x86, platform, kconfig: move kvmconfig functionality to a helper

The new mergeconfig helper makes it easier to add other partial
configurations similar to kvmconfig.  Architecture-independent portions
of those partial configurations should go in
kernel/configs/${name}.config, and architecture-dependent portions
should go in arch/${arch}/configs/${name}.config.

Based on a patch by Luis R. Rodriguez <mcgrof@suse.com>.
Originally-Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>

Modified to make the helper name more general than just virtualization,
support architecture-dependent and architecture-independent partial
configurations, move the helper and kvmconfig to
scripts/kconfig/Makefile, and factor out more of the common file path.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
x86: Add "make tinyconfig" to configure the tiniest possible kernel

Since commit 5d2acfc7b974bbd3858b4dd3f2cdc6362dd8843a ("kconfig: make
allnoconfig disable options behind EMBEDDED and EXPERT") in 3.15-rc1,
"make allnoconfig" disables every possible config option.

However, a few configuration options (CC_OPTIMIZE_FOR_SIZE,
OPTIMIZE_INLINING) produce a smaller kernel when turned on, and a few
choices exist (compression, highmem, allocator) for which a non-default
option produces a smaller kernel.

Add a "tinyconfig" option, which starts from allnoconfig and then sets
these options to configure the tiniest possible kernel.  This provides a
better baseline for embedded systems or efforts to reduce kernel size.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
x86, boot: Use the usual -y -n mechanism for objects in vmlinux

Switch VMLINUX_OBJS to vmlinux-objs-y, to eliminate Makefile
conditionals in favor of vmlinux-objs-$(CONFIG_*) constructs.

This does not change the generated code at all.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
x86, boot: Don't compile aslr.c when !CONFIG_RANDOMIZE_BASE

All the code in aslr.c gets compiled out if !CONFIG_RANDOMIZE_BASE, but
aslr.o itself still gets compiled in.  Eliminate it from the compile
entirely in that case.

This does not change the generated code at all, in either case.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
x86, boot: Don't compile early_serial_console.c when !CONFIG_EARLY_PRINTK

All the code in early_serial_console.c gets compiled out if
!CONFIG_EARLY_PRINTK, but early_serial_console.o itself still gets
compiled in.  Eliminate it from the compile entirely in that case.

This does not change the generated code at all, in either case.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
x86: Drop support for /proc files when !CONFIG_PROC_FS

arch/x86/kernel/cpu/proc.c only exists to support files in /proc; omit that
file when compiling without CONFIG_PROC_FS.

Saves 645 additional bytes on 32-bit x86 when !CONFIG_PROC_FS:

add/remove: 0/5 grow/shrink: 0/0 up/down: 0/-645 (-645)
function                                     old     new   delta
c_stop                                         1       -      -1
c_next                                        11       -     -11
cpuinfo_op                                    16       -     -16
c_start                                       24       -     -24
show_cpuinfo                                 593       -    -593

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
x86: Support compiling out human-friendly processor feature names

The table mapping CPUID bits to human-readable strings takes up a
non-trivial amount of space, and only exists to support /proc/cpuinfo
and a couple of kernel messages.  Since programs depend on the format of
/proc/cpuinfo, force inclusion of the table when building with /proc
support; otherwise, support omitting that table to save space, in which
case the kernel messages will print features numerically instead.

In addition to saving 1408 bytes out of vmlinux, this also saves 1373
bytes out of the uncompressed setup code, which contributes directly to
the size of bzImage.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
mm: Support compiling out madvise and fadvise

Many embedded systems will not need these syscalls, and omitting them
saves space.  Add a new EXPERT config option CONFIG_ADVISE_SYSCALLS
(default y) to support compiling them out.

bloat-o-meter:
add/remove: 0/3 grow/shrink: 0/0 up/down: 0/-2250 (-2250)
function                                     old     new   delta
sys_fadvise64                                 57       -     -57
sys_fadvise64_64                             691       -    -691
sys_madvise                                 1502       -   -1502

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
bloat-o-meter: Ignore syscall aliases SyS_ and compat_SyS_

This avoids double-counting size changes in syscall implementations.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Merge branches 'tiny/bloat-o-meter-no-SyS', 'tiny/more-procless', 'tiny/no-advice', 'tiny/tinyconfig' and 'tiny/x86-boot-compressed-use-yn' into tiny/next
Merge tag 'tiny/for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/josh/linux

Pull "tinification" patches from Josh Triplett.

Work on making smaller kernels.

* tag 'tiny/for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/josh/linux:
  bloat-o-meter: Ignore syscall aliases SyS_ and compat_SyS_
  mm: Support compiling out madvise and fadvise
  x86: Support compiling out human-friendly processor feature names
  x86: Drop support for /proc files when !CONFIG_PROC_FS
  x86, boot: Don't compile early_serial_console.c when !CONFIG_EARLY_PRINTK
  x86, boot: Don't compile aslr.c when !CONFIG_RANDOMIZE_BASE
  x86, boot: Use the usual -y -n mechanism for objects in vmlinux
  x86: Add "make tinyconfig" to configure the tiniest possible kernel
  x86, platform, kconfig: move kvmconfig functionality to a helper
ipmi: Clean up the error handling for channel config errors

The code to send the channel config errors was missing an error report
in one place and needed some more information in another, and had an
extraneous bit of code.  Clean all that up.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipmi/of: Don't use unavailable interfaces

If an IPMI controller is used by the firmware and as such marked with
a reserved status, we shouldn't use it.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipmi: work around gcc-4.9 build warning

Building ipmi on arm with gcc-4.9 results in this warning for an
allmodconfig build:

  drivers/char/ipmi/ipmi_si_intf.c: In function 'ipmi_thread':
  include/linux/time.h:28:5: warning: 'busy_until.tv_sec' may be used uninitialized in this function [-Wmaybe-uninitialized]
    if (lhs->tv_sec > rhs->tv_sec)
       ^
  drivers/char/ipmi/ipmi_si_intf.c:1007:18: note: 'busy_until.tv_sec' was declared here
    struct timespec busy_until;
                    ^

The warning is bogus and this case can not occur.  Apparently this is a
false positive resulting from gcc getting a little smarter about
tracking assignments but not smart enough.

Marking the ipmi_thread_busy_wait function as inline gives the gcc
optimization logic enough information to figure out for itself that the
case cannot happen, which gets rid of the warning without adding any
fake initialization.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipmi: Clear drvdata when interface is removed

This patch fixes a bug on hotmod removing.

After ipmi interface is removed using hotmod, kernel panic occurs when
rmmod impi_si.  For example, try this:

 # echo "remove,"`cat /proc/ipmi/0/params` > \
 /sys/module/ipmi_si/parameters/hotmod
 # rmmod ipmi_si

Then, rmmod fails with the following messages.

  ------------[ cut here ]------------
  WARNING: CPU: 12 PID: 10819 at /mnt/repos/linux/lib/list_debug.c:53 __list_del_entry+0x63/0xd0()
  CPU: 12 PID: 10819 Comm: rmmod Not tainted 3.17.0-rc1 #19
  Hardware name: FUJITSU-SV PRIMERGY BX920 S2/D3030, BIOS 080015 Rev.3D81.3030 02/10/2012
  Call Trace:
    dump_stack+0x45/0x56
    warn_slowpath_common+0x7d/0xa0
    warn_slowpath_fmt+0x4c/0x50
    __list_del_entry+0x63/0xd0
    list_del+0xd/0x30
    cleanup_one_si+0x2a/0x230 [ipmi_si]
    ipmi_pnp_remove+0x15/0x20 [ipmi_si]
    pnp_device_remove+0x24/0x40
    __device_release_driver+0x7f/0xf0
    driver_detach+0xb0/0xc0
    bus_remove_driver+0x55/0xd0
    driver_unregister+0x2c/0x50
    pnp_unregister_driver+0x12/0x20
    cleanup_ipmi_si+0xbc/0xf0 [ipmi_si]
    SyS_delete_module+0x132/0x1c0
    system_call_fastpath+0x16/0x1b
  ---[ end trace 70b4377268f85c23 ]---

list_del in cleanup_one_si() fails because the smi_info is already
removed when hotmod removing.

When ipmi interface is removed by hotmod, smi_info is removed by
cleanup_one_si(), but is is still set in drvdata.  Therefore when rmmod
ipmi_si, ipmi_pnp_remove tries to remove it again and fails.

By this patch, a pointer to smi_info in drvdata is cleared when hotmod
removing so that it will be not accessed when rmmod.

changelog:
v2:
- Clear drvdata in cleanup_one_si
- Change subject

v1:
https://lkml.org/lkml/2014/9/8/741

Signed-off-by: Takao Indoh <indou.takao@jp.fujitsu.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'ipmi' (patches from Corey Minyard)

Merge ipmi patches from Corey Minyard:
 "These have been in linux-next for a while, ready for 3.18"

* emailed patches from Corey Minyard <minyard@acm.org>:
  ipmi: Clear drvdata when interface is removed
  ipmi: work around gcc-4.9 build warning
  ipmi/of: Don't use unavailable interfaces
  ipmi: Clean up the error handling for channel config errors