[MIPS] Leave room for frame header on stack for MIPS arch

src/trusted/service_runtime/nacl_config.h

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /*
  * NaCl Simple/secure ELF loader (NaCl SEL).
  *
  * NOTE: This header is ALSO included by assembler files and hence
@@ skipping 166 matching lines @@
 #  define NACL_USERRET_FIX        (-0x4)
 #  define NACL_SYSARGS_FIX        (0)
 /*
  * System V Application Binary Interface, Intel386 Architcture
  * Processor Supplement, section 3-10, says stack alignment is
  * 4-bytes, but gcc-generated code can require 16-byte alignment
  * (depending on compiler flags in force) for SSE instructions, so we
  * must do so here as well.
  */
 #  define NACL_STACK_ALIGN_MASK   (0xf)
+#  define NACL_STACK_ARG_SIZE     (0)
 #  define NACL_STACK_GETS_ARG     (1)
 #  define NACL_STACK_PAD_BELOW_ALIGN (4)
 #  define NACL_STACK_RED_ZONE     (0)
 
 # elif NACL_BUILD_SUBARCH == 64
 /*
  * The untrusted stack looks like this on x86-64:
  *   rsp-0x08: 8 byte return address pushed by untrusted code's call
  *   rsp-0x10: 8 byte return address pushed by the trampoline's call
  *   rsp-0x28: 0x18 bytes of syscall arguments saved by NaClSyscallSeg
  */
 #  define NACL_TRAMPRET_FIX       (-0x10)
 #  define NACL_USERRET_FIX        (-0x8)
 #  define NACL_SYSARGS_FIX        (-0x28)
 /*
  * System V Application Binary Interface, AMD64 Architecture Processor
  * Supplement, at http://www.x86-64.org/documentation/abi.pdf, section
  * 3.2.2 discusses stack alignment.
  */
 #  define NACL_STACK_ALIGN_MASK   (0xf)
+#  define NACL_STACK_ARG_SIZE     (0)
 #  define NACL_STACK_GETS_ARG     (0)
 #  define NACL_STACK_PAD_BELOW_ALIGN (8)
 #  define NACL_STACK_RED_ZONE     (128)
 # else /* NACL_BUILD_SUBARCH */
 #  error Unknown platform!
 # endif /* NACL_BUILD_SUBARCH */
 
 #elif NACL_ARCH(NACL_BUILD_ARCH) == NACL_arm
 
 # define NACL_BLOCK_SHIFT         (4)
@@ skipping 15 matching lines @@
 # define NACL_SYSARGS_FIX         (-0x10)
 /*
  * See ARM Procedure Call Standard, ARM IHI 0042D, section 5.2.1.2.
  * http://infocenter.arm.com/help/topic/com.arm.doc.ihi0042a/IHI0042A_aapcs.pdf
  * -- the "public" stack alignment is required to be 8 bytes.
  * While ARM vector loads and stores work with misaligned addresses, there can
  * be performance penalties on some microarchitectures.  To improve the
  * performance of vector instructions, we increase this to 16.
  */
 # define NACL_STACK_ALIGN_MASK    (0xf)
+# define NACL_STACK_ARG_SIZE      (0)
 # define NACL_STACK_GETS_ARG      (0)
 # define NACL_STACK_PAD_BELOW_ALIGN (0)
 # define NACL_STACK_RED_ZONE      (0)
 
 /*
  * NOTE: Used by various assembler files, needs to be
  *       synchronized with NaClThreadContext
  */
 # define NACL_CALLEE_SAVE_LIST {r4, r5, r6, r7, r8, r9, r10, fp, sp}
 
@@ skipping 11 matching lines @@
  * The untrusted stack looks like this on MIPS:
  *   $sp+0x10: 0-8 bytes for 0-2 syscall arguments saved by untrusted code
  *   $sp+0x00: 16 bytes for 4 syscall arguments saved by NaClSyscallSeg
  *   $sp-0x04: 4 byte user return address saved by NaClSyscallSeg
  *   $sp-0x08: 4 byte trampoline address saved by NaClSyscallSeg
  */
 # define NACL_TRAMPRET_FIX          (-0x8)
 # define NACL_USERRET_FIX           (-0x4)
 # define NACL_SYSARGS_FIX           (0)
 # define NACL_STACK_ALIGN_MASK      (0x7)
+/*
+ * The MIPS o32 ABI requires callers to reserve 16 bytes above the stack
+ * pointer, which the callee can spill arguments to.
+ */
+# define NACL_STACK_ARG_SIZE        (0x10)

[Mark Seaborn, 2013/03/07 16:07:53]

Maybe calls this "ARGS_SIZE" rather than "ARG_SIZE", because it's the size of
all the arguments passed in registers rather than a single argument.  (Is there
a better term for this?  In Windows' x64 ABI, it's referred to as "shadow space"
here: http://en.wikipedia.org/wiki/X86_calling_conventions.)

[petarj, 2013/03/07 17:33:12]

Done.
There is no common name everybody uses for it.
I used "stack frame header" line for some other projects like v8.
GCC calls it "args_size".

 # define NACL_STACK_GETS_ARG        (0)
 # define NACL_STACK_PAD_BELOW_ALIGN (0)
 # define NACL_STACK_RED_ZONE        (0)
 /* 16 byte bundles */
 
 #else /* NACL_ARCH(NACL_BUILD_ARCH) */
 
 # error Unknown platform!
 
 #endif /* NACL_ARCH(NACL_BUILD_ARCH) */
 
 #ifdef __ASSEMBLER__
 # if NACL_WINDOWS
 #  define NACL_RODATA           .section .rdata, "dr"
 # elif NACL_OSX
 #  define NACL_RODATA           .section __TEXT, __const
 # else
 #  define NACL_RODATA           .section .rodata, "a"
 # endif
 #endif
 
 #endif  /* NATIVE_CLIENT_SRC_TRUSTED_SERVICE_RUNTIME_NACL_CONFIG_H_ */