This is the mail archive of the
gdb-patches@sourceware.org
mailing list for the GDB project.
Re: [PATCH v3 12/14] add linux_infcall_mmap
- From: Pedro Alves <palves at redhat dot com>
- To: Jan Kratochvil <jan dot kratochvil at redhat dot com>
- Cc: gdb-patches at sourceware dot org
- Date: Fri, 12 Dec 2014 14:37:59 +0000
- Subject: Re: [PATCH v3 12/14] add linux_infcall_mmap
- Authentication-results: sourceware.org; auth=none
- References: <20141101214552 dot 13230 dot 45564 dot stgit at host1 dot jankratochvil dot net> <20141101214719 dot 13230 dot 96367 dot stgit at host1 dot jankratochvil dot net> <54623CA7 dot 8060702 at redhat dot com> <20141123191136 dot GA31798 at host2 dot jankratochvil dot net>
On 11/23/2014 07:11 PM, Jan Kratochvil wrote:
> On Tue, 11 Nov 2014 17:43:19 +0100, Pedro Alves wrote:
>> On 11/01/2014 09:47 PM, Jan Kratochvil wrote:
>>> +/* See gdbarch.sh 'infcall_mmap'. */
>>> +
>>> +static CORE_ADDR
>>> +linux_infcall_mmap (CORE_ADDR size, unsigned prot)
>>> +{
>>> + struct objfile *objf;
>>> + /* Do there still exist any Linux systems without "mmap64"?
>>> + "mmap" uses 64-bit off_t on x86_64 and 32-bit off_t on i386 and x32. */
>>> + struct value *mmap_val = find_function_in_inferior ("mmap64", &objf);
>>> + struct value *addr_val;
>>> + struct gdbarch *gdbarch = get_objfile_arch (objf);
>>> + CORE_ADDR retval;
>>> + enum
>>> + {
>>> + ARG_ADDR, ARG_LENGTH, ARG_PROT, ARG_FLAGS, ARG_FD, ARG_OFFSET, ARG_MAX
>>> + };
>>> + struct value *arg[ARG_MAX];
>>> +
>>> + arg[ARG_ADDR] = value_from_pointer (builtin_type (gdbarch)->builtin_data_ptr,
>>> + 0);
>>> + /* Assuming sizeof (unsigned long) == sizeof (size_t). */
>>> + arg[ARG_LENGTH] = value_from_ulongest
>>> + (builtin_type (gdbarch)->builtin_unsigned_long, size);
>>> + gdb_assert ((prot & ~7) == 0);
>>> + arg[ARG_PROT] = value_from_longest (builtin_type (gdbarch)->builtin_int,
>>> + 0
>>> + | ((prot & 4) != 0 ? PROT_READ : 0)
>>> + | ((prot & 2) != 0 ? PROT_WRITE : 0)
>>> + | ((prot & 1) != 0 ? PROT_EXEC : 0));
>>> + arg[ARG_FLAGS] = value_from_longest (builtin_type (gdbarch)->builtin_int,
>>> + MAP_PRIVATE | MAP_ANONYMOUS);
>>
>> PROT_READ, PROT_WRITE, PROT_EXEC, MAP_PRIVATE, MAP_ANONYMOUS
>> are host values/macros.
>
> Added to arch-utils.h:
> +/* Symbols for gdbarch_infcall_mmap; their Linux PROT_* system
> + definitions would be dependent on compilation host. */
> +#define GDB_MMAP_PROT_READ 0x1 /* Page can be read. */
> +#define GDB_MMAP_PROT_WRITE 0x2 /* Page can be written. */
> +#define GDB_MMAP_PROT_EXEC 0x4 /* Page can be executed. */
>
> Added to linux-tdep.c:
> +/* Symbols for linux_infcall_mmap's ARG_FLAGS; their Linux MAP_* system
> + definitions would be dependent on compilation host. */
> +#define GDB_MMAP_MAP_PRIVATE 0x02 /* Changes are private. */
> +#define GDB_MMAP_MAP_ANONYMOUS 0x20 /* Don't use a file. */
> and
> - gdb_assert ((prot & ~7) == 0);
> + gdb_assert ((prot & ~(GDB_MMAP_PROT_READ | GDB_MMAP_PROT_WRITE
> + | GDB_MMAP_PROT_EXEC))
> + == 0);
>
> Changed gdbarch.sh comment:
> -# PROT has rwx bitmask format - bit 2 (value 4) is for readable memory, bit 1
> -# (value 2) is for writable memory and bit 0 (value 1) is for executable memory.
> +# PROT has GDB_MMAP_PROT_* bitmask format.
>
> Change changed the magic numbers to GDB_MMAP_PROT_* accordingly:
> // Make the memory always readable.
> - prot = 4;
> + prot = GDB_MMAP_PROT_READ;
> if ((bfd_get_section_flags (abfd, sect) & SEC_READONLY) == 0)
> - prot |= 2;
> + prot |= GDB_MMAP_PROT_WRITE;
> if ((bfd_get_section_flags (abfd, sect) & SEC_CODE) != 0)
> - prot |= 1;
> + prot |= GDB_MMAP_PROT_EXEC;
> [...]
> - TYPE_LENGTH (regs_type), 4);
> + TYPE_LENGTH (regs_type),
> + GDB_MMAP_PROT_READ);
>
Thanks Jan. This sounds good.
Thanks,
Pedro Alves