powerpc: Merge enough to start building in arch/powerpc.
This creates the directory structure under arch/powerpc and a bunch
of Kconfig files. It does a first-cut merge of arch/powerpc/mm,
arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough
to build a 32-bit powermac kernel with ARCH=powerpc.
For now we are getting some unmerged files from arch/ppc/kernel and
arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes
to files in those directories and files outside arch/powerpc.
The boot directory is still not merged. That's going to be interesting.
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
new file mode 100644
index 0000000..e79123d
--- /dev/null
+++ b/arch/powerpc/lib/sstep.c
@@ -0,0 +1,141 @@
+/*
+ * Single-step support.
+ *
+ * Copyright (C) 2004 Paul Mackerras <paulus@au.ibm.com>, IBM
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include <linux/kernel.h>
+#include <linux/ptrace.h>
+#include <asm/sstep.h>
+#include <asm/processor.h>
+
+extern char system_call_common[];
+
+/* Bits in SRR1 that are copied from MSR */
+#define MSR_MASK 0xffffffff87c0ffff
+
+/*
+ * Determine whether a conditional branch instruction would branch.
+ */
+static int branch_taken(unsigned int instr, struct pt_regs *regs)
+{
+ unsigned int bo = (instr >> 21) & 0x1f;
+ unsigned int bi;
+
+ if ((bo & 4) == 0) {
+ /* decrement counter */
+ --regs->ctr;
+ if (((bo >> 1) & 1) ^ (regs->ctr == 0))
+ return 0;
+ }
+ if ((bo & 0x10) == 0) {
+ /* check bit from CR */
+ bi = (instr >> 16) & 0x1f;
+ if (((regs->ccr >> (31 - bi)) & 1) != ((bo >> 3) & 1))
+ return 0;
+ }
+ return 1;
+}
+
+/*
+ * Emulate instructions that cause a transfer of control.
+ * Returns 1 if the step was emulated, 0 if not,
+ * or -1 if the instruction is one that should not be stepped,
+ * such as an rfid, or a mtmsrd that would clear MSR_RI.
+ */
+int emulate_step(struct pt_regs *regs, unsigned int instr)
+{
+ unsigned int opcode, rd;
+ unsigned long int imm;
+
+ opcode = instr >> 26;
+ switch (opcode) {
+ case 16: /* bc */
+ imm = (signed short)(instr & 0xfffc);
+ if ((instr & 2) == 0)
+ imm += regs->nip;
+ regs->nip += 4;
+ if ((regs->msr & MSR_SF) == 0)
+ regs->nip &= 0xffffffffUL;
+ if (instr & 1)
+ regs->link = regs->nip;
+ if (branch_taken(instr, regs))
+ regs->nip = imm;
+ return 1;
+ case 17: /* sc */
+ /*
+ * N.B. this uses knowledge about how the syscall
+ * entry code works. If that is changed, this will
+ * need to be changed also.
+ */
+ regs->gpr[9] = regs->gpr[13];
+ regs->gpr[11] = regs->nip + 4;
+ regs->gpr[12] = regs->msr & MSR_MASK;
+ regs->gpr[13] = (unsigned long) get_paca();
+ regs->nip = (unsigned long) &system_call_common;
+ regs->msr = MSR_KERNEL;
+ return 1;
+ case 18: /* b */
+ imm = instr & 0x03fffffc;
+ if (imm & 0x02000000)
+ imm -= 0x04000000;
+ if ((instr & 2) == 0)
+ imm += regs->nip;
+ if (instr & 1) {
+ regs->link = regs->nip + 4;
+ if ((regs->msr & MSR_SF) == 0)
+ regs->link &= 0xffffffffUL;
+ }
+ if ((regs->msr & MSR_SF) == 0)
+ imm &= 0xffffffffUL;
+ regs->nip = imm;
+ return 1;
+ case 19:
+ switch (instr & 0x7fe) {
+ case 0x20: /* bclr */
+ case 0x420: /* bcctr */
+ imm = (instr & 0x400)? regs->ctr: regs->link;
+ regs->nip += 4;
+ if ((regs->msr & MSR_SF) == 0) {
+ regs->nip &= 0xffffffffUL;
+ imm &= 0xffffffffUL;
+ }
+ if (instr & 1)
+ regs->link = regs->nip;
+ if (branch_taken(instr, regs))
+ regs->nip = imm;
+ return 1;
+ case 0x24: /* rfid, scary */
+ return -1;
+ }
+ case 31:
+ rd = (instr >> 21) & 0x1f;
+ switch (instr & 0x7fe) {
+ case 0xa6: /* mfmsr */
+ regs->gpr[rd] = regs->msr & MSR_MASK;
+ regs->nip += 4;
+ if ((regs->msr & MSR_SF) == 0)
+ regs->nip &= 0xffffffffUL;
+ return 1;
+ case 0x164: /* mtmsrd */
+ /* only MSR_EE and MSR_RI get changed if bit 15 set */
+ /* mtmsrd doesn't change MSR_HV and MSR_ME */
+ imm = (instr & 0x10000)? 0x8002: 0xefffffffffffefffUL;
+ imm = (regs->msr & MSR_MASK & ~imm)
+ | (regs->gpr[rd] & imm);
+ if ((imm & MSR_RI) == 0)
+ /* can't step mtmsrd that would clear MSR_RI */
+ return -1;
+ regs->msr = imm;
+ regs->nip += 4;
+ if ((imm & MSR_SF) == 0)
+ regs->nip &= 0xffffffffUL;
+ return 1;
+ }
+ }
+ return 0;
+}
