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Blackfin: adjust asm constraints with NMI workaround

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Newer gcc versions will sometimes use a Preg when "r" constraints, but
that'll fail if we use an Ireg in the assignment.  So force the code
to always use a Dreg.

This also fixes early boot crashes for older Blackfin parts when compiled
with gcc-4.5.  This version ends up selecting the same register for the
input and output variables which corrupts the output assignment triggering
an exception.
	P2 = 0xffe02008;	/* EVT2 */
	R0 = RETS;
	CALL 1f;
	RTN;
1:	P2 = RETS;	<-- BAD
	RETS = R0;
	[P2] = P2;	<-- BAD

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
This commit is contained in:
Mike Frysinger 2012-07-31 05:38:56 -04:00 committed by Sonic Zhang
parent e0ae433e92
commit 2e2ed3f4ff
1 changed files with 2 additions and 1 deletions
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3
arch/blackfin/cpu/initcode.c
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@ -262,7 +262,8 @@ program_nmi_handler(void)
"%1 = RETS;" /* Load addr of NMI handler */
"RETS = %0;" /* Restore RETS */
"[%2] = %1;" /* Write NMI handler */
: "=r"(tmp1), "=r"(tmp2) : "ab"(EVT2)
: "=d"(tmp1), "=d"(tmp2)
: "ab"(EVT2)
);
}