[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6

The attached patches provides part 6 of an architecture implementation for the
Tensilica Xtensa CPU series.

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 222 insertions, 0 deletions

diff --git a/include/asm-xtensa/elf.h b/include/asm-xtensa/elf.h
new file mode 100644
index 000000000000..64f1f53874fe
--- /dev/null
+++ b/include/asm-xtensa/elf.h
@@ -0,0 +1,222 @@
+/*
+ * include/asm-xtensa/elf.h
+ *
+ * ELF register definitions
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2001 - 2005 Tensilica Inc.
+ */
+
+#ifndef _XTENSA_ELF_H
+#define _XTENSA_ELF_H
+
+#include <asm/ptrace.h>
+#include <asm/coprocessor.h>
+#include <xtensa/config/core.h>
+
+/* Xtensa processor ELF architecture-magic number */
+
+#define EM_XTENSA       94
+#define EM_XTENSA_OLD   0xABC7
+
+/* ELF register definitions. This is needed for core dump support.  */
+
+/*
+ * elf_gregset_t contains the application-level state in the following order:
+ * Processor info:      config_version, cpuxy
+ * Processor state:     pc, ps, exccause, excvaddr, wb, ws,
+ *                      lbeg, lend, lcount, sar
+ * GP regs:             ar0 - arXX
+ */
+
+typedef unsigned long elf_greg_t;
+
+typedef struct {
+        elf_greg_t xchal_config_id0;
+        elf_greg_t xchal_config_id1;
+        elf_greg_t cpux;
+        elf_greg_t cpuy;
+        elf_greg_t pc;
+        elf_greg_t ps;
+        elf_greg_t exccause;
+        elf_greg_t excvaddr;
+        elf_greg_t windowbase;
+        elf_greg_t windowstart;
+        elf_greg_t lbeg;
+        elf_greg_t lend;
+        elf_greg_t lcount;
+        elf_greg_t sar;
+        elf_greg_t syscall;
+        elf_greg_t ar[XCHAL_NUM_AREGS];
+} xtensa_gregset_t;
+
+#define ELF_NGREG       (sizeof(xtensa_gregset_t) / sizeof(elf_greg_t))
+
+typedef elf_greg_t elf_gregset_t[ELF_NGREG];
+
+/*
+ *  Compute the size of the coprocessor and extra state layout (register info)
+ *  table (in bytes).
+ *  This is actually the maximum size of the table, as opposed to the size,
+ *  which is available from the _xtensa_reginfo_table_size global variable.
+ *
+ *  (See also arch/xtensa/kernel/coprocessor.S)
+ *
+ */
+
+#ifndef XCHAL_EXTRA_SA_CONTENTS_LIBDB_NUM
+# define XTENSA_CPE_LTABLE_SIZE         0
+#else
+# define XTENSA_CPE_SEGMENT(num)        (num ? (1+num) : 0)
+# define XTENSA_CPE_LTABLE_ENTRIES      \
+                ( XTENSA_CPE_SEGMENT(XCHAL_EXTRA_SA_CONTENTS_LIBDB_NUM) \
+                + XTENSA_CPE_SEGMENT(XCHAL_CP0_SA_CONTENTS_LIBDB_NUM)   \
+                + XTENSA_CPE_SEGMENT(XCHAL_CP1_SA_CONTENTS_LIBDB_NUM)   \
+                + XTENSA_CPE_SEGMENT(XCHAL_CP2_SA_CONTENTS_LIBDB_NUM)   \
+                + XTENSA_CPE_SEGMENT(XCHAL_CP3_SA_CONTENTS_LIBDB_NUM)   \
+                + XTENSA_CPE_SEGMENT(XCHAL_CP4_SA_CONTENTS_LIBDB_NUM)   \
+                + XTENSA_CPE_SEGMENT(XCHAL_CP5_SA_CONTENTS_LIBDB_NUM)   \
+                + XTENSA_CPE_SEGMENT(XCHAL_CP6_SA_CONTENTS_LIBDB_NUM)   \
+                + XTENSA_CPE_SEGMENT(XCHAL_CP7_SA_CONTENTS_LIBDB_NUM)   \
+                + 1             /* final entry */                       \
+                )
+# define XTENSA_CPE_LTABLE_SIZE         (XTENSA_CPE_LTABLE_ENTRIES * 8)
+#endif
+
+
+/*
+ * Instantiations of the elf_fpregset_t type contain, in most
+ * architectures, the floating point (FPU) register set.
+ * For Xtensa, this type is extended to contain all custom state,
+ * ie. coprocessor and "extra" (non-coprocessor) state (including,
+ * for example, TIE-defined states and register files; as well
+ * as other optional processor state).
+ * This includes FPU state if a floating-point coprocessor happens
+ * to have been configured within the Xtensa processor.
+ *
+ * TOTAL_FPREGS_SIZE is the required size (without rounding)
+ * of elf_fpregset_t.  It provides space for the following:
+ *
+ *  a)  32-bit mask of active coprocessors for this task (similar
+ *      to CPENABLE in single-threaded Xtensa processor systems)
+ *
+ *  b)  table describing the layout of custom states (ie. of
+ *      individual registers, etc) within the save areas
+ *
+ *  c)  save areas for each coprocessor and for non-coprocessor
+ *      ("extra") state
+ *
+ * Note that save areas may require up to 16-byte alignment when
+ * accessed by save/restore sequences.  We do not need to ensure
+ * such alignment in an elf_fpregset_t structure because custom
+ * state is not directly loaded/stored into it; rather, save area
+ * contents are copied to elf_fpregset_t from the active save areas
+ * (see 'struct task_struct' definition in processor.h for that)
+ * using memcpy().  But we do allow space for such alignment,
+ * to allow optimizations of layout and copying.
+ */
+
+#define TOTAL_FPREGS_SIZE                                               \
+        (4 + XTENSA_CPE_LTABLE_SIZE + XTENSA_CP_EXTRA_SIZE)
+#define ELF_NFPREG                                                      \
+        ((TOTAL_FPREGS_SIZE + sizeof(elf_fpreg_t) - 1) / sizeof(elf_fpreg_t))
+
+typedef unsigned int elf_fpreg_t;
+typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
+
+#define ELF_CORE_COPY_REGS(_eregs, _pregs)                              \
+        xtensa_elf_core_copy_regs (&_eregs, _pregs);
+
+extern void xtensa_elf_core_copy_regs (xtensa_gregset_t *, struct pt_regs *);
+
+/*
+ * This is used to ensure we don't load something for the wrong architecture.
+ */
+
+#define elf_check_arch(x) ( ( (x)->e_machine == EM_XTENSA )  || \
+                            ( (x)->e_machine == EM_XTENSA_OLD ) )
+
+/*
+ * These are used to set parameters in the core dumps.
+ */
+
+#ifdef __XTENSA_EL__
+# define ELF_DATA       ELFDATA2LSB
+#elif defined(__XTENSA_EB__)
+# define ELF_DATA       ELFDATA2MSB
+#else
+# error processor byte order undefined!
+#endif
+
+#define ELF_CLASS       ELFCLASS32
+#define ELF_ARCH        EM_XTENSA
+
+#define USE_ELF_CORE_DUMP
+#define ELF_EXEC_PAGESIZE       PAGE_SIZE
+
+/*
+ * This is the location that an ET_DYN program is loaded if exec'ed.  Typical
+ * use of this is to invoke "./ld.so someprog" to test out a new version of
+ * the loader.  We need to make sure that it is out of the way of the program
+ * that it will "exec", and that there is sufficient room for the brk.
+ */
+
+#define ELF_ET_DYN_BASE         (2 * TASK_SIZE / 3)
+
+/*
+ * This yields a mask that user programs can use to figure out what
+ * instruction set this CPU supports.  This could be done in user space,
+ * but it's not easy, and we've already done it here.
+ */
+
+#define ELF_HWCAP       (0)
+
+/*
+ * This yields a string that ld.so will use to load implementation
+ * specific libraries for optimization.  This is more specific in
+ * intent than poking at uname or /proc/cpuinfo.
+ * For the moment, we have only optimizations for the Intel generations,
+ * but that could change...
+ */
+
+#define ELF_PLATFORM  (NULL)
+
+/*
+ * The Xtensa processor ABI says that when the program starts, a2
+ * contains a pointer to a function which might be registered using
+ * `atexit'.  This provides a mean for the dynamic linker to call
+ * DT_FINI functions for shared libraries that have been loaded before
+ * the code runs.
+ *
+ * A value of 0 tells we have no such handler.
+ *
+ * We might as well make sure everything else is cleared too (except
+ * for the stack pointer in a1), just to make things more
+ * deterministic.  Also, clearing a0 terminates debugger backtraces.
+ */
+
+#define ELF_PLAT_INIT(_r, load_addr) \
+  do { _r->areg[0]=0; /*_r->areg[1]=0;*/ _r->areg[2]=0;  _r->areg[3]=0;  \
+       _r->areg[4]=0;  _r->areg[5]=0;    _r->areg[6]=0;  _r->areg[7]=0;  \
+       _r->areg[8]=0;  _r->areg[9]=0;    _r->areg[10]=0; _r->areg[11]=0; \
+       _r->areg[12]=0; _r->areg[13]=0;   _r->areg[14]=0; _r->areg[15]=0; \
+  } while (0)
+
+#ifdef __KERNEL__
+
+#define SET_PERSONALITY(ex, ibcs2) set_personality(PER_LINUX_32BIT)
+
+extern void do_copy_regs (xtensa_gregset_t*, struct pt_regs*,
+                          struct task_struct*);
+extern void do_restore_regs (xtensa_gregset_t*, struct pt_regs*,
+                             struct task_struct*);
+extern void do_save_fpregs (elf_fpregset_t*, struct pt_regs*,
+                            struct task_struct*);
+extern int do_restore_fpregs (elf_fpregset_t*, struct pt_regs*,
+                              struct task_struct*);
+
+#endif  /* __KERNEL__ */
+#endif  /* _XTENSA_ELF_H */