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69e8544cd0
This is a preparatory patch for change in "struct pt_regs"
handling in entry_64.S.
trace_hardirqs*() thunks were (ab)using a part of the
'pt_regs' handling code, namely the SAVE_ARGS/RESTORE_ARGS
macros, to save/restore registers across C function calls.
Since SAVE_ARGS is going to be changed, open-code
register saving/restoring here.
Incidentally, this removes a bit of dead code:
one SAVE_ARGS was used just to emit a CFI annotation,
but it also generated unreachable assembly instructions.
Take a page from thunk_32.S and use push/pop instructions
instead of movq, they are far shorter:
1 or 2 bytes versus 5, and no need for instructions to adjust %rsp:
text data bss dec hex filename
333 40 0 373 175 thunk_64_movq.o
104 40 0 144 90 thunk_64_push_pop.o
[ This is ugly as sin, but we'll fix up the ugliness in the next
patch. I see no point in reordering patches just to avoid an
ugly intermediate state. --Andy ]
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1420927210-19738-4-git-send-email-dvlasenk@redhat.com
Link: http://lkml.kernel.org/r/4c979ad604f0f02c5ade3b3da308b53eabd5e198.1424989793.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
94 lines
2.0 KiB
ArmAsm
94 lines
2.0 KiB
ArmAsm
/*
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* Save registers before calling assembly functions. This avoids
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* disturbance of register allocation in some inline assembly constructs.
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* Copyright 2001,2002 by Andi Kleen, SuSE Labs.
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* Added trace_hardirqs callers - Copyright 2007 Steven Rostedt, Red Hat, Inc.
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* Subject to the GNU public license, v.2. No warranty of any kind.
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*/
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#include <linux/linkage.h>
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#include <asm/dwarf2.h>
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#include <asm/calling.h>
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#include <asm/asm.h>
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/* rdi: arg1 ... normal C conventions. rax is saved/restored. */
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.macro THUNK name, func, put_ret_addr_in_rdi=0
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.globl \name
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\name:
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CFI_STARTPROC
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/* this one pushes 9 elems, the next one would be %rIP */
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pushq_cfi %rdi
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CFI_REL_OFFSET rdi, 0
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pushq_cfi %rsi
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CFI_REL_OFFSET rsi, 0
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pushq_cfi %rdx
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CFI_REL_OFFSET rdx, 0
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pushq_cfi %rcx
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CFI_REL_OFFSET rcx, 0
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pushq_cfi %rax
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CFI_REL_OFFSET rax, 0
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pushq_cfi %r8
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CFI_REL_OFFSET r8, 0
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pushq_cfi %r9
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CFI_REL_OFFSET r9, 0
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pushq_cfi %r10
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CFI_REL_OFFSET r10, 0
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pushq_cfi %r11
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CFI_REL_OFFSET r11, 0
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.if \put_ret_addr_in_rdi
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/* 9*8(%rsp) is return addr on stack */
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movq_cfi_restore 9*8, rdi
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.endif
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call \func
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jmp restore
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CFI_ENDPROC
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_ASM_NOKPROBE(\name)
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.endm
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#ifdef CONFIG_TRACE_IRQFLAGS
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THUNK trace_hardirqs_on_thunk,trace_hardirqs_on_caller,1
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THUNK trace_hardirqs_off_thunk,trace_hardirqs_off_caller,1
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#endif
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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THUNK lockdep_sys_exit_thunk,lockdep_sys_exit
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#endif
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#ifdef CONFIG_PREEMPT
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THUNK ___preempt_schedule, preempt_schedule
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#ifdef CONFIG_CONTEXT_TRACKING
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THUNK ___preempt_schedule_context, preempt_schedule_context
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#endif
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#endif
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#if defined(CONFIG_TRACE_IRQFLAGS) \
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|| defined(CONFIG_DEBUG_LOCK_ALLOC) \
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|| defined(CONFIG_PREEMPT)
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CFI_STARTPROC
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CFI_ADJUST_CFA_OFFSET 9*8
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restore:
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popq_cfi %r11
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CFI_RESTORE r11
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popq_cfi %r10
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CFI_RESTORE r10
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popq_cfi %r9
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CFI_RESTORE r9
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popq_cfi %r8
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CFI_RESTORE r8
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popq_cfi %rax
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CFI_RESTORE rax
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popq_cfi %rcx
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CFI_RESTORE rcx
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popq_cfi %rdx
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CFI_RESTORE rdx
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popq_cfi %rsi
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CFI_RESTORE rsi
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popq_cfi %rdi
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CFI_RESTORE rdi
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ret
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CFI_ENDPROC
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_ASM_NOKPROBE(restore)
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#endif
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