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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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10fa1155a2
Currently we have a confused udelay implementation. * __const_udelay does not accept usecs but xloops in i386 and x86_64 * our implementation requires usecs as arg * it gets a xloops count when called by asm/arch/delay.h Bugs related to this (extremely long shutdown times) where reported by some x86_64 users, especially using Device Mapper. To hit this bug, a compile-time constant time parameter must be passed - that's why UML seems to work most times. Fix this with a simple udelay implementation. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Acked-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
30 lines
510 B
C
30 lines
510 B
C
#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/delay.h>
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#include <asm/param.h>
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void __delay(unsigned long time)
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{
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/* Stolen from the i386 __loop_delay */
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int d0;
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__asm__ __volatile__(
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"\tjmp 1f\n"
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".align 16\n"
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"1:\tjmp 2f\n"
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".align 16\n"
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"2:\tdecl %0\n\tjns 2b"
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:"=&a" (d0)
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:"0" (time));
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}
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void __udelay(unsigned long usecs)
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{
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int i, n;
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n = (loops_per_jiffy * HZ * usecs) / MILLION;
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for(i=0;i<n;i++)
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cpu_relax();
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}
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EXPORT_SYMBOL(__udelay);
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