![H. Peter Anvin](/assets/img/avatar_default.png)
Fix incorrect assembly constraints. In particular, fix memory constraints used inside push..pop, which can cause invalid operation since gcc may generate %esp-relative references. Additionally: outl() should have "dN" not "dn". query_mca() shouldn't listen 16/32-bit registers in an 8-bit only context. has_eflag(): the "mask" is only used well after both the stack pointer and the output registers have been touched; this requires the output registers to be earlyclobbers (=&) and the input to exclude memory (so "ri", not "g"). Thanks to Etienne Lorrain and Chuck Ebbert for prompting this review. Cc: Etienne Lorrain <etienne_lorrain@yahoo.fr> Cc: Chuck Ebbert <cebbert@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
44 lines
945 B
C
44 lines
945 B
C
/* -*- linux-c -*- ------------------------------------------------------- *
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright 2007 rPath, Inc. - All Rights Reserved
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*
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* This file is part of the Linux kernel, and is made available under
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* the terms of the GNU General Public License version 2.
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*
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* ----------------------------------------------------------------------- */
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/*
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* arch/i386/boot/mca.c
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*
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* Get the MCA system description table
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*/
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#include "boot.h"
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int query_mca(void)
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{
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u8 err;
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u16 es, bx, len;
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asm("pushw %%es ; "
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"int $0x15 ; "
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"setc %0 ; "
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"movw %%es, %1 ; "
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"popw %%es"
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: "=acd" (err), "=acdSD" (es), "=b" (bx)
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: "a" (0xc000));
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if (err)
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return -1; /* No MCA present */
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set_fs(es);
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len = rdfs16(bx);
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if (len > sizeof(boot_params.sys_desc_table))
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len = sizeof(boot_params.sys_desc_table);
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copy_from_fs(&boot_params.sys_desc_table, bx, len);
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return 0;
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}
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