Blackfin: add support for the DBG (debug output) pseudo insn

Another pseudo insn used by Blackfin simulators.  Also factor some now
common register lookup code out of the DBGA handlers.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

3 files changed, 71 insertions, 18 deletions

diff --git a/arch/blackfin/include/asm/pseudo_instructions.h b/arch/blackfin/include/asm/pseudo_instructions.h
index 7173719fb531..b00adfa08169 100644
--- a/arch/blackfin/include/asm/pseudo_instructions.h
+++ b/arch/blackfin/include/asm/pseudo_instructions.h
@@ -13,5 +13,6 @@
 #include <asm/ptrace.h>
 
 extern bool execute_pseudodbg_assert(struct pt_regs *fp, unsigned int opcode);
+extern bool execute_pseudodbg(struct pt_regs *fp, unsigned int opcode);
 
 #endif
diff --git a/arch/blackfin/kernel/pseudodbg.c b/arch/blackfin/kernel/pseudodbg.c
index 4474b8db3501..a5a4636124aa 100644
--- a/arch/blackfin/kernel/pseudodbg.c
+++ b/arch/blackfin/kernel/pseudodbg.c
@@ -9,6 +9,30 @@
 #include <linux/kernel.h>
 #include <linux/ptrace.h>
 
+/*
+ * Unfortunately, the pt_regs structure is not laid out the same way as the
+ * hardware register file, so we need to do some fix ups.
+ */
+static bool fix_up_reg(struct pt_regs *fp, long *value, int grp, int reg)
+{
+        long *val = &fp->r0;
+
+        /* Only do Dregs and Pregs for now */
+        if (grp > 1)
+                return false;
+
+        if (grp == 0 || (grp == 1 && reg < 6))
+                val -= (reg + 8 * grp);
+        else if (grp == 1 && reg == 6)
+                val = &fp->usp;
+        else if (grp == 1 && reg == 7)
+                val = &fp->fp;
+
+        *value = *val;
+        return true;
+
+}
+
 #define PseudoDbg_Assert_opcode         0xf0000000
 #define PseudoDbg_Assert_expected_bits  0
 #define PseudoDbg_Assert_expected_mask  0xffff
@@ -23,47 +47,38 @@
 #define PseudoDbg_Assert_code_bits      27
 #define PseudoDbg_Assert_code_mask      0x1f
 
+/*
+ * DBGA - debug assert
+ */
 bool execute_pseudodbg_assert(struct pt_regs *fp, unsigned int opcode)
 {
         int expected = ((opcode >> PseudoDbg_Assert_expected_bits) & PseudoDbg_Assert_expected_mask);
         int dbgop    = ((opcode >> (PseudoDbg_Assert_dbgop_bits)) & PseudoDbg_Assert_dbgop_mask);
         int grp      = ((opcode >> (PseudoDbg_Assert_grp_bits)) & PseudoDbg_Assert_grp_mask);
         int regtest  = ((opcode >> (PseudoDbg_Assert_regtest_bits)) & PseudoDbg_Assert_regtest_mask);
-        long *value = &fp->r0;
+        long value;
 
         if ((opcode & 0xFF000000) != PseudoDbg_Assert_opcode)
                 return false;
 
-        /* Only do Dregs and Pregs for now */
-        if (grp > 1)
+        if (!fix_up_reg(fp, &value, grp, regtest))
                 return false;
 
-        /*
-         * Unfortunately, the pt_regs structure is not laid out the same way as the
-         * hardware register file, so we need to do some fix ups.
-         */
-        if (grp == 0 || (grp == 1 && regtest < 6))
-                value -= (regtest + 8 * grp);
-        else if (grp == 1 && regtest == 6)
-                value = &fp->usp;
-        else if (grp == 1 && regtest == 7)
-                value = &fp->fp;
-
         if (dbgop == 0 || dbgop == 2) {
                 /* DBGA ( regs_lo , uimm16 ) */
                 /* DBGAL ( regs , uimm16 ) */
-                if (expected != (*value & 0xFFFF)) {
+                if (expected != (value & 0xFFFF)) {
                         pr_notice("DBGA (%s%i.L,0x%x) failure, got 0x%x\n", grp ? "P" : "R",
-                                regtest, expected, (unsigned int)(*value & 0xFFFF));
+                                regtest, expected, (unsigned int)(value & 0xFFFF));
                         return false;
                 }
 
         } else if (dbgop == 1 || dbgop == 3) {
                 /* DBGA ( regs_hi , uimm16 ) */
                 /* DBGAH ( regs , uimm16 ) */
-                if (expected != ((*value >> 16) & 0xFFFF)) {
+                if (expected != ((value >> 16) & 0xFFFF)) {
                         pr_notice("DBGA (%s%i.H,0x%x) failure, got 0x%x\n", grp ? "P" : "R",
-                                regtest, expected, (unsigned int)((*value >> 16) & 0xFFFF));
+                                regtest, expected, (unsigned int)((value >> 16) & 0xFFFF));
                         return false;
                 }
         }
@@ -71,3 +86,38 @@ bool execute_pseudodbg_assert(struct pt_regs *fp, unsigned int opcode)
         fp->pc += 4;
         return true;
 }
+
+#define PseudoDbg_opcode        0xf8000000
+#define PseudoDbg_reg_bits      0
+#define PseudoDbg_reg_mask      0x7
+#define PseudoDbg_grp_bits      3
+#define PseudoDbg_grp_mask      0x7
+#define PseudoDbg_fn_bits       6
+#define PseudoDbg_fn_mask       0x3
+#define PseudoDbg_code_bits     8
+#define PseudoDbg_code_mask     0xff
+
+/*
+ * DBG - debug (dump a register value out)
+ */
+bool execute_pseudodbg(struct pt_regs *fp, unsigned int opcode)
+{
+        int grp, fn, reg;
+        long value;
+
+        if ((opcode & 0xFF000000) != PseudoDbg_opcode)
+                return false;
+
+        opcode >>= 16;
+        grp = ((opcode >> PseudoDbg_grp_bits) & PseudoDbg_reg_mask);
+        fn  = ((opcode >> PseudoDbg_fn_bits)  & PseudoDbg_fn_mask);
+        reg = ((opcode >> PseudoDbg_reg_bits) & PseudoDbg_reg_mask);
+
+        if (!fix_up_reg(fp, &value, grp, reg))
+                return false;
+
+        pr_notice("DBG %s%d = %08lx\n", grp ? "P" : "R", reg, value);
+
+        fp->pc += 2;
+        return true;
+}
diff --git a/arch/blackfin/kernel/traps.c b/arch/blackfin/kernel/traps.c
index 9369836365bb..59c1df75e4de 100644
--- a/arch/blackfin/kernel/traps.c
+++ b/arch/blackfin/kernel/traps.c
@@ -213,6 +213,8 @@ asmlinkage notrace void trap_c(struct pt_regs *fp)
                 if (!kernel_mode_regs(fp) && get_instruction(&opcode, (unsigned short *)fp->pc)) {
                         if (execute_pseudodbg_assert(fp, opcode))
                                 goto traps_done;
+                        if (execute_pseudodbg(fp, opcode))
+                                goto traps_done;
                 }
 #endif
                 info.si_code = ILL_ILLOPC;