98 lines
1.5 KiB
ArmAsm
98 lines
1.5 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-only */
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#include <linux/export.h>
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#include <linux/linkage.h>
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#include <asm/percpu.h>
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#include <asm/processor-flags.h>
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.text
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#ifndef CONFIG_X86_CMPXCHG64
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/*
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* Emulate 'cmpxchg8b (%esi)' on UP
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*
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* Inputs:
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* %esi : memory location to compare
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* %eax : low 32 bits of old value
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* %edx : high 32 bits of old value
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* %ebx : low 32 bits of new value
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* %ecx : high 32 bits of new value
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*/
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SYM_FUNC_START(cmpxchg8b_emu)
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pushfl
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cli
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cmpl (%esi), %eax
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jne .Lnot_same
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cmpl 4(%esi), %edx
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jne .Lnot_same
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movl %ebx, (%esi)
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movl %ecx, 4(%esi)
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orl $X86_EFLAGS_ZF, (%esp)
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popfl
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RET
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.Lnot_same:
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movl (%esi), %eax
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movl 4(%esi), %edx
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andl $(~X86_EFLAGS_ZF), (%esp)
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popfl
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RET
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SYM_FUNC_END(cmpxchg8b_emu)
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EXPORT_SYMBOL(cmpxchg8b_emu)
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#endif
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#ifndef CONFIG_UML
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/*
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* Emulate 'cmpxchg8b %fs:(%rsi)'
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*
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* Inputs:
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* %esi : memory location to compare
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* %eax : low 32 bits of old value
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* %edx : high 32 bits of old value
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* %ebx : low 32 bits of new value
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* %ecx : high 32 bits of new value
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*
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* Notably this is not LOCK prefixed and is not safe against NMIs
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*/
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SYM_FUNC_START(this_cpu_cmpxchg8b_emu)
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pushfl
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cli
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cmpl __percpu (%esi), %eax
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jne .Lnot_same2
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cmpl __percpu 4(%esi), %edx
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jne .Lnot_same2
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movl %ebx, __percpu (%esi)
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movl %ecx, __percpu 4(%esi)
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orl $X86_EFLAGS_ZF, (%esp)
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popfl
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RET
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.Lnot_same2:
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movl __percpu (%esi), %eax
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movl __percpu 4(%esi), %edx
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andl $(~X86_EFLAGS_ZF), (%esp)
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popfl
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RET
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SYM_FUNC_END(this_cpu_cmpxchg8b_emu)
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#endif
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