powerpc: Add prefixed instructions to instruction data type

For powerpc64, redefine the ppc_inst type so both word and prefixed
instructions can be represented. On powerpc32 the type will remain the
same. Update places which had assumed instructions to be 4 bytes long.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
[mpe: Rework the get_user_inst() macros to be parameterised, and don't
      assign to the dest if an error occurred. Use CONFIG_PPC64 not
      __powerpc64__ in a few places. Address other comments from
      Christophe. Fix some sparse complaints.]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-24-jniethe5@gmail.com

4 files changed, 58 insertions, 4 deletions

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index d946f7d6bb32..e9a0ea1c7ba4 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -24,7 +24,18 @@ static int __patch_instruction(struct ppc_inst *exec_addr, struct ppc_inst instr
 {
 	int err = 0;
 
-	__put_user_asm(ppc_inst_val(instr), patch_addr, err, "stw");
+	if (!ppc_inst_prefixed(instr)) {
+		__put_user_asm(ppc_inst_val(instr), patch_addr, err, "stw");
+	} else {
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+		__put_user_asm((u64)ppc_inst_suffix(instr) << 32 |
+			       ppc_inst_val(instr), patch_addr, err, "std");
+#else
+		__put_user_asm((u64)ppc_inst_val(instr) << 32 |
+			       ppc_inst_suffix(instr), patch_addr, err, "std");
+#endif
+	}
+
 	if (err)
 		return err;
 
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
index 0c9ffdef8096..1fb845f60f43 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -84,12 +84,13 @@ static int patch_feature_section(unsigned long value, struct fixup_entry *fcur)
 	src = alt_start;
 	dest = start;
 
-	for (; src < alt_end; src++, dest++) {
+	for (; src < alt_end; src = (void *)src + ppc_inst_len(ppc_inst_read(src)),
+	     (dest = (void *)dest + ppc_inst_len(ppc_inst_read(dest)))) {
 		if (patch_alt_instruction(src, dest, alt_start, alt_end))
 			return 1;
 	}
 
-	for (; dest < end; dest++)
+	for (; dest < end; dest = (void *)dest + ppc_inst_len(ppc_inst(PPC_INST_NOP)))
 		raw_patch_instruction(dest, ppc_inst(PPC_INST_NOP));
 
 	return 0;
diff --git a/arch/powerpc/lib/inst.c b/arch/powerpc/lib/inst.c
index bf3126ee399d..aedfd6e31e53 100644
--- a/arch/powerpc/lib/inst.c
+++ b/arch/powerpc/lib/inst.c
@@ -4,8 +4,47 @@
  */
 
 #include <linux/uaccess.h>
+#include <asm/disassemble.h>
 #include <asm/inst.h>
+#include <asm/ppc-opcode.h>
 
+#ifdef CONFIG_PPC64
+int probe_user_read_inst(struct ppc_inst *inst,
+			 struct ppc_inst __user *nip)
+{
+	unsigned int val, suffix;
+	int err;
+
+	err = probe_user_read(&val, nip, sizeof(val));
+	if (err)
+		return err;
+	if (get_op(val) == OP_PREFIX) {
+		err = probe_user_read(&suffix, (void __user *)nip + 4, 4);
+		*inst = ppc_inst_prefix(val, suffix);
+	} else {
+		*inst = ppc_inst(val);
+	}
+	return err;
+}
+
+int probe_kernel_read_inst(struct ppc_inst *inst,
+			   struct ppc_inst *src)
+{
+	unsigned int val, suffix;
+	int err;
+
+	err = probe_kernel_read(&val, src, sizeof(val));
+	if (err)
+		return err;
+	if (get_op(val) == OP_PREFIX) {
+		err = probe_kernel_read(&suffix, (void *)src + 4, 4);
+		*inst = ppc_inst_prefix(val, suffix);
+	} else {
+		*inst = ppc_inst(val);
+	}
+	return err;
+}
+#else /* !CONFIG_PPC64 */
 int probe_user_read_inst(struct ppc_inst *inst,
 			 struct ppc_inst __user *nip)
 {
@@ -31,3 +70,4 @@ int probe_kernel_read_inst(struct ppc_inst *inst,
 
 	return err;
 }
+#endif /* CONFIG_PPC64 */
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 95a56bb1ba3f..ecd756c346fd 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1169,10 +1169,12 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
 	unsigned long int imm;
 	unsigned long int val, val2;
 	unsigned int mb, me, sh;
-	unsigned int word;
+	unsigned int word, suffix;
 	long ival;
 
 	word = ppc_inst_val(instr);
+	suffix = ppc_inst_suffix(instr);
+
 	op->type = COMPUTE;
 
 	opcode = ppc_inst_primary_opcode(instr);