Commit Graph

26 Commits

Author SHA1 Message Date
Masahiro Yamada
5f2fb52fac kbuild: rename hostprogs-y/always to hostprogs/always-y
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 <masahiroy@kernel.org>
2020-02-04 01:53:07 +09:00
Linus Torvalds
ceb3074745 y2038: syscall implementation cleanups
This is a series of cleanups for the y2038 work, mostly intended
 for namespace cleaning: the kernel defines the traditional
 time_t, timeval and timespec types that often lead to y2038-unsafe
 code. Even though the unsafe usage is mostly gone from the kernel,
 having the types and associated functions around means that we
 can still grow new users, and that we may be missing conversions
 to safe types that actually matter.
 
 There are still a number of driver specific patches needed to
 get the last users of these types removed, those have been
 submitted to the respective maintainers.
 
 Link: https://lore.kernel.org/lkml/20191108210236.1296047-1-arnd@arndb.de/
 Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Merge tag 'y2038-cleanups-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground

Pull y2038 cleanups from Arnd Bergmann:
 "y2038 syscall implementation cleanups

  This is a series of cleanups for the y2038 work, mostly intended for
  namespace cleaning: the kernel defines the traditional time_t, timeval
  and timespec types that often lead to y2038-unsafe code. Even though
  the unsafe usage is mostly gone from the kernel, having the types and
  associated functions around means that we can still grow new users,
  and that we may be missing conversions to safe types that actually
  matter.

  There are still a number of driver specific patches needed to get the
  last users of these types removed, those have been submitted to the
  respective maintainers"

Link: https://lore.kernel.org/lkml/20191108210236.1296047-1-arnd@arndb.de/

* tag 'y2038-cleanups-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground: (26 commits)
  y2038: alarm: fix half-second cut-off
  y2038: ipc: fix x32 ABI breakage
  y2038: fix typo in powerpc vdso "LOPART"
  y2038: allow disabling time32 system calls
  y2038: itimer: change implementation to timespec64
  y2038: move itimer reset into itimer.c
  y2038: use compat_{get,set}_itimer on alpha
  y2038: itimer: compat handling to itimer.c
  y2038: time: avoid timespec usage in settimeofday()
  y2038: timerfd: Use timespec64 internally
  y2038: elfcore: Use __kernel_old_timeval for process times
  y2038: make ns_to_compat_timeval use __kernel_old_timeval
  y2038: socket: use __kernel_old_timespec instead of timespec
  y2038: socket: remove timespec reference in timestamping
  y2038: syscalls: change remaining timeval to __kernel_old_timeval
  y2038: rusage: use __kernel_old_timeval
  y2038: uapi: change __kernel_time_t to __kernel_old_time_t
  y2038: stat: avoid 'time_t' in 'struct stat'
  y2038: ipc: remove __kernel_time_t reference from headers
  y2038: vdso: powerpc: avoid timespec references
  ...
2019-12-01 14:00:59 -08:00
Arnd Bergmann
82210fc778 y2038: vdso: change timespec to __kernel_old_timespec
In order to remove 'timespec' completely from the kernel, all
internal uses should be converted to a y2038-safe type, while
those that are only for compatibity with existing user space
should be marked appropriately.

Change vdso to use __kernel_old_timespec in order to avoid
the deprecated type and mark these interfaces as outdated.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-11-15 14:38:28 +01:00
Arnd Bergmann
ddccf40fe8 y2038: vdso: change timeval to __kernel_old_timeval
The gettimeofday() function in vdso uses the traditional 'timeval'
structure layout, which will be incompatible with future versions of
glibc on 32-bit architectures that use a 64-bit time_t.

This interface is problematic for y2038, when time_t overflows on 32-bit
architectures, but the plan so far is that a libc with 64-bit time_t
will not call into the gettimeofday() vdso helper at all, and only
have a method for entering clock_gettime().  This means we don't have
to fix it here, though we probably want to add a new clock_gettime()
entry point using a 64-bit version of 'struct timespec' at some point.

Changing the vdso code to use __kernel_old_timeval helps isolate
this usage from the other ones that still need to be fixed properly,
and it gets us closer to removing the 'timeval' definition from the
kernel sources.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-11-15 14:38:27 +01:00
Masahiro Yamada
5347291415 sparc: vdso: fix build error of vdso32
Since commit 54b8ae66ae ("kbuild: change *FLAGS_<basetarget>.o to
take the path relative to $(obj)"), sparc allmodconfig fails to build
as follows:

  CC      arch/sparc/vdso/vdso32/vclock_gettime.o
unrecognized e_machine 18 arch/sparc/vdso/vdso32/vclock_gettime.o
arch/sparc/vdso/vdso32/vclock_gettime.o: failed

The cause of the breakage is that -pg flag not being dropped.

The vdso32 files are located in the vdso32/ subdirectory, but I missed
to update the Makefile.

I removed the meaningless CFLAGS_REMOVE_vdso-note.o since it is only
effective for C file.

vdso-note.o is compiled from assembly file:

  arch/sparc/vdso/vdso-note.S
  arch/sparc/vdso/vdso32/vdso-note.S

Fixes: 54b8ae66ae ("kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj)")
Reported-by: Anatoly Pugachev <matorola@gmail.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Anatoly Pugachev <matorola@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
2019-11-15 00:12:28 +09:00
Masahiro Yamada
89ff7131f7 kbuild: add --hash-style= and --build-id unconditionally
As commit 1e0221374e ("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 <yamada.masahiro@socionext.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
2019-07-17 22:37:51 +09:00
Thomas Gleixner
7e300dabb7 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 223
Based on 1 normalized pattern(s):

  subject to the gnu public license v 2

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 9 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528171440.130801526@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:29:55 -07:00
Thomas Gleixner
003ba95791 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 214
Based on 1 normalized pattern(s):

  subject to the gpl v 2

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 2 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528171439.372657724@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:29:54 -07:00
Thomas Gleixner
ec8f24b7fa treewide: Add SPDX license identifier - Makefile/Kconfig
Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 10:50:46 +02:00
Masahiro Yamada
269fe56551 sparc: vdso: add FORCE to the build rule of %.so
$(call if_changed,...) must have FORCE as a prerequisite.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-08 16:58:35 -07:00
ndesaulniers@google.com
0ff70f62c6 sparc: vdso: Drop implicit common-page-size linker flag
GNU linker's -z common-page-size's default value is based on the target
architecture. arch/sparc/vdso/Makefile sets it to the architecture
default, which is implicit and redundant. Drop it.

Link: https://lkml.kernel.org/r/20181206191231.192355-1-ndesaulniers@google.com
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-12-21 11:24:38 -08:00
David S. Miller
caf539cd10 sparc: Fix VDSO build with older binutils.
Older versions of bintutils do not allow symbol math across different
segments on sparc:

====================
Assembler messages:
99: Error: operation combines symbols in different segments
====================

This is controlled by whether or not DIFF_EXPR_OK is defined in
gas/config/tc-*.h and for sparc this was not the case until mid-2017.

So we have to patch between %stick and %tick another way.

Do what powerpc does and emit two versions of the relevant functions,
one using %tick and one using %stick, and patch the symbols in the
dynamic symbol table.

Fixes: 2f6c9bf31a ("sparc: Improve VDSO instruction patching.")
Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-25 10:36:19 -07:00
David S. Miller
19832d2449 sparc: Several small VDSO vclock_gettime.c improvements.
Almost entirely borrowed from the x86 code.

Main improvement is to avoid having to initialize
ts->tv_nsec to zero before the sequence loops, by
expanding timespec_add_ns().

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22 17:42:10 -07:00
David S. Miller
ecd4c19f3d sparc: Validate VDSO for undefined symbols.
There should be no undefined symbols in the resulting VDSO image(s).

On sparc, fixed register usage can result in undefined symbols ending
up in the image.  To combat this, we do two things:

1) Define current_thread_info() specially when BUILD_DSO.

2) Ignore "#scratch" register undefined symbols in the output.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22 16:09:27 -07:00
David S. Miller
3c2b2d9408 sparc: Really use linker with LDFLAGS.
Rather than funneling through CC.

Also, use --hash-style=both just like other VDSO architectures and
glibc do.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22 16:02:05 -07:00
David S. Miller
5615edcca9 sparc: Improve VDSO CFLAGS.
Do not set any special register usage options, use the default which
is exactly what we should use for userspace code.

Make sure we remove the gcc plugin options from the 64-bit build.
The 32-bit cflags got it right already.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22 15:56:11 -07:00
David S. Miller
44231b7fee sparc: Set DISABLE_BRANCH_PROFILING in VDSO CFLAGS.
Not in vclock_gettime.c itself.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22 15:51:45 -07:00
David S. Miller
3fe5d7e861 sparc: Don't bother masking out TICK_PRIV_BIT in VDSO code.
If the TICK_PRIV_BIT was set, we would not be able to read the tick
register in user space, which is where this code runs.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22 15:31:38 -07:00
David S. Miller
794b88e047 sparc: Inline VDSO gettime code aggressively.
One interesting thing we need to do is stop using
__builtin_return_address() in get_vvar_data().

Simply read the %pc register instead.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22 15:27:49 -07:00
David S. Miller
2f6c9bf31a sparc: Improve VDSO instruction patching.
The current VDSO patch mechanism has several problems:

1) It assumes how gcc will emit a function, with a register
   window, an initial save instruction and then immediately
   the %tick read when compiling vread_tick().

   There is no such guarantees, code generation could change
   at any time, gcc could put a nop between the save and
   the %tick read, etc.

   So this is extremely fragile and would fail some day.

2) It disallows us to properly inline vread_tick() into the callers
   and thus get the best possible code sequences.

So fix this to patch properly, with location based annotations.

We have to be careful because we cannot do it the way we do
patches elsewhere in the kernel.  Those use a sequence like:

	1:
	insn
	.section	.whatever_patch, "ax"
	.word		1b
	replacement_insn
	.previous

This is a dynamic shared object, so that .word cannot be resolved at
build time, and thus cannot be used to execute the patches when the
kernel initializes the images.

Even trying to use label difference equations doesn't work in the
above kind of scheme:

	1:
	insn
	.section	.whatever_patch, "ax"
	.word		. - 1b
	replacement_insn
	.previous

The assembler complains that it cannot resolve that computation.
The issue is that this is contained in an executable section.

Borrow the sequence used by x86 alternatives, which is:

	1:
	insn
	.pushsection	.whatever_patch, "a"
	.word		. - 1b, . - 1f
	.popsection
	.pushsection	.whatever_patch_replacements, "ax"
	1:
	replacement_insn
	.previous

This works, allows us to inline vread_tick() as much as we like, and
can be used for arbitrary kinds of VDSO patching in the future.

Also, reverse the condition for patching.  Most systems are %stick
based, so if we only patch on %tick systems the patching code will
get little or no testing.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22 15:22:14 -07:00
Dan Carpenter
62d6f3b7b8 sparc: vDSO: Silence an uninitialized variable warning
Smatch complains that "val" would be uninitialized if kstrtoul() fails.

Fixes: 9a08862a5d ("vDSO for sparc")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17 21:55:02 -07:00
David S. Miller
776ca1543b sparc: Fix syscall fallback bugs in VDSO.
First, the trap number for 32-bit syscalls is 0x10.

Also, only negate the return value when syscall error is indicated by
the carry bit being set.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17 21:29:23 -07:00
Masahiro Yamada
8cf7765d33 sparc: vdso: clean-up vdso Makefile
arch/sparc/vdso/Makefile is a replica of arch/x86/entry/vdso/Makefile.

Clean-up the Makefile in the same way as I did for x86:

 - Remove unnecessary export
 - Put the generated linker script to $(obj)/ instead of $(src)/
 - Simplify cmd_vdso2c

The corresponding x86 commits are:

 - 61615faf0a ("x86/build/vdso: Remove unnecessary export in Makefile")
 - 1742ed2088 ("x86/build/vdso: Put generated linker scripts to $(obj)/")
 - c5fcdbf155 ("x86/build/vdso: Simplify 'cmd_vdso2c'")

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-07 22:42:01 -07:00
Masahiro Yamada
54a702f705 kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markers
GNU Make automatically deletes intermediate files that are updated
in a chain of pattern rules.

Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
Example 2) %.o <- %.c <- %.c_shipped

A couple of makefiles mark such targets as .PRECIOUS to prevent Make
from deleting them, but the correct way is to use .SECONDARY.

  .SECONDARY
    Prerequisites of this special target are treated as intermediate
    files but are never automatically deleted.

  .PRECIOUS
    When make is interrupted during execution, it may delete the target
    file it is updating if the file was modified since make started.
    If you mark the file as precious, make will never delete the file
    if interrupted.

Both can avoid deletion of intermediate files, but the difference is
the behavior when Make is interrupted; .SECONDARY deletes the target,
but .PRECIOUS does not.

The use of .PRECIOUS is relatively rare since we do not want to keep
partially constructed (possibly corrupted) targets.

Another difference is that .PRECIOUS works with pattern rules whereas
.SECONDARY does not.

  .PRECIOUS: $(obj)/%.lex.c

works, but

  .SECONDARY: $(obj)/%.lex.c

has no effect.  However, for the reason above, I do not want to use
.PRECIOUS which could cause obscure build breakage.

The targets specified as .SECONDARY must be explicit.  $(targets)
contains all targets that need to include .*.cmd files.  So, the
intermediates you want to keep are mostly in there.  Therefore, mark
$(targets) as .SECONDARY.  It means primary targets are also marked
as .SECONDARY, but I do not see any drawback for this.

I replaced some .SECONDARY / .PRECIOUS markers with 'targets'.  This
will make Kbuild search for non-existing .*.cmd files, but this is
not a noticeable performance issue.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Frank Rowand <frowand.list@gmail.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
2018-04-07 19:04:02 +09:00
Dan Carpenter
b3ca676f68 sparc: vDSO: remove an extra tab
This statement is indented one tab too far which is confusing and
leads to a Smatch warning:

    arch/sparc/vdso/vma.c:254 arch_setup_additional_pages()
    warn: curly braces intended?

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-22 12:01:11 -08:00
Nagarathnam Muthusamy
9a08862a5d vDSO for sparc
Following patch is based on work done by Nick Alcock on 64-bit vDSO for sparc
in Oracle linux. I have extended it to include support for 32-bit vDSO for sparc
on 64-bit kernel.

vDSO for sparc is based on the X86 implementation. This patch
provides vDSO support for both 64-bit and 32-bit programs on 64-bit kernel.
vDSO will be disabled on 32-bit linux kernel on sparc.

*) vclock_gettime.c contains all the vdso functions. Since data page is mapped
   before the vdso code page, the pointer to data page is got by subracting offset
   from an address in the vdso code page. The return address stored in
   %i7 is used for this purpose.
*) During compilation, both 32-bit and 64-bit vdso images are compiled and are
   converted into raw bytes by vdso2c program to be ready for mapping into the
   process. 32-bit images are compiled only if CONFIG_COMPAT is enabled. vdso2c
   generates two files vdso-image-64.c and vdso-image-32.c which contains the
   respective vDSO image in C structure.
*) During vdso initialization, required number of vdso pages are allocated and
   raw bytes are copied into the pages.
*) During every exec, these pages are mapped into the process through
   arch_setup_additional_pages and the location of mapping is passed on to the
   process through aux vector AT_SYSINFO_EHDR which is used by glibc.
*) A new update_vsyscall routine for sparc is added to keep the data page in
   vdso updated.
*) As vDSO cannot contain dynamically relocatable references, a new version of
   cpu_relax is added for the use of vDSO.

This change also requires a putback to glibc to use vDSO. For testing,
programs planning to try vDSO can be compiled against the generated
vdso(64/32).so in the source.

Testing:

========
[root@localhost ~]# cat vdso_test.c
int main() {
        struct timespec tv_start, tv_end;
        struct timeval tv_tmp;
	int i;
        int count = 1 * 1000 * 10000;
	long long diff;

        clock_gettime(0, &tv_start);
        for (i = 0; i < count; i++)
              gettimeofday(&tv_tmp, NULL);
        clock_gettime(0, &tv_end);
        diff = (long long)(tv_end.tv_sec -
		tv_start.tv_sec)*(1*1000*1000*1000);
        diff += (tv_end.tv_nsec - tv_start.tv_nsec);
	printf("Start sec: %d\n", tv_start.tv_sec);
	printf("End sec  : %d\n", tv_end.tv_sec);
        printf("%d cycles in %lld ns = %f ns/cycle\n", count, diff,
		(double)diff / (double)count);
        return 0;
}

[root@localhost ~]# cc vdso_test.c -o t32_without_fix -m32 -lrt
[root@localhost ~]# ./t32_without_fix
Start sec: 1502396130
End sec  : 1502396140
10000000 cycles in 9565148528 ns = 956.514853 ns/cycle
[root@localhost ~]# cc vdso_test.c -o t32_with_fix -m32 ./vdso32.so.dbg
[root@localhost ~]# ./t32_with_fix
Start sec: 1502396168
End sec  : 1502396169
10000000 cycles in 798141262 ns = 79.814126 ns/cycle
[root@localhost ~]# cc vdso_test.c -o t64_without_fix -m64 -lrt
[root@localhost ~]# ./t64_without_fix
Start sec: 1502396208
End sec  : 1502396218
10000000 cycles in 9846091800 ns = 984.609180 ns/cycle
[root@localhost ~]# cc vdso_test.c -o t64_with_fix -m64 ./vdso64.so.dbg
[root@localhost ~]# ./t64_with_fix
Start sec: 1502396257
End sec  : 1502396257
10000000 cycles in 380984048 ns = 38.098405 ns/cycle

V1 to V2 Changes:
=================
	Added hot patching code to switch the read stick instruction to read
tick instruction based on the hardware.

V2 to V3 Changes:
=================
	Merged latest changes from sparc-next and moved the initialization
of clocksource_tick.archdata.vclock_mode to time_init_early. Disabled
queued spinlock and rwlock configuration when simulating 32-bit config
to compile 32-bit VDSO.

V3 to V4 Changes:
=================
	Hardcoded the page size as 8192 in linker script for both 64-bit and
32-bit binaries. Removed unused variables in vdso2c.h. Added -mv8plus flag to
Makefile to prevent the generation of relocation entries for __lshrdi3 in 32-bit
vdso binary.

Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Signed-off-by: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-15 14:21:03 +09:00