powerpc: Use a datatype for instructions

Currently unsigned ints are used to represent instructions on powerpc.
This has worked well as instructions have always been 4 byte words.

However, ISA v3.1 introduces some changes to instructions that mean
this scheme will no longer work as well. This change is Prefixed
Instructions. A prefixed instruction is made up of a word prefix
followed by a word suffix to make an 8 byte double word instruction.
No matter the endianness of the system the prefix always comes first.
Prefixed instructions are only planned for powerpc64.

Introduce a ppc_inst type to represent both prefixed and word
instructions on powerpc64 while keeping it possible to exclusively
have word instructions on powerpc32.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
[mpe: Fix compile error in emulate_spe()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-12-jniethe5@gmail.com

4 files changed, 77 insertions, 74 deletions

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index d298bb16936e..1dff9d9d6645 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -19,12 +19,12 @@
 #include <asm/setup.h>
 #include <asm/inst.h>
 
-static int __patch_instruction(unsigned int *exec_addr, unsigned int instr,
-			       unsigned int *patch_addr)
+static int __patch_instruction(struct ppc_inst *exec_addr, struct ppc_inst instr,
+			       struct ppc_inst *patch_addr)
 {
 	int err = 0;
 
-	__put_user_asm(instr, patch_addr, err, "stw");
+	__put_user_asm(ppc_inst_val(instr), patch_addr, err, "stw");
 	if (err)
 		return err;
 
@@ -34,7 +34,7 @@ static int __patch_instruction(unsigned int *exec_addr, unsigned int instr,
 	return 0;
 }
 
-int raw_patch_instruction(unsigned int *addr, unsigned int instr)
+int raw_patch_instruction(struct ppc_inst *addr, struct ppc_inst instr)
 {
 	return __patch_instruction(addr, instr, addr);
 }
@@ -137,10 +137,10 @@ static inline int unmap_patch_area(unsigned long addr)
 	return 0;
 }
 
-static int do_patch_instruction(unsigned int *addr, unsigned int instr)
+static int do_patch_instruction(struct ppc_inst *addr, struct ppc_inst instr)
 {
 	int err;
-	unsigned int *patch_addr = NULL;
+	struct ppc_inst *patch_addr = NULL;
 	unsigned long flags;
 	unsigned long text_poke_addr;
 	unsigned long kaddr = (unsigned long)addr;
@@ -161,8 +161,7 @@ static int do_patch_instruction(unsigned int *addr, unsigned int instr)
 		goto out;
 	}
 
-	patch_addr = (unsigned int *)(text_poke_addr) +
-			((kaddr & ~PAGE_MASK) / sizeof(unsigned int));
+	patch_addr = (struct ppc_inst *)(text_poke_addr + (kaddr & ~PAGE_MASK));
 
 	__patch_instruction(addr, instr, patch_addr);
 
@@ -177,14 +176,14 @@ out:
 }
 #else /* !CONFIG_STRICT_KERNEL_RWX */
 
-static int do_patch_instruction(unsigned int *addr, unsigned int instr)
+static int do_patch_instruction(struct ppc_inst *addr, struct ppc_inst instr)
 {
 	return raw_patch_instruction(addr, instr);
 }
 
 #endif /* CONFIG_STRICT_KERNEL_RWX */
 
-int patch_instruction(unsigned int *addr, unsigned int instr)
+int patch_instruction(struct ppc_inst *addr, struct ppc_inst instr)
 {
 	/* Make sure we aren't patching a freed init section */
 	if (init_mem_is_free && init_section_contains(addr, 4)) {
@@ -195,9 +194,9 @@ int patch_instruction(unsigned int *addr, unsigned int instr)
 }
 NOKPROBE_SYMBOL(patch_instruction);
 
-int patch_branch(unsigned int *addr, unsigned long target, int flags)
+int patch_branch(struct ppc_inst *addr, unsigned long target, int flags)
 {
-	unsigned int instr;
+	struct ppc_inst instr;
 
 	create_branch(&instr, addr, target, flags);
 	return patch_instruction(addr, instr);
@@ -229,7 +228,7 @@ bool is_offset_in_branch_range(long offset)
  * Helper to check if a given instruction is a conditional branch
  * Derived from the conditional checks in analyse_instr()
  */
-bool is_conditional_branch(unsigned int instr)
+bool is_conditional_branch(struct ppc_inst instr)
 {
 	unsigned int opcode = ppc_inst_primary_opcode(instr);
 
@@ -247,13 +246,13 @@ bool is_conditional_branch(unsigned int instr)
 }
 NOKPROBE_SYMBOL(is_conditional_branch);
 
-int create_branch(unsigned int *instr,
-		  const unsigned int *addr,
+int create_branch(struct ppc_inst *instr,
+		  const struct ppc_inst *addr,
 		  unsigned long target, int flags)
 {
 	long offset;
 
-	*instr = 0;
+	*instr = ppc_inst(0);
 	offset = target;
 	if (! (flags & BRANCH_ABSOLUTE))
 		offset = offset - (unsigned long)addr;
@@ -263,12 +262,12 @@ int create_branch(unsigned int *instr,
 		return 1;
 
 	/* Mask out the flags and target, so they don't step on each other. */
-	*instr = 0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC);
+	*instr = ppc_inst(0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC));
 
 	return 0;
 }
 
-int create_cond_branch(unsigned int *instr, const unsigned int *addr,
+int create_cond_branch(struct ppc_inst *instr, const struct ppc_inst *addr,
 		       unsigned long target, int flags)
 {
 	long offset;
@@ -282,27 +281,27 @@ int create_cond_branch(unsigned int *instr, const unsigned int *addr,
 		return 1;
 
 	/* Mask out the flags and target, so they don't step on each other. */
-	*instr = 0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC);
+	*instr = ppc_inst(0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC));
 
 	return 0;
 }
 
-static unsigned int branch_opcode(unsigned int instr)
+static unsigned int branch_opcode(struct ppc_inst instr)
 {
 	return ppc_inst_primary_opcode(instr) & 0x3F;
 }
 
-static int instr_is_branch_iform(unsigned int instr)
+static int instr_is_branch_iform(struct ppc_inst instr)
 {
 	return branch_opcode(instr) == 18;
 }
 
-static int instr_is_branch_bform(unsigned int instr)
+static int instr_is_branch_bform(struct ppc_inst instr)
 {
 	return branch_opcode(instr) == 16;
 }
 
-int instr_is_relative_branch(unsigned int instr)
+int instr_is_relative_branch(struct ppc_inst instr)
 {
 	if (ppc_inst_val(instr) & BRANCH_ABSOLUTE)
 		return 0;
@@ -310,12 +309,12 @@ int instr_is_relative_branch(unsigned int instr)
 	return instr_is_branch_iform(instr) || instr_is_branch_bform(instr);
 }
 
-int instr_is_relative_link_branch(unsigned int instr)
+int instr_is_relative_link_branch(struct ppc_inst instr)
 {
 	return instr_is_relative_branch(instr) && (ppc_inst_val(instr) & BRANCH_SET_LINK);
 }
 
-static unsigned long branch_iform_target(const unsigned int *instr)
+static unsigned long branch_iform_target(const struct ppc_inst *instr)
 {
 	signed long imm;
 
@@ -331,7 +330,7 @@ static unsigned long branch_iform_target(const unsigned int *instr)
 	return (unsigned long)imm;
 }
 
-static unsigned long branch_bform_target(const unsigned int *instr)
+static unsigned long branch_bform_target(const struct ppc_inst *instr)
 {
 	signed long imm;
 
@@ -347,7 +346,7 @@ static unsigned long branch_bform_target(const unsigned int *instr)
 	return (unsigned long)imm;
 }
 
-unsigned long branch_target(const unsigned int *instr)
+unsigned long branch_target(const struct ppc_inst *instr)
 {
 	if (instr_is_branch_iform(*instr))
 		return branch_iform_target(instr);
@@ -357,7 +356,7 @@ unsigned long branch_target(const unsigned int *instr)
 	return 0;
 }
 
-int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr)
+int instr_is_branch_to_addr(const struct ppc_inst *instr, unsigned long addr)
 {
 	if (instr_is_branch_iform(*instr) || instr_is_branch_bform(*instr))
 		return branch_target(instr) == addr;
@@ -365,8 +364,8 @@ int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr)
 	return 0;
 }
 
-int translate_branch(unsigned int *instr, const unsigned int *dest,
-		     const unsigned int *src)
+int translate_branch(struct ppc_inst *instr, const struct ppc_inst *dest,
+		     const struct ppc_inst *src)
 {
 	unsigned long target;
 
@@ -392,7 +391,7 @@ void __patch_exception(int exc, unsigned long addr)
 	 * instruction of the exception, not the first one
 	 */
 
-	patch_branch(ibase + (exc / 4) + 1, addr, 0);
+	patch_branch((struct ppc_inst *)(ibase + (exc / 4) + 1), addr, 0);
 }
 #endif
 
@@ -409,7 +408,7 @@ static void __init test_trampoline(void)
 static void __init test_branch_iform(void)
 {
 	int err;
-	unsigned int instr;
+	struct ppc_inst instr;
 	unsigned long addr;
 
 	addr = (unsigned long)&instr;
@@ -484,12 +483,12 @@ static void __init test_branch_iform(void)
 
 static void __init test_create_function_call(void)
 {
-	unsigned int *iptr;
+	struct ppc_inst *iptr;
 	unsigned long dest;
-	unsigned int instr;
+	struct ppc_inst instr;
 
 	/* Check we can create a function call */
-	iptr = (unsigned int *)ppc_function_entry(test_trampoline);
+	iptr = (struct ppc_inst *)ppc_function_entry(test_trampoline);
 	dest = ppc_function_entry(test_create_function_call);
 	create_branch(&instr, iptr, dest, BRANCH_SET_LINK);
 	patch_instruction(iptr, instr);
@@ -500,7 +499,8 @@ static void __init test_branch_bform(void)
 {
 	int err;
 	unsigned long addr;
-	unsigned int *iptr, instr, flags;
+	struct ppc_inst *iptr, instr;
+	unsigned int flags;
 
 	iptr = &instr;
 	addr = (unsigned long)iptr;
@@ -570,8 +570,8 @@ static void __init test_branch_bform(void)
 static void __init test_translate_branch(void)
 {
 	unsigned long addr;
-	unsigned int *p, *q;
-	unsigned int instr;
+	struct ppc_inst *p, *q;
+	struct ppc_inst instr;
 	void *buf;
 
 	buf = vmalloc(PAGE_ALIGN(0x2000000 + 1));
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
index 6e7479b8887a..fd978b8ee6d6 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -32,26 +32,26 @@ struct fixup_entry {
 	long		alt_end_off;
 };
 
-static unsigned int *calc_addr(struct fixup_entry *fcur, long offset)
+static struct ppc_inst *calc_addr(struct fixup_entry *fcur, long offset)
 {
 	/*
 	 * We store the offset to the code as a negative offset from
 	 * the start of the alt_entry, to support the VDSO. This
 	 * routine converts that back into an actual address.
 	 */
-	return (unsigned int *)((unsigned long)fcur + offset);
+	return (struct ppc_inst *)((unsigned long)fcur + offset);
 }
 
-static int patch_alt_instruction(unsigned int *src, unsigned int *dest,
-				 unsigned int *alt_start, unsigned int *alt_end)
+static int patch_alt_instruction(struct ppc_inst *src, struct ppc_inst *dest,
+				 struct ppc_inst *alt_start, struct ppc_inst *alt_end)
 {
 	int err;
-	unsigned int instr;
+	struct ppc_inst instr;
 
 	instr = *src;
 
 	if (instr_is_relative_branch(*src)) {
-		unsigned int *target = (unsigned int *)branch_target(src);
+		struct ppc_inst *target = (struct ppc_inst *)branch_target(src);
 
 		/* Branch within the section doesn't need translating */
 		if (target < alt_start || target > alt_end) {
@@ -68,7 +68,7 @@ static int patch_alt_instruction(unsigned int *src, unsigned int *dest,
 
 static int patch_feature_section(unsigned long value, struct fixup_entry *fcur)
 {
-	unsigned int *start, *end, *alt_start, *alt_end, *src, *dest;
+	struct ppc_inst *start, *end, *alt_start, *alt_end, *src, *dest;
 
 	start = calc_addr(fcur, fcur->start_off);
 	end = calc_addr(fcur, fcur->end_off);
@@ -147,15 +147,17 @@ static void do_stf_entry_barrier_fixups(enum stf_barrier_type types)
 
 		pr_devel("patching dest %lx\n", (unsigned long)dest);
 
-		patch_instruction(dest, ppc_inst(instrs[0]));
+		patch_instruction((struct ppc_inst *)dest, ppc_inst(instrs[0]));
 
 		if (types & STF_BARRIER_FALLBACK)
-			patch_branch(dest + 1, (unsigned long)&stf_barrier_fallback,
+			patch_branch((struct ppc_inst *)(dest + 1),
+				     (unsigned long)&stf_barrier_fallback,
 				     BRANCH_SET_LINK);
 		else
-			patch_instruction(dest + 1, ppc_inst(instrs[1]));
+			patch_instruction((struct ppc_inst *)(dest + 1),
+					  ppc_inst(instrs[1]));
 
-		patch_instruction(dest + 2, ppc_inst(instrs[2]));
+		patch_instruction((struct ppc_inst *)(dest + 2), ppc_inst(instrs[2]));
 	}
 
 	printk(KERN_DEBUG "stf-barrier: patched %d entry locations (%s barrier)\n", i,
@@ -208,12 +210,12 @@ static void do_stf_exit_barrier_fixups(enum stf_barrier_type types)
 
 		pr_devel("patching dest %lx\n", (unsigned long)dest);
 
-		patch_instruction(dest, ppc_inst(instrs[0]));
-		patch_instruction(dest + 1, ppc_inst(instrs[1]));
-		patch_instruction(dest + 2, ppc_inst(instrs[2]));
-		patch_instruction(dest + 3, ppc_inst(instrs[3]));
-		patch_instruction(dest + 4, ppc_inst(instrs[4]));
-		patch_instruction(dest + 5, ppc_inst(instrs[5]));
+		patch_instruction((struct ppc_inst *)dest, ppc_inst(instrs[0]));
+		patch_instruction((struct ppc_inst *)(dest + 1), ppc_inst(instrs[1]));
+		patch_instruction((struct ppc_inst *)(dest + 2), ppc_inst(instrs[2]));
+		patch_instruction((struct ppc_inst *)(dest + 3), ppc_inst(instrs[3]));
+		patch_instruction((struct ppc_inst *)(dest + 4), ppc_inst(instrs[4]));
+		patch_instruction((struct ppc_inst *)(dest + 5), ppc_inst(instrs[5]));
 	}
 	printk(KERN_DEBUG "stf-barrier: patched %d exit locations (%s barrier)\n", i,
 		(types == STF_BARRIER_NONE)                  ? "no" :
@@ -261,9 +263,9 @@ void do_rfi_flush_fixups(enum l1d_flush_type types)
 
 		pr_devel("patching dest %lx\n", (unsigned long)dest);
 
-		patch_instruction(dest, ppc_inst(instrs[0]));
-		patch_instruction(dest + 1, ppc_inst(instrs[1]));
-		patch_instruction(dest + 2, ppc_inst(instrs[2]));
+		patch_instruction((struct ppc_inst *)dest, ppc_inst(instrs[0]));
+		patch_instruction((struct ppc_inst *)(dest + 1), ppc_inst(instrs[1]));
+		patch_instruction((struct ppc_inst *)(dest + 2), ppc_inst(instrs[2]));
 	}
 
 	printk(KERN_DEBUG "rfi-flush: patched %d locations (%s flush)\n", i,
@@ -296,7 +298,7 @@ void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_
 		dest = (void *)start + *start;
 
 		pr_devel("patching dest %lx\n", (unsigned long)dest);
-		patch_instruction(dest, ppc_inst(instr));
+		patch_instruction((struct ppc_inst *)dest, ppc_inst(instr));
 	}
 
 	printk(KERN_DEBUG "barrier-nospec: patched %d locations\n", i);
@@ -339,8 +341,8 @@ void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_
 		dest = (void *)start + *start;
 
 		pr_devel("patching dest %lx\n", (unsigned long)dest);
-		patch_instruction(dest, ppc_inst(instr[0]));
-		patch_instruction(dest + 1, ppc_inst(instr[1]));
+		patch_instruction((struct ppc_inst *)dest, ppc_inst(instr[0]));
+		patch_instruction((struct ppc_inst *)(dest + 1), ppc_inst(instr[1]));
 	}
 
 	printk(KERN_DEBUG "barrier-nospec: patched %d locations\n", i);
@@ -354,7 +356,7 @@ static void patch_btb_flush_section(long *curr)
 	end = (void *)curr + *(curr + 1);
 	for (; start < end; start++) {
 		pr_devel("patching dest %lx\n", (unsigned long)start);
-		patch_instruction(start, ppc_inst(PPC_INST_NOP));
+		patch_instruction((struct ppc_inst *)start, ppc_inst(PPC_INST_NOP));
 	}
 }
 
@@ -373,7 +375,7 @@ void do_btb_flush_fixups(void)
 void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end)
 {
 	long *start, *end;
-	unsigned int *dest;
+	struct ppc_inst *dest;
 
 	if (!(value & CPU_FTR_LWSYNC))
 		return ;
@@ -390,18 +392,18 @@ void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end)
 static void do_final_fixups(void)
 {
 #if defined(CONFIG_PPC64) && defined(CONFIG_RELOCATABLE)
-	int *src, *dest;
+	struct ppc_inst *src, *dest;
 	unsigned long length;
 
 	if (PHYSICAL_START == 0)
 		return;
 
-	src = (int *)(KERNELBASE + PHYSICAL_START);
-	dest = (int *)KERNELBASE;
-	length = (__end_interrupts - _stext) / sizeof(int);
+	src = (struct ppc_inst *)(KERNELBASE + PHYSICAL_START);
+	dest = (struct ppc_inst *)KERNELBASE;
+	length = (__end_interrupts - _stext) / sizeof(struct ppc_inst);
 
 	while (length--) {
-		raw_patch_instruction(dest, ppc_inst(*src));
+		raw_patch_instruction(dest, *src);
 		src++;
 		dest++;
 	}
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 7f7be154da7e..95a56bb1ba3f 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1163,7 +1163,7 @@ static nokprobe_inline int trap_compare(long v1, long v2)
  * otherwise.
  */
 int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
-		  unsigned int instr)
+		  struct ppc_inst instr)
 {
 	unsigned int opcode, ra, rb, rc, rd, spr, u;
 	unsigned long int imm;
@@ -3103,7 +3103,7 @@ NOKPROBE_SYMBOL(emulate_loadstore);
  * 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)
+int emulate_step(struct pt_regs *regs, struct ppc_inst instr)
 {
 	struct instruction_op op;
 	int r, err, type;
diff --git a/arch/powerpc/lib/test_emulate_step.c b/arch/powerpc/lib/test_emulate_step.c
index b928b21feac1..46af80279ebc 100644
--- a/arch/powerpc/lib/test_emulate_step.c
+++ b/arch/powerpc/lib/test_emulate_step.c
@@ -462,7 +462,7 @@ struct compute_test {
 	struct {
 		char *descr;
 		unsigned long flags;
-		unsigned int instr;
+		struct ppc_inst instr;
 		struct pt_regs regs;
 	} subtests[MAX_SUBTESTS + 1];
 };
@@ -843,7 +843,7 @@ static struct compute_test compute_tests[] = {
 };
 
 static int __init emulate_compute_instr(struct pt_regs *regs,
-					unsigned int instr)
+					struct ppc_inst instr)
 {
 	struct instruction_op op;
 
@@ -861,7 +861,7 @@ static int __init emulate_compute_instr(struct pt_regs *regs,
 }
 
 static int __init execute_compute_instr(struct pt_regs *regs,
-					unsigned int instr)
+					struct ppc_inst instr)
 {
 	extern int exec_instr(struct pt_regs *regs);
 	extern s32 patch__exec_instr;
@@ -892,7 +892,8 @@ static void __init run_tests_compute(void)
 	unsigned long flags;
 	struct compute_test *test;
 	struct pt_regs *regs, exp, got;
-	unsigned int i, j, k, instr;
+	unsigned int i, j, k;
+	struct ppc_inst instr;
 	bool ignore_gpr, ignore_xer, ignore_ccr, passed;
 
 	for (i = 0; i < ARRAY_SIZE(compute_tests); i++) {