sys/arch/amd64/include/frame_regs.h

   1 /*      $NetBSD: frame_regs.h,v 1.3 2008/01/05 12:08:51 dsl Exp $       */
   2
   3 #ifndef _AMD64_FRAME_REGS_H_
   4 #define _AMD64_FRAME_REGS_H_
   5
   6 /*
   7  * amd64 registers (and friends) ordered as in a trap/interrupt/syscall frame.
   8  * Also the indexes into the 'general register state' (__greg_t) passed to
   9  * userland.
  10  * Historically they were in the same order, but the order in the frames
  11  * has been changed to improve syscall efficiency.
  12  *
  13  * Notes:
  14  * 1) gdb (src/gnu/dist/gdb6/gdb/amd64nbsd-tdep.c) has a lookup table that
  15  *    assumes the __greg_t ordering.
  16  * 2) src/lib/libc/arch/x86_64/gen/makecontext.c assumes that the first
  17  *    6 entries in the __greg_t array match the registers used to pass
  18  *    function arguments.
  19  * 3) The 'struct reg' from machine/reg.h has to match __greg_t.
  20  *    Since they are both arrays and indexed with the same tokens this
  21  *    shouldn't be a problem, but is rather confusing.
  22  *    This assumption is made in a lot of places!
  23  * 4) There might be other code out there that relies on the ordering.
  24  *
  25  * The first entries below match the registers used for syscall arguments
  26  * (%rcx is destroyed by the syscall instruction, the libc system call
  27  * stubs copy %rcx to %r10).
  28  * arg6-arg9 are copied from the user stack for system calls with more
  29  * than 6 args (SYS_MAXSYSARGS is 8, + 2 entries for SYS___SYSCALL).
  30  */
  31 #define _FRAME_REG(greg, freg)  \
  32         greg(rdi, RDI, 0)       \
  33         greg(rsi, RSI, 1)       \
  34         greg(rdx, RDX, 2)       \
  35         greg(r10, R10, 6)       \
  36         greg(r8,  R8,  4)       \
  37         greg(r9,  R9,  5)       \
  38         freg(arg6, @,  @)       /* syscall arg from stack */ \
  39         freg(arg7, @,  @)       /* syscall arg from stack */ \
  40         freg(arg8, @,  @)       /* syscall arg from stack */ \
  41         freg(arg9, @,  @)       /* syscall arg from stack */ \
  42         greg(rcx, RCX, 3)       \
  43         greg(r11, R11, 7)       \
  44         greg(r12, R12, 8)       \
  45         greg(r13, R13, 9)       \
  46         greg(r14, R14, 10)      \
  47         greg(r15, R15, 11)      \
  48         greg(rbp, RBP, 12)      \
  49         greg(rbx, RBX, 13)      \
  50         greg(rax, RAX, 14)      \
  51         greg(gs,  GS,  15)      \
  52         greg(fs,  FS,  16)      \
  53         greg(es,  ES,  17)      \
  54         greg(ds,  DS,  18)      \
  55         greg(trapno, TRAPNO, 19)        \
  56         /* below portion defined in hardware */ \
  57         greg(err, ERR, 20)      /* Dummy inserted if not defined */ \
  58         greg(rip, RIP, 21)      \
  59         greg(cs,  CS,  22)      \
  60         greg(rflags, RFLAGS, 23)        \
  61         /* These are pushed unconditionally on the x86-64 */ \
  62         greg(rsp, RSP, 24)      \
  63         greg(ss,  SS,  25)
  64
  65 #define _FRAME_NOREG(reg, REG, idx)
  66
  67 #define _FRAME_GREG(greg) _FRAME_REG(greg, _FRAME_NOREG)
  68
  69 #endif