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* kernel: Fix defining of .init_array and .fini_array sectionsZhenlei Huang2024-09-221-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | These input sections can have decimal numbers as the priority suffix. Clang emits the '%u' form, while SORT is an alias for SORT_BY_NAME, hence will result in wrong order of constructors / destructors in output sections. Fix by using the correct sorting command SORT_BY_INIT_PRIORITY instead [1]. The functions referenced by section .fini_array is in the normal order, but been executed in the reverse order. The order is same with .init_array section. Currently these sections are not used, there should be no functional change. Note: As for the .ctors and .dtors sections, both Clang and GCC emit the priority suffix in the form of '%05u', so there is no semantic difference between SORT_BY_NAME and SORT_BY_INIT_PRIORITY for those sections [2]. This fix is extracted from a bigger patch [3] of hselasky, with additional fix for .fini_array section. 1. https://sourceware.org/binutils/docs/ld/Input-Section-Wildcards.html 2. https://reviews.llvm.org/D91187 3. https://reviews.freebsd.org/D40467 Reviewed by: imp (previous version) Obtained from: hselasky MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D45194 (cherry picked from commit e15b5ba77d693609c9a452d1b0a1cdd5eb29350d)
* sys: Remove $FreeBSD$: one-line .c comment patternWarner Losh2023-08-161-1/+0
| | | | Remove /^/[*/]\s*\$FreeBSD\$.*\n/
* amd64: do not assume that kernel is loaded at 2M physicalKonstantin Belousov2021-07-311-3/+2
| | | | | | | | | | | | | | | Allow any 2M aligned contiguous location below 4G for the staging area location. It should still be mapped by loader at KERNBASE. The assumption kernel makes about loader->kernel handoff with regard to the MMU programming are explicitly listed at the beginning of hammer_time(), where kernphys is calculated. Now kernphys is the variable instead of symbol designating the physical address. Reviewed by: markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D31121
* Unobfuscate "KERNLOAD" parameter on amd64. This change lines-up amd64 with theMaxim Sobolev2020-11-251-1/+1
| | | | | | | | | | | | | | | | | i386 and the rest of supported architectures by defining KERNLOAD in the vmparam.h and getting rid of magic constant in the linker script, which albeit documented via comment but isn't programmatically accessible at a compile time. Use KERNLOAD to eliminate another (matching) magic constant 100 lines down inside unremarkable TU "copy.c" 3 levels deep in the EFI loader tree. Reviewed by: markj Approved by: markj MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D27355 Notes: svn path=/head/; revision=368041
* Tighten mapping protections on preloaded files on amd64.Mark Johnston2019-10-181-29/+3
| | | | | | | | | | | | | | | | | | | | | | | | - We load the kernel at 0x200000. Memory below that address need not be executable, so do not map it as such. - Remove references to .ldata and related sections in the kernel linker script. They come from ld.bfd's default linker script, but are not used, and we now use ld.lld to link the amd64 kernel. lld does not contain a default linker script. - Pad the .bss to a 2MB as we do between .text and .data. This forces the loader to load additional files starting in the following 2MB page, preserving the use of superpage mappings for kernel data. - Map memory above the kernel image with NX. The kernel linker now upgrades protections as needed, and other preloaded file types (e.g., entropy, microcode) need not be mapped with execute permissions in the first place. Reviewed by: kib MFC after: 1 month Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D21859 Notes: svn path=/head/; revision=353731
* Expose the kernel's build-ID through sysctlEd Maste2019-06-041-0/+5
| | | | | | | | | | | | | | | After our migration (of certain architectures) to lld the kernel is built with a unique build-ID. Make it available via a sysctl and uname(1) to allow the user to identify their running kernel. Submitted by: Ali Mashtizadeh <ali_mashtizadeh.com> MFC after: 2 weeks Relnotes: Yes Event: Waterloo Hackathon 2019 Differential Revision: https://reviews.freebsd.org/D20326 Notes: svn path=/head/; revision=348611
* Add comment to explain kernel ldscript 0x200000 constantEd Maste2018-11-091-1/+1
| | | | | | | Reported by: linimon Notes: svn path=/head/; revision=340301
* amd64: tweak the read_frequently sectionMateusz Guzik2018-05-181-2/+2
| | | | | | | | | | | | | | | 1. align to 128 bytes to avoid possible waste from the preceeding section 2. sort entries by alignment SORT_BY_ALIGNMENT, plugging the holes (most entries are one byte in size, but they got interleaved with bigger ones) Interestingly I was looking for a feature of the sort earlier and failed to find it. It turns out the script was already utilizing sorting in other places, so shame on me. Thanks for Travis Geiselbrecht for pointing me at the feature. Notes: svn path=/head/; revision=333784
* amd64: align the .data.exclusive_cache_line section to 128Mateusz Guzik2018-05-111-2/+2
| | | | | | | | | | | | This aligns the section itself compared to other sections, does not change internal alignment of fields stored inside. This may or may not come later. The motivation is partially combating adverse effects of the adjacent cache line prefetcher. Without the annotation part of read_mostly section was on the line of fire. Notes: svn path=/head/; revision=333486
* amd64: Protect the kernel text, data, and BSS by setting the RW/NX bitsJonathan T. Looney2018-03-061-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | correctly for the data contained on each memory page. There are several components to this change: * Add a variable to indicate the start of the R/W portion of the initial memory. * Stop detecting NX bit support for each AP. Instead, use the value from the BSP and, if supported, activate the feature on the other APs just before loading the correct page table. (Functionally, we already assume that the BSP and all APs had the same support or lack of support for the NX bit.) * Set the RW and NX bits correctly for the kernel text, data, and BSS (subject to some caveats below). * Ensure DDB can write to memory when necessary (such as to set a breakpoint). * Ensure GDB can write to memory when necessary (such as to set a breakpoint). For this purpose, add new MD functions gdb_begin_write() and gdb_end_write() which the GDB support code can call before and after writing to memory. This change is not comprehensive: * It doesn't do anything to protect modules. * It doesn't do anything for kernel memory allocated after the kernel starts running. * In order to avoid excessive memory inefficiency, it may let multiple types of data share a 2M page, and assigns the most permissions needed for data on that page. Reviewed by: jhb, kib Discussed with: emaste MFC after: 2 weeks Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D14282 Notes: svn path=/head/; revision=330539
* Introduce __read_frequentlyMateusz Guzik2017-09-061-0/+4
| | | | | | | | | | | | | | While __read_mostly groups variables together, their placement is not specified. In particular 2 frequently used variables can end up in different lines. This annotation is only expected to be used for variables read all the time, e.g. on each syscall entry. MFC after: 1 week Notes: svn path=/head/; revision=323235
* use INT3 instead of NOP for x86 binary paddingEd Maste2017-03-191-3/+3
| | | | | | | | | | | | | | | | | We should never end up executing the inter-function padding, so we are better off faulting than silently carrying on to whatever function happens to be next. Note that LLD will soon do this by default (although it currently pads with zeros). Reviewed by: dim, kib MFC after: 1 month Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D10047 Notes: svn path=/head/; revision=315522
* Introduce __read_mostly and __exclusive_cache_line macros.Mateusz Guzik2017-01-271-0/+11
| | | | | | | | | | | | | | | | The intended use is to annotate frequently used globals which either rarely change (and thus can be grouped in the same cacheline) or are an atomic counter (which means it may benefit from being the only variable in the cacheline). Linker script support is provided only for amd64. Architectures without it risk having other variables put in, i.e. as if they were not annotated. This is harmless from correctness point of view. Reviewed by: bde (previous version) MFC after: 1 month Notes: svn path=/head/; revision=312888
* Use explicit 0x200000 instead of MAXPAGESIZE for the amd64 kernel physaddrEd Maste2016-11-251-1/+1
| | | | | | | | | | | | | | | | | | MAXPAGESIZE is not well defined by the GNU ld documentation. Different linkers, and different versions of the same linker, use different MAXPAGESIZE values. Current versions of GNU gold and LLVM's lld use 4K. When set to 4K the kernel panics at boot due to an issue with x86bios. Here we want the kernel physaddr to be the amd64 superpage size, so use that value (2MB) explicitly. With this change GNU gold and LLVM lld can link a working amd64 kernel. PR: 214718 (x86bios) Differential Revision: https://reviews.freebsd.org/D8610 Notes: svn path=/head/; revision=309151
* remove CONSTRUCTORS from kernel linker scriptsEd Maste2016-07-281-1/+0
| | | | | | | | | | | | | | | | | | The linker script CONSTRUCTORS keyword is only meaningful "when linking object file formats which do not support arbitrary sections, such as ECOFF and XCOFF"[1] and is ignored for other object file formats. LLVM's lld does not yet accept (and ignore) CONSTRUCTORS, so just remove CONSTRUCTORS from the linker scripts as it has no effect. [1] https://sourceware.org/binutils/docs/ld/Output-Section-Keywords.html Reviewed by: kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D7343 Notes: svn path=/head/; revision=303442
* amd64: set the correct LMA valuesRoger Pau Monné2015-06-261-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current linker script generates program headers with VMA == LMA: Entry point 0xffffffff802e7000 There are 6 program headers, starting at offset 64 Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align PHDR 0x0000000000000040 0xffffffff80200040 0xffffffff80200040 0x0000000000000150 0x0000000000000150 R E 8 INTERP 0x0000000000000190 0xffffffff80200190 0xffffffff80200190 0x000000000000000d 0x000000000000000d R 1 [Requesting program interpreter: /red/herring] LOAD 0x0000000000000000 0xffffffff80200000 0xffffffff80200000 0x00000000010559b0 0x00000000010559b0 R E 200000 LOAD 0x0000000001056000 0xffffffff81456000 0xffffffff81456000 0x0000000000132638 0x000000000052ecf8 RW 200000 DYNAMIC 0x0000000001056000 0xffffffff81456000 0xffffffff81456000 0x00000000000000d0 0x00000000000000d0 RW 8 GNU_STACK 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 RWE 8 This is fine for the FreeBSD loader, because it completely ignores p_paddr and instead uses p_vaddr with a hardcoded offset. Other loaders however acknowledge p_paddr (like the Xen ELF loader), in which case they will try to load the kernel at the wrong place. Fix this by adding an AT keyword to the first section specifying the physical address, other sections will follow suit, so it ends up looking like: Entry point 0xffffffff802e7000 There are 6 program headers, starting at offset 64 Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align PHDR 0x0000000000000040 0xffffffff80200040 0x0000000000200040 0x0000000000000150 0x0000000000000150 R E 8 INTERP 0x0000000000000190 0xffffffff80200190 0x0000000000200190 0x000000000000000d 0x000000000000000d R 1 [Requesting program interpreter: /red/herring] LOAD 0x0000000000000000 0xffffffff80200000 0x0000000000200000 0x00000000010559b0 0x00000000010559b0 R E 200000 LOAD 0x0000000001056000 0xffffffff81456000 0x0000000001456000 0x0000000000132638 0x000000000052ecf8 RW 200000 DYNAMIC 0x0000000001056000 0xffffffff81456000 0x0000000001456000 0x00000000000000d0 0x00000000000000d0 RW 8 GNU_STACK 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 RWE 8 Tested on bare metal using the native FreeBSD loader and grub2 from TRUEOS. Sponsored by: Citrix Systems R&D Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D2783 Notes: svn path=/head/; revision=284870
* The new binutils has correctly redefined MAXPAGESIZE on amd64 as 0x200000Alan Cox2011-03-281-1/+2
| | | | | | | | | | | | | | | | instead of 0x100000. As a side effect, an amd64 kernel now loads at physical address 0x200000 instead of 0x100000. This is probably for the best because it avoids the use of a 2MB page mapping for the first 1MB of the kernel that also spans the fixed MTRRs. However, getmemsize() still thinks that the kernel loads at 0x100000, and so the physical memory between 0x100000 and 0x200000 is lost. Fix this problem by replacing the hard-wired constant in getmemsize() by a symbol "kernphys" that is defined by the linker script. In collaboration with: kib Notes: svn path=/head/; revision=220090
* Sync sys/conf/ldscript.amd64 with the upstream version, preservingDimitry Andric2010-11-041-35/+81
| | | | | | | | FreeBSD-specific customizations (in particular, the addition of _start_ctors and _stop_ctors). Notes: svn path=/projects/binutils-2.17/; revision=214806
* Binutils commit 0c845abb5a0083c6deebc75975608237015badba increasedDimitry Andric2010-11-041-2/+3
| | | | | | | | | | | | | | | | | | ELF_MAXPAGESIZE for amd64 from 0x00100000 to 0x00200000. This caused the kernel to be incorrectly linked, using the existing linker script, resulting in a virtual address of 0xffffffff80000000 for the LOAD program header. The boot loader will load such a kernel at a real address of 0x00000000, which either causes protection faults in btx, crashes the machine, or (in case of a VMware guest) even makes it power down. :) Fix this by partially synchronizing the amd64 linker script with binutils own updated version, in particular replacing a hardcoded value of 0x00100000 by CONSTANT(MAXPAGESIZE). Notes: svn path=/projects/binutils-2.17/; revision=214799
* Use new output format 'elf64-x86-64-freebsd' instead of 'elf64-x86-64',Dimitry Andric2010-11-011-1/+1
| | | | | | | and similarly 'elf64-sparc-freebsd' instead of 'elf64-sparc'. Notes: svn path=/projects/binutils-2.17/; revision=214647
* Provide the _start_ctors and _stop_ctors symbols. As on i386, the addressesTim J. Robbins2004-05-291-0/+4
| | | | | | | of these are the start and end of the .ctors section. Notes: svn path=/head/; revision=129824
* Sync up with the files in the hammer branch in the p4 tree to get basicPeter Wemm2003-05-011-81/+117
| | | | | | | AMD64 support. There is still more to add. Notes: svn path=/head/; revision=114370
* Add two symbols start_ctors and stop_ctors to allow us to find thePoul-Henning Kamp2003-01-061-0/+4
| | | | | | | .ctors section so we can call the constructors. Notes: svn path=/head/; revision=108777
* Use the new freebsd output format from Binutils 2.13.1.David E. O'Brien2002-10-111-1/+1
| | | | Notes: svn path=/head/; revision=104930
* Remove hard coded magic load address. Now to change the load address,Peter Wemm2001-09-181-1/+1
| | | | | | | | we just have to change the pmap.h constants and ld will automatically adapt based on the "kernbase" symbol. Notes: svn path=/head/; revision=83598
* Add $FreeBSD$Peter Wemm2000-01-111-0/+1
| | | | | | | | Make the alpha linker script more like the i386 version - delete the /usr/local and egcs directories Notes: svn path=/head/; revision=55825
* Remove a rather bogus search path reference..Peter Wemm1999-06-031-1/+1
| | | | Notes: svn path=/head/; revision=47719
* Increased kernel virtual address space to 1GB. NOTE: You MUST have fixedDavid Greenman1999-03-111-1/+1
| | | | | | | | | | | bootblocks in order to boot the kernel after this! Also note that this change breaks BSDI BSD/OS compatibility. Also increased default NKPT to 17 so that FreeBSD can boot on machines with >=2GB of RAM. Booting on machines with exactly 4GB requires other patches, not included. Notes: svn path=/head/; revision=44670
* Make the ELF kernel build produce a dynamic executable (!). This enablesPeter Wemm1998-09-301-0/+128
the in-kernel linker to access the _DYNAMIC data for doing loadable elf modules. The alpha kernel is already done this way, I've borrowed some of the hacks from there. This is primarily aimed at the 3-stage boot process which is intended to be able to do pre-loading of kernel modules. Note that the entry point isn't 0xf0100000 any more, it'll be a little further on - but this value is stored in the headers. I don't think this will be a problem, but I'm sure somebody will tell me if it is. :-) I'm not sure if btxboot is going to like this, it doesn't do proper ELF header checking and assumes that there are exactly two program header entries and that they are both PT_LOAD entries - a bad assumption. Notes: svn path=/head/; revision=39818
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