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Commit d65e5677 authored by Leonid Yegoshin's avatar Leonid Yegoshin Committed by Ralf Baechle
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MIPS: R2-on-R6 MULTU/MADDU/MSUBU emulation bugfix 



MIPS instructions MULTU, MADDU and MSUBU emulation requires registers HI/LO
to be converted to signed 32bits before 64bit sign extension on MIPS64.

Bug was found on running MIPS32 R2 test application on MIPS64 R6 kernel.

Fixes: b0a668fb ("MIPS: kernel: mips-r2-to-r6-emul: Add R2 emulator for MIPS R6")
Signed-off-by: default avatarLeonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Reported-by: default avatar <Nikola.Veljkovic@imgtec.com>
Cc: paul.burton@imgtec.com
Cc: yamada.masahiro@socionext.com
Cc: akpm@linux-foundation.org
Cc: andrea.gelmini@gelma.net
Cc: macro@imgtec.com
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14043/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 1d79bf0e

arch/mips/kernel/mips-r2-to-r6-emul.c

+6 −6
Original line number Diff line number Diff line
@@ -433,8 +433,8 @@ static int multu_func(struct pt_regs *regs, u32 ir) 
	rs = regs->regs[MIPSInst_RS(ir)];

	res = (u64)rt * (u64)rs;

	rt = res;

	regs->lo = (s64)rt;

	regs->hi = (s64)(res >> 32);

	regs->lo = (s64)(s32)rt;

	regs->hi = (s64)(s32)(res >> 32);



	MIPS_R2_STATS(muls);
@@ -670,9 +670,9 @@ static int maddu_func(struct pt_regs *regs, u32 ir) 
	res += ((((s64)rt) << 32) | (u32)rs);



	rt = res;

	regs->lo = (s64)rt;

	regs->lo = (s64)(s32)rt;

	rs = res >> 32;

	regs->hi = (s64)rs;

	regs->hi = (s64)(s32)rs;



	MIPS_R2_STATS(dsps);
@@ -728,9 +728,9 @@ static int msubu_func(struct pt_regs *regs, u32 ir) 
	res = ((((s64)rt) << 32) | (u32)rs) - res;



	rt = res;

	regs->lo = (s64)rt;

	regs->lo = (s64)(s32)rt;

	rs = res >> 32;

	regs->hi = (s64)rs;

	regs->hi = (s64)(s32)rs;



	MIPS_R2_STATS(dsps);