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* x86/vdso: Fix vdso2c's special_pages[] error checkingAndy Lutomirski2014-09-241-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | Stephen Rothwell's compiler did something amazing: it unrolled a loop, discovered that one iteration of that loop contained an always-true test, and emitted a warning that will IMO only serve to convince people to disable the warning. That bogus warning caused me to wonder what prompted such an absurdity from his compiler, and I discovered that the code in question was, in fact, completely wrong -- I was looking things up in the wrong array. This affects 3.16 as well, but the only effect is to screw up the error checking a bit. vdso2c's output is unaffected. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/53d96ad5.80ywqrbs33ZBCQej%25akpm@linux-foundation.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* arm64,ia64,ppc,s390,sh,tile,um,x86,mm: remove default gate areaAndy Lutomirski2014-08-091-18/+1Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The core mm code will provide a default gate area based on FIXADDR_USER_START and FIXADDR_USER_END if !defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR). This default is only useful for ia64. arm64, ppc, s390, sh, tile, 64-bit UML, and x86_32 have their own code just to disable it. arm, 32-bit UML, and x86_64 have gate areas, but they have their own implementations. This gets rid of the default and moves the code into ia64. This should save some code on architectures without a gate area: it's now possible to inline the gate_area functions in the default case. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Acked-by: Nathan Lynch <nathan_lynch@mentor.com> Acked-by: H. Peter Anvin <hpa@linux.intel.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> [in principle] Acked-by: Richard Weinberger <richard@nod.at> [for um] Acked-by: Will Deacon <will.deacon@arm.com> [for arm64] Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Nathan Lynch <Nathan_Lynch@mentor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86/vdso: Set VM_MAYREAD for the vvar vmaAndy Lutomirski2014-07-261-1/+1
| | | | | | | | | | | | The VVAR area can, obviously, be read; that is kind of the point. AFAIK this has no effect whatsoever unless x86 suddenly turns into a nommu architecture. Nonetheless, not setting it is suspicious. Reported-by: Nathan Lynch <Nathan_Lynch@mentor.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/e4c8bf4bc2725bda22c4a4b7d0c82adcd8f8d9b8.1406330779.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86, vdso: Get rid of the fake section mechanismAndy Lutomirski2014-07-124-229/+126Star
| | | | | | | | | | | | | Now that we can tolerate extra things dangling off the end of the vdso image, we can strip the vdso the old fashioned way rather than using an overcomplicated custom stripping algorithm. This is a partial reversion of: 6f121e5 x86, vdso: Reimplement vdso.so preparation in build-time C Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/50e01ed6dcc0575d20afd782f9fe98d5ee3e2d8a.1405040914.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86, vdso: Move the vvar area before the vdso textAndy Lutomirski2014-07-124-48/+53
| | | | | | | | | | | | | | | | Putting the vvar area after the vdso text is rather complicated: it only works of the total length of the vdso text mapping is known at vdso link time, and the linker doesn't allow symbol addresses to depend on the sizes of non-allocatable data after the PT_LOAD segment. Moving the vvar area before the vdso text will allow is to safely map non-allocatable data after the vdso text, which is a nice simplification. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/156c78c0d93144ff1055a66493783b9e56813983.1405040914.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86-32, vdso: Fix vDSO build error due to missing align_vdso_addr()Jan Beulich2014-07-111-0/+4
| | | | | | | | | | | | | | | | | | | Relying on static functions used just once to get inlined (and subsequently have dead code paths eliminated) is wrong: Compilers are free to decide whether they do this, regardless of optimization level. With this not happening for vdso_addr() (observed with gcc 4.1.x), an unresolved reference to align_vdso_addr() causes the build to fail. [ hpa: vdso_addr() is never actually used on x86-32, as calculate_addr in map_vdso() is always false. It ought to be possible to clean this up further, but this fixes the immediate problem. ] Signed-off-by: Jan Beulich <jbeulich@suse.com> Link: http://lkml.kernel.org/r/53B5863B02000078000204D5@mail.emea.novell.com Acked-by: Andy Lutomirski <luto@amacapital.net> Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Tested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86-64, vdso: Fix vDSO build breakage due to empty .rela.dynJan Beulich2014-07-111-0/+3
| | | | | | | | | | | | | | Certain ld versions (observed with 2.20.0) put an empty .rela.dyn section into shared object files, breaking the assumption on the number of sections to be copied to the final output. Simply discard any empty SHT_REL and SHT_RELA sections to address this. Signed-off-by: Jan Beulich <jbeulich@suse.com> Link: http://lkml.kernel.org/r/53B5861E02000078000204D1@mail.emea.novell.com Acked-by: Andy Lutomirski <luto@amacapital.net> Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Tested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86/vdso: Error out in vdso2c if DT_RELA is presentAndy Lutomirski2014-06-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | vdso2c was checking for various types of relocations to detect when the vdso had undefined symbols or was otherwise dependent on relocation at load time. Undefined symbols in the vdso would fail if accessed at runtime, and certain implementation errors (e.g. branch profiling or incorrect symbol visibilities) could result in data access through the GOT that requires relocations. This could be as simple as: extern char foo; return foo; Without some kind of visibility control, the compiler would assume that foo could be interposed at load time and would generate a relocation. x86-64 and x32 (as opposed to i386) use explicit-addent (RELA) instead of implicit-addent (REL) relocations for data access, and vdso2c forgot to detect those. Whether these bad relocations would actually fail at runtime depends on what the linker sticks in the unrelocated references. Nonetheless, these relocations have no business existing in the vDSO and should be fixed rather than silently ignored. This error could trigger on some configurations due to branch profiling. The previous patch fixed that. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/74ef0c00b4d2a3b573e00a4113874e62f772e348.1403642755.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86/vdso: Move DISABLE_BRANCH_PROFILING into the vdso makefileAndy Lutomirski2014-06-242-4/+3Star
| | | | | | | | | | | | | | | | | | DISABLE_BRANCH_PROFILING turns off branch profiling (i.e. a redefinition of 'if'). Branch profiling depends on a bunch of kernel-internal symbols and generates extra output sections, none of which are useful or functional in the vDSO. It's currently turned off for vclock_gettime.c, but vgetcpu.c also triggers branch profiling, so just turn it off in the makefile. This fixes the build on some configurations: the vdso could contain undefined symbols, and the fake section table overflowed due to ftrace's added sections. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/bf1ec29e03b2bbc081f6dcaefa64db1c3a83fb21.1403642755.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86/vdso: Create .build-id links for unstripped vdso filesAndy Lutomirski2014-06-201-3/+13
| | | | | | | | | | | | | | | | | | | | | | | | With this change, doing 'make vdso_install' and telling gdb: set debug-file-directory /lib/modules/KVER/vdso will enable vdso debugging with symbols. This is useful for testing, but kernel RPM builds will probably want to manually delete these symlinks or otherwise do something sensible when they strip the vdso/*.so files. If ld does not support --build-id, then the symlinks will not be created. Note that kernel packagers that use vdso_install may need to adjust their packaging scripts to accomdate this change. For example, Fedora's scripts create build-id symlinks themselves in a different location, so the spec should probably be updated to remove the symlinks created by make vdso_install. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/a424b189ce3ced85fe1e82d032a20e765e0fe0d3.1403291930.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86/vdso: Remove some redundant in-memory section headersAndy Lutomirski2014-06-203-24/+26
| | | | | | | | | | | | | | | | | | | | | | | | | .data doesn't need to be separate from .rodata: they're both readonly. .altinstructions and .altinstr_replacement aren't needed by anything except vdso2c; strip them from the final image. While we're at it, rather than aligning the actual executable text, just shove some unused-at-runtime data in between real data and text. My vdso image is still above 4k, but I'm disinclined to try to trim it harder for 3.16. For future trimming, I suspect that these sections could be moved to later in the file and dropped from the in-memory image: .gnu.version and .gnu.version_d (this may lose versions in gdb) .eh_frame (should be harmless) .eh_frame_hdr (I'm not really sure) .hash (AFAIK nothing needs this section header) Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/2e96d0c49016ea6d026a614ae645e93edd325961.1403129369.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86/vdso: Improve the fake section headersAndy Lutomirski2014-06-208-67/+237
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fully stripping the vDSO has other unfortunate side effects: - binutils is unable to find ELF notes without a SHT_NOTE section. - Even elfutils has trouble: it can find ELF notes without a section table at all, but if a section table is present, it won't look for PT_NOTE. - gdb wants section names to match between stripped DSOs and their symbols; otherwise it will corrupt symbol addresses. We're also breaking the rules: section 0 is supposed to be SHT_NULL. Fix these problems by building a better fake section table. While we're at it, we might as well let buggy Go versions keep working well by giving the SHT_DYNSYM entry the correct size. This is a bit unfortunate: it adds quite a bit of size to the vdso image. If/when binutils improves and the improved versions become widespread, it would be worth considering dropping most of this. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/0e546a5eeaafdf1840e6ee654a55c1e727c26663.1403129369.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86/vdso2c: Use better macros for ELF bitnessAndy Lutomirski2014-06-202-40/+25Star
| | | | | | | | | Rather than using a separate macro for each replacement, use generic macros. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/d953cd2e70ceee1400985d091188cdd65fba2f05.1403129369.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86/vdso: Discard the __bug_table sectionAndy Lutomirski2014-06-201-0/+1
| | | | | | | | It serves no purpose in user code. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/2a5bebff42defd8a5e81d96f7dc00f21143c80e8.1403129369.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86/vdso: Fix vdso_installAndy Lutomirski2014-06-131-11/+11
| | | | | | | | | | | | | | | | | | | | | | | "make vdso_install" installs unstripped versions of the vdso objects for the benefit of the debugger. This was broken by checkin: 6f121e548f83 x86, vdso: Reimplement vdso.so preparation in build-time C The filenames are different now, so update the Makefile to cope. This still installs the 64-bit vdso as vdso64.so. We believe this will be okay, as the only known user is a patched gdb which is known to use build-ids, but if it turns out to be a problem we may have to add a link. Inspired by a patch from Sam Ravnborg. Acked-by: Sam Ravnborg <sam@ravnborg.org> Reported-by: Josh Boyer <jwboyer@fedoraproject.org> Tested-by: Josh Boyer <jwboyer@fedoraproject.org> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/b10299edd8ba98d17e07dafcd895b8ecf4d99eff.1402586707.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* x86/vdso: Hack to keep 64-bit Go programs workingAndy Lutomirski2014-06-133-13/+60
| | | | | | | | | | | | | | The Go runtime has a buggy vDSO parser that currently segfaults. This writes an empty SHT_DYNSYM entry that causes Go's runtime to malfunction by thinking that the vDSO is empty rather than malfunctioning by running off the end and segfaulting. This affects x86-64 only as far as we know, so we do not need this for the i386 and x32 vdsos. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/d10618176c4bd39b457a5e85c497295c90cab1bc.1402620737.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* x86/vdso: Add PUT_LE to store little-endian valuesAndy Lutomirski2014-06-131-3/+16
| | | | | | | | | Add PUT_LE() by analogy with GET_LE() to write littleendian values in addition to reading them. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/3d9b27e92745b27b6fda1b9a98f70dc9c1246c7a.1402620737.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* x86, vdso: Remove one final use of htole16()H. Peter Anvin2014-06-111-1/+1
| | | | | | | | | | | | | | One final use of the macros from <endian.h> which are not available on older system. In this case we had one sole case of *writing* a littleendian number, but the number is SHN_UNDEF which is the constant zero, so rather than dealing with the general case of littleendian puts here, just document that the constant is zero and be done with it. Reported-and-Tested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/20140610135051.c3c34165f73d67d218b62bd9@linux-foundation.org
* x86, vdso: Use <tools/le_byteshift.h> for littleendian accessH. Peter Anvin2014-06-063-35/+38
| | | | | | | | | | | | | There are no standard functions for littleendian data (unlike bigendian data.) Thus, use <tools/le_byteshift.h> to access littleendian data members. Those are fairly inefficient, but it doesn't matter for this purpose (and can be optimized later.) This avoids portability problems. Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Tested-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/20140606140017.afb7f91142f66cb3dd13c186@linux-foundation.org
* x86/vdso, build: Make LE access macros clearer, host-safeH. Peter Anvin2014-05-312-39/+42
| | | | | | | | | | | | | | | Make it a little clearer what the littleendian access macros in vdso2c.[ch] actually do. This way they can probably also be moved to a central location (e.g. tools/include) for the benefit of other host tools. We should avoid implementation namespace symbols when writing code that is compiling for the compiler host, so avoid names starting with double underscore or underscore-capital. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/2cf258df123cb24bad63c274c8563c050547d99d.1401464755.git.luto@amacapital.net
* x86/vdso, build: Fix cross-compilation from big-endian architecturesAndy Lutomirski2014-05-312-28/+50
| | | | | | | | | | This adds a macro GET(x) to convert x from big-endian to little-endian. Hopefully I put it everywhere it needs to go and got all the cases needed for everyone's linux/elf.h. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/2cf258df123cb24bad63c274c8563c050547d99d.1401464755.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86/vdso, build: When vdso2c fails, unlink the outputAndy Lutomirski2014-05-312-16/+14Star
| | | | | | | | This avoids bizarre failures if make is run again. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/1764385fe9931e8940b9d001132515448ea89523.1401464755.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86, mm: Improve _install_special_mapping and fix x86 vdso namingAndy Lutomirski2014-05-203-17/+20
| | | | | | | | | | | | | | | | | | | | | | | | Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86, vdso: Fix an OOPS accessing the HPET mapping w/o an HPETAndy Lutomirski2014-05-201-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | The oops can be triggered in qemu using -no-hpet (but not nohpet) by reading a couple of pages past the end of the vdso text. This should send SIGBUS instead of OOPSing. The bug was introduced by: commit 7a59ed415f5b57469e22e41fc4188d5399e0b194 Author: Stefani Seibold <stefani@seibold.net> Date: Mon Mar 17 23:22:09 2014 +0100 x86, vdso: Add 32 bit VDSO time support for 32 bit kernel which is new in 3.15. This will be fixed separately in 3.15, but that patch will not apply to tip/x86/vdso. This is the equivalent fix for tip/x86/vdso and, presumably, 3.16. Cc: Stefani Seibold <stefani@seibold.net> Reported-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/c8b0a9a0b8d011a8b273cbb2de88d37190ed2751.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86, vdso: Remove vestiges of VDSO_PRELINK and some outdated commentsAndy Lutomirski2014-05-053-16/+3Star
| | | | | | | | These definitions had no effect. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/946c104e40c47319f8ab406e54118799cb55bd99.1399317206.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86, vdso: Move the vvar and hpet mappings next to the 64-bit vDSOAndy Lutomirski2014-05-052-19/+5Star
| | | | | | | | | This makes the 64-bit and x32 vdsos use the same mechanism as the 32-bit vdso. Most of the churn is deleting all the old fixmap code. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/8af87023f57f6bb96ec8d17fce3f88018195b49b.1399317206.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86, vdso: Move the 32-bit vdso special pages after the textAndy Lutomirski2014-05-055-150/+166
| | | | | | | | | | | This unifies the vdso mapping code and teaches it how to map special pages at addresses corresponding to symbols in the vdso image. The new code is used for all vdso variants, but so far only the 32-bit variants use the new vvar page position. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/b6d7858ad7b5ac3fd3c29cab6d6d769bc45d195e.1399317206.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86, vdso: Reimplement vdso.so preparation in build-time CAndy Lutomirski2014-05-0511-202/+351
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, vdso.so files are prepared and analyzed by a combination of objcopy, nm, some linker script tricks, and some simple ELF parsers in the kernel. Replace all of that with plain C code that runs at build time. All five vdso images now generate .c files that are compiled and linked in to the kernel image. This should cause only one userspace-visible change: the loaded vDSO images are stripped more heavily than they used to be. Everything outside the loadable segment is dropped. In particular, this causes the section table and section name strings to be missing. This should be fine: real dynamic loaders don't load or inspect these tables anyway. The result is roughly equivalent to eu-strip's --strip-sections option. The purpose of this change is to enable the vvar and hpet mappings to be moved to the page following the vDSO load segment. Currently, it is possible for the section table to extend into the page after the load segment, so, if we map it, it risks overlapping the vvar or hpet page. This happens whenever the load segment is just under a multiple of PAGE_SIZE. The only real subtlety here is that the old code had a C file with inline assembler that did 'call VDSO32_vsyscall' and a linker script that defined 'VDSO32_vsyscall = __kernel_vsyscall'. This most likely worked by accident: the linker script entry defines a symbol associated with an address as opposed to an alias for the real dynamic symbol __kernel_vsyscall. That caused ld to relocate the reference at link time instead of leaving an interposable dynamic relocation. Since the VDSO32_vsyscall hack is no longer needed, I now use 'call __kernel_vsyscall', and I added -Bsymbolic to make it work. vdso2c will generate an error and abort the build if the resulting image contains any dynamic relocations, so we won't silently generate bad vdso images. (Dynamic relocations are a problem because nothing will even attempt to relocate the vdso.) Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/2c4fcf45524162a34d87fdda1eb046b2a5cecee7.1399317206.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86, vdso: Move syscall and sysenter setup into kernel/cpu/common.cAndy Lutomirski2014-05-051-30/+0Star
| | | | | | | | | | | | | This code is used during CPU setup, and it isn't strictly speaking related to the 32-bit vdso. It's easier to understand how this works when the code is closer to its callers. This also lets syscall32_cpu_init be static, which might save some trivial amount of kernel text. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/4e466987204e232d7b55a53ff6b9739f12237461.1399317206.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86, vdso: Clean up 32-bit vs 64-bit vdso paramsAndy Lutomirski2014-05-052-14/+11Star
| | | | | | | | | Rather than using 'vdso_enabled' and an awful #define, just call the parameters vdso32_enabled and vdso64_enabled. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/87913de56bdcbae3d93917938302fc369b05caee.1399317206.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* Merge branch 'x86-vdso-for-linus' of ↵Linus Torvalds2014-04-221-11/+8Star
|\ | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 vdso fix from Peter Anvin: "This is a single build fix for building with gold as opposed to GNU ld. It got queued up separately and was expected to be pushed during the merge window, but it got left behind" * 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, vdso: Make the vdso linker script compatible with Gold
| * x86, vdso: Make the vdso linker script compatible with GoldAndy Lutomirski2014-04-031-11/+8Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Gold can't parse the script due to: https://sourceware.org/bugzilla/show_bug.cgi?id=16804 With a workaround in place for that issue, Gold 2.23 crashes due to: https://sourceware.org/bugzilla/show_bug.cgi?id=15355 This works around the former bug and avoids the second by removing the unnecessary vvar and hpet sections and segments. The vdso and hpet symbols are still there, and nothing needed the sections or segments. Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/243fa205098d112ec759c9b1b26785c09f399833.1396547532.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* | Merge branch 'x86-vdso-for-linus' of ↵Linus Torvalds2014-04-0210-383/+349Star
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 vdso changes from Peter Anvin: "This is the revamp of the 32-bit vdso and the associated cleanups. This adds timekeeping support to the 32-bit vdso that we already have in the 64-bit vdso. Although 32-bit x86 is legacy, it is likely to remain in the embedded space for a very long time to come. This removes the traditional COMPAT_VDSO support; the configuration variable is reused for simply removing the 32-bit vdso, which will produce correct results but obviously suffer a performance penalty. Only one beta version of glibc was affected, but that version was unfortunately included in one OpenSUSE release. This is not the end of the vdso cleanups. Stefani and Andy have agreed to continue work for the next kernel cycle; in fact Andy has already produced another set of cleanups that came too late for this cycle. An incidental, but arguably important, change is that this ensures that unused space in the VVAR page is properly zeroed. It wasn't before, and would contain whatever garbage was left in memory by BIOS or the bootloader. Since the VVAR page is accessible to user space this had the potential of information leaks" * 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) x86, vdso: Fix the symbol versions on the 32-bit vDSO x86, vdso, build: Don't rebuild 32-bit vdsos on every make x86, vdso: Actually discard the .discard sections x86, vdso: Fix size of get_unmapped_area() x86, vdso: Finish removing VDSO32_PRELINK x86, vdso: Move more vdso definitions into vdso.h x86: Load the 32-bit vdso in place, just like the 64-bit vdsos x86, vdso32: handle 32 bit vDSO larger one page x86, vdso32: Disable stack protector, adjust optimizations x86, vdso: Zero-pad the VVAR page x86, vdso: Add 32 bit VDSO time support for 64 bit kernel x86, vdso: Add 32 bit VDSO time support for 32 bit kernel x86, vdso: Patch alternatives in the 32-bit VDSO x86, vdso: Introduce VVAR marco for vdso32 x86, vdso: Cleanup __vdso_gettimeofday() x86, vdso: Replace VVAR(vsyscall_gtod_data) by gtod macro x86, vdso: __vdso_clock_gettime() cleanup x86, vdso: Revamp vclock_gettime.c mm: Add new func _install_special_mapping() to mmap.c x86, vdso: Make vsyscall_gtod_data handling x86 generic ...
| * x86, vdso: Fix the symbol versions on the 32-bit vDSOAndy Lutomirski2014-03-301-3/+7
| | | | | | | | | | | | | | | | | | | | | | The new symbols provide the same API as the 64-bit variants, so they should have the same symbol version name. This can't break userspace, since these symbols are new for 32-bit Linux. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/0a869bce03d25619565b1eee7d69a4fd15fd203a.1396124118.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@zytor.com>
| * x86, vdso, build: Don't rebuild 32-bit vdsos on every makeAndy Lutomirski2014-03-261-1/+1
| | | | | | | | | | | | | | | | | | vdso32/vclock_gettime.o was confusing kbuild. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/d741449340642213744dd659471a35bb970a0c4c.1395789923.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * x86, vdso: Actually discard the .discard sectionsH. Peter Anvin2014-03-251-0/+5
| | | | | | | | | | | | | | | | | | | | | | The .discard/.discard.* sections are used to generate intermediate results for the assembler (effectively "test assembly".) The output is waste and should not be retained. Cc: Stefani Seibold <stefani@seibold.net> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/n/tip-psizrnant8x3nrhbgvq2vekr@git.kernel.org
| * x86, vdso: Fix size of get_unmapped_area()Stefani Seibold2014-03-241-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | The size of the reserved memory for a 32 bit vdso must be the size of the 32 bit vDSO in pages + HPET page + VVAR page. One page is not enough for this. Grrrr.... silly copy and paste bug, was right in previous patch. Signed-off-by: Stefani Seibold <stefani@seibold.net> Cc: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/1395592694-20571-1-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * x86, vdso: Move more vdso definitions into vdso.hAndy Lutomirski2014-03-216-41/+3Star
| | | | | | | | | | | | | | | | | | This fixes the Xen build and gets rid of a silly header file. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1df77311795aff75f5742c787d277518314a38d3.1395366931.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@zytor.com>
| * x86: Load the 32-bit vdso in place, just like the 64-bit vdsosAndy Lutomirski2014-03-206-83/+70Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This replaces a decent amount of incomprehensible and buggy code with much more straightforward code. It also brings the 32-bit vdso more in line with the 64-bit vdsos, so maybe someday they can share even more code. This wastes a small amount of kernel .data and .text space, but it avoids a couple of allocations on startup, so it should be more or less a wash memory-wise. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/b8093933fad09ce181edb08a61dcd5d2592e9814.1395352498.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * x86, vdso32: handle 32 bit vDSO larger one pageStefani Seibold2014-03-181-7/+15
| | | | | | | | | | | | | | | | This patch enables 32 bit vDSO which are larger than a page. Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-14-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * x86, vdso32: Disable stack protector, adjust optimizationsH. Peter Anvin2014-03-181-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | For the 32-bit VDSO, match the 64-bit VDSO in: 1. Disable the stack protector. 2. Use -fno-omit-frame-pointer for user space debugging sanity. 3. Use -foptimize-sibling-calls like the 64-bit VDSO does. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-13-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * x86, vdso: Add 32 bit VDSO time support for 64 bit kernelStefani Seibold2014-03-182-41/+71
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch add the VDSO time support for the IA32 Emulation Layer. Due the nature of the kernel headers and the LP64 compiler where the size of a long and a pointer differs against a 32 bit compiler, there is some type hacking necessary for optimal performance. The vsyscall_gtod_data struture must be a rearranged to serve 32- and 64-bit code access at the same time: - The seqcount_t was replaced by an unsigned, this makes the vsyscall_gtod_data intedepend of kernel configuration and internal functions. - All kernel internal structures are replaced by fix size elements which works for 32- and 64-bit access - The inner struct clock was removed to pack the whole struct. The "unsigned seq" would be handled by functions derivated from seqcount_t. Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-11-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * x86, vdso: Add 32 bit VDSO time support for 32 bit kernelStefani Seibold2014-03-186-11/+162
| | | | | | | | | | | | | | | | | | | | | | | | This patch add the time support for 32 bit a VDSO to a 32 bit kernel. For 32 bit programs running on a 32 bit kernel, the same mechanism is used as for 64 bit programs running on a 64 bit kernel. Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-10-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * x86, vdso: Patch alternatives in the 32-bit VDSOAndy Lutomirski2014-03-183-15/+24
| | | | | | | | | | | | | | | | We need the alternatives mechanism for rdtsc_barrier() to work. Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-9-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * x86, vdso: Cleanup __vdso_gettimeofday()Stefani Seibold2014-03-181-5/+2Star
| | | | | | | | | | | | | | | | | | | | | | | | This patch cleans up the __vdso_gettimeofday() function a little. It kicks out an unneeded ret local variable and makes the code faster if only the timezone is needed (an admittedly rare case.) Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-7-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * x86, vdso: Replace VVAR(vsyscall_gtod_data) by gtod macroStefani Seibold2014-03-181-3/+3
| | | | | | | | | | | | | | | | | | | | There a currently more than 30 users of the gtod macro, so replace the last VVAR(vsyscall_gtod_data) by gtod macro. Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-6-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * x86, vdso: __vdso_clock_gettime() cleanupStefani Seibold2014-03-181-13/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch is a small code cleanup for the __vdso_clock_gettime() function. It removes the unneeded return values from do_monotonic_coarse() and do_realtime_coarse() and add a fallback label for doing the kernel gettimeofday() system call. Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-5-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * x86, vdso: Revamp vclock_gettime.cStefani Seibold2014-03-181-43/+42Star
| | | | | | | | | | | | | | | | | | | | | | This intermediate patch revamps the vclock_gettime.c by moving some functions around. It is only for spliting purpose, to make whole the 32 bit vdso timer patch easier to review. Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-4-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * x86, vdso: Remove compat vdso supportAndy Lutomirski2014-03-143-214/+22Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The compat vDSO is a complicated hack that's needed to maintain compatibility with a small range of glibc versions. This removes it and replaces it with a much simpler hack: a config option to disable the 32-bit vDSO by default. This also changes the default value of CONFIG_COMPAT_VDSO to n -- users configuring kernels from scratch almost certainly want that choice. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/4bb4690899106eb11430b1186d5cc66ca9d1660c.1394751608.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* | x86, lto: Disable LTO for the x86 VDSOAndi Kleen2014-02-141-3/+7
|/ | | | | | | | | | | The VDSO does not play well with LTO, so just disable LTO for it. Also pass a 32bit linker flag for the 32bit version. [ hpa: change braces to parens to match kernel Makefile style ] Signed-off-by: Andi Kleen <ak@linux.intel.com> Link: http://lkml.kernel.org/r/1391846481-31491-1-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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