Changes in fixmap.h

24a295e4 - x86/headers: Replace ASSEMBLY with ASSEMBLER in non-UAPI headers

Wed, 19 Mar 2025 10:30:57 +0000

x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-UAPI headersWhile the GCC and Clang compilers already define __ASSEMBLER__automatically when compiling assembly code, __ASSEMBLY__ is amacro that only gets defined by the Makefiles in the kernel.This can be very confusing when switching between userspaceand kernelspace coding, or when dealing with UAPI headers thatrather should use __ASSEMBLER__ instead. So let's standardize onthe __ASSEMBLER__ macro that is provided by the compilers now.This is mostly a mechanical patch (done with a simple "sed -i"statement), with some manual tweaks in , and that mentioned this macro in comments with somemissing underscores.Signed-off-by: Thomas Huth Signed-off-by: Ingo Molnar Cc: Brian Gerst Cc: Juergen Gross Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Link: https://lore.kernel.org/r/20250314071013.1575167-38-thuth@redhat.com List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

2468f933 - x86/platform/intel-mid: Remove unused leftovers (vRTC)

Mon, 25 Jan 2021 19:39:46 +0000

x86/platform/intel-mid: Remove unused leftovers (vRTC)There is no driver present, remove the device creation and otherleftovers.Signed-off-by: Andy Shevchenko Acked-by: Linus Walleij Signed-off-by: Rafael J. Wysocki List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

14df3267 - x86: Support kmap_local() forced debugging

Wed, 18 Nov 2020 19:48:41 +0000

x86: Support kmap_local() forced debuggingkmap_local() and related interfaces are NOOPs on 64bit and only createtemporary fixmaps for highmem pages on 32bit. That means the test coveragefor this code is pretty small.CONFIG_KMAP_LOCAL can be enabled independent from CONFIG_HIGHMEM, whichallows to provide support for enforced kmap_local() debugging even on64bit.For 32bit the support is unconditional, for 64bit it's only supported whenCONFIG_NR_CPUS <= 4096 as supporting it for 8192 CPUs would require to setup yet another fixmap PGT.If CONFIG_KMAP_LOCAL_FORCE_DEBUG is enabled then kmap_local()/kmap_atomic()will use the temporary fixmap mapping path.Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20201118204007.169209557@linutronix.de List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

157e118b - x86/mm/highmem: Use generic kmap atomic implementation

Tue, 03 Nov 2020 09:27:20 +0000

x86/mm/highmem: Use generic kmap atomic implementationConvert X86 to the generic kmap atomic implementation and make theiomap_atomic() naming convention consistent while at it.Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20201103095857.375127260@linutronix.de List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

ecac7181 - x86/paravirt: Use CONFIG_PARAVIRT_XXL instead of CONFIG_PARAVIRT

Sat, 15 Aug 2020 10:06:38 +0000

x86/paravirt: Use CONFIG_PARAVIRT_XXL instead of CONFIG_PARAVIRTThere are some code parts using CONFIG_PARAVIRT for Xen pvops relatedissues instead of the more stringent CONFIG_PARAVIRT_XXL.Signed-off-by: Juergen Gross Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20200815100641.26362-4-jgross@suse.com List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

0cd39f46 - locking/seqlock, headers: Untangle the spaghetti monster

Thu, 06 Aug 2020 12:35:11 +0000

locking/seqlock, headers: Untangle the spaghetti monsterBy using lockdep_assert_*() from seqlock.h, the spaghetti monsterattacked.Attack back by reducing seqlock.h dependencies from two key high level headers: - : -Remove - : -Remove - : +Add The price was to add it to sched.h ...Core header fallout, we add direct header dependencies instead of gaining themparasitically from higher level headers: - : +Add - : +Add - : +Add - : +Add - : +Add - : +Add Arch headers fallout: - PARISC: : +Add - SH: : +Add - SPARC: : +Add - SPARC: : +Add , -Remove - X86: : +Add -Remove There's also a bunch of parasitic header dependency fallout in .c files, not listedseparately.[ mingo: Extended the changelog, split up & fixed the original patch. ]Co-developed-by: Ingo Molnar Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20200804133438.GK2674@hirez.programming.kicks-ass.net List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

090e77e1 - kmap: consolidate kmap_prot definitions

Thu, 04 Jun 2020 23:48:18 +0000

kmap: consolidate kmap_prot definitionsMost architectures define kmap_prot to be PAGE_KERNEL.Let sparc and xtensa define there own and define PAGE_KERNEL as thedefault if not overridden.[akpm@linux-foundation.org: coding style fixes]Suggested-by: Christoph Hellwig Signed-off-by: Ira Weiny Signed-off-by: Andrew Morton Cc: Al Viro Cc: Andy Lutomirski Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Christian König Cc: Chris Zankel Cc: Daniel Vetter Cc: Dan Williams Cc: Dave Hansen Cc: "David S. Miller" Cc: Helge Deller Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: "James E.J. Bottomley" Cc: Max Filippov Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20200507150004.1423069-16-ira.weiny@intel.comSigned-off-by: Linus Torvalds List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

f53e2cd0 - x86/mm: Use the correct function type for native_set_fixmap()

Fri, 13 Sep 2019 21:14:02 +0000

x86/mm: Use the correct function type for native_set_fixmap()We call native_set_fixmap indirectly through the function pointerstruct pv_mmu_ops::set_fixmap, which expects the first parameter to be'unsigned' instead of 'enum fixed_addresses'. This patch changes thefunction type for native_set_fixmap to match the pointer, which fixesindirect call mismatches with Control-Flow Integrity (CFI) checking.Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H . Peter Anvin Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20190913211402.193018-1-samitolvanen@google.comSigned-off-by: Ingo Molnar List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

c84b82dd - x86/fixmap: Cleanup outdated comments

Fri, 09 Aug 2019 11:46:12 +0000

x86/fixmap: Cleanup outdated commentsRemove stale comments and fix the not longer valid pagetable entryreference.Signed-off-by: Cao jin Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20190809114612.2569-1-caoj.fnst@cn.fujitsu.com List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

b3fd8e83 - x86/alternatives: Use temporary mm for text poking

Fri, 26 Apr 2019 00:11:27 +0000

x86/alternatives: Use temporary mm for text pokingtext_poke() can potentially compromise security as it sets temporaryPTEs in the fixmap. These PTEs might be used to rewrite the kernel codefrom other cores accidentally or maliciously, if an attacker gains theability to write onto kernel memory.Moreover, since remote TLBs are not flushed after the temporary PTEs areremoved, the time-window in which the code is writable is not limited ifthe fixmap PTEs - maliciously or accidentally - are cached in the TLB.To address these potential security hazards, use a temporary mm forpatching the code.Finally, text_poke() is also not conservative enough when mapping pages,as it always tries to map 2 pages, even when a single one is sufficient.So try to be more conservative, and do not map more than needed.Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Rik van Riel Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20190426001143.4983-8-namit@vmware.comSigned-off-by: Ingo Molnar List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

05ab1d8a - x86/mm: Expand static page table for fixmap space

Thu, 20 Sep 2018 02:58:28 +0000

x86/mm: Expand static page table for fixmap spaceWe met a kernel panic when enabling earlycon, which is due to the fixmapaddress of earlycon is not statically setup.Currently the static fixmap setup in head_64.S only covers 2M virtualaddress space, while it actually could be in 4M space with differentkernel configurations, e.g. when VSYSCALL emulation is disabled.So increase the static space to 4M for now by defining FIXMAP_PMD_NUM to 2,and add a build time check to ensure that the fixmap is covered by theinitial static page tables.Fixes: 1ad83c858c7d ("x86_64,vsyscall: Make vsyscall emulation configurable")Suggested-by: Thomas Gleixner Signed-off-by: Feng Tang Signed-off-by: Thomas Gleixner Tested-by: kernel test robot Reviewed-by: Juergen Gross (Xen parts)Cc: H Peter Anvin Cc: Peter Zijlstra Cc: Michal Hocko Cc: Yinghai Lu Cc: Dave Hansen Cc: Andi Kleen Cc: Andy Lutomirsky Cc: stable@vger.kernel.orgLink: https://lkml.kernel.org/r/20180920025828.23699-1-feng.tang@intel.com List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

fdc0269e - x86/paravirt: Move the Xen-only pv_mmu_ops under the PARAVIRT_XXL umbrella

Tue, 28 Aug 2018 07:40:25 +0000

x86/paravirt: Move the Xen-only pv_mmu_ops under the PARAVIRT_XXL umbrellaMost of the paravirt ops defined in pv_mmu_ops are for Xen PV guestsonly. Define them only if CONFIG_PARAVIRT_XXL is set.Signed-off-by: Juergen Gross Signed-off-by: Thomas Gleixner Cc: xen-devel@lists.xenproject.orgCc: virtualization@lists.linux-foundation.orgCc: akataria@vmware.comCc: rusty@rustcorp.com.auCc: boris.ostrovsky@oracle.comCc: hpa@zytor.comLink: https://lkml.kernel.org/r/20180828074026.820-15-jgross@suse.com List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

55f49fcb - x86/mm: Fix overlap of i386 CPU_ENTRY_AREA with FIX_BTMAP

Tue, 30 Jan 2018 11:22:55 +0000

x86/mm: Fix overlap of i386 CPU_ENTRY_AREA with FIX_BTMAPSince commit 92a0f81d8957 ("x86/cpu_entry_area: Move it out of thefixmap"), i386's CPU_ENTRY_AREA has been mapped to the memory area justbelow FIXADDR_START. But already immediately before FIXADDR_START is theFIX_BTMAP area, which means that early_ioremap can collide with the entryarea.It's especially bad on PAE where FIX_BTMAP_BEGIN gets aligned to exactlymatch CPU_ENTRY_AREA_BASE, so the first early_ioremap slot clobbers theIDT and causes interrupts during early boot to reset the system.The overlap wasn't a problem before the CPU entry area was introduced,as the fixmap has classically been preceded by the pkmap or vmallocareas, neither of which is used until early_ioremap is out of thepicture.Relocate CPU_ENTRY_AREA to below FIX_BTMAP, not just below the permanentfixmap area.Fixes: commit 92a0f81d8957 ("x86/cpu_entry_area: Move it out of the fixmap")Signed-off-by: William Grant Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.orgLink: https://lkml.kernel.org/r/7041d181-a019-e8b9-4e4e-48215f841e2c@canonical.com List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

92a0f81d - x86/cpu_entry_area: Move it out of the fixmap

Wed, 20 Dec 2017 17:51:31 +0000

x86/cpu_entry_area: Move it out of the fixmapPut the cpu_entry_area into a separate P4D entry. The fixmap gets too bigand 0-day already hit a case where the fixmap PTEs were cleared bycleanup_highmap().Aside of that the fixmap API is a pain as it's all backwards.Signed-off-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: linux-kernel@vger.kernel.orgSigned-off-by: Ingo Molnar List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

ed1bbc40 - x86/cpu_entry_area: Move it to a separate unit

Wed, 20 Dec 2017 17:28:54 +0000

x86/cpu_entry_area: Move it to a separate unitSeparate the cpu_entry_area code out of cpu/common.c and the fixmap.Signed-off-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Signed-off-by: Ingo Molnar List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

4fe2d8b1 - x86/entry: Rename SYSENTER_stack to CPU_ENTRY_AREA_entry_stack

Tue, 05 Dec 2017 01:25:07 +0000

x86/entry: Rename SYSENTER_stack to CPU_ENTRY_AREA_entry_stackIf the kernel oopses while on the trampoline stack, it will print"" even if SYSENTER is not involved. That is rather confusing.The "SYSENTER" stack is used for a lot more than SYSENTER now. Give it abetter string to display in stack dumps, and rename the kernel code tomatch.Also move the 32-bit code over to the new naming even though it still usesthe entry stack only for SYSENTER.Signed-off-by: Dave Hansen Signed-off-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Signed-off-by: Ingo Molnar List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

c482feef - x86/entry/64: Make cpu_entry_area.tss read-only

Mon, 04 Dec 2017 14:07:29 +0000

x86/entry/64: Make cpu_entry_area.tss read-onlyThe TSS is a fairly juicy target for exploits, and, now that the TSSis in the cpu_entry_area, it's no longer protected by kASLR. Make itread-only on x86_64.On x86_32, it can't be RO because it's written by the CPU during taskswitches, and we use a task gate for double faults. I'd also benervous about errata if we tried to make it RO even on configurationswithout double fault handling.[ tglx: AMD confirmed that there is no problem on 64-bit with TSS RO. So it's probably safe to assume that it's a non issue, though Intel might have been creative in that area. Still waiting for confirmation. ]Signed-off-by: Andy Lutomirski Signed-off-by: Thomas Gleixner Reviewed-by: Borislav Petkov Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Dave Hansen Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Kees Cook Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: Will Deacon Cc: aliguori@amazon.comCc: daniel.gruss@iaik.tugraz.atCc: hughd@google.comCc: keescook@google.comLink: https://lkml.kernel.org/r/20171204150606.733700132@linutronix.deSigned-off-by: Ingo Molnar List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

0f9a4810 - x86/entry: Clean up the SYSENTER_stack code

Mon, 04 Dec 2017 14:07:28 +0000

x86/entry: Clean up the SYSENTER_stack codeThe existing code was a mess, mainly because C arrays are nasty. TurnSYSENTER_stack into a struct, add a helper to find it, and do all theobvious cleanups this enables.Signed-off-by: Andy Lutomirski Signed-off-by: Thomas Gleixner Reviewed-by: Thomas Gleixner Reviewed-by: Borislav Petkov Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Dave Hansen Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: Will Deacon Cc: aliguori@amazon.comCc: daniel.gruss@iaik.tugraz.atCc: hughd@google.comCc: keescook@google.comLink: https://lkml.kernel.org/r/20171204150606.653244723@linutronix.deSigned-off-by: Ingo Molnar List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

40e7f949 - x86/entry/64: Move the IST stacks into struct cpu_entry_area

Mon, 04 Dec 2017 14:07:26 +0000

x86/entry/64: Move the IST stacks into struct cpu_entry_areaThe IST stacks are needed when an IST exception occurs and are accessedbefore any kernel code at all runs. Move them into struct cpu_entry_area.The IST stacks are unlike the rest of cpu_entry_area: they're used even forentries from kernel mode. This means that they should be set up before weload the final IDT. Move cpu_entry_area setup to trap_init() for the bootCPU and set it up for all possible CPUs at once in native_smp_prepare_cpus().Signed-off-by: Andy Lutomirski Signed-off-by: Thomas Gleixner Reviewed-by: Thomas Gleixner Reviewed-by: Borislav Petkov Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Dave Hansen Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: Will Deacon Cc: aliguori@amazon.comCc: daniel.gruss@iaik.tugraz.atCc: hughd@google.comCc: keescook@google.comLink: https://lkml.kernel.org/r/20171204150606.480598743@linutronix.deSigned-off-by: Ingo Molnar List of files: /linux-6.15/arch/x86/include/asm/fixmap.h

3386bc8a - x86/entry/64: Create a per-CPU SYSCALL entry trampoline

Mon, 04 Dec 2017 14:07:25 +0000

x86/entry/64: Create a per-CPU SYSCALL entry trampolineHandling SYSCALL is tricky: the SYSCALL handler is entered with everysingle register (except FLAGS), including RSP, live. It somehow needsto set RSP to point to a valid stack, which means it needs to save theuser RSP somewhere and find its own stack pointer. The canonical wayto do this is with SWAPGS, which lets us access percpu data using the%gs prefix.With PAGE_TABLE_ISOLATION-like pagetable switching, this isproblematic. Without a scratch register, switching CR3 is impossible, so%gs-based percpu memory would need to be mapped in the user pagetables.Doing that without information leaks is difficult or impossible.Instead, use a different sneaky trick. Map a copy of the first partof the SYSCALL asm at a different address for each CPU. Now RIPvaries depending on the CPU, so we can use RIP-relative memory accessto access percpu memory. By putting the relevant information (onescratch slot and the stack address) at a constant offset relative toRIP, we can make SYSCALL work without relying on %gs.A nice thing about this approach is that we can easily switch it onand off if we want pagetable switching to be configurable.The compat variant of SYSCALL doesn't have this problem in the firstplace -- there are plenty of scratch registers, since we don't careabout preserving r8-r15. This patch therefore doesn't touch SYSCALL32at all.This patch actually seems to be a small speedup. With this patch,SYSCALL touches an extra cache line and an extra virtual page, butthe pipeline no longer stalls waiting for SWAPGS. It seems that, atleast in a tight loop, the latter outweights the former.Thanks to David Laight for an optimization tip.Signed-off-by: Andy Lutomirski Signed-off-by: Thomas Gleixner Reviewed-by: Thomas Gleixner Reviewed-by: Borislav Petkov Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Dave Hansen Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: Will Deacon Cc: aliguori@amazon.comCc: daniel.gruss@iaik.tugraz.atCc: hughd@google.comCc: keescook@google.comLink: https://lkml.kernel.org/r/20171204150606.403607157@linutronix.deSigned-off-by: Ingo Molnar List of files: /linux-6.15/arch/x86/include/asm/fixmap.h