sh: Initial ELF FDPIC support.

This adds initial support for ELF FDPIC on MMU-less SH, as per version
0.2 of the ABI definition at:

	http://www.codesourcery.com/public/docs/sh-fdpic/sh-fdpic-abi.txt

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

6 files changed, 108 insertions, 4 deletions

diff --git a/arch/sh/kernel/ptrace_32.c b/arch/sh/kernel/ptrace_32.c
index fddb547f3c2b..2bc72def5cf8 100644
--- a/arch/sh/kernel/ptrace_32.c
+++ b/arch/sh/kernel/ptrace_32.c
@@ -241,6 +241,29 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                 break;
         }
 #endif
+#ifdef CONFIG_BINFMT_ELF_FDPIC
+        case PTRACE_GETFDPIC: {
+                unsigned long tmp = 0;
+
+                switch (addr) {
+                case PTRACE_GETFDPIC_EXEC:
+                        tmp = child->mm->context.exec_fdpic_loadmap;
+                        break;
+                case PTRACE_GETFDPIC_INTERP:
+                        tmp = child->mm->context.interp_fdpic_loadmap;
+                        break;
+                default:
+                        break;
+                }
+
+                ret = 0;
+                if (put_user(tmp, (unsigned long *) data)) {
+                        ret = -EFAULT;
+                        break;
+                }
+                break;
+        }
+#endif
         default:
                 ret = ptrace_request(child, request, addr, data);
                 break;
diff --git a/arch/sh/kernel/signal_32.c b/arch/sh/kernel/signal_32.c
index f311551d9a05..46170a9a7221 100644
--- a/arch/sh/kernel/signal_32.c
+++ b/arch/sh/kernel/signal_32.c
@@ -33,6 +33,11 @@
 
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
+struct fdpic_func_descriptor {
+        unsigned long   text;
+        unsigned long   GOT;
+};
+
 /*
  * Atomically swap in the new signal mask, and wait for a signal.
  */
@@ -378,7 +383,15 @@ static int setup_frame(int sig, struct k_sigaction *ka,
         regs->regs[4] = signal; /* Arg for signal handler */
         regs->regs[5] = 0;
         regs->regs[6] = (unsigned long) &frame->sc;
-        regs->pc = (unsigned long) ka->sa.sa_handler;
+
+        if (current->personality & FDPIC_FUNCPTRS) {
+                struct fdpic_func_descriptor __user *funcptr =
+                        (struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
+
+                __get_user(regs->pc, &funcptr->text);
+                __get_user(regs->regs[12], &funcptr->GOT);
+        } else
+                regs->pc = (unsigned long)ka->sa.sa_handler;
 
         set_fs(USER_DS);
 
@@ -458,7 +471,15 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
         regs->regs[4] = signal; /* Arg for signal handler */
         regs->regs[5] = (unsigned long) &frame->info;
         regs->regs[6] = (unsigned long) &frame->uc;
-        regs->pc = (unsigned long) ka->sa.sa_handler;
+
+        if (current->personality & FDPIC_FUNCPTRS) {
+                struct fdpic_func_descriptor __user *funcptr =
+                        (struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
+
+                __get_user(regs->pc, &funcptr->text);
+                __get_user(regs->regs[12], &funcptr->GOT);
+        } else
+                regs->pc = (unsigned long)ka->sa.sa_handler;
 
         set_fs(USER_DS);
 
diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index 3263084eef9e..4a551af6f3fc 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -30,7 +30,7 @@ config COMPAT_BINFMT_ELF
 config BINFMT_ELF_FDPIC
         bool "Kernel support for FDPIC ELF binaries"
         default y
-        depends on (FRV || BLACKFIN)
+        depends on (FRV || BLACKFIN || (SUPERH32 && !MMU))
         help
           ELF FDPIC binaries are based on ELF, but allow the individual load
           segments of a binary to be located in memory independently of each
diff --git a/include/asm-sh/elf.h b/include/asm-sh/elf.h
index 05092da1aa59..f01449a8d378 100644
--- a/include/asm-sh/elf.h
+++ b/include/asm-sh/elf.h
@@ -1,10 +1,15 @@
 #ifndef __ASM_SH_ELF_H
 #define __ASM_SH_ELF_H
 
+#include <linux/utsname.h>
 #include <asm/auxvec.h>
 #include <asm/ptrace.h>
 #include <asm/user.h>
 
+/* ELF header e_flags defines */
+#define EF_SH_PIC               0x100   /* -fpic */
+#define EF_SH_FDPIC             0x8000  /* -mfdpic */
+
 /* SH (particularly SHcompact) relocation types  */
 #define R_SH_NONE               0
 #define R_SH_DIR32              1
@@ -43,6 +48,28 @@
 #define R_SH_RELATIVE           165
 #define R_SH_GOTOFF             166
 #define R_SH_GOTPC              167
+
+/* FDPIC relocs */
+#define R_SH_GOT20              70
+#define R_SH_GOTOFF20           71
+#define R_SH_GOTFUNCDESC        72
+#define R_SH_GOTFUNCDESC20      73
+#define R_SH_GOTOFFFUNCDESC     74
+#define R_SH_GOTOFFFUNCDESC20   75
+#define R_SH_FUNCDESC           76
+#define R_SH_FUNCDESC_VALUE     77
+
+#if 0 /* XXX - later .. */
+#define R_SH_GOT20              198
+#define R_SH_GOTOFF20           199
+#define R_SH_GOTFUNCDESC        200
+#define R_SH_GOTFUNCDESC20      201
+#define R_SH_GOTOFFFUNCDESC     202
+#define R_SH_GOTOFFFUNCDESC20   203
+#define R_SH_FUNCDESC           204
+#define R_SH_FUNCDESC_VALUE     205
+#endif
+
 /* SHmedia relocs */
 #define R_SH_IMM_LOW16          246
 #define R_SH_IMM_LOW16_PCREL    247
@@ -77,9 +104,12 @@ typedef struct user_fpu_struct elf_fpregset_t;
 /*
  * This is used to ensure we don't load something for the wrong architecture.
  */
-#define elf_check_arch(x) ( (x)->e_machine == EM_SH )
+#define elf_check_arch(x)               ((x)->e_machine == EM_SH)
+#define elf_check_fdpic(x)              ((x)->e_flags & EF_SH_FDPIC)
+#define elf_check_const_displacement(x) ((x)->e_flags & EF_SH_PIC)
 
 #define USE_ELF_CORE_DUMP
+#define ELF_FDPIC_CORE_EFLAGS   EF_SH_FDPIC
 #define ELF_EXEC_PAGESIZE       PAGE_SIZE
 
 /* This is the location that an ET_DYN program is loaded if exec'ed.  Typical
@@ -136,6 +166,27 @@ typedef struct user_fpu_struct elf_fpregset_t;
        _r->regs[8]=0; _r->regs[9]=0; _r->regs[10]=0; _r->regs[11]=0; \
        _r->regs[12]=0; _r->regs[13]=0; _r->regs[14]=0; \
        _r->sr = SR_FD; } while (0)
+
+#define ELF_FDPIC_PLAT_INIT(_r, _exec_map_addr, _interp_map_addr,       \
+                            _dynamic_addr)                              \
+do {                                                                    \
+        _r->regs[0]     = 0;                                            \
+        _r->regs[1]     = 0;                                            \
+        _r->regs[2]     = 0;                                            \
+        _r->regs[3]     = 0;                                            \
+        _r->regs[4]     = 0;                                            \
+        _r->regs[5]     = 0;                                            \
+        _r->regs[6]     = 0;                                            \
+        _r->regs[7]     = 0;                                            \
+        _r->regs[8]     = _exec_map_addr;                               \
+        _r->regs[9]     = _interp_map_addr;                             \
+        _r->regs[10]    = _dynamic_addr;                                \
+        _r->regs[11]    = 0;                                            \
+        _r->regs[12]    = 0;                                            \
+        _r->regs[13]    = 0;                                            \
+        _r->regs[14]    = 0;                                            \
+        _r->sr          = SR_FD;                                        \
+} while (0)
 #endif
 
 #define SET_PERSONALITY(ex, ibcs2) set_personality(PER_LINUX_32BIT)
diff --git a/include/asm-sh/mmu.h b/include/asm-sh/mmu.h
index eb0358c097d0..fdcb93bc6d11 100644
--- a/include/asm-sh/mmu.h
+++ b/include/asm-sh/mmu.h
@@ -12,6 +12,10 @@ typedef struct {
         struct vm_list_struct   *vmlist;
         unsigned long           end_brk;
 #endif
+#ifdef CONFIG_BINFMT_ELF_FDPIC
+        unsigned long           exec_fdpic_loadmap;
+        unsigned long           interp_fdpic_loadmap;
+#endif
 } mm_context_t;
 
 /*
diff --git a/include/asm-sh/ptrace.h b/include/asm-sh/ptrace.h
index 7d36dc3bee69..643ab5a7cf3b 100644
--- a/include/asm-sh/ptrace.h
+++ b/include/asm-sh/ptrace.h
@@ -87,6 +87,11 @@ struct pt_dspregs {
         unsigned long   mod;
 };
 
+#define PTRACE_GETFDPIC         31      /* get the ELF fdpic loadmap address */
+
+#define PTRACE_GETFDPIC_EXEC    0       /* [addr] request the executable loadmap */
+#define PTRACE_GETFDPIC_INTERP  1       /* [addr] request the interpreter loadmap */
+
 #define PTRACE_GETDSPREGS       55
 #define PTRACE_SETDSPREGS       56
 #endif