Re: PATCH: new "void" memory region attribute

Michael Snyder
2002-02-14T01:42:44Z

Greg McGary wrote:
>
> Add "void" attribute, which disallows both read & write access. This
> useful for guarding holes in a target's address space that cause the
> system to hang when read/written.
>
> OK to commit?

I like it. Would you consider adding a test to the testsuite?

>
> gdb:
>
> 2002-02-13 Greg McGary <greg@mcgary.org>
>
> * memattr.h (enum mem_access_mode): s/MEM_RO/MEM_READ/
> s/MEM_WO/MEM_WRITE/. New member MEM_VOID.
> * memattr.c (mem_command, mem_info_command): Handle MEM_VOID.
> * target.c (target_xfer_memory, target_xfer_memory_partial):
> Check read/write validity with bit test.
> * dcache.c (dcache_write_line, dcache_read_line): Likewise.
>
> doc:
>
> 2002-02-13 Greg McGary <greg@mcgary.org>
>
> * gdb.texinfo (Memory Region Attributes): Describe `void' attribute.
>
> Index: dcache.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/dcache.c,v
> retrieving revision 1.15
> diff -u -p -r1.15 dcache.c
> --- dcache.c 2001/04/06 22:43:55 1.15
> +++ dcache.c 2002/02/14 00:17:25
> @@ -1,5 +1,5 @@
> /* Caching code.
> - Copyright 1992, 1993, 1995, 1996, 1998, 1999, 2000, 2001
> + Copyright 1992, 1993, 1995, 1996, 1998, 1999, 2000, 2001, 2002
> Free Software Foundation, Inc.
>
> This file is part of GDB.
> @@ -267,7 +267,7 @@ dcache_write_line (DCACHE *dcache, regis
> else
> reg_len = region->hi - memaddr;
>
> - if (!region->attrib.cache || region->attrib.mode == MEM_RO)
> + if (!region->attrib.cache || !(region->attrib.mode == MEM_WRITE))
> {
> memaddr += reg_len;
> myaddr += reg_len;
> @@ -349,7 +349,7 @@ dcache_read_line (DCACHE *dcache, struct
> else
> reg_len = region->hi - memaddr;
>
> - if (!region->attrib.cache || region->attrib.mode == MEM_WO)
> + if (!region->attrib.cache || !(region->attrib.mode & MEM_READ))
> {
> memaddr += reg_len;
> myaddr += reg_len;
> Index: memattr.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/memattr.c,v
> retrieving revision 1.9
> diff -u -p -r1.9 memattr.c
> --- memattr.c 2002/02/13 19:00:47 1.9
> +++ memattr.c 2002/02/14 00:17:25
> @@ -1,5 +1,5 @@
> /* Memory attributes support, for GDB.
> - Copyright 2001 Free Software Foundation, Inc.
> + Copyright 2001, 2002 Free Software Foundation, Inc.
>
> This file is part of GDB.
>
> @@ -156,9 +156,11 @@ mem_command (char *args, int from_tty)
> if (strcmp (tok, "rw") == 0)
> attrib.mode = MEM_RW;
> else if (strcmp (tok, "ro") == 0)
> - attrib.mode = MEM_RO;
> + attrib.mode = MEM_READ;
> else if (strcmp (tok, "wo") == 0)
> - attrib.mode = MEM_WO;
> + attrib.mode = MEM_WRITE;
> + else if (strcmp (tok, "void") == 0)
> + attrib.mode = MEM_VOID;
>
> else if (strcmp (tok, "8") == 0)
> attrib.width = MEM_WIDTH_8;
> @@ -266,13 +268,16 @@ mem_info_command (char *args, int from_t
> attrib = &m->attrib;
> switch (attrib->mode)
> {
> + case MEM_VOID:
> + printf_filtered ("void ");
> + break;
> case MEM_RW:
> printf_filtered ("rw ");
> break;
> - case MEM_RO:
> + case MEM_READ:
> printf_filtered ("ro ");
> break;
> - case MEM_WO:
> + case MEM_WRITE:
> printf_filtered ("wo ");
> break;
> }
> Index: memattr.h
> ===================================================================
> RCS file: /cvs/src/src/gdb/memattr.h,v
> retrieving revision 1.4
> diff -u -p -r1.4 memattr.h
> --- memattr.h 2001/08/02 11:58:29 1.4
> +++ memattr.h 2002/02/14 00:17:25
> @@ -1,5 +1,5 @@
> /* Memory attributes support, for GDB.
> - Copyright 2001 Free Software Foundation, Inc.
> + Copyright 2001, 2002 Free Software Foundation, Inc.
>
> This file is part of GDB.
>
> @@ -23,9 +23,10 @@
>
> enum mem_access_mode
> {
> - MEM_RW, /* read/write */
> - MEM_RO, /* read only */
> - MEM_WO /* write only */
> + MEM_VOID = 0,
> + MEM_READ = 1,
> + MEM_WRITE = 2,
> + MEM_RW = MEM_READ | MEM_WRITE,
> };
>
> enum mem_access_width
> Index: target.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/target.c,v
> retrieving revision 1.33
> diff -u -p -r1.33 target.c
> --- target.c 2002/02/01 01:01:21 1.33
> +++ target.c 2002/02/14 00:17:25
> @@ -933,18 +933,10 @@ target_xfer_memory (CORE_ADDR memaddr, c
> else
> reg_len = region->hi - memaddr;
>
> - switch (region->attrib.mode)
> - {
> - case MEM_RO:
> - if (write)
> - return EIO;
> - break;
> -
> - case MEM_WO:
> - if (!write)
> - return EIO;
> - break;
> - }
> + if (write
> + ? !(region->attrib.mode & MEM_WRITE)
> + : !(region->attrib.mode & MEM_READ))
> + return EIO;
>
> while (reg_len > 0)
> {
> @@ -1004,23 +996,12 @@ target_xfer_memory_partial (CORE_ADDR me
> else
> reg_len = region->hi - memaddr;
>
> - switch (region->attrib.mode)
> + if (write_p
> + ? !(region->attrib.mode & MEM_WRITE)
> + : !(region->attrib.mode & MEM_READ))
> {
> - case MEM_RO:
> - if (write_p)
> - {
> - *err = EIO;
> - return -1;
> - }
> - break;
> -
> - case MEM_WO:
> - if (write_p)
> - {
> - *err = EIO;
> - return -1;
> - }
> - break;
> + *err = EIO;
> + return -1;
> }
>
> if (region->attrib.cache)
> Index: doc/gdb.texinfo
> ===================================================================
> RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
> retrieving revision 1.89
> diff -u -p -r1.89 gdb.texinfo
> --- gdb.texinfo 2002/02/08 00:39:45 1.89
> +++ gdb.texinfo 2002/02/14 00:17:32
> @@ -5642,6 +5642,8 @@ Memory is read only.
> Memory is write only.
> @item rw
> Memory is read/write. This is the default.
> +@item void
> +Memory is inaccessible.
> @end table
>
> @subsubsection Memory Access Size
>