghue <pure.logic@nexus-software.ie> Link: http://lkml.kernel.org/r/1420628150-16872-1-git-send-email-chaowang@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | | Merge branch 'x86-platform-for-linus' of ↵Linus Torvalds2015-02-09
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 SoC updates from Ingo Molnar: "Various Intel Atom SoC updates (mostly to enhance debuggability), plus an apb_timer cleanup" * 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86: pmc_atom: Expose contents of PSS x86: pmc_atom: Clean up init function x86: pmc-atom: Remove unused macro x86: pmc_atom: don%27t check for NULL twice x86: pmc-atom: Assign debugfs node as soon as possible x86/platform: Remove unused function from apb_timer.c
| * | | | | x86: pmc_atom: Expose contents of PSSAndy Shevchenko2015-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The PSS register reflects the power state of each island on SoC. It would be useful to know which of the islands is on or off at the momemnt. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Aubrey Li <aubrey.li@linux.intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Kumar P. Mahesh <mahesh.kumar.p@intel.com> Link: http://lkml.kernel.org/r/1421253575-22509-6-git-send-email-andriy.shevchenko@linux.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | | x86: pmc_atom: Clean up init functionAndy Shevchenko2015-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is no need to use err variable. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Aubrey Li <aubrey.li@linux.intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Kumar P. Mahesh <mahesh.kumar.p@intel.com> Link: http://lkml.kernel.org/r/1421253575-22509-5-git-send-email-andriy.shevchenko@linux.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | | x86: pmc-atom: Remove unused macroAndy Shevchenko2015-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | DRIVER_NAME seems unused. This patch just removes it. There is no functional change. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Aubrey Li <aubrey.li@linux.intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Kumar P. Mahesh <mahesh.kumar.p@intel.com> Link: http://lkml.kernel.org/r/1421253575-22509-4-git-send-email-andriy.shevchenko@linux.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | | x86: pmc_atom: don%27t check for NULL twiceAndy Shevchenko2015-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | debugfs_remove_recursive() is NULL-aware, thus, we may safely remove the check here. There is no need to assing NULL to variable since it will be not used anywhere. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Aubrey Li <aubrey.li@linux.intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Kumar P. Mahesh <mahesh.kumar.p@intel.com> Link: http://lkml.kernel.org/r/1421253575-22509-3-git-send-email-andriy.shevchenko@linux.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | | x86: pmc-atom: Assign debugfs node as soon as possibleAndy Shevchenko2015-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | pmc_dbgfs_unregister() will be called when pmc->dbgfs_dir is unconditionally NULL on error path in pmc_dbgfs_register(). To prevent this we move the assignment to where is should be. Fixes: f855911c1f48 (x86/pmc_atom: Expose PMC device state and platform sleep state) Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Aubrey Li <aubrey.li@linux.intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Kumar P. Mahesh <mahesh.kumar.p@intel.com> Link: http://lkml.kernel.org/r/1421253575-22509-2-git-send-email-andriy.shevchenko@linux.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | | x86/platform: Remove unused function from apb_timer.cRickard Strandqvist2014-12-23
| | |_|/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the function is_apbt_capable() that is not used anywhere. This was partially found by using a static code analysis program called 'cppcheck'. Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se> Reviewed-by: Jiang Liu <jiang.liu@linux.intel.com> Cc: Christoph Lameter <cl@linux.com> Cc: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/1419166698-2470-1-git-send-email-rickard_strandqvist@spectrumdigital.se Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | | Merge branch 'x86-fpu-for-linus' of ↵Linus Torvalds2015-02-09
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fpu updates from Ingo Molnar: "Initial round of kernel_fpu_begin/end cleanups from Oleg Nesterov, plus a cleanup from Borislav Petkov" * 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, fpu: Fix math_state_restore() race with kernel_fpu_begin() x86, fpu: Don't abuse has_fpu in __kernel_fpu_begin/end() x86, fpu: Introduce per-cpu in_kernel_fpu state x86/fpu: Use a symbolic name for asm operand
| * | | | | x86, fpu: Fix math_state_restore() race with kernel_fpu_begin()Oleg Nesterov2015-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | math_state_restore() can race with kernel_fpu_begin() if irq comes right after __thread_fpu_begin(), __save_init_fpu() will overwrite fpu->state we are going to restore. Add 2 simple helpers, kernel_fpu_disable() and kernel_fpu_enable() which simply set/clear in_kernel_fpu, and change math_state_restore() to exclude kernel_fpu_begin() in between. Alternatively we could use local_irq_save/restore, but probably these new helpers can have more users. Perhaps they should disable/enable preemption themselves, in this case we can remove preempt_disable() in __restore_xstate_sig(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: matt.fleming@intel.com Cc: bp@suse.de Cc: pbonzini@redhat.com Cc: luto@amacapital.net Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Suresh Siddha <sbsiddha@gmail.com> Link: http://lkml.kernel.org/r/20150115192028.GD27332@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | | x86, fpu: Don't abuse has_fpu in __kernel_fpu_begin/end()Oleg Nesterov2015-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that we have in_kernel_fpu we can remove __thread_clear_has_fpu() in __kernel_fpu_begin(). And this allows to replace the asymmetrical and nontrivial use_eager_fpu + tsk_used_math check in kernel_fpu_end() with the same __thread_has_fpu() check. The logic becomes really simple; if _begin() does save() then _end() needs restore(), this is controlled by __thread_has_fpu(). Otherwise they do clts/stts unless use_eager_fpu(). Not only this makes begin/end symmetrical and imo more understandable, potentially this allows to change irq_fpu_usable() to avoid all other checks except "in_kernel_fpu". Also, with this patch __kernel_fpu_end() does restore_fpu_checking() and WARNs if it fails instead of math_state_restore(). I think this looks better because we no longer need __thread_fpu_begin(), and it would be better to report the failure in this case. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: matt.fleming@intel.com Cc: bp@suse.de Cc: pbonzini@redhat.com Cc: luto@amacapital.net Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Suresh Siddha <sbsiddha@gmail.com> Link: http://lkml.kernel.org/r/20150115192005.GC27332@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | | x86, fpu: Introduce per-cpu in_kernel_fpu stateOleg Nesterov2015-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | interrupted_kernel_fpu_idle() tries to detect if kernel_fpu_begin() is safe or not. In particular it should obviously deny the nested kernel_fpu_begin() and this logic looks very confusing. If use_eager_fpu() == T we rely on a) __thread_has_fpu() check in interrupted_kernel_fpu_idle(), and b) on the fact that _begin() does __thread_clear_has_fpu(). Otherwise we demand that the interrupted task has no FPU if it is in kernel mode, this works because __kernel_fpu_begin() does clts() and interrupted_kernel_fpu_idle() checks X86_CR0_TS. Add the per-cpu "bool in_kernel_fpu" variable, and change this code to check/set/clear it. This allows to do more cleanups and fixes, see the next changes. The patch also moves WARN_ON_ONCE() under preempt_disable() just to make this_cpu_read() look better, this is not really needed. And in fact I think we should move it into __kernel_fpu_begin(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: matt.fleming@intel.com Cc: bp@suse.de Cc: pbonzini@redhat.com Cc: luto@amacapital.net Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Suresh Siddha <sbsiddha@gmail.com> Link: http://lkml.kernel.org/r/20150115191943.GB27332@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | | x86/fpu: Use a symbolic name for asm operandBorislav Petkov2014-12-23
| |/ / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix up the else-case in fpu_fxsave() which seems like it has been overlooked. Correct comment style in restore_fpu_checking() while at it. Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1419170543-11393-1-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | | Merge branch 'x86-efi-for-linus' of ↵Linus Torvalds2015-02-09
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull EFI updates from Ingo Molnar: "Main changes: - Move efivarfs from the misc filesystem section to pseudo filesystem - Expose firmware platform size in sysfs - Improve robustness of get_memory_map() by removing assumptions on the size of efi_memory_desc_t. - various cleanups and fixes The biggest risk is the get_memory_map() change, which changes the way that both the arm64 and x86 EFI boot stub build the early memory map. There are no known regressions with it at the moment, BYMMV" * 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: efi: Don't look for chosen@0 node on DT platforms firmware: efi: Remove unneeded guid unparse efi/libstub: Call get_memory_map() to obtain map and desc sizes efi: Small leak on error in runtime map code efi: rtc-efi: Mark UIE as unsupported arm64/efi: efistub: Apply __init annotation efi: Expose underlying UEFI firmware platform size to userland efi: Rename efi_guid_unparse to efi_guid_to_str efi: Update the URLs for efibootmgr fs: Make efivarfs a pseudo filesystem, built by default with EFI
| * \ \ \ \ Merge tag 'efi-next' of ↵Ingo Molnar2015-01-29
| |\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/efi Pull EFI updates from Matt Fleming: " - Move efivarfs from the misc filesystem section to pseudo filesystem, since that's a more logical and accurate place - Leif Lindholm - Update efibootmgr URL in Kconfig help - Peter Jones - Improve accuracy of EFI guid function names - Borislav Petkov - Expose firmware platform size in sysfs for the benefit of EFI boot loader installers and other utilities - Steve McIntyre - Cleanup __init annotations for arm64/efi code - Ard Biesheuvel - Mark the UIE as unsupported for rtc-efi - Ard Biesheuvel - Fix memory leak in error code path of runtime map code - Dan Carpenter - Improve robustness of get_memory_map() by removing assumptions on the size of efi_memory_desc_t (which could change in future spec versions) and querying the firmware instead of guessing about the memmap size - Ard Biesheuvel - Remove superfluous guid unparse calls - Ivan Khoronzhuk - Delete unnecessary chosen@0 DT node FDT code since was duplicated from code in drivers/of and is entirely unnecessary - Leif Lindholm There's nothing super scary, mainly cleanups, and a merge from Ricardo who kindly picked up some patches from the linux-efi mailing list while I was out on annual leave in December. Perhaps the biggest risk is the get_memory_map() change from Ard, which changes the way that both the arm64 and x86 EFI boot stub build the early memory map. It would be good to have it bake in linux-next for a while. " Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | | | efi: Don't look for chosen@0 node on DT platformsLeif Lindholm2015-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Due to some scary special case handling noticed in drivers/of, various bits of the ARM* EFI support patches did duplicate looking for @0 variants of various nodes. Unless on an ancient PPC system, these are not in fact required. Most instances have become refactored out along the way, this removes the last one. Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| | * | | | | firmware: efi: Remove unneeded guid unparseIvan Khoronzhuk2015-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is no reason to translate guid number to string here. So remove it in order to not do unneeded work. Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Leif Lindholm <leif.lindholm@linaro.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| | * | | | | efi/libstub: Call get_memory_map() to obtain map and desc sizesArd Biesheuvel2015-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fixes two minor issues in the implementation of get_memory_map(): - Currently, it assumes that sizeof(efi_memory_desc_t) == desc_size, which is usually true, but not mandated by the spec. (This was added intentionally to allow future additions to the definition of efi_memory_desc_t). The way the loop is implemented currently, the added slack space may be insufficient if desc_size is larger, which in some corner cases could result in the loop never terminating. - It allocates 32 efi_memory_desc_t entries first (again, using the size of the struct instead of desc_size), and frees and reallocates if it turns out to be insufficient. Few implementations of UEFI have such small memory maps, which results in a unnecessary allocate/free pair on each invocation. Fix this by calling the get_memory_map() boot service first with a '0' input value for map size to retrieve the map size and desc size from the firmware and only then perform the allocation, using desc_size rather than sizeof(efi_memory_desc_t). Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| | * | | | | efi: Small leak on error in runtime map codeDan Carpenter2015-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The "> 0" here should ">= 0" so we free map_entries[0]. Fixes: 926172d46038 ('efi: Export EFI runtime memory mapping to sysfs') Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Dave Young <dyoung@redhat.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| | * | | | | efi: rtc-efi: Mark UIE as unsupportedArd Biesheuvel2015-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Tools like hwclock attempt to enable the RTC update interrupt (UIE) to maximize the accuracy of the reported time value. The EFI rtc does not have interrupt capability so this is a pointless exercise to begin with, but the generic RTC framework ends up issuing a SetWakeupTime() Runtime Services call before drawing that conclusion on its own. Instead, we can mark UIE as unsupported at driver probe time. The net result is the same, but without the spurious SetWakeupTime() call. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| | * | | | | arm64/efi: efistub: Apply __init annotationArd Biesheuvel2015-01-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This ensures all stub component are freed when the kernel proper is done booting, by prefixing the names of all ELF sections that have the SHF_ALLOC attribute with ".init". This approach ensures that even implicitly emitted allocated data (like initializer values and string literals) are covered. At the same time, remove some __init annotations in the stub that have now become redundant, and add the __init annotation to handle_kernel_image which will now trigger a section mismatch warning without it. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| | * | | | | efi: Expose underlying UEFI firmware platform size to userlandSteve McIntyre2015-01-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In some cases (e.g. Intel Bay Trail machines), the kernel will happily run in 64-bit even if the underlying UEFI firmware platform is 32-bit. That's great, but it's difficult for userland utilities like grub-install to do the right thing in such a situation. The kernel already knows about the size of the firmware via efi_enabled(EFI_64BIT). Add an extra sysfs interface /sys/firmware/efi/fw_platform_size to expose that information to userland for low-level utilities to use. Signed-off-by: Steve McIntyre <steve@einval.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| | * | | | | Merge tag 'rneri-efi-next' of https://github.com/ricardon/efi into nextMatt Fleming2015-01-12
| | |\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull EFI changes for v3.20 from Ricardo Neri, who kindly picked them up while I was out on annual leave in December. Updates included: *Rename the function efi_guid_unparse to reflect better its behavior. - Borislav Petkov *Update the EFI firmware Kconfig help with the URL of efibootmgr. - Peter Jones Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| | | * | | | | efi: Rename efi_guid_unparse to efi_guid_to_strBorislav Petkov2015-01-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Call it what it does - "unparse" is plain-misleading. Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
| | | * | | | | efi: Update the URLs for efibootmgrPeter Jones2015-01-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Matt Domsch changed the dell page to point to the new upstream quite some time ago; kernel should reflect that here as well. Cc: Matt Domsch <Matt_Domsch@dell.com> Signed-off-by: Peter Jones <pjones@redhat.com> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
| | * | | | | | fs: Make efivarfs a pseudo filesystem, built by default with EFILeif Lindholm2015-01-05
| | |/ / / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | efivars is currently enabled under MISC_FILESYSTEMS, which is decribed as "such as filesystems that came from other operating systems". In reality, it is a pseudo filesystem, providing access to the kernel UEFI variable interface. Since this is the preferred interface for accessing UEFI variables, over the legacy efivars interface, also build it by default as a module if CONFIG_EFI. Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* | | | | | | Merge branch 'x86-cleanups-for-linus' of ↵Linus Torvalds2015-02-09
|\ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cleanups from Ingo Molnar: "Misc cleanups" * 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/rtc: Remove duplicate const specifier x86, early_serial_console: Remove unnecessary check x86, early_serial_console: Remove unused macro XMTRDY x86, setup: Rename BOOT_ISDIGIT_H to BOOT_CTYPE_H x86, CPU: Fix trivial printk formatting issues with dmesg
| * | | | | | | x86/rtc: Remove duplicate const specifierColin King2015-01-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Building with clang: CC arch/x86/kernel/rtc.o arch/x86/kernel/rtc.c:173:29: warning: duplicate 'const' declaration specifier [-Wduplicate-decl-specifier] static const char * const const ids[] __initconst = Remove the duplicate const, it is not needed and causes a warning. Signed-off-by: Colin Ian King <colin.king@canonical.com> Link: http://lkml.kernel.org/r/1421244475-313-1-git-send-email-colin.king@canonical.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | | | | Merge tag 'x86_queue' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp ↵Ingo Molnar2015-01-15
| |\ \ \ \ \ \ \ | | |_|_|_|_|/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | into x86/cleanups Pull minor x86 cleanups from Borislav Petkov. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | | | | x86, early_serial_console: Remove unnecessary checkAlexander Kuleshov2015-01-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We do this check already a couple of lines up. Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com> Link: http://lkml.kernel.org/r/1420009958-4803-1-git-send-email-kuleshovmail@gmail.com Signed-off-by: Borislav Petkov <bp@suse.de>
| | * | | | | | x86, early_serial_console: Remove unused macro XMTRDYAlexander Kuleshov2015-01-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is no write to serial routine, no need for XMTRDY macro. Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com> Link: http://lkml.kernel.org/r/1420034191-20721-1-git-send-email-kuleshovmail@gmail.com Signed-off-by: Borislav Petkov <bp@suse.de>
| | * | | | | | x86, setup: Rename BOOT_ISDIGIT_H to BOOT_CTYPE_HAlexander Kuleshov2015-01-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | arch/x86/boot/isdigit.h was renamed to arch/x86/boot/ctype.h in 6238b47b5848 ("x86, setup: move isdigit.h to ctype.h, header files on top.") Adjust guards too. Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com> Link: http://lkml.kernel.org/r/1420267941-26390-1-git-send-email-kuleshovmail@gmail.com Signed-off-by: Borislav Petkov <bp@suse.de>
| | * | | | | | x86, CPU: Fix trivial printk formatting issues with dmesgSteven Honeyman2015-01-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | dmesg (from util-linux) currently has two methods for reading the kernel message ring buffer: /dev/kmsg and syslog(2). Since kernel 3.5.0 kmsg has been the default, which escapes control characters (e.g. new lines) before they are shown. This change means that when dmesg is using /dev/kmsg, a 2 line printk makes the output messy, because the second line does not get a timestamp. For example: [ 0.012863] CPU0: Thermal monitoring enabled (TM1) [ 0.012869] Last level iTLB entries: 4KB 1024, 2MB 1024, 4MB 1024 Last level dTLB entries: 4KB 1024, 2MB 1024, 4MB 1024, 1GB 4 [ 0.012958] Freeing SMP alternatives memory: 28K (ffffffff81d86000 - ffffffff81d8d000) [ 0.014961] dmar: Host address width 39 Because printk.c intentionally escapes control characters, they should not be there in the first place. This patch fixes two occurrences of this. Signed-off-by: Steven Honeyman <stevenhoneyman@gmail.com> Link: https://lkml.kernel.org/r/1414856696-8094-1-git-send-email-stevenhoneyman@gmail.com [ Boris: make cpu_detect_tlb() static, while at it. ] Signed-off-by: Borislav Petkov <bp@suse.de>
* | | | | | | | Merge branch 'x86-asm-for-linus' of ↵Linus Torvalds2015-02-09
|\ \ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 asm changes from Ingo Molnar: "The main changes in this cycle were the x86/entry and sysret enhancements from Andy Lutomirski, see merge commits 772a9aca125 and b57c0b5175dd for details" [ Exectutive summary: IST exceptions that interrupt user space will run on the regular kernel stack instead of the IST stack. Which simplifies things particularly on return to user space. The sysret cleanup ends up simplifying the logic on when we can use sysret vs when we have to use iret. - Linus ] * 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86_64, entry: Remove the syscall exit audit and schedule optimizations x86_64, entry: Use sysret to return to userspace when possible x86, traps: Fix ist_enter from userspace x86, vdso: teach 'make clean' remove vdso64 binaries x86_64 entry: Fix RCX for ptraced syscalls x86: entry_64.S: fold SAVE_ARGS_IRQ macro into its sole user x86: ia32entry.S: fix wrong symbolic constant usage: R11->ARGOFFSET x86: entry_64.S: delete unused code x86, mce: Get rid of TIF_MCE_NOTIFY and associated mce tricks x86, traps: Add ist_begin_non_atomic and ist_end_non_atomic x86: Clean up current_stack_pointer x86, traps: Track entry into and exit from IST context x86, entry: Switch stacks on a paranoid entry from userspace
| * \ \ \ \ \ \ \ Merge tag 'pr-20150201-x86-entry' of ↵Ingo Molnar2015-02-03
| |\ \ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/luto/linux into x86/asm Pull "x86: Entry cleanups and a bugfix for 3.20" from Andy Lutomirski: " This fixes a bug in the RCU code I added in ist_enter. It also includes the sysret stuff discussed here: http://lkml.kernel.org/g/cover.1421453410.git.luto%40amacapital.net " Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | | | | | | x86_64, entry: Remove the syscall exit audit and schedule optimizationsAndy Lutomirski2015-02-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We used to optimize rescheduling and audit on syscall exit. Now that the full slow path is reasonably fast, remove these optimizations. Syscall exit auditing is now handled exclusively by syscall_trace_leave. This adds something like 10ns to the previously optimized paths on my computer, presumably due mostly to SAVE_REST / RESTORE_REST. I think that we should eventually replace both the syscall and non-paranoid interrupt exit slow paths with a pair of C functions along the lines of the syscall entry hooks. Link: http://lkml.kernel.org/r/22f2aa4a0361707a5cfb1de9d45260b39965dead.1421453410.git.luto@amacapital.net Acked-by: Borislav Petkov <bp@suse.de> Signed-off-by: Andy Lutomirski <luto@amacapital.net>
| | * | | | | | | | x86_64, entry: Use sysret to return to userspace when possibleAndy Lutomirski2015-02-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The x86_64 entry code currently jumps through complex and inconsistent hoops to try to minimize the impact of syscall exit work. For a true fast-path syscall, almost nothing needs to be done, so returning is just a check for exit work and sysret. For a full slow-path return from a syscall, the C exit hook is invoked if needed and we join the iret path. Using iret to return to userspace is very slow, so the entry code has accumulated various special cases to try to do certain forms of exit work without invoking iret. This is error-prone, since it duplicates assembly code paths, and it's dangerous, since sysret can malfunction in interesting ways if used carelessly. It's also inefficient, since a lot of useful cases aren't optimized and therefore force an iret out of a combination of paranoia and the fact that no one has bothered to write even more asm code to avoid it. I would argue that this approach is backwards. Rather than trying to avoid the iret path, we should instead try to make the iret path fast. Under a specific set of conditions, iret is unnecessary. In particular, if RIP==RCX, RFLAGS==R11, RIP is canonical, RF is not set, and both SS and CS are as expected, then movq 32(%rsp),%rsp;sysret does the same thing as iret. This set of conditions is nearly always satisfied on return from syscalls, and it can even occasionally be satisfied on return from an irq. Even with the careful checks for sysret applicability, this cuts nearly 80ns off of the overhead from syscalls with unoptimized exit work. This includes tracing and context tracking, and any return that invokes KVM's user return notifier. For example, the cost of getpid with CONFIG_CONTEXT_TRACKING_FORCE=y drops from ~360ns to ~280ns on my computer. This may allow the removal and even eventual conversion to C of a respectable amount of exit asm. This may require further tweaking to give the full benefit on Xen. It may be worthwhile to adjust signal delivery and exec to try hit the sysret path. This does not optimize returns to 32-bit userspace. Making the same optimization for CS == __USER32_CS is conceptually straightforward, but it will require some tedious code to handle the differences between sysretl and sysexitl. Link: http://lkml.kernel.org/r/71428f63e681e1b4aa1a781e3ef7c27f027d1103.1421453410.git.luto@amacapital.net Signed-off-by: Andy Lutomirski <luto@amacapital.net>
| | * | | | | | | | x86, traps: Fix ist_enter from userspaceAndy Lutomirski2015-02-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | context_tracking_user_exit() has no effect if in_interrupt() returns true, so ist_enter() didn't work. Fix it by calling exception_enter(), and thus context_tracking_user_exit(), before incrementing the preempt count. This also adds an assertion that will catch the problem reliably if CONFIG_PROVE_RCU=y to help prevent the bug from being reintroduced. Link: http://lkml.kernel.org/r/261ebee6aee55a4724746d0d7024697013c40a08.1422709102.git.luto@amacapital.net Fixes: 959274753857 x86, traps: Track entry into and exit from IST context Reported-and-tested-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net>
generated by cgit v1.2.2 (git 2.25.0) at 2025-08-18 00:34:23 -0400