fbac266f09
s390 has instructions to support 128 bit arithmetics, e.g. a 64 bit multiply instruction with a 128 bit result. Also 128 bit integer artithmetics are already used in s390 specific architecture code (see e.g. read_persistent_clock64()). Therefore select ARCH_SUPPORTS_INT128. However limit this to clang for now, since gcc generates inefficient code, which may lead to stack overflows, when compiling lib/crypto/curve25519-hacl64.c which depends on ARCH_SUPPORTS_INT128. The gcc generated functions have 6kb stack frames, compared to only 1kb of the code generated with clang. If the kernel is compiled with -Os library calls for __ashlti3(), __ashrti3(), and __lshrti3() may be generated. Similar to arm64 and riscv provide assembler implementations for these functions. Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
63 lines
1 KiB
ArmAsm
63 lines
1 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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#include <linux/linkage.h>
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#include <asm/nospec-insn.h>
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#include <asm/export.h>
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.section .noinstr.text, "ax"
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GEN_BR_THUNK %r14
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SYM_FUNC_START(__ashlti3)
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lmg %r0,%r1,0(%r3)
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cije %r4,0,1f
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lhi %r3,64
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sr %r3,%r4
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jnh 0f
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srlg %r3,%r1,0(%r3)
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sllg %r0,%r0,0(%r4)
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sllg %r1,%r1,0(%r4)
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ogr %r0,%r3
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j 1f
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0: sllg %r0,%r1,-64(%r4)
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lghi %r1,0
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1: stmg %r0,%r1,0(%r2)
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BR_EX %r14
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SYM_FUNC_END(__ashlti3)
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EXPORT_SYMBOL(__ashlti3)
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SYM_FUNC_START(__ashrti3)
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lmg %r0,%r1,0(%r3)
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cije %r4,0,1f
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lhi %r3,64
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sr %r3,%r4
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jnh 0f
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sllg %r3,%r0,0(%r3)
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srlg %r1,%r1,0(%r4)
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srag %r0,%r0,0(%r4)
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ogr %r1,%r3
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j 1f
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0: srag %r1,%r0,-64(%r4)
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srag %r0,%r0,63
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1: stmg %r0,%r1,0(%r2)
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BR_EX %r14
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SYM_FUNC_END(__ashrti3)
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EXPORT_SYMBOL(__ashrti3)
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SYM_FUNC_START(__lshrti3)
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lmg %r0,%r1,0(%r3)
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cije %r4,0,1f
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lhi %r3,64
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sr %r3,%r4
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jnh 0f
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sllg %r3,%r0,0(%r3)
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srlg %r1,%r1,0(%r4)
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srlg %r0,%r0,0(%r4)
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ogr %r1,%r3
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j 1f
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0: srlg %r1,%r0,-64(%r4)
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lghi %r0,0
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1: stmg %r0,%r1,0(%r2)
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BR_EX %r14
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SYM_FUNC_END(__lshrti3)
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EXPORT_SYMBOL(__lshrti3)
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