a048a07d7f
On some CPUs we can prevent a vulnerability related to store-to-load forwarding by preventing store forwarding between privilege domains, by inserting a barrier in kernel entry and exit paths. This is known to be the case on at least Power7, Power8 and Power9 powerpc CPUs. Barriers must be inserted generally before the first load after moving to a higher privilege, and after the last store before moving to a lower privilege, HV and PR privilege transitions must be protected. Barriers are added as patch sections, with all kernel/hypervisor entry points patched, and the exit points to lower privilge levels patched similarly to the RFI flush patching. Firmware advertisement is not implemented yet, so CPU flush types are hard coded. Thanks to Michal Suchánek for bug fixes and review. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com> Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michal Suchánek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
228 lines
7.7 KiB
C
228 lines
7.7 KiB
C
#ifndef __ASM_POWERPC_FEATURE_FIXUPS_H
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#define __ASM_POWERPC_FEATURE_FIXUPS_H
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/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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/*
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* Feature section common macros
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*
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* Note that the entries now contain offsets between the table entry
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* and the code rather than absolute code pointers in order to be
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* useable with the vdso shared library. There is also an assumption
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* that values will be negative, that is, the fixup table has to be
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* located after the code it fixes up.
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*/
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#if defined(CONFIG_PPC64) && !defined(__powerpc64__)
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/* 64 bits kernel, 32 bits code (ie. vdso32) */
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#define FTR_ENTRY_LONG .8byte
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#define FTR_ENTRY_OFFSET .long 0xffffffff; .long
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#elif defined(CONFIG_PPC64)
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#define FTR_ENTRY_LONG .8byte
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#define FTR_ENTRY_OFFSET .8byte
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#else
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#define FTR_ENTRY_LONG .long
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#define FTR_ENTRY_OFFSET .long
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#endif
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#define START_FTR_SECTION(label) label##1:
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#define FTR_SECTION_ELSE_NESTED(label) \
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label##2: \
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.pushsection __ftr_alt_##label,"a"; \
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.align 2; \
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label##3:
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#define MAKE_FTR_SECTION_ENTRY(msk, val, label, sect) \
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label##4: \
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.popsection; \
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.pushsection sect,"a"; \
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.align 3; \
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label##5: \
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FTR_ENTRY_LONG msk; \
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FTR_ENTRY_LONG val; \
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FTR_ENTRY_OFFSET label##1b-label##5b; \
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FTR_ENTRY_OFFSET label##2b-label##5b; \
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FTR_ENTRY_OFFSET label##3b-label##5b; \
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FTR_ENTRY_OFFSET label##4b-label##5b; \
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.ifgt (label##4b- label##3b)-(label##2b- label##1b); \
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.error "Feature section else case larger than body"; \
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.endif; \
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.popsection;
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/* CPU feature dependent sections */
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#define BEGIN_FTR_SECTION_NESTED(label) START_FTR_SECTION(label)
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#define BEGIN_FTR_SECTION START_FTR_SECTION(97)
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#define END_FTR_SECTION_NESTED(msk, val, label) \
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FTR_SECTION_ELSE_NESTED(label) \
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MAKE_FTR_SECTION_ENTRY(msk, val, label, __ftr_fixup)
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#define END_FTR_SECTION(msk, val) \
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END_FTR_SECTION_NESTED(msk, val, 97)
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#define END_FTR_SECTION_NESTED_IFSET(msk, label) \
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END_FTR_SECTION_NESTED((msk), (msk), label)
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#define END_FTR_SECTION_IFSET(msk) END_FTR_SECTION((msk), (msk))
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#define END_FTR_SECTION_IFCLR(msk) END_FTR_SECTION((msk), 0)
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/* CPU feature sections with alternatives, use BEGIN_FTR_SECTION to start */
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#define FTR_SECTION_ELSE FTR_SECTION_ELSE_NESTED(97)
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#define ALT_FTR_SECTION_END_NESTED(msk, val, label) \
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MAKE_FTR_SECTION_ENTRY(msk, val, label, __ftr_fixup)
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#define ALT_FTR_SECTION_END_NESTED_IFSET(msk, label) \
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ALT_FTR_SECTION_END_NESTED(msk, msk, label)
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#define ALT_FTR_SECTION_END_NESTED_IFCLR(msk, label) \
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ALT_FTR_SECTION_END_NESTED(msk, 0, label)
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#define ALT_FTR_SECTION_END(msk, val) \
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ALT_FTR_SECTION_END_NESTED(msk, val, 97)
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#define ALT_FTR_SECTION_END_IFSET(msk) \
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ALT_FTR_SECTION_END_NESTED_IFSET(msk, 97)
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#define ALT_FTR_SECTION_END_IFCLR(msk) \
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ALT_FTR_SECTION_END_NESTED_IFCLR(msk, 97)
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/* MMU feature dependent sections */
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#define BEGIN_MMU_FTR_SECTION_NESTED(label) START_FTR_SECTION(label)
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#define BEGIN_MMU_FTR_SECTION START_FTR_SECTION(97)
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#define END_MMU_FTR_SECTION_NESTED(msk, val, label) \
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FTR_SECTION_ELSE_NESTED(label) \
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MAKE_FTR_SECTION_ENTRY(msk, val, label, __mmu_ftr_fixup)
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#define END_MMU_FTR_SECTION(msk, val) \
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END_MMU_FTR_SECTION_NESTED(msk, val, 97)
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#define END_MMU_FTR_SECTION_IFSET(msk) END_MMU_FTR_SECTION((msk), (msk))
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#define END_MMU_FTR_SECTION_IFCLR(msk) END_MMU_FTR_SECTION((msk), 0)
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/* MMU feature sections with alternatives, use BEGIN_FTR_SECTION to start */
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#define MMU_FTR_SECTION_ELSE_NESTED(label) FTR_SECTION_ELSE_NESTED(label)
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#define MMU_FTR_SECTION_ELSE MMU_FTR_SECTION_ELSE_NESTED(97)
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#define ALT_MMU_FTR_SECTION_END_NESTED(msk, val, label) \
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MAKE_FTR_SECTION_ENTRY(msk, val, label, __mmu_ftr_fixup)
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#define ALT_MMU_FTR_SECTION_END_NESTED_IFSET(msk, label) \
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ALT_MMU_FTR_SECTION_END_NESTED(msk, msk, label)
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#define ALT_MMU_FTR_SECTION_END_NESTED_IFCLR(msk, label) \
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ALT_MMU_FTR_SECTION_END_NESTED(msk, 0, label)
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#define ALT_MMU_FTR_SECTION_END(msk, val) \
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ALT_MMU_FTR_SECTION_END_NESTED(msk, val, 97)
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#define ALT_MMU_FTR_SECTION_END_IFSET(msk) \
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ALT_MMU_FTR_SECTION_END_NESTED_IFSET(msk, 97)
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#define ALT_MMU_FTR_SECTION_END_IFCLR(msk) \
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ALT_MMU_FTR_SECTION_END_NESTED_IFCLR(msk, 97)
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/* Firmware feature dependent sections */
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#define BEGIN_FW_FTR_SECTION_NESTED(label) START_FTR_SECTION(label)
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#define BEGIN_FW_FTR_SECTION START_FTR_SECTION(97)
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#define END_FW_FTR_SECTION_NESTED(msk, val, label) \
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FTR_SECTION_ELSE_NESTED(label) \
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MAKE_FTR_SECTION_ENTRY(msk, val, label, __fw_ftr_fixup)
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#define END_FW_FTR_SECTION(msk, val) \
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END_FW_FTR_SECTION_NESTED(msk, val, 97)
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#define END_FW_FTR_SECTION_IFSET(msk) END_FW_FTR_SECTION((msk), (msk))
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#define END_FW_FTR_SECTION_IFCLR(msk) END_FW_FTR_SECTION((msk), 0)
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/* Firmware feature sections with alternatives */
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#define FW_FTR_SECTION_ELSE_NESTED(label) FTR_SECTION_ELSE_NESTED(label)
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#define FW_FTR_SECTION_ELSE FTR_SECTION_ELSE_NESTED(97)
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#define ALT_FW_FTR_SECTION_END_NESTED(msk, val, label) \
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MAKE_FTR_SECTION_ENTRY(msk, val, label, __fw_ftr_fixup)
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#define ALT_FW_FTR_SECTION_END_NESTED_IFSET(msk, label) \
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ALT_FW_FTR_SECTION_END_NESTED(msk, msk, label)
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#define ALT_FW_FTR_SECTION_END_NESTED_IFCLR(msk, label) \
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ALT_FW_FTR_SECTION_END_NESTED(msk, 0, label)
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#define ALT_FW_FTR_SECTION_END(msk, val) \
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ALT_FW_FTR_SECTION_END_NESTED(msk, val, 97)
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#define ALT_FW_FTR_SECTION_END_IFSET(msk) \
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ALT_FW_FTR_SECTION_END_NESTED_IFSET(msk, 97)
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#define ALT_FW_FTR_SECTION_END_IFCLR(msk) \
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ALT_FW_FTR_SECTION_END_NESTED_IFCLR(msk, 97)
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#ifndef __ASSEMBLY__
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#define ASM_FTR_IF(section_if, section_else, msk, val) \
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stringify_in_c(BEGIN_FTR_SECTION) \
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section_if "; " \
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stringify_in_c(FTR_SECTION_ELSE) \
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section_else "; " \
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stringify_in_c(ALT_FTR_SECTION_END((msk), (val)))
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#define ASM_FTR_IFSET(section_if, section_else, msk) \
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ASM_FTR_IF(section_if, section_else, (msk), (msk))
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#define ASM_FTR_IFCLR(section_if, section_else, msk) \
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ASM_FTR_IF(section_if, section_else, (msk), 0)
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#define ASM_MMU_FTR_IF(section_if, section_else, msk, val) \
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stringify_in_c(BEGIN_MMU_FTR_SECTION) \
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section_if "; " \
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stringify_in_c(MMU_FTR_SECTION_ELSE) \
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section_else "; " \
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stringify_in_c(ALT_MMU_FTR_SECTION_END((msk), (val)))
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#define ASM_MMU_FTR_IFSET(section_if, section_else, msk) \
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ASM_MMU_FTR_IF(section_if, section_else, (msk), (msk))
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#define ASM_MMU_FTR_IFCLR(section_if, section_else, msk) \
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ASM_MMU_FTR_IF(section_if, section_else, (msk), 0)
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#endif /* __ASSEMBLY__ */
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/* LWSYNC feature sections */
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#define START_LWSYNC_SECTION(label) label##1:
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#define MAKE_LWSYNC_SECTION_ENTRY(label, sect) \
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label##2: \
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.pushsection sect,"a"; \
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.align 2; \
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label##3: \
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FTR_ENTRY_OFFSET label##1b-label##3b; \
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.popsection;
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#define STF_ENTRY_BARRIER_FIXUP_SECTION \
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953: \
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.pushsection __stf_entry_barrier_fixup,"a"; \
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.align 2; \
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954: \
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FTR_ENTRY_OFFSET 953b-954b; \
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.popsection;
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#define STF_EXIT_BARRIER_FIXUP_SECTION \
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955: \
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.pushsection __stf_exit_barrier_fixup,"a"; \
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.align 2; \
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956: \
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FTR_ENTRY_OFFSET 955b-956b; \
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.popsection;
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#define RFI_FLUSH_FIXUP_SECTION \
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951: \
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.pushsection __rfi_flush_fixup,"a"; \
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.align 2; \
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952: \
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FTR_ENTRY_OFFSET 951b-952b; \
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.popsection;
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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extern long stf_barrier_fallback;
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extern long __start___stf_entry_barrier_fixup, __stop___stf_entry_barrier_fixup;
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extern long __start___stf_exit_barrier_fixup, __stop___stf_exit_barrier_fixup;
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extern long __start___rfi_flush_fixup, __stop___rfi_flush_fixup;
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void apply_feature_fixups(void);
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void setup_feature_keys(void);
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#endif
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#endif /* __ASM_POWERPC_FEATURE_FIXUPS_H */
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