linux-dev - Linux kernel development work

Age	Commit message (Collapse)	Author	Files	Lines
2018-05-25	powerpc/altivec: Add missing prototypes for altivec	Mathieu Malaterre	1	-0/+1
	Some functions prototypes were missing for the non-altivec code. Add the missing prototypes in a new header file, fix warnings treated as errors with W=1: arch/powerpc/lib/xor_vmx_glue.c:18:6: error: no previous prototype for ‘xor_altivec_2’ [-Werror=missing-prototypes] arch/powerpc/lib/xor_vmx_glue.c:29:6: error: no previous prototype for ‘xor_altivec_3’ [-Werror=missing-prototypes] arch/powerpc/lib/xor_vmx_glue.c:40:6: error: no previous prototype for ‘xor_altivec_4’ [-Werror=missing-prototypes] arch/powerpc/lib/xor_vmx_glue.c:52:6: error: no previous prototype for ‘xor_altivec_5’ [-Werror=missing-prototypes] The prototypes were already present in <asm/xor.h> but this header file is meant to be included after <include/linux/raid/xor.h>. Trying to re-use <asm/xor.h> directly would lead to warnings such as: arch/powerpc/include/asm/xor.h:39:15: error: variable ‘xor_block_altivec’ has initializer but incomplete type Trying to re-use <asm/xor.h> after <include/linux/raid/xor.h> in xor_vmx_glue.c would in turn trigger the following warnings: include/asm-generic/xor.h:688:34: error: ‘xor_block_32regs’ defined but not used [-Werror=unused-variable] Signed-off-by: Mathieu Malaterre <malat@debian.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-02	powerpc/lib/xor_vmx: Ensure no altivec code executes before enable_kernel_altivec()	Matt Brown	1	-0/+62
	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>