talos-op-linux/arch/x86/entry/vdso/Makefile, branch master

kbuild: rename hostprogs-y/always to hostprogs/always-y

2020-02-03T16:53:07+00:00

In old days, the "host-progs" syntax was used for specifying host programs. It was renamed to the current "hostprogs-y" in 2004. It is typically useful in scripts/Makefile because it allows Kbuild to selectively compile host programs based on the kernel configuration. This commit renames like follows: always -> always-y hostprogs-y -> hostprogs So, scripts/Makefile will look like this: always-$(CONFIG_BUILD_BIN2C) += ... always-$(CONFIG_KALLSYMS) += ... ... hostprogs := $(always-y) $(always-m) I think this makes more sense because a host program is always a host program, irrespective of the kernel configuration. We want to specify which ones to compile by CONFIG options, so always-y will be handier. The "always", "hostprogs-y", "hostprogs-m" will be kept for backward compatibility for a while. Signed-off-by: Masahiro Yamada

x86/build/vdso: Remove meaningless CFLAGS_REMOVE_*.o

2019-11-15T11:07:32+00:00

CFLAGS_REMOVE_*.o syntax is used to drop particular flags when building objects from C files. It has no effect for assembly files. vdso-note.o is compiled from the assembly file, vdso-note.S, hence CFLAGS_REMOVE_vdso-note.o is meaningless. Neither vvar.c nor vvar.S is found in the vdso directory. Since there is no source file to create vvar.o, CFLAGS_REMOVE_vvar.o is also meaningless. Signed-off-by: Masahiro Yamada Signed-off-by: Borislav Petkov Cc: Andy Lutomirski Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Thomas Gleixner Cc: x86-ml Link: https://lkml.kernel.org/r/20191114154922.30365-1-yamada.masahiro@socionext.com

kbuild: change *FLAGS_.o to take the path relative to $(obj)

2019-09-04T14:12:50+00:00

Kbuild provides per-file compiler flag addition/removal: CFLAGS_.o CFLAGS_REMOVE_.o AFLAGS_.o AFLAGS_REMOVE_.o CPPFLAGS_.lds HOSTCFLAGS_.o HOSTCXXFLAGS_.o The is the filename of the target with its directory and suffix stripped. This syntax comes into a trouble when two files with the same basename appear in one Makefile, for example: obj-y += foo.o obj-y += dir/foo.o CFLAGS_foo.o := Here, the applies to both foo.o and dir/foo.o The real world problem is: scripts/kconfig/util.c scripts/kconfig/lxdialog/util.c Both files are compiled into scripts/kconfig/mconf, but only the latter should be given with the ncurses flags. It is more sensible to use the relative path to the Makefile, like this: obj-y += foo.o CFLAGS_foo.o := obj-y += dir/foo.o CFLAGS_dir/foo.o := At first, I attempted to replace $(basetarget) with $*. The $* variable is replaced with the stem ('%') part in a pattern rule. This works with most of cases, but does not for explicit rules. For example, arch/ia64/lib/Makefile reuses rule_as_o_S in its own explicit rules, so $* will be empty, resulting in ignoring the per-file AFLAGS. I introduced a new variable, target-stem, which can be used also from explicit rules. Signed-off-by: Masahiro Yamada Acked-by: Marc Zyngier

kbuild: add --hash-style= and --build-id unconditionally

2019-07-17T13:37:51+00:00

As commit 1e0221374e30 ("mips: vdso: drop unnecessary cc-ldoption") explained, these flags are supported by the minimal required version of binutils. They are supported by ld.lld too. Signed-off-by: Masahiro Yamada Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor

x86/vdso: Fix flip/flop vdso build bug

2019-07-12T15:35:07+00:00

Two consecutive "make" on an already compiled kernel tree will show different behavior: $ make CALL scripts/checksyscalls.sh CALL scripts/atomic/check-atomics.sh DESCEND objtool CHK include/generated/compile.h VDSOCHK arch/x86/entry/vdso/vdso64.so.dbg VDSOCHK arch/x86/entry/vdso/vdso32.so.dbg Kernel: arch/x86/boot/bzImage is ready (#3) Building modules, stage 2. MODPOST 12 modules $ make make CALL scripts/checksyscalls.sh CALL scripts/atomic/check-atomics.sh DESCEND objtool CHK include/generated/compile.h VDSO arch/x86/entry/vdso/vdso64.so.dbg OBJCOPY arch/x86/entry/vdso/vdso64.so VDSO2C arch/x86/entry/vdso/vdso-image-64.c CC arch/x86/entry/vdso/vdso-image-64.o VDSO arch/x86/entry/vdso/vdso32.so.dbg OBJCOPY arch/x86/entry/vdso/vdso32.so VDSO2C arch/x86/entry/vdso/vdso-image-32.c CC arch/x86/entry/vdso/vdso-image-32.o AR arch/x86/entry/vdso/built-in.a AR arch/x86/entry/built-in.a AR arch/x86/built-in.a GEN .version CHK include/generated/compile.h UPD include/generated/compile.h CC init/version.o AR init/built-in.a LD vmlinux.o This is causing "LD vmlinux" once every two times even without any modifications. This is the same bug fixed in commit 92a4728608a8 ("x86/boot: Fix if_changed build flip/flop bug"). Two "if_changed" cannot be used in one target. Fix this merging two commands into one function. Fixes: 7ac870747988 ("x86/vdso: Switch to generic vDSO implementation") Signed-off-by: Naohiro Aota Signed-off-by: Thomas Gleixner Tested-by: Vincenzo Frascino Reviewed-by: Vincenzo Frascino Reviewed-by: Masahiro Yamada Link: https://lkml.kernel.org/r/20190712101556.17833-1-naohiro.aota@wdc.com

x86/vdso: Switch to generic vDSO implementation

2019-06-22T19:21:10+00:00

The x86 vDSO library requires some adaptations to take advantage of the newly introduced generic vDSO library. Introduce the following changes: - Modification of vdso.c to be compliant with the common vdso datapage - Use of lib/vdso for gettimeofday [ tglx: Massaged changelog and cleaned up the function signature formatting ] Signed-off-by: Vincenzo Frascino Signed-off-by: Thomas Gleixner Cc: linux-arch@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mips@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Cc: Catalin Marinas Cc: Will Deacon Cc: Arnd Bergmann Cc: Russell King Cc: Ralf Baechle Cc: Paul Burton Cc: Daniel Lezcano Cc: Mark Salyzyn Cc: Peter Collingbourne Cc: Shuah Khan Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Rasmus Villemoes Cc: Huw Davies Cc: Shijith Thotton Cc: Andre Przywara Link: https://lkml.kernel.org/r/20190621095252.32307-23-vincenzo.frascino@arm.com

x86/build/vdso: Add FORCE to the build rule of %.so

2019-04-18T08:05:34+00:00

$(call if_changed,...) must have FORCE as a prerequisite. Signed-off-by: Masahiro Yamada Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1554280212-10578-1-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Ingo Molnar

x86/vdso: Pass --eh-frame-hdr to the linker

2018-12-15T10:37:51+00:00

Commit 379d98ddf413 ("x86: vdso: Use $LD instead of $CC to link") accidentally broke unwinding from userspace, because ld would strip the .eh_frame sections when linking. Originally, the compiler would implicitly add --eh-frame-hdr when invoking the linker, but when this Makefile was converted from invoking ld via the compiler, to invoking it directly (like vmlinux does), the flag was missed. (The EH_FRAME section is important for the VDSO shared libraries, but not for vmlinux.) Fix the problem by explicitly specifying --eh-frame-hdr, which restores parity with the old method. See relevant bug reports for additional info: https://bugzilla.kernel.org/show_bug.cgi?id=201741 https://bugzilla.redhat.com/show_bug.cgi?id=1659295 Fixes: 379d98ddf413 ("x86: vdso: Use $LD instead of $CC to link") Reported-by: Florian Weimer Reported-by: Carlos O'Donell Reported-by: "H. J. Lu" Signed-off-by: Alistair Strachan Signed-off-by: Borislav Petkov Tested-by: Laura Abbott Cc: Andy Lutomirski Cc: Carlos O'Donell Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Joel Fernandes Cc: kernel-team@android.com Cc: Laura Abbott Cc: stable Cc: Thomas Gleixner Cc: X86 ML Link: https://lkml.kernel.org/r/20181214223637.35954-1-astrachan@google.com

x86/vdso: Drop implicit common-page-size linker flag

2018-12-07T17:57:38+00:00

GNU linker's -z common-page-size's default value is based on the target architecture. arch/x86/entry/vdso/Makefile sets it to the architecture default, which is implicit and redundant. Drop it. Fixes: 2aae950b21e4 ("x86_64: Add vDSO for x86-64 with gettimeofday/clock_gettime/getcpu") Reported-by: Dmitry Golovin Reported-by: Bill Wendling Suggested-by: Dmitry Golovin Suggested-by: Rui Ueyama Signed-off-by: Nick Desaulniers Signed-off-by: Borislav Petkov Acked-by: Andy Lutomirski Cc: Andi Kleen Cc: Fangrui Song Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Thomas Gleixner Cc: x86-ml Link: https://lkml.kernel.org/r/20181206191231.192355-1-ndesaulniers@google.com Link: https://bugs.llvm.org/show_bug.cgi?id=38774 Link: https://github.com/ClangBuiltLinux/linux/issues/31

x86/vdso: Only enable vDSO retpolines when enabled and supported

2018-10-03T06:26:14+00:00

When I fixed the vDSO build to use inline retpolines, I messed up the Makefile logic and made it unconditional. It should have depended on CONFIG_RETPOLINE and on the availability of compiler support. This broke the build on some older compilers. Reported-by: nikola.ciprich@linuxbox.cz Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: David Woodhouse Cc: Linus Torvalds Cc: Matt Rickard Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: jason.vas.dias@gmail.com Cc: stable@vger.kernel.org Fixes: 2e549b2ee0e3 ("x86/vdso: Fix vDSO build if a retpoline is emitted") Link: http://lkml.kernel.org/r/08a1f29f2c238dd1f493945e702a521f8a5aa3ae.1538540801.git.luto@kernel.org Signed-off-by: Ingo Molnar