Commit fc585d4a authored by Olof Johansson's avatar Olof Johansson Committed by Paul Walmsley
Browse files

riscv: Less inefficient gcc tishift helpers (and export their symbols) 



The existing __lshrti3 was really inefficient, and the other two helpers
are also needed to compile some modules.

Add the missing versions, and export all of the symbols like arm64
already does.

This code is based on the assembly generated by libgcc builds.

This fixes a build break triggered by ubsan:

riscv64-unknown-linux-gnu-ld: lib/ubsan.o: in function `.L2':
ubsan.c:(.text.unlikely+0x38): undefined reference to `__ashlti3'
riscv64-unknown-linux-gnu-ld: ubsan.c:(.text.unlikely+0x42): undefined reference to `__ashrti3'

Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
[paul.walmsley@sifive.com: use SYM_FUNC_{START,END} instead of
 ENTRY/ENDPROC; note libgcc origin]
Signed-off-by: default avatarPaul Walmsley <paul.walmsley@sifive.com>
parent 95f4d9cc

arch/riscv/include/asm/asm-prototypes.h

+4 −0
Original line number Diff line number Diff line
@@ -5,4 +5,8 @@ 
#include <linux/ftrace.h>

#include <asm-generic/asm-prototypes.h>



long long __lshrti3(long long a, int b);

long long __ashrti3(long long a, int b);

long long __ashlti3(long long a, int b);



#endif /* _ASM_RISCV_PROTOTYPES_H */

arch/riscv/lib/tishift.S

+57 −18
Original line number Diff line number Diff line
@@ -4,34 +4,73 @@ 
 */



#include <linux/linkage.h>

#include <asm-generic/export.h>



ENTRY(__lshrti3)

SYM_FUNC_START(__lshrti3)

	beqz	a2, .L1

	li	a5,64

	sub	a5,a5,a2

	addi	sp,sp,-16

	sext.w	a4,a5

	blez	a5, .L2

	sext.w	a2,a2

	sll	a4,a1,a4

	srl	a0,a0,a2

	srl	a1,a1,a2

	sll	a4,a1,a4

	srl	a2,a1,a2

	or	a0,a0,a4

	sd	a1,8(sp)

	sd	a0,0(sp)

	ld	a0,0(sp)

	ld	a1,8(sp)

	addi	sp,sp,16

	ret

	mv	a1,a2

.L1:

	ret

.L2:

	negw	a4,a4

	srl	a1,a1,a4

	sd	a1,0(sp)

	sd	zero,8(sp)

	ld	a0,0(sp)

	ld	a1,8(sp)

	addi	sp,sp,16

	negw	a0,a4

	li	a2,0

	srl	a0,a1,a0

	mv	a1,a2

	ret

SYM_FUNC_END(__lshrti3)

EXPORT_SYMBOL(__lshrti3)



SYM_FUNC_START(__ashrti3)

	beqz	a2, .L3

	li	a5,64

	sub	a5,a5,a2

	sext.w	a4,a5

	blez	a5, .L4

	sext.w	a2,a2

	srl	a0,a0,a2

	sll	a4,a1,a4

	sra	a2,a1,a2

	or	a0,a0,a4

	mv	a1,a2

.L3:

	ret

.L4:

	negw	a0,a4

	srai	a2,a1,0x3f

	sra	a0,a1,a0

	mv	a1,a2

	ret

SYM_FUNC_END(__ashrti3)

EXPORT_SYMBOL(__ashrti3)



SYM_FUNC_START(__ashlti3)

	beqz	a2, .L5

	li	a5,64

	sub	a5,a5,a2

	sext.w	a4,a5

	blez	a5, .L6

	sext.w	a2,a2

	sll	a1,a1,a2

	srl	a4,a0,a4

	sll	a2,a0,a2

	or	a1,a1,a4

	mv	a0,a2

.L5:

	ret

.L6:

	negw	a1,a4

	li	a2,0

	sll	a1,a0,a1

	mv	a0,a2

	ret

ENDPROC(__lshrti3)
 
SYM_FUNC_END(__ashlti3)

EXPORT_SYMBOL(__ashlti3)

CRA Git | Maintained and supported by SUSTech CRA and CCSE