x86-64 vDSO changes for 3.1
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- v3 Latest8 patches 21 repliesIn review
- v28 patches 9 repliesSuperseded
Changes in v3 from the cover letter
- Make vsyscall_nr decoding prettier and add a missing local_irq_disable in patch 1.
- Mark patch_vdso __init.
- Print a warning if patch_vdso does not find .altinstructions.
Patches in v3 No applies recorded yet
| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 1/8 | x86-64: Improve vsyscall emulation CS and RIP handlingarch/ arch/ | +41 | 1 reply | |
| 2/8 | x86: Make alternative instruction pointers relativearch/ arch/ arch/ +3 more | +31 | 1 reply | |
| 3/8 | x86-64: Allow alternative patching in the vDSOarch/ | +33 | 4 replies | |
| 4/8 | x86-64: Add --no-undefined to vDSO buildarch/ | +1 | 1 reply | |
| 5/8 | clocksource: Replace vread with generic arch dataarch/ arch/ arch/ +3 more | +31 | 9 replies | |
| 6/8 | x86-64: Move vread_tsc and vread_hpet into the vDSOarch/ arch/ arch/ +9 more | +56 | 3 replies | |
| 7/8 | ia64: Replace clocksource.fsys_mmio with generic arch dataarch/ arch/ arch/ +3 more | +16 | 1 reply | |
| 8/8 | Document the vDSO and add a reference parserDocumentation/ Documentation/ Documentation/ | +395 | 1 reply |
Reviews trailers per patch
1 of 8 patches has a Reviewed-by or Acked-by.
| Patch | Andy Lutomirski |
|---|---|
| 1/8 | |
| 2/8 | |
| 3/8 | A-b A-b |
| 4/8 | |
| 5/8 | |
| 6/8 | |
| 7/8 | |
| 8/8 |
Trailers given in replies are filled; those carried in the patches from earlier versions are outlined with dashes.
Cover letter [PATCH v3 0/8] x86-64 vDSO changes for 3.1
This series applies to the x86/vdso branch of the -tip tree.
The first patch cleans up the vsyscall emulation code.
After the vsyscall emulation patches, the only real executable code left in the vsyscall page is vread_tsc and vread_hpet. That code is only called from the vDSO, so patches 2-6 move it into the vDSO.
vread_tsc() uses rdtsc_barrier(), which contains two alternatives. Patches 2 and 3 make alternative patching work in the vDSO. (This has a slightly odd side effect that the vDSO image dumped from memory doesn't quite match the debug version anymore, but it's hard to imagine that causing problems.)
Patch 4 fixes an annoyance I found while writing this code. If you introduce an undefined symbol into the vDSO, you get an unhelpful error message. ld is smart enough to give a nice error if you ask it to.
Patch 5 cleans up the architecture-specific part of struct clocksource. IA64 had its own ifdefed code in there, and the supposedly generic vread pointer was only used by x86-64. With the patch, each arch gets to set up its own private part of struct clocksource.
Patch 6 is the meat. It moves vread_tsc and vread_hpet into the vDSO where they belong, and it's a net deletion of code because it removes a bunch of magic needed to make regular functions accessible through the vsyscall page.
With patches 1-6 applied, every single byte in the vsyscall page is some sort of trap instruction.
Patches 7 and 8 are optional. Patch 7 changes IA64 to use the new arch gtod data. It presumably should not go in through the x86 tree. Patch 8 adds some vDSO documentation and a reference vDSO parser for user code to use. It's meant for projects that don't dynamically link to glibc (e.g. Go) but still want to call the vDSO. Someone who knows more about ELF than I should take a look.
*** Note to IA64 people: I have not even compile-tested this on IA64. ***
Changes from v2:
- Make vsyscall_nr decoding prettier and add a missing local_irq_disable in patch 1.
- Mark patch_vdso __init.
- Print a warning if patch_vdso does not find .altinstructions.
Changes from v1:
- Tidy up vDSO alternative patching (thanks, Borislav).
- Fix really dumb bugs in the IA64 stuff.
- Add the cleanup patch and the reference vDSO parser.
- Split the main IA-64 patch out.
Andy Lutomirski (8):
x86-64: Improve vsyscall emulation CS and RIP handling
x86: Make alternative instruction pointers relative
x86-64: Allow alternative patching in the vDSO
x86-64: Add --no-undefined to vDSO build
clocksource: Replace vread with generic arch data
x86-64: Move vread_tsc and vread_hpet into the vDSO
ia64: Replace clocksource.fsys_mmio with generic arch data Document the vDSO and add a reference parser
Documentation/ABI/stable/vdso | 27 ++++ Documentation/vDSO/parse_vdso.c | 256 ++++++++++++++++++++++++++++++++ Documentation/vDSO/vdso_test.c | 112 ++++++++++++++ arch/ia64/include/asm/clocksource.h | 12 ++ arch/ia64/kernel/cyclone.c | 2 +- arch/ia64/kernel/time.c | 2 +- arch/ia64/sn/kernel/sn2/timer.c | 2 +- arch/x86/include/asm/alternative-asm.h | 4 +- arch/x86/include/asm/alternative.h | 8 +- arch/x86/include/asm/clocksource.h | 20 +++ arch/x86/include/asm/cpufeature.h | 8 +- arch/x86/include/asm/tsc.h | 4 - arch/x86/include/asm/vgtod.h | 2 +- arch/x86/include/asm/vsyscall.h | 16 -- arch/x86/kernel/Makefile | 7 +- arch/x86/kernel/alternative.c | 23 ++-- arch/x86/kernel/hpet.c | 9 +- arch/x86/kernel/tsc.c | 2 +- arch/x86/kernel/vmlinux.lds.S | 3 - arch/x86/kernel/vread_tsc_64.c | 36 ----- arch/x86/kernel/vsyscall_64.c | 63 +++++--- arch/x86/lib/copy_page_64.S | 9 +- arch/x86/lib/memmove_64.S | 11 +- arch/x86/vdso/Makefile | 1 + arch/x86/vdso/vclock_gettime.c | 52 ++++++- arch/x86/vdso/vma.c | 33 ++++ drivers/char/hpet.c | 2 +- include/asm-generic/clocksource.h | 4 + include/linux/clocksource.h | 13 +- 29 files changed, 595 insertions(+), 148 deletions(-) create mode 100644 Documentation/ABI/stable/vdso create mode 100644 Documentation/vDSO/parse_vdso.c create mode 100644 Documentation/vDSO/vdso_test.c create mode 100644 arch/ia64/include/asm/clocksource.h create mode 100644 arch/x86/include/asm/clocksource.h delete mode 100644 arch/x86/kernel/vread_tsc_64.c create mode 100644 include/asm-generic/clocksource.h
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