kernel/linux.git/arch/powerpc/lib/copy_32.S, branch linux-4.16.y

powerpc/32: remove a NOP from memset()

2017-09-01T06:42:46+00:00

memset() is patched after initialisation to activate the optimised part which uses cache instructions. Today we have a 'b 2f' to skip the optimised patch, which then gets replaced by a NOP, implying a useless cycle consumption. As we have a 'bne 2f' just before, we could use that instruction for the live patching, hence removing the need to have a dedicated 'b 2f' to be replaced by a NOP. This patch changes the 'bne 2f' by a 'b 2f'. During init, that 'b 2f' is then replaced by 'bne 2f' Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman

powerpc/32: optimise memset()

2017-09-01T06:42:46+00:00

There is no need to extend the set value to an int when the length is lower than 4 as in that case we only do byte stores. We can therefore immediately branch to the part handling it. By separating it from the normal case, we are able to eliminate a few actions on the destination pointer. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman

powerpc: fix location of two EXPORT_SYMBOL

2017-09-01T06:42:45+00:00

Commit 9445aa1a3062a ("ppc: move exports to definitions") added EXPORT_SYMBOL() for memset() and flush_hash_pages() in the middle of the functions. This patch moves them at the end of the two functions. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman

powerpc/32: add memset16()

2017-09-01T06:42:45+00:00

Commit 694fc88ce271f ("powerpc/string: Implement optimized memset variants") added memset16(), memset32() and memset64() for the 64 bits PPC. On 32 bits, memset64() is not relevant, and as shown below, the generic version of memset32() gives a good code, so only memset16() is candidate for an optimised version. 000009c0 : 9c0: 2c 05 00 00 cmpwi r5,0 9c4: 39 23 ff fc addi r9,r3,-4 9c8: 4d 82 00 20 beqlr 9cc: 7c a9 03 a6 mtctr r5 9d0: 94 89 00 04 stwu r4,4(r9) 9d4: 42 00 ff fc bdnz 9d0 9d8: 4e 80 00 20 blr The last part of memset() handling the not 4-bytes multiples operates on bytes, making it unsuitable for handling word without modification. As it would increase memset() complexity, it is better to implement memset16() from scratch. In addition it has the advantage of allowing a more optimised memset16() than what we would have by using the memset() function. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman

powerpc: get rid of zeroing, switch to RAW_COPY_USER

2017-04-06T19:08:42+00:00

Signed-off-by: Al Viro

powerpc: EX_TABLE macro for exception tables

2016-11-14T00:11:51+00:00

This macro is taken from s390, and allows more flexibility in changing exception table format. mpe: Put it in ppc_asm.h and only define one version using stringinfy_in_c(). Add some empty definitions and headers to keep the selftests happy. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman

ppc: move exports to definitions

2016-08-08T03:50:09+00:00

Signed-off-by: Al Viro

powerpc: Make generic_memcpy() private to copy_32.S

2016-04-11T10:30:41+00:00

generic_memcpy() is only called from copy_32.S, so there's no reason for it to be global. Reported-by: Al Viro Signed-off-by: Michael Ellerman

powerpc32: memset: only use dcbz once cache is enabled

2015-09-17T00:36:53+00:00

memset() uses instruction dcbz to speed up clearing by not wasting time loading cache line with data that will be overwritten. Some platform like mpc52xx do no have cache active at startup and can therefore not use memset(). Allthough no part of the code explicitly uses memset(), GCC may make calls to it. This patch modifies memset() such that at startup, memset() unconditionally skip the optimised bloc that uses dcbz instruction. Once the initial MMU is set up, in machine_init() we patch memset() by replacing this inconditional jump by a NOP Tested-by: Thomas Gleixner Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman

powerpc32: memcpy: only use dcbz once cache is enabled

2015-09-17T00:36:44+00:00

memcpy() uses instruction dcbz to speed up copy by not wasting time loading cache line with data that will be overwritten. Some platform like mpc52xx do no have cache active at startup and can therefore not use memcpy(). Allthough no part of the code explicitly uses memcpy(), GCC makes calls to it. This patch modifies memcpy() such that at startup, memcpy() unconditionally jumps to generic_memcpy() which doesn't use the dcbz instruction. Once the initial MMU is set up, in machine_init() we patch memcpy() by replacing this inconditional jump by a NOP Reported-by: Michal Sojka Tested-by: Thomas Gleixner Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman