Re: [PATCH 1/2] Libsanitizer merge from upstream r253555.

[Maxim Ostapenko <m.ostapenko@partner.samsung.com>]

On 23/11/15 16:00, Christophe Lyon wrote:
> On 23 November 2015 at 13:41, Jakub Jelinek <jakub@redhat.com> wrote:
>> On Mon, Nov 23, 2015 at 03:33:57PM +0300, Maxim Ostapenko wrote:
>>> + Adhemerval
>>>
>>> Christophe, it looks like your kernel headers (asm/ptrace.h) don't contain
>>> ARM_VFPREGS_SIZE. Do you use old kernel version?
> Yes, I do use old kernel headers.
> I could upgrade them, but I tend to avoid changing versions (binutils,
> glibc, newlib, kernel headers) unless really necessary.
>
>> Unlike LLVM, we do care to support older kernel headers.
>> So, if it is say a define, you could add
>> libsanitizer/include/system/linux/ptrace.h
>> or
>> libsanitizer/include/system/asm/ptrace.h
>> that would #include_next the original header and ifdef __arm__ and
>> that define is not defined (or some other condition, kernel version etc.),
>> define it.
>>
>>          Jakub
> So, given Jakub's answer I'll not upgrade them yet on my side :-)
>
>

Yeah, right. I've asked about kernel headers just to make sure I 
correctly understand the issue.

Actually, I see such code in 
lib/sanitizer_common/sanitizer_platform_limits_posix.cc:

#if defined(PTRACE_GETVFPREGS) && defined(PTRACE_SETVFPREGS)
   int ptrace_getvfpregs = PTRACE_GETVFPREGS;
   int ptrace_setvfpregs = PTRACE_SETVFPREGS;
#else
   int ptrace_getvfpregs = -1;
   int ptrace_setvfpregs = -1;
#endif

and in ptrace interceptor:

  else if (request == ptrace_setvfpregs)
     COMMON_INTERCEPTOR_READ_RANGE(ctx, data, 
struct_user_vfpregs_struct_sz);
  else if (request == ptrace_getvfpregs)
     COMMON_INTERCEPTOR_WRITE_RANGE(ctx, data, 
struct_user_vfpregs_struct_sz)

So, perhaps we can do the same thing with ARM_VFPREGS_SIZE, something 
like this?

diff --git 
a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc 
b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
index 9866cc9..20ff224 100644
--- a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
+++ b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc
@@ -323,10 +323,14 @@ unsigned struct_ElfW_Phdr_sz = sizeof(Elf_Phdr);
    unsigned struct_user_fpxregs_struct_sz = sizeof(struct 
user_fpxregs_struct);
  #endif // __x86_64 || __mips64 || __powerpc64__ || __aarch64__ || __arm__
  #ifdef __arm__
+#if defined(ARM_VFPREGS_SIZE)
    unsigned struct_user_vfpregs_struct_sz = ARM_VFPREGS_SIZE;
  #else
    unsigned struct_user_vfpregs_struct_sz = 0;
  #endif
+#else
+  unsigned struct_user_vfpregs_struct_sz = 0;
+#endif