diff options
| author | Matt Brown <matthew.brown.dev@gmail.com> | 2017-05-24 09:45:59 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-06-02 20:17:52 +1000 |
| commit | f718d426d7e42eec6e5d2932f52a51de23bd3b30 (patch) | |
| tree | 82c3b5b118929622eeeaa41d3f11402b6d9d8935 /arch/powerpc/lib/Makefile | |
| parent | 48a316e350974739235c234430ec0e129f864a43 (diff) | |
powerpc/lib/xor_vmx: Ensure no altivec code executes before enable_kernel_altivec()
The xor_vmx.c file is used for the RAID5 xor operations. In these functions
altivec is enabled to run the operation and then disabled.
The code uses enable_kernel_altivec() around the core of the algorithm, however
the whole file is built with -maltivec, so the compiler is within its rights to
generate altivec code anywhere. This has been seen at least once in the wild:
0:mon> di $xor_altivec_2
c0000000000b97d0 3c4c01d9 addis r2,r12,473
c0000000000b97d4 3842db30 addi r2,r2,-9424
c0000000000b97d8 7c0802a6 mflr r0
c0000000000b97dc f8010010 std r0,16(r1)
c0000000000b97e0 60000000 nop
c0000000000b97e4 7c0802a6 mflr r0
c0000000000b97e8 faa1ffa8 std r21,-88(r1)
...
c0000000000b981c f821ff41 stdu r1,-192(r1)
c0000000000b9820 7f8101ce stvx v28,r1,r0 <-- POP
c0000000000b9824 38000030 li r0,48
c0000000000b9828 7fa101ce stvx v29,r1,r0
...
c0000000000b984c 4bf6a06d bl c0000000000238b8 # enable_kernel_altivec
This patch splits the non-altivec code into xor_vmx_glue.c which calls the
altivec functions in xor_vmx.c. By compiling xor_vmx_glue.c without
-maltivec we can guarantee that altivec instruction will not be executed
outside of the enable/disable block.
Signed-off-by: Matt Brown <matthew.brown.dev@gmail.com>
[mpe: Rework change log and include disassembly]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/lib/Makefile')
| -rw-r--r-- | arch/powerpc/lib/Makefile | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile index 2c56f4636c2b..3c3146ba62da 100644 --- a/arch/powerpc/lib/Makefile +++ b/arch/powerpc/lib/Makefile @@ -37,7 +37,7 @@ obj-$(CONFIG_PPC_LIB_RHEAP) += rheap.o obj-$(CONFIG_FTR_FIXUP_SELFTEST) += feature-fixups-test.o -obj-$(CONFIG_ALTIVEC) += xor_vmx.o +obj-$(CONFIG_ALTIVEC) += xor_vmx.o xor_vmx_glue.o CFLAGS_xor_vmx.o += -maltivec $(call cc-option,-mabi=altivec) obj-$(CONFIG_PPC64) += $(obj64-y) |