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      1 
      2 /*--------------------------------------------------------------------*/
      3 /*--- The core dispatch loop, for jumping to a code address.       ---*/
      4 /*---                                       dispatch-amd64-linux.S ---*/
      5 /*--------------------------------------------------------------------*/
      6 
      7 /*
      8   This file is part of Valgrind, a dynamic binary instrumentation
      9   framework.
     10 
     11   Copyright (C) 2000-2015 Julian Seward
     12      jseward (at) acm.org
     13 
     14   This program is free software; you can redistribute it and/or
     15   modify it under the terms of the GNU General Public License as
     16   published by the Free Software Foundation; either version 2 of the
     17   License, or (at your option) any later version.
     18 
     19   This program is distributed in the hope that it will be useful, but
     20   WITHOUT ANY WARRANTY; without even the implied warranty of
     21   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     22   General Public License for more details.
     23 
     24   You should have received a copy of the GNU General Public License
     25   along with this program; if not, write to the Free Software
     26   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
     27   02111-1307, USA.
     28 
     29   The GNU General Public License is contained in the file COPYING.
     30 */
     31 
     32 #include "pub_core_basics_asm.h"
     33 
     34 #if defined(VGP_amd64_linux)
     35 
     36 #include "pub_core_dispatch_asm.h"
     37 #include "pub_core_transtab_asm.h"
     38 #include "libvex_guest_offsets.h"	/* for OFFSET_amd64_RIP */
     39 
     40 
     41 /*------------------------------------------------------------*/
     42 /*---                                                      ---*/
     43 /*--- The dispatch loop.  VG_(disp_run_translations) is    ---*/
     44 /*--- used to run all translations,                        ---*/
     45 /*--- including no-redir ones.                             ---*/
     46 /*---                                                      ---*/
     47 /*------------------------------------------------------------*/
     48 
     49 /*----------------------------------------------------*/
     50 /*--- Entry and preamble (set everything up)       ---*/
     51 /*----------------------------------------------------*/
     52 
     53 /* signature:
     54 void VG_(disp_run_translations)( UWord* two_words,
     55                                  void*  guest_state,
     56                                  Addr   host_addr );
     57 */
     58 .text
     59 .globl VG_(disp_run_translations)
     60 .type  VG_(disp_run_translations), @function
     61 VG_(disp_run_translations):
     62         /* %rdi holds two_words    */
     63 	/* %rsi holds guest_state  */
     64 	/* %rdx holds host_addr    */
     65 
     66         /* The preamble */
     67 
     68         /* Save integer registers, since this is a pseudo-function. */
     69         pushq   %rax
     70 	pushq	%rbx
     71 	pushq	%rcx
     72         pushq   %rdx
     73 	pushq	%rsi
     74 	pushq	%rbp
     75 	pushq	%r8
     76 	pushq	%r9
     77 	pushq	%r10
     78 	pushq	%r11
     79 	pushq	%r12
     80 	pushq	%r13
     81 	pushq	%r14
     82 	pushq	%r15
     83         /* %rdi must be saved last */
     84 	pushq	%rdi
     85 
     86         /* Get the host CPU in the state expected by generated code. */
     87 
     88 	/* set host FPU control word to the default mode expected
     89            by VEX-generated code.  See comments in libvex.h for
     90            more info. */
     91 	finit
     92 	pushq	$0x027F
     93 	fldcw	(%rsp)
     94 	addq	$8, %rsp
     95 
     96 	/* set host SSE control word to the default mode expected
     97 	   by VEX-generated code. */
     98 	pushq	$0x1F80
     99 	ldmxcsr	(%rsp)
    100 	addq	$8, %rsp
    101 
    102 	/* set dir flag to known value */
    103 	cld
    104 
    105 	/* Set up the guest state pointer */
    106 	movq	%rsi, %rbp
    107 
    108         /* and jump into the code cache.  Chained translations in
    109            the code cache run, until for whatever reason, they can't
    110            continue.  When that happens, the translation in question
    111            will jump (or call) to one of the continuation points
    112            VG_(cp_...) below. */
    113         jmpq    *%rdx
    114        	/*NOTREACHED*/
    115 
    116 /*----------------------------------------------------*/
    117 /*--- Postamble and exit.                          ---*/
    118 /*----------------------------------------------------*/
    119 
    120 postamble:
    121         /* At this point, %rax and %rdx contain two
    122            words to be returned to the caller.  %rax
    123            holds a TRC value, and %rdx optionally may
    124            hold another word (for CHAIN_ME exits, the
    125            address of the place to patch.) */
    126 
    127 	/* We're leaving.  Check that nobody messed with %mxcsr
    128            or %fpucw.  We can't mess with %rax or %rdx here as they
    129            hold the tentative return values, but any others are OK. */
    130 #if !defined(ENABLE_INNER)
    131         /* This check fails for self-hosting, so skip in that case */
    132 	pushq	$0
    133 	fstcw	(%rsp)
    134 	cmpl	$0x027F, (%rsp)
    135 	popq	%r15 /* get rid of the word without trashing %rflags */
    136 	jnz	invariant_violation
    137 #endif
    138 	pushq	$0
    139 	stmxcsr	(%rsp)
    140 	andl	$0xFFFFFFC0, (%rsp)  /* mask out status flags */
    141 	cmpl	$0x1F80, (%rsp)
    142 	popq	%r15
    143 	jnz	invariant_violation
    144 	/* otherwise we're OK */
    145 	jmp	remove_frame
    146 invariant_violation:
    147 	movq	$VG_TRC_INVARIANT_FAILED, %rax
    148         movq    $0, %rdx
    149 
    150 remove_frame:
    151         /* Pop %rdi, stash return values */
    152 	popq	%rdi
    153         movq    %rax, 0(%rdi)
    154         movq    %rdx, 8(%rdi)
    155         /* Now pop everything else */
    156 	popq	%r15
    157 	popq	%r14
    158 	popq	%r13
    159 	popq	%r12
    160 	popq	%r11
    161 	popq	%r10
    162 	popq	%r9
    163 	popq	%r8
    164 	popq	%rbp
    165 	popq	%rsi
    166 	popq	%rdx
    167 	popq	%rcx
    168 	popq	%rbx
    169 	popq	%rax
    170 	ret
    171 
    172 /*----------------------------------------------------*/
    173 /*--- Continuation points                          ---*/
    174 /*----------------------------------------------------*/
    175 
    176 /* ------ Chain me to slow entry point ------ */
    177 .global VG_(disp_cp_chain_me_to_slowEP)
    178 VG_(disp_cp_chain_me_to_slowEP):
    179         /* We got called.  The return address indicates
    180            where the patching needs to happen.  Collect
    181            the return address and, exit back to C land,
    182            handing the caller the pair (Chain_me_S, RA) */
    183         movq    $VG_TRC_CHAIN_ME_TO_SLOW_EP, %rax
    184         popq    %rdx
    185         /* 10 = movabsq $VG_(disp_chain_me_to_slowEP), %r11;
    186            3  = call *%r11 */
    187         subq    $10+3, %rdx
    188         jmp     postamble
    189 
    190 /* ------ Chain me to fast entry point ------ */
    191 .global VG_(disp_cp_chain_me_to_fastEP)
    192 VG_(disp_cp_chain_me_to_fastEP):
    193         /* We got called.  The return address indicates
    194            where the patching needs to happen.  Collect
    195            the return address and, exit back to C land,
    196            handing the caller the pair (Chain_me_F, RA) */
    197         movq    $VG_TRC_CHAIN_ME_TO_FAST_EP, %rax
    198         popq    %rdx
    199         /* 10 = movabsq $VG_(disp_chain_me_to_fastEP), %r11;
    200            3  = call *%r11 */
    201         subq    $10+3, %rdx
    202         jmp     postamble
    203 
    204 /* ------ Indirect but boring jump ------ */
    205 .global VG_(disp_cp_xindir)
    206 VG_(disp_cp_xindir):
    207 	/* Where are we going? */
    208 	movq	OFFSET_amd64_RIP(%rbp), %rax
    209 
    210         /* stats only */
    211         addl    $1, VG_(stats__n_xindirs_32)
    212 
    213 	/* try a fast lookup in the translation cache */
    214 	movabsq $VG_(tt_fast), %rcx
    215 	movq	%rax, %rbx		/* next guest addr */
    216 	andq	$VG_TT_FAST_MASK, %rbx	/* entry# */
    217 	shlq	$4, %rbx		/* entry# * sizeof(FastCacheEntry) */
    218 	movq	0(%rcx,%rbx,1), %r10	/* .guest */
    219 	movq	8(%rcx,%rbx,1), %r11	/* .host */
    220 	cmpq	%rax, %r10
    221 	jnz	fast_lookup_failed
    222 
    223         /* Found a match.  Jump to .host. */
    224 	jmp 	*%r11
    225 	ud2	/* persuade insn decoders not to speculate past here */
    226 
    227 fast_lookup_failed:
    228         /* stats only */
    229         addl    $1, VG_(stats__n_xindir_misses_32)
    230 
    231 	movq	$VG_TRC_INNER_FASTMISS, %rax
    232         movq    $0, %rdx
    233 	jmp	postamble
    234 
    235 /* ------ Assisted jump ------ */
    236 .global VG_(disp_cp_xassisted)
    237 VG_(disp_cp_xassisted):
    238         /* %rbp contains the TRC */
    239         movq    %rbp, %rax
    240         movq    $0, %rdx
    241         jmp     postamble
    242 
    243 /* ------ Event check failed ------ */
    244 .global VG_(disp_cp_evcheck_fail)
    245 VG_(disp_cp_evcheck_fail):
    246        	movq	$VG_TRC_INNER_COUNTERZERO, %rax
    247         movq    $0, %rdx
    248 	jmp	postamble
    249 
    250 
    251 .size VG_(disp_run_translations), .-VG_(disp_run_translations)
    252 
    253 #endif // defined(VGP_amd64_linux)
    254 
    255 /* Let the linker know we don't need an executable stack */
    256 MARK_STACK_NO_EXEC
    257 
    258 /*--------------------------------------------------------------------*/
    259 /*--- end                                                          ---*/
    260 /*--------------------------------------------------------------------*/
    261