6041b57c6c
A recent change makes my Dell 1501 hang on boot. It's an AMD MK-36. I use an x86_64 kernel. It is 100% reproducible. I debugged this problem a bit and my compiler[1]interprets the =A constraint as %rax instead of %edx:%eax on x86_64 which causes the problem. The appended patch provides a workaround for this and fixed the hang on my machine. [1] gcc version 4.1.3 20070429 (prerelease) (Debian 4.1.2-5) Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Cc: Andi Kleen <ak@suse.de> Cc: Benny Halevy <bhalevy@panasas.com> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: "Joerg Roedel" <joerg.roedel@amd.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
155 lines
5.3 KiB
C
155 lines
5.3 KiB
C
#ifndef _X86_64_ALTERNATIVE_H
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#define _X86_64_ALTERNATIVE_H
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#ifdef __KERNEL__
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#include <linux/types.h>
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#include <linux/stddef.h>
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#include <asm/cpufeature.h>
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struct alt_instr {
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u8 *instr; /* original instruction */
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u8 *replacement;
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u8 cpuid; /* cpuid bit set for replacement */
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u8 instrlen; /* length of original instruction */
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u8 replacementlen; /* length of new instruction, <= instrlen */
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u8 pad[5];
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};
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extern void alternative_instructions(void);
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extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
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struct module;
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#ifdef CONFIG_SMP
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extern void alternatives_smp_module_add(struct module *mod, char *name,
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void *locks, void *locks_end,
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void *text, void *text_end);
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extern void alternatives_smp_module_del(struct module *mod);
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extern void alternatives_smp_switch(int smp);
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#else
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static inline void alternatives_smp_module_add(struct module *mod, char *name,
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void *locks, void *locks_end,
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void *text, void *text_end) {}
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static inline void alternatives_smp_module_del(struct module *mod) {}
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static inline void alternatives_smp_switch(int smp) {}
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#endif
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#endif
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/*
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* Alternative instructions for different CPU types or capabilities.
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*
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* This allows to use optimized instructions even on generic binary
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* kernels.
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*
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* length of oldinstr must be longer or equal the length of newinstr
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* It can be padded with nops as needed.
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*
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* For non barrier like inlines please define new variants
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* without volatile and memory clobber.
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*/
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#define alternative(oldinstr, newinstr, feature) \
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asm volatile ("661:\n\t" oldinstr "\n662:\n" \
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".section .altinstructions,\"a\"\n" \
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" .align 8\n" \
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" .quad 661b\n" /* label */ \
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" .quad 663f\n" /* new instruction */ \
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" .byte %c0\n" /* feature bit */ \
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" .byte 662b-661b\n" /* sourcelen */ \
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" .byte 664f-663f\n" /* replacementlen */ \
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".previous\n" \
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".section .altinstr_replacement,\"ax\"\n" \
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"663:\n\t" newinstr "\n664:\n" /* replacement */ \
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".previous" :: "i" (feature) : "memory")
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/*
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* Alternative inline assembly with input.
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*
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* Pecularities:
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* No memory clobber here.
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* Argument numbers start with 1.
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* Best is to use constraints that are fixed size (like (%1) ... "r")
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* If you use variable sized constraints like "m" or "g" in the
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* replacement make sure to pad to the worst case length.
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*/
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#define alternative_input(oldinstr, newinstr, feature, input...) \
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asm volatile ("661:\n\t" oldinstr "\n662:\n" \
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".section .altinstructions,\"a\"\n" \
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" .align 8\n" \
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" .quad 661b\n" /* label */ \
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" .quad 663f\n" /* new instruction */ \
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" .byte %c0\n" /* feature bit */ \
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" .byte 662b-661b\n" /* sourcelen */ \
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" .byte 664f-663f\n" /* replacementlen */ \
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".previous\n" \
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".section .altinstr_replacement,\"ax\"\n" \
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"663:\n\t" newinstr "\n664:\n" /* replacement */ \
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".previous" :: "i" (feature), ##input)
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/* Like alternative_input, but with a single output argument */
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#define alternative_io(oldinstr, newinstr, feature, output, input...) \
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asm volatile ("661:\n\t" oldinstr "\n662:\n" \
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".section .altinstructions,\"a\"\n" \
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" .align 8\n" \
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" .quad 661b\n" /* label */ \
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" .quad 663f\n" /* new instruction */ \
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" .byte %c[feat]\n" /* feature bit */ \
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" .byte 662b-661b\n" /* sourcelen */ \
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" .byte 664f-663f\n" /* replacementlen */ \
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".previous\n" \
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".section .altinstr_replacement,\"ax\"\n" \
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"663:\n\t" newinstr "\n664:\n" /* replacement */ \
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".previous" : output : [feat] "i" (feature), ##input)
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/*
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* use this macro(s) if you need more than one output parameter
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* in alternative_io
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*/
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#define ASM_OUTPUT2(a, b) a, b
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/*
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* Alternative inline assembly for SMP.
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*
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* The LOCK_PREFIX macro defined here replaces the LOCK and
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* LOCK_PREFIX macros used everywhere in the source tree.
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*
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* SMP alternatives use the same data structures as the other
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* alternatives and the X86_FEATURE_UP flag to indicate the case of a
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* UP system running a SMP kernel. The existing apply_alternatives()
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* works fine for patching a SMP kernel for UP.
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*
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* The SMP alternative tables can be kept after boot and contain both
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* UP and SMP versions of the instructions to allow switching back to
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* SMP at runtime, when hotplugging in a new CPU, which is especially
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* useful in virtualized environments.
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*
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* The very common lock prefix is handled as special case in a
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* separate table which is a pure address list without replacement ptr
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* and size information. That keeps the table sizes small.
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*/
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#ifdef CONFIG_SMP
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#define LOCK_PREFIX \
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".section .smp_locks,\"a\"\n" \
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" .align 8\n" \
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" .quad 661f\n" /* address */ \
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".previous\n" \
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"661:\n\tlock; "
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#else /* ! CONFIG_SMP */
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#define LOCK_PREFIX ""
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#endif
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struct paravirt_patch;
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#ifdef CONFIG_PARAVIRT
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void apply_paravirt(struct paravirt_patch *start, struct paravirt_patch *end);
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#else
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static inline void
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apply_paravirt(struct paravirt_patch *start, struct paravirt_patch *end)
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{}
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#define __parainstructions NULL
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#define __parainstructions_end NULL
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#endif
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#endif /* _X86_64_ALTERNATIVE_H */
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