| Message ID | 29ab51dc0909132212u63862efbm8a0359e9efc038be@mail.gmail.com (mailing list archive) |
|---|---|
| State | Rejected |
| Headers | show |
On Mon, Sep 14, 2009 at 02:12:34PM +0900, Nobuhiro Iwamatsu wrote: > 2009/8/28 Matt Fleming <matt@console-pimps.org>: > > Index: gas/config/tc-sh.c > > =================================================================== > > RCS file: /cvs/src/src/gas/config/tc-sh.c,v > > retrieving revision 1.132 > > diff -u -r1.132 tc-sh.c > > --- gas/config/tc-sh.c ?24 Jul 2009 11:45:00 -0000 ? ? ?1.132 > > +++ gas/config/tc-sh.c ?27 Aug 2009 20:09:14 -0000 > > @@ -156,6 +156,11 @@ > > ?#define ENCODE_RELAX(what,length) (((what) << 4) + (length)) > > ?#define GET_WHAT(x) ((x>>4)) > > > > +/* Truncate and sign-extend at 32 bits, so that building on a 64-bit host > > + ? gives identical results to a 32-bit host. ?*/ > > +#define TRUNC(X) ? ? ? ((long) (X) & 0xffffffff) > > +#define SEXT(X) ? ? ? ? ? ? ? ?((TRUNC (X) ^ 0x80000000) - 0x80000000) > > + > > ?/* These are the three types of relaxable instruction. ?*/ > > ?/* These are the types of relaxable instructions; except for END which is > > ? ?a marker. ?*/ > > @@ -4183,7 +4188,7 @@ > > ? ? ? ?val = ((val >> shift) > > ? ? ? ? ? ? ? | ((long) -1 & ~ ((long) -1 >> shift))); > > ? ? } > > - ?if (max != 0 && (val < min || val > max)) > > + ?if (max != 0 && (SEXT(val) < min || SEXT(val) > max)) > > ? ? as_bad_where (fixP->fx_file, fixP->fx_line, _("offset out of range")); > > ? else if (max != 0) > > ? ? /* Stop the generic code from trying to overlow check the value as well. > > I think that I should cope in a kernel, because this problem is thing > by the limit of mov. > # mov of this case supports only 8bit. > The whole reason that the toolchain patch is necessary is because 64-bit hosts weren't doing sign extension on a truncated 32-bit value, which is a legitimate bug. As far as the mov size, a manually sign extended value is perfectly acceptable, and any toolchain should be intelligent enough to get the size calculation right. It's obviously not entirely elegant, but it's much less confusing than running in to situations where the same immediate is used and it may or may not be sign extended, depending on which instruction it gets used with. That ambiguity is what this approach solves, and I think it is definitely worthwhile trying to keep it as simple as possible to prevent sign extension bugs from popping up. If you've ever had to chase a sign extension bug, you will appreciate the value of this (especially given the sometimes rather inconsistent instruction set). -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/sh/include/asm/entry-macros.S b/arch/sh/include/asm/entry-macros.S index cc43a55..64fd0de 100644 --- a/arch/sh/include/asm/entry-macros.S +++ b/arch/sh/include/asm/entry-macros.S @@ -7,7 +7,7 @@ .endm .macro sti - mov #0xfffffff0, r11 + mov #0xf0, r11 extu.b r11, r11 not r11, r11 stc sr, r10 diff --git a/arch/sh/kernel/cpu/sh3/entry.S b/arch/sh/kernel/cpu/sh3/entry.S index 0151933..4e3dc2d 100644 --- a/arch/sh/kernel/cpu/sh3/entry.S +++ b/arch/sh/kernel/cpu/sh3/entry.S @@ -260,7 +260,7 @@ restore_all: ! ! Calculate new SR value mov k3, k2 ! original SR value - mov #0xfffffff0, k1 + mov #0xf0, k1 extu.b k1, k1 not k1, k1 and k1, k2 ! Mask original SR value diff --git a/arch/sh/lib/__clear_user.S b/arch/sh/lib/__clear_user.S index db1dca7..31b692e 100644 --- a/arch/sh/lib/__clear_user.S +++ b/arch/sh/lib/__clear_user.S @@ -11,7 +11,7 @@ ENTRY(__clear_user) ! mov #0, r0 - mov #0xffffffe0, r1 + mov #0xe0, r1 ! ! r4..(r4+31)&~32 -------- not aligned [ Area 0 ] ! (r4+31)&~32..(r4+r5)&~32 -------- aligned [ Area 1 ]