[ARM] 3110/5: old ABI compat: multi-ABI syscall entry support

Patch from Nicolas Pitre

This patch adds the required code to support both user space ABIs at
the same time. A second syscall table is created to include legacy ABI
syscalls that need an ABI compat wrapper.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 100 insertions, 35 deletions

diff --git a/arch/arm/kernel/calls.S b/arch/arm/kernel/calls.S
index 8c0bf04814b1..75e6f9a94713 100644
--- a/arch/arm/kernel/calls.S
+++ b/arch/arm/kernel/calls.S
@@ -13,7 +13,7 @@
 #define NR_syscalls 328
 #else
 
-__syscall_start:
+100:
 /* 0 */         .long   sys_restart_syscall
                 .long   sys_exit
                 .long   sys_fork_wrapper
@@ -27,7 +27,7 @@ __syscall_start:
 /* 10 */        .long   sys_unlink
                 .long   sys_execve_wrapper
                 .long   sys_chdir
-                .long   sys_time                /* used by libc4 */
+                .long   OBSOLETE(sys_time)      /* used by libc4 */
                 .long   sys_mknod
 /* 15 */        .long   sys_chmod
                 .long   sys_lchown16
@@ -36,15 +36,15 @@ __syscall_start:
                 .long   sys_lseek
 /* 20 */        .long   sys_getpid
                 .long   sys_mount
-                .long   sys_oldumount           /* used by libc4 */
+                .long   OBSOLETE(sys_oldumount) /* used by libc4 */
                 .long   sys_setuid16
                 .long   sys_getuid16
-/* 25 */        .long   sys_stime
+/* 25 */        .long   OBSOLETE(sys_stime)
                 .long   sys_ptrace
-                .long   sys_alarm               /* used by libc4 */
+                .long   OBSOLETE(sys_alarm)     /* used by libc4 */
                 .long   sys_ni_syscall          /* was sys_fstat */
                 .long   sys_pause
-/* 30 */        .long   sys_utime               /* used by libc4 */
+/* 30 */        .long   OBSOLETE(sys_utime)     /* used by libc4 */
                 .long   sys_ni_syscall          /* was sys_stty */
                 .long   sys_ni_syscall          /* was sys_getty */
                 .long   sys_access
@@ -90,21 +90,21 @@ __syscall_start:
                 .long   sys_sigpending
                 .long   sys_sethostname
 /* 75 */        .long   sys_setrlimit
-                .long   sys_old_getrlimit       /* used by libc4 */
+                .long   OBSOLETE(sys_old_getrlimit) /* used by libc4 */
                 .long   sys_getrusage
                 .long   sys_gettimeofday
                 .long   sys_settimeofday
 /* 80 */        .long   sys_getgroups16
                 .long   sys_setgroups16
-                .long   old_select              /* used by libc4 */
+                .long   OBSOLETE(old_select)    /* used by libc4 */
                 .long   sys_symlink
                 .long   sys_ni_syscall          /* was sys_lstat */
 /* 85 */        .long   sys_readlink
                 .long   sys_uselib
                 .long   sys_swapon
                 .long   sys_reboot
-                .long   old_readdir             /* used by libc4 */
-/* 90 */        .long   old_mmap                /* used by libc4 */
+                .long   OBSOLETE(old_readdir)   /* used by libc4 */
+/* 90 */        .long   OBSOLETE(old_mmap)      /* used by libc4 */
                 .long   sys_munmap
                 .long   sys_truncate
                 .long   sys_ftruncate
@@ -116,7 +116,7 @@ __syscall_start:
                 .long   sys_statfs
 /* 100 */       .long   sys_fstatfs
                 .long   sys_ni_syscall
-                .long   sys_socketcall
+                .long   OBSOLETE(sys_socketcall)
                 .long   sys_syslog
                 .long   sys_setitimer
 /* 105 */       .long   sys_getitimer
@@ -127,11 +127,11 @@ __syscall_start:
 /* 110 */       .long   sys_ni_syscall          /* was sys_iopl */
                 .long   sys_vhangup
                 .long   sys_ni_syscall
-                .long   sys_syscall             /* call a syscall */
+                .long   OBSOLETE(sys_syscall)   /* call a syscall */
                 .long   sys_wait4
 /* 115 */       .long   sys_swapoff
                 .long   sys_sysinfo
-                .long   sys_ipc
+                .long   OBSOLETE(ABI(sys_ipc, sys_oabi_ipc))
                 .long   sys_fsync
                 .long   sys_sigreturn_wrapper
 /* 120 */       .long   sys_clone_wrapper
@@ -194,8 +194,8 @@ __syscall_start:
                 .long   sys_rt_sigtimedwait
                 .long   sys_rt_sigqueueinfo
                 .long   sys_rt_sigsuspend_wrapper
-/* 180 */       .long   sys_pread64
-                .long   sys_pwrite64
+/* 180 */       .long   ABI(sys_pread64, sys_oabi_pread64)
+                .long   ABI(sys_pwrite64, sys_oabi_pwrite64)
                 .long   sys_chown16
                 .long   sys_getcwd
                 .long   sys_capget
@@ -207,11 +207,11 @@ __syscall_start:
 /* 190 */       .long   sys_vfork_wrapper
                 .long   sys_getrlimit
                 .long   sys_mmap2
-                .long   sys_truncate64
-                .long   sys_ftruncate64
-/* 195 */       .long   sys_stat64
-                .long   sys_lstat64
-                .long   sys_fstat64
+                .long   ABI(sys_truncate64, sys_oabi_truncate64)
+                .long   ABI(sys_ftruncate64, sys_oabi_ftruncate64)
+/* 195 */       .long   ABI(sys_stat64, sys_oabi_stat64)
+                .long   ABI(sys_lstat64, sys_oabi_lstat64)
+                .long   ABI(sys_fstat64, sys_oabi_fstat64)
                 .long   sys_lchown
                 .long   sys_getuid
 /* 200 */       .long   sys_getgid
@@ -235,11 +235,11 @@ __syscall_start:
                 .long   sys_pivot_root
                 .long   sys_mincore
 /* 220 */       .long   sys_madvise
-                .long   sys_fcntl64
+                .long   ABI(sys_fcntl64, sys_oabi_fcntl64)
                 .long   sys_ni_syscall /* TUX */
                 .long   sys_ni_syscall
                 .long   sys_gettid
-/* 225 */       .long   sys_readahead
+/* 225 */       .long   ABI(sys_readahead, sys_oabi_readahead)
                 .long   sys_setxattr
                 .long   sys_lsetxattr
                 .long   sys_fsetxattr
@@ -265,8 +265,8 @@ __syscall_start:
                 .long   sys_exit_group
                 .long   sys_lookup_dcookie
 /* 250 */       .long   sys_epoll_create
-                .long   sys_epoll_ctl
-                .long   sys_epoll_wait
+                .long   ABI(sys_epoll_ctl, sys_oabi_epoll_ctl)
+                .long   ABI(sys_epoll_wait, sys_oabi_epoll_wait)
                 .long   sys_remap_file_pages
                 .long   sys_ni_syscall  /* sys_set_thread_area */
 /* 255 */       .long   sys_ni_syscall  /* sys_get_thread_area */
@@ -312,7 +312,7 @@ __syscall_start:
 /* 295 */       .long   sys_getsockopt
                 .long   sys_sendmsg
                 .long   sys_recvmsg
-                .long   sys_semop
+                .long   ABI(sys_semop, sys_oabi_semop)
                 .long   sys_semget
 /* 300 */       .long   sys_semctl
                 .long   sys_msgsnd
@@ -326,7 +326,7 @@ __syscall_start:
                 .long   sys_add_key
 /* 310 */       .long   sys_request_key
                 .long   sys_keyctl
-                .long   sys_semtimedop
+                .long   ABI(sys_semtimedop, sys_oabi_semtimedop)
 /* vserver */   .long   sys_ni_syscall
                 .long   sys_ioprio_set
 /* 315 */       .long   sys_ioprio_get
@@ -336,9 +336,8 @@ __syscall_start:
                 .long   sys_mbind
 /* 320 */       .long   sys_get_mempolicy
                 .long   sys_set_mempolicy
-__syscall_end:
 
-                .rept   NR_syscalls - (__syscall_end - __syscall_start) / 4
+                .rept   NR_syscalls - (. - 100b) / 4
                         .long   sys_ni_syscall
                 .endr
 #endif
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 59ce1bcec42b..8826d9803aeb 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -123,23 +123,49 @@ ENTRY(vector_swi)
         /*
          * Get the system call number.
          */
-#if defined(CONFIG_AEABI)
 
-        @ syscall number is in scno (r7) already.
+#if defined(CONFIG_OABI_COMPAT)
 
+        /*
+         * If we have CONFIG_OABI_COMPAT then we need to look at the swi
+         * value to determine if it is an EABI or an old ABI call.
+         */
+#ifdef CONFIG_ARM_THUMB
+        tst     r8, #PSR_T_BIT
+        movne   r10, #0                         @ no thumb OABI emulation
+        ldreq   r10, [lr, #-4]                  @ get SWI instruction
+#else
+        ldr     r10, [lr, #-4]                  @ get SWI instruction
+  A710( and     ip, r10, #0x0f000000            @ check for SWI         )
+  A710( teq     ip, #0x0f000000                                         )
+  A710( bne     .Larm710bug                                             )
+#endif
+
+#elif defined(CONFIG_AEABI)
+
+        /*
+         * Pure EABI user space always put syscall number into scno (r7).
+         */
   A710( ldr     ip, [lr, #-4]                   @ get SWI instruction   )
   A710( and     ip, ip, #0x0f000000             @ check for SWI         )
   A710( teq     ip, #0x0f000000                                         )
   A710( bne     .Larm710bug                                             )
+
 #elif defined(CONFIG_ARM_THUMB)
+
+        /* Legacy ABI only, possibly thumb mode. */
         tst     r8, #PSR_T_BIT                  @ this is SPSR from save_user_regs
         addne   scno, r7, #__NR_SYSCALL_BASE    @ put OS number in
         ldreq   scno, [lr, #-4]
+
 #else
+
+        /* Legacy ABI only. */
         ldr     scno, [lr, #-4]                 @ get SWI instruction
   A710( and     ip, scno, #0x0f000000           @ check for SWI         )
   A710( teq     ip, #0x0f000000                                         )
   A710( bne     .Larm710bug                                             )
+
 #endif
 
 #ifdef CONFIG_ALIGNMENT_TRAP
@@ -150,12 +176,24 @@ ENTRY(vector_swi)
         enable_irq
 
         get_thread_info tsk
+        adr     tbl, sys_call_table             @ load syscall table pointer
         ldr     ip, [tsk, #TI_FLAGS]            @ check for syscall tracing
-#ifndef CONFIG_AEABI
+
+#if defined(CONFIG_OABI_COMPAT)
+        /*
+         * If the swi argument is zero, this is an EABI call and we do nothing.
+         *
+         * If this is an old ABI call, get the syscall number into scno and
+         * get the old ABI syscall table address.
+         */
+        bics    r10, r10, #0xff000000
+        eorne   scno, r10, #__NR_OABI_SYSCALL_BASE
+        ldrne   tbl, =sys_oabi_call_table
+#elif !defined(CONFIG_AEABI)
         bic     scno, scno, #0xff000000         @ mask off SWI op-code
         eor     scno, scno, #__NR_SYSCALL_BASE  @ check OS number
 #endif
-        adr     tbl, sys_call_table             @ load syscall table pointer
+
         stmdb   sp!, {r4, r5}                   @ push fifth and sixth args
         tst     ip, #_TIF_SYSCALL_TRACE         @ are we tracing syscalls?
         bne     __sys_trace
@@ -200,10 +238,24 @@ __sys_trace_return:
 __cr_alignment:
         .word   cr_alignment
 #endif
+        .ltorg
+
+/*
+ * This is the syscall table declaration for native ABI syscalls.
+ * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
+ */
+#define ABI(native, compat) native
+#ifdef CONFIG_AEABI
+#define OBSOLETE(syscall) sys_ni_syscall
+#else
+#define OBSOLETE(syscall) syscall
+#endif
 
         .type   sys_call_table, #object
 ENTRY(sys_call_table)
 #include "calls.S"
+#undef ABI
+#undef OBSOLETE
 
 /*============================================================================
  * Special system call wrappers
@@ -212,8 +264,7 @@ ENTRY(sys_call_table)
 @ r8 = syscall table
                 .type   sys_syscall, #function
 sys_syscall:
-#ifndef CONFIG_AEABI
-                eor     scno, r0, #__NR_SYSCALL_BASE
+                eor     scno, r0, #__NR_OABI_SYSCALL_BASE
                 cmp     scno, #__NR_syscall - __NR_SYSCALL_BASE
                 cmpne   scno, #NR_syscalls      @ check range
                 stmloia sp, {r5, r6}            @ shuffle args
@@ -222,7 +273,6 @@ sys_syscall:
                 movlo   r2, r3
                 movlo   r3, r4
                 ldrlo   pc, [tbl, scno, lsl #2]
-#endif
                 b       sys_ni_syscall
 
 sys_fork_wrapper:
@@ -290,6 +340,7 @@ sys_mmap2:
 #endif
 
 #ifdef CONFIG_OABI_COMPAT
+
 /*
  * These are syscalls with argument register differences
  */
@@ -318,5 +369,18 @@ sys_oabi_readahead:
                 mov     r2, r1
                 b       sys_readahead
 
+/*
+ * Let's declare a second syscall table for old ABI binaries
+ * using the compatibility syscall entries.
+ */
+#define ABI(native, compat) compat
+#define OBSOLETE(syscall) syscall
+
+        .type   sys_oabi_call_table, #object
+ENTRY(sys_oabi_call_table)
+#include "calls.S"
+#undef ABI
+#undef OBSOLETE
+
 #endif
 
diff --git a/arch/arm/kernel/sys_arm.c b/arch/arm/kernel/sys_arm.c
index ea569ba482b1..a491de2d9024 100644
--- a/arch/arm/kernel/sys_arm.c
+++ b/arch/arm/kernel/sys_arm.c
@@ -147,6 +147,7 @@ asmlinkage int old_select(struct sel_arg_struct __user *arg)
         return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp);
 }
 
+#if !defined(CONFIG_AEABI) || defined(CONFIG_OABI_COMPAT)
 /*
  * sys_ipc() is the de-multiplexer for the SysV IPC calls..
  *
@@ -226,6 +227,7 @@ asmlinkage int sys_ipc(uint call, int first, int second, int third,
                 return -ENOSYS;
         }
 }
+#endif
 
 /* Fork a new task - this creates a new program thread.
  * This is called indirectly via a small wrapper