sh64: Attempt to make reserved insn trap handler resemble C.
authorPaul Mundt <lethal@linux-sh.org>
Thu, 14 Jun 2012 05:46:36 +0000 (14:46 +0900)
committerPaul Mundt <lethal@linux-sh.org>
Thu, 14 Jun 2012 05:46:36 +0000 (14:46 +0900)
This has been long overdue. No functional changes.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
arch/sh/kernel/traps_64.c

index 75bef61892d25742bc33b76a86f8e9654da1b53f..f87d20da17916cc0c3cf8c6cfb286cbbb0d50d5b 100644 (file)
 #include <asm/pgtable.h>
 #include <asm/fpu.h>
 
-static void do_unhandled_exception(int trapnr, int signr, char *str, char *fn_name,
-               unsigned long error_code, struct pt_regs *regs, struct task_struct *tsk);
-
-#define DO_ERROR(trapnr, signr, str, name, tsk) \
-asmlinkage void do_##name(unsigned long error_code, struct pt_regs *regs) \
-{ \
-       do_unhandled_exception(trapnr, signr, str, __stringify(name), error_code, regs, current); \
-}
-
-DO_ERROR(13, SIGILL,  "illegal slot instruction", illegal_slot_inst, current)
-DO_ERROR(87, SIGSEGV, "address error (exec)", address_error_exec, current)
-
-
-/* Implement misaligned load/store handling for kernel (and optionally for user
-   mode too).  Limitation : only SHmedia mode code is handled - there is no
-   handling at all for misaligned accesses occurring in SHcompact code yet. */
-
-static int misaligned_fixup(struct pt_regs *regs);
-
-asmlinkage void do_address_error_load(unsigned long error_code, struct pt_regs *regs)
-{
-       if (misaligned_fixup(regs) < 0) {
-               do_unhandled_exception(7, SIGSEGV, "address error(load)",
-                               "do_address_error_load",
-                               error_code, regs, current);
-       }
-       return;
-}
-
-asmlinkage void do_address_error_store(unsigned long error_code, struct pt_regs *regs)
-{
-       if (misaligned_fixup(regs) < 0) {
-               do_unhandled_exception(8, SIGSEGV, "address error(store)",
-                               "do_address_error_store",
-                               error_code, regs, current);
-       }
-       return;
-}
-
-#if defined(CONFIG_SH64_ID2815_WORKAROUND)
-
-#define OPCODE_INVALID      0
-#define OPCODE_USER_VALID   1
-#define OPCODE_PRIV_VALID   2
-
-/* getcon/putcon - requires checking which control register is referenced. */
-#define OPCODE_CTRL_REG     3
-
-/* Table of valid opcodes for SHmedia mode.
-   Form a 10-bit value by concatenating the major/minor opcodes i.e.
-   opcode[31:26,20:16].  The 6 MSBs of this value index into the following
-   array.  The 4 LSBs select the bit-pair in the entry (bits 1:0 correspond to
-   LSBs==4'b0000 etc). */
-static unsigned long shmedia_opcode_table[64] = {
-       0x55554044,0x54445055,0x15141514,0x14541414,0x00000000,0x10001000,0x01110055,0x04050015,
-       0x00000444,0xc0000000,0x44545515,0x40405555,0x55550015,0x10005555,0x55555505,0x04050000,
-       0x00000555,0x00000404,0x00040445,0x15151414,0x00000000,0x00000000,0x00000000,0x00000000,
-       0x00000055,0x40404444,0x00000404,0xc0009495,0x00000000,0x00000000,0x00000000,0x00000000,
-       0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
-       0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
-       0x80005050,0x04005055,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
-       0x81055554,0x00000404,0x55555555,0x55555555,0x00000000,0x00000000,0x00000000,0x00000000
-};
-
-void do_reserved_inst(unsigned long error_code, struct pt_regs *regs)
-{
-       /* Workaround SH5-101 cut2 silicon defect #2815 :
-          in some situations, inter-mode branches from SHcompact -> SHmedia
-          which should take ITLBMISS or EXECPROT exceptions at the target
-          falsely take RESINST at the target instead. */
-
-       unsigned long opcode = 0x6ff4fff0; /* guaranteed reserved opcode */
-       unsigned long pc, aligned_pc;
-       int get_user_error;
-       int trapnr = 12;
-       int signr = SIGILL;
-       char *exception_name = "reserved_instruction";
-
-       pc = regs->pc;
-       if ((pc & 3) == 1) {
-               /* SHmedia : check for defect.  This requires executable vmas
-                  to be readable too. */
-               aligned_pc = pc & ~3;
-               if (!access_ok(VERIFY_READ, aligned_pc, sizeof(unsigned long))) {
-                       get_user_error = -EFAULT;
-               } else {
-                       get_user_error = __get_user(opcode, (unsigned long *)aligned_pc);
-               }
-               if (get_user_error >= 0) {
-                       unsigned long index, shift;
-                       unsigned long major, minor, combined;
-                       unsigned long reserved_field;
-                       reserved_field = opcode & 0xf; /* These bits are currently reserved as zero in all valid opcodes */
-                       major = (opcode >> 26) & 0x3f;
-                       minor = (opcode >> 16) & 0xf;
-                       combined = (major << 4) | minor;
-                       index = major;
-                       shift = minor << 1;
-                       if (reserved_field == 0) {
-                               int opcode_state = (shmedia_opcode_table[index] >> shift) & 0x3;
-                               switch (opcode_state) {
-                                       case OPCODE_INVALID:
-                                               /* Trap. */
-                                               break;
-                                       case OPCODE_USER_VALID:
-                                               /* Restart the instruction : the branch to the instruction will now be from an RTE
-                                                  not from SHcompact so the silicon defect won't be triggered. */
-                                               return;
-                                       case OPCODE_PRIV_VALID:
-                                               if (!user_mode(regs)) {
-                                                       /* Should only ever get here if a module has
-                                                          SHcompact code inside it.  If so, the same fix up is needed. */
-                                                       return; /* same reason */
-                                               }
-                                               /* Otherwise, user mode trying to execute a privileged instruction -
-                                                  fall through to trap. */
-                                               break;
-                                       case OPCODE_CTRL_REG:
-                                               /* If in privileged mode, return as above. */
-                                               if (!user_mode(regs)) return;
-                                               /* In user mode ... */
-                                               if (combined == 0x9f) { /* GETCON */
-                                                       unsigned long regno = (opcode >> 20) & 0x3f;
-                                                       if (regno >= 62) {
-                                                               return;
-                                                       }
-                                                       /* Otherwise, reserved or privileged control register, => trap */
-                                               } else if (combined == 0x1bf) { /* PUTCON */
-                                                       unsigned long regno = (opcode >> 4) & 0x3f;
-                                                       if (regno >= 62) {
-                                                               return;
-                                                       }
-                                                       /* Otherwise, reserved or privileged control register, => trap */
-                                               } else {
-                                                       /* Trap */
-                                               }
-                                               break;
-                                       default:
-                                               /* Fall through to trap. */
-                                               break;
-                               }
-                       }
-                       /* fall through to normal resinst processing */
-               } else {
-                       /* Error trying to read opcode.  This typically means a
-                          real fault, not a RESINST any more.  So change the
-                          codes. */
-                       trapnr = 87;
-                       exception_name = "address error (exec)";
-                       signr = SIGSEGV;
-               }
-       }
-
-       do_unhandled_exception(trapnr, signr, exception_name, "do_reserved_inst", error_code, regs, current);
-}
-
-#else /* CONFIG_SH64_ID2815_WORKAROUND */
-
-/* If the workaround isn't needed, this is just a straightforward reserved
-   instruction */
-DO_ERROR(12, SIGILL,  "reserved instruction", reserved_inst, current)
-
-#endif /* CONFIG_SH64_ID2815_WORKAROUND */
-
-/* Called with interrupts disabled */
-asmlinkage void do_exception_error(unsigned long ex, struct pt_regs *regs)
-{
-       die_if_kernel("exception", regs, ex);
-}
-
-int do_unknown_trapa(unsigned long scId, struct pt_regs *regs)
-{
-       /* Syscall debug */
-        printk("System call ID error: [0x1#args:8 #syscall:16  0x%lx]\n", scId);
-
-       die_if_kernel("unknown trapa", regs, scId);
-
-       return -ENOSYS;
-}
-
-static void do_unhandled_exception(int trapnr, int signr, char *str, char *fn_name,
-               unsigned long error_code, struct pt_regs *regs, struct task_struct *tsk)
-{
-       if (user_mode(regs))
-               force_sig(signr, tsk);
-
-       die_if_no_fixup(str, regs, error_code);
-}
-
 static int read_opcode(reg_size_t pc, insn_size_t *result_opcode, int from_user_mode)
 {
        int get_user_error;
@@ -784,7 +595,201 @@ static int misaligned_fixup(struct pt_regs *regs)
                regs->pc += 4; /* Skip the instruction that's just been emulated */
                return 0;
        }
+}
+
+static void do_unhandled_exception(int signr, char *str, unsigned long error,
+                                  struct pt_regs *regs)
+{
+       if (user_mode(regs))
+               force_sig(signr, current);
+
+       die_if_no_fixup(str, regs, error);
+}
+
+#define DO_ERROR(signr, str, name) \
+asmlinkage void do_##name(unsigned long error_code, struct pt_regs *regs) \
+{ \
+       do_unhandled_exception(signr, str, error_code, regs); \
+}
+
+DO_ERROR(SIGILL,  "illegal slot instruction", illegal_slot_inst)
+DO_ERROR(SIGSEGV, "address error (exec)", address_error_exec)
+
+#if defined(CONFIG_SH64_ID2815_WORKAROUND)
+
+#define OPCODE_INVALID      0
+#define OPCODE_USER_VALID   1
+#define OPCODE_PRIV_VALID   2
+
+/* getcon/putcon - requires checking which control register is referenced. */
+#define OPCODE_CTRL_REG     3
+
+/* Table of valid opcodes for SHmedia mode.
+   Form a 10-bit value by concatenating the major/minor opcodes i.e.
+   opcode[31:26,20:16].  The 6 MSBs of this value index into the following
+   array.  The 4 LSBs select the bit-pair in the entry (bits 1:0 correspond to
+   LSBs==4'b0000 etc). */
+static unsigned long shmedia_opcode_table[64] = {
+       0x55554044,0x54445055,0x15141514,0x14541414,0x00000000,0x10001000,0x01110055,0x04050015,
+       0x00000444,0xc0000000,0x44545515,0x40405555,0x55550015,0x10005555,0x55555505,0x04050000,
+       0x00000555,0x00000404,0x00040445,0x15151414,0x00000000,0x00000000,0x00000000,0x00000000,
+       0x00000055,0x40404444,0x00000404,0xc0009495,0x00000000,0x00000000,0x00000000,0x00000000,
+       0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
+       0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
+       0x80005050,0x04005055,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
+       0x81055554,0x00000404,0x55555555,0x55555555,0x00000000,0x00000000,0x00000000,0x00000000
+};
+
+/* Workaround SH5-101 cut2 silicon defect #2815 :
+   in some situations, inter-mode branches from SHcompact -> SHmedia
+   which should take ITLBMISS or EXECPROT exceptions at the target
+   falsely take RESINST at the target instead. */
+void do_reserved_inst(unsigned long error_code, struct pt_regs *regs)
+{
+       insn_size_t opcode = 0x6ff4fff0; /* guaranteed reserved opcode */
+       unsigned long pc, aligned_pc;
+       unsigned long index, shift;
+       unsigned long major, minor, combined;
+       unsigned long reserved_field;
+       int opcode_state;
+       int get_user_error;
+       int signr = SIGILL;
+       char *exception_name = "reserved_instruction";
+
+       pc = regs->pc;
+
+       /* SHcompact is not handled */
+       if (unlikely((pc & 3) == 0))
+               goto out;
+
+       /* SHmedia : check for defect.  This requires executable vmas
+          to be readable too. */
+       aligned_pc = pc & ~3;
+       if (!access_ok(VERIFY_READ, aligned_pc, sizeof(insn_size_t)))
+               get_user_error = -EFAULT;
+       else
+               get_user_error = __get_user(opcode, (insn_size_t *)aligned_pc);
+
+       if (get_user_error < 0) {
+               /*
+                * Error trying to read opcode.  This typically means a
+                * real fault, not a RESINST any more.  So change the
+                * codes.
+                */
+               exception_name = "address error (exec)";
+               signr = SIGSEGV;
+               goto out;
+       }
+
+       /* These bits are currently reserved as zero in all valid opcodes */
+       reserved_field = opcode & 0xf;
+       if (unlikely(reserved_field))
+               goto out;       /* invalid opcode */
+
+       major = (opcode >> 26) & 0x3f;
+       minor = (opcode >> 16) & 0xf;
+       combined = (major << 4) | minor;
+       index = major;
+       shift = minor << 1;
+       opcode_state = (shmedia_opcode_table[index] >> shift) & 0x3;
+       switch (opcode_state) {
+       case OPCODE_INVALID:
+               /* Trap. */
+               break;
+       case OPCODE_USER_VALID:
+               /*
+                * Restart the instruction: the branch to the instruction
+                * will now be from an RTE not from SHcompact so the
+                * silicon defect won't be triggered.
+                */
+               return;
+       case OPCODE_PRIV_VALID:
+               if (!user_mode(regs)) {
+                       /*
+                        * Should only ever get here if a module has
+                        * SHcompact code inside it. If so, the same fix
+                        * up is needed.
+                        */
+                       return; /* same reason */
+               }
+
+               /*
+                * Otherwise, user mode trying to execute a privileged
+                * instruction - fall through to trap.
+                */
+               break;
+       case OPCODE_CTRL_REG:
+               /* If in privileged mode, return as above. */
+               if (!user_mode(regs))
+                       return;
+
+               /* In user mode ... */
+               if (combined == 0x9f) { /* GETCON */
+                       unsigned long regno = (opcode >> 20) & 0x3f;
+
+                       if (regno >= 62)
+                               return;
+
+                       /* reserved/privileged control register => trap */
+               } else if (combined == 0x1bf) { /* PUTCON */
+                       unsigned long regno = (opcode >> 4) & 0x3f;
+
+                       if (regno >= 62)
+                               return;
+
+                       /* reserved/privileged control register => trap */
+               }
+
+               break;
+       default:
+               /* Fall through to trap. */
+               break;
+       }
 
+out:
+       do_unhandled_exception(signr, exception_name, error_code, regs);
+}
+
+#else /* CONFIG_SH64_ID2815_WORKAROUND */
+
+/* If the workaround isn't needed, this is just a straightforward reserved
+   instruction */
+DO_ERROR(SIGILL, "reserved instruction", reserved_inst)
+
+#endif /* CONFIG_SH64_ID2815_WORKAROUND */
+
+/* Called with interrupts disabled */
+asmlinkage void do_exception_error(unsigned long ex, struct pt_regs *regs)
+{
+       die_if_kernel("exception", regs, ex);
+}
+
+asmlinkage int do_unknown_trapa(unsigned long scId, struct pt_regs *regs)
+{
+       /* Syscall debug */
+       printk("System call ID error: [0x1#args:8 #syscall:16  0x%lx]\n", scId);
+
+       die_if_kernel("unknown trapa", regs, scId);
+
+       return -ENOSYS;
+}
+
+/* Implement misaligned load/store handling for kernel (and optionally for user
+   mode too).  Limitation : only SHmedia mode code is handled - there is no
+   handling at all for misaligned accesses occurring in SHcompact code yet. */
+
+asmlinkage void do_address_error_load(unsigned long error_code, struct pt_regs *regs)
+{
+       if (misaligned_fixup(regs) < 0)
+               do_unhandled_exception(SIGSEGV, "address error(load)",
+                                      error_code, regs);
+}
+
+asmlinkage void do_address_error_store(unsigned long error_code, struct pt_regs *regs)
+{
+       if (misaligned_fixup(regs) < 0)
+               do_unhandled_exception(SIGSEGV, "address error(store)",
+                               error_code, regs);
 }
 
 asmlinkage void do_debug_interrupt(unsigned long code, struct pt_regs *regs)
@@ -797,10 +802,9 @@ asmlinkage void do_debug_interrupt(unsigned long code, struct pt_regs *regs)
           of access we make to them - just go direct to their physical
           addresses. */
        exp_cause = peek_real_address_q(DM_EXP_CAUSE_PHY);
-       if (exp_cause & ~4) {
+       if (exp_cause & ~4)
                printk("DM.EXP_CAUSE had unexpected bits set (=%08lx)\n",
                        (unsigned long)(exp_cause & 0xffffffff));
-       }
        show_state();
        /* Clear all DEBUGINT causes */
        poke_real_address_q(DM_EXP_CAUSE_PHY, 0x0);