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| author | Heiko Carstens <hca@linux.ibm.com> | 2023-04-25 14:42:11 +0300 |
|---|---|---|
| committer | Alexander Gordeev <agordeev@linux.ibm.com> | 2023-05-15 15:12:14 +0300 |
| commit | fbac266f095de92b93e7c91c71cdca432c2c9275 (patch) | |
| tree | 75c1f682e65031c03532b880eab1cab559afba82 /arch/s390/lib/tishift.S | |
| parent | 1f2597cd3686955a4d64e01909dbfe625a2a35a1 (diff) | |
| download | linux-fbac266f095de92b93e7c91c71cdca432c2c9275.tar.xz | |
s390: select ARCH_SUPPORTS_INT128
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>
Diffstat (limited to 'arch/s390/lib/tishift.S')
| -rw-r--r-- | arch/s390/lib/tishift.S | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/arch/s390/lib/tishift.S b/arch/s390/lib/tishift.S new file mode 100644 index 000000000000..de33cf02cfd2 --- /dev/null +++ b/arch/s390/lib/tishift.S @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include <linux/linkage.h> +#include <asm/nospec-insn.h> +#include <asm/export.h> + + .section .noinstr.text, "ax" + + GEN_BR_THUNK %r14 + +SYM_FUNC_START(__ashlti3) + lmg %r0,%r1,0(%r3) + cije %r4,0,1f + lhi %r3,64 + sr %r3,%r4 + jnh 0f + srlg %r3,%r1,0(%r3) + sllg %r0,%r0,0(%r4) + sllg %r1,%r1,0(%r4) + ogr %r0,%r3 + j 1f +0: sllg %r0,%r1,-64(%r4) + lghi %r1,0 +1: stmg %r0,%r1,0(%r2) + BR_EX %r14 +SYM_FUNC_END(__ashlti3) +EXPORT_SYMBOL(__ashlti3) + +SYM_FUNC_START(__ashrti3) + lmg %r0,%r1,0(%r3) + cije %r4,0,1f + lhi %r3,64 + sr %r3,%r4 + jnh 0f + sllg %r3,%r0,0(%r3) + srlg %r1,%r1,0(%r4) + srag %r0,%r0,0(%r4) + ogr %r1,%r3 + j 1f +0: srag %r1,%r0,-64(%r4) + srag %r0,%r0,63 +1: stmg %r0,%r1,0(%r2) + BR_EX %r14 +SYM_FUNC_END(__ashrti3) +EXPORT_SYMBOL(__ashrti3) + +SYM_FUNC_START(__lshrti3) + lmg %r0,%r1,0(%r3) + cije %r4,0,1f + lhi %r3,64 + sr %r3,%r4 + jnh 0f + sllg %r3,%r0,0(%r3) + srlg %r1,%r1,0(%r4) + srlg %r0,%r0,0(%r4) + ogr %r1,%r3 + j 1f +0: srlg %r1,%r0,-64(%r4) + lghi %r0,0 +1: stmg %r0,%r1,0(%r2) + BR_EX %r14 +SYM_FUNC_END(__lshrti3) +EXPORT_SYMBOL(__lshrti3) |