kernel_optimize_test/arch/powerpc/lib
Kevin Hao 4db7327194 powerpc: Add option to use jump label for cpu_has_feature()
We do binary patching of asm code using CPU features, which is a
one-time operation, done during early boot. However checks of CPU
features in C code are currently done at run time, even though the set
of CPU features can never change after boot.

We can optimise this by using jump labels to implement cpu_has_feature(),
meaning checks in C code are binary patched into a single nop or branch.

For a C sequence along the lines of:

    if (cpu_has_feature(FOO))
         return 2;

The generated code before is roughly:

    ld      r9,-27640(r2)
    ld      r9,0(r9)
    lwz     r9,32(r9)
    cmpwi   cr7,r9,0
    bge     cr7, 1f
    li      r3,2
    blr
1:  ...

After (true):
    nop
    li      r3,2
    blr

After (false):
    b	1f
    li      r3,2
    blr
1:  ...

mpe: Rename MAX_CPU_FEATURES as we already have a #define with that
name, and define it simply as a constant, rather than doing tricks with
sizeof and NULL pointers. Rename the array to cpu_feature_keys. Use the
kconfig we added to guard it. Add BUILD_BUG_ON() if the feature is not a
compile time constant. Rewrite the change log.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-01 11:15:05 +10:00
..
alloc.c powerpc: Replace mem_init_done with slab_is_available() 2015-04-10 20:02:48 +10:00
checksum_32.S powerpc: optimise csum_partial() call when len is constant 2016-03-09 10:44:18 -06:00
checksum_64.S powerpc/lib: Clarify that adde is an instruction and we mean plural 2016-07-15 20:18:37 +10:00
checksum_wrappers.c powerpc32: checksum_wrappers_64 becomes checksum_wrappers 2016-03-04 21:47:47 -06:00
code-patching.c powerpc: Move the patch_exception to a common place 2013-12-02 14:06:54 +11:00
copy_32.S powerpc: Make generic_memcpy() private to copy_32.S 2016-04-11 20:30:41 +10:00
copypage_64.S powerpc: Exported functions __clear_user and copy_page use r2 so need _GLOBAL_TOC() 2014-06-05 13:20:41 +10:00
copypage_power7.S powerpc: Change vrX register defines to vX to match gcc and glibc 2015-03-16 18:32:11 +11:00
copyuser_64.S powerpc: Remove power3 from comments 2014-07-28 14:10:26 +10:00
copyuser_power7.S powerpc: Change vrX register defines to vX to match gcc and glibc 2015-03-16 18:32:11 +11:00
crtsavres.S powerpc: Change vrX register defines to vX to match gcc and glibc 2015-03-16 18:32:11 +11:00
div64.S powerpc: Fix a corner case in __div64_32 2005-10-20 09:37:02 +10:00
feature-fixups-test.S powerpc: Ensure the else case of feature sections will fit 2011-01-21 14:08:33 +11:00
feature-fixups.c powerpc: Add option to use jump label for cpu_has_feature() 2016-08-01 11:15:05 +10:00
hweight_64.S powerpc: No need to use dot symbols when branching to a function 2014-04-23 10:05:16 +10:00
ldstfp.S powerpc: Change vsrX register defines to vsX to match gcc and glibc 2015-03-16 18:32:11 +11:00
locks.c powerpc/spinlock: Fix spin_unlock_wait() 2016-06-14 16:05:44 +10:00
Makefile Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/scottwood/linux into next 2016-03-14 20:05:14 +11:00
mem_64.S powerpc: use _GLOBAL_TOC for memmove 2014-07-22 15:56:04 +10:00
memcmp_64.S powerpc: Add 64bit optimised memcmp 2015-01-23 14:02:55 +11:00
memcpy_64.S Merge remote-tracking branch 'anton/abiv2' into next 2014-05-05 20:57:12 +10:00
memcpy_power7.S powerpc: Change vrX register defines to vX to match gcc and glibc 2015-03-16 18:32:11 +11:00
ppc_ksyms.c powerpc: Remove assembly versions of strcpy, strcat, strlen and strcmp 2016-06-14 13:58:25 +10:00
rheap.c powerpc: Various typo fixes 2016-06-14 13:58:26 +10:00
sstep.c powerpc/sstep: Fix emulation fall-through 2016-05-11 21:54:08 +10:00
string_64.S powerpc: Exported functions __clear_user and copy_page use r2 so need _GLOBAL_TOC() 2014-06-05 13:20:41 +10:00
string.S powerpc: Align hot loops of some string functions 2016-06-14 13:58:25 +10:00
usercopy_64.c powerpc: Rename files to have consistent _32/_64 suffixes 2005-10-10 21:52:43 +10:00
vmx-helper.c powerpc: Introduce asm-prototypes.h 2016-06-16 22:39:54 +10:00
xor_vmx.c powerpc: rework sparse for lib/xor_vmx.c 2016-04-27 09:33:37 +10:00