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From: Jordan Niethe <jniethe5@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: alistair@popple.id.au, npiggin@gmail.com, bala24@linux.ibm.com,
	naveen.n.rao@linux.vnet.ibm.com,
	Jordan Niethe <jniethe5@gmail.com>,
	dja@axtens.net
Subject: [PATCH v8 12/30] powerpc: Use a function for reading instructions
Date: Wed,  6 May 2020 13:40:32 +1000	[thread overview]
Message-ID: <20200506034050.24806-13-jniethe5@gmail.com> (raw)
In-Reply-To: <20200506034050.24806-1-jniethe5@gmail.com>

Prefixed instructions will mean there are instructions of different
length. As a result dereferencing a pointer to an instruction will not
necessarily give the desired result. Introduce a function for reading
instructions from memory into the instruction data type.

Reviewed-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
v4: New to series
v5: - Rename read_inst() -> probe_kernel_read_inst()
    - No longer modify uprobe probe type in this patch
v6: - feature-fixups.c: do_final_fixups(): Use here
    - arch_prepare_kprobe(): patch_instruction(): no longer part of this
      patch
    - Move probe_kernel_read_inst() out of this patch
    - Use in uprobes
v8: style
---
 arch/powerpc/include/asm/inst.h    |  5 +++++
 arch/powerpc/kernel/kprobes.c      |  6 +++---
 arch/powerpc/kernel/mce_power.c    |  2 +-
 arch/powerpc/kernel/optprobes.c    |  4 ++--
 arch/powerpc/kernel/trace/ftrace.c |  4 ++--
 arch/powerpc/kernel/uprobes.c      |  2 +-
 arch/powerpc/lib/code-patching.c   | 26 ++++++++++++++------------
 arch/powerpc/lib/feature-fixups.c  |  4 ++--
 arch/powerpc/xmon/xmon.c           |  6 +++---
 9 files changed, 33 insertions(+), 26 deletions(-)

diff --git a/arch/powerpc/include/asm/inst.h b/arch/powerpc/include/asm/inst.h
index 19d8bb7a1c2b..552e953bf04f 100644
--- a/arch/powerpc/include/asm/inst.h
+++ b/arch/powerpc/include/asm/inst.h
@@ -27,6 +27,11 @@ static inline struct ppc_inst ppc_inst_swab(struct ppc_inst x)
 	return ppc_inst(swab32(ppc_inst_val(x)));
 }
 
+static inline struct ppc_inst ppc_inst_read(const struct ppc_inst *ptr)
+{
+	return *ptr;
+}
+
 static inline bool ppc_inst_equal(struct ppc_inst x, struct ppc_inst y)
 {
 	return ppc_inst_val(x) == ppc_inst_val(y);
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index a08ae5803622..f64312dca84f 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -106,7 +106,7 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset)
 int arch_prepare_kprobe(struct kprobe *p)
 {
 	int ret = 0;
-	struct ppc_inst insn = *(struct ppc_inst *)p->addr;
+	struct ppc_inst insn = ppc_inst_read((struct ppc_inst *)p->addr);
 
 	if ((unsigned long)p->addr & 0x03) {
 		printk("Attempt to register kprobe at an unaligned address\n");
@@ -127,7 +127,7 @@ int arch_prepare_kprobe(struct kprobe *p)
 	if (!ret) {
 		memcpy(p->ainsn.insn, p->addr,
 				MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
-		p->opcode = *p->addr;
+		p->opcode = ppc_inst_val(insn);
 		flush_icache_range((unsigned long)p->ainsn.insn,
 			(unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
 	}
@@ -217,7 +217,7 @@ NOKPROBE_SYMBOL(arch_prepare_kretprobe);
 static int try_to_emulate(struct kprobe *p, struct pt_regs *regs)
 {
 	int ret;
-	struct ppc_inst insn = *(struct ppc_inst *)p->ainsn.insn;
+	struct ppc_inst insn = ppc_inst_read((struct ppc_inst *)p->ainsn.insn);
 
 	/* regs->nip is also adjusted if emulate_step returns 1 */
 	ret = emulate_step(regs, insn);
diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c
index cd23218c60bb..45c51ba0071b 100644
--- a/arch/powerpc/kernel/mce_power.c
+++ b/arch/powerpc/kernel/mce_power.c
@@ -374,7 +374,7 @@ static int mce_find_instr_ea_and_phys(struct pt_regs *regs, uint64_t *addr,
 	pfn = addr_to_pfn(regs, regs->nip);
 	if (pfn != ULONG_MAX) {
 		instr_addr = (pfn << PAGE_SHIFT) + (regs->nip & ~PAGE_MASK);
-		instr = *(struct ppc_inst *)(instr_addr);
+		instr = ppc_inst_read((struct ppc_inst *)instr_addr);
 		if (!analyse_instr(&op, &tmp, instr)) {
 			pfn = addr_to_pfn(regs, op.ea);
 			*addr = op.ea;
diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c
index 5a71fef71c22..52c1ab3f85aa 100644
--- a/arch/powerpc/kernel/optprobes.c
+++ b/arch/powerpc/kernel/optprobes.c
@@ -100,9 +100,9 @@ static unsigned long can_optimize(struct kprobe *p)
 	 * Ensure that the instruction is not a conditional branch,
 	 * and that can be emulated.
 	 */
-	if (!is_conditional_branch(*(struct ppc_inst *)p->ainsn.insn) &&
+	if (!is_conditional_branch(ppc_inst_read((struct ppc_inst *)p->ainsn.insn)) &&
 	    analyse_instr(&op, &regs,
-			  *(struct ppc_inst *)p->ainsn.insn) == 1) {
+			  ppc_inst_read((struct ppc_inst *)p->ainsn.insn)) == 1) {
 		emulate_update_regs(&regs, &op);
 		nip = regs.nip;
 	}
diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c
index 3117ed675735..acd5b889815f 100644
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -848,7 +848,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
 	struct ppc_inst old, new;
 	int ret;
 
-	old = *(struct ppc_inst *)&ftrace_call;
+	old = ppc_inst_read((struct ppc_inst *)&ftrace_call);
 	new = ftrace_call_replace(ip, (unsigned long)func, 1);
 	ret = ftrace_modify_code(ip, old, new);
 
@@ -856,7 +856,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
 	/* Also update the regs callback function */
 	if (!ret) {
 		ip = (unsigned long)(&ftrace_regs_call);
-		old = *(struct ppc_inst *)&ftrace_regs_call;
+		old = ppc_inst_read((struct ppc_inst *)&ftrace_regs_call);
 		new = ftrace_call_replace(ip, (unsigned long)func, 1);
 		ret = ftrace_modify_code(ip, old, new);
 	}
diff --git a/arch/powerpc/kernel/uprobes.c b/arch/powerpc/kernel/uprobes.c
index 31c870287f2b..6893d40a48c5 100644
--- a/arch/powerpc/kernel/uprobes.c
+++ b/arch/powerpc/kernel/uprobes.c
@@ -174,7 +174,7 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
 	 * emulate_step() returns 1 if the insn was successfully emulated.
 	 * For all other cases, we need to single-step in hardware.
 	 */
-	ret = emulate_step(regs, auprobe->insn);
+	ret = emulate_step(regs, ppc_inst_read(&auprobe->insn));
 	if (ret > 0)
 		return true;
 
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 1dff9d9d6645..435fc8e9f45d 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -348,9 +348,9 @@ static unsigned long branch_bform_target(const struct ppc_inst *instr)
 
 unsigned long branch_target(const struct ppc_inst *instr)
 {
-	if (instr_is_branch_iform(*instr))
+	if (instr_is_branch_iform(ppc_inst_read(instr)))
 		return branch_iform_target(instr);
-	else if (instr_is_branch_bform(*instr))
+	else if (instr_is_branch_bform(ppc_inst_read(instr)))
 		return branch_bform_target(instr);
 
 	return 0;
@@ -358,7 +358,8 @@ unsigned long branch_target(const struct ppc_inst *instr)
 
 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))
+	if (instr_is_branch_iform(ppc_inst_read(instr)) ||
+	    instr_is_branch_bform(ppc_inst_read(instr)))
 		return branch_target(instr) == addr;
 
 	return 0;
@@ -368,13 +369,14 @@ int translate_branch(struct ppc_inst *instr, const struct ppc_inst *dest,
 		     const struct ppc_inst *src)
 {
 	unsigned long target;
-
 	target = branch_target(src);
 
-	if (instr_is_branch_iform(*src))
-		return create_branch(instr, dest, target, ppc_inst_val(*src));
-	else if (instr_is_branch_bform(*src))
-		return create_cond_branch(instr, dest, target, ppc_inst_val(*src));
+	if (instr_is_branch_iform(ppc_inst_read(src)))
+		return create_branch(instr, dest, target,
+				     ppc_inst_val(ppc_inst_read(src)));
+	else if (instr_is_branch_bform(ppc_inst_read(src)))
+		return create_cond_branch(instr, dest, target,
+					  ppc_inst_val(ppc_inst_read(src)));
 
 	return 1;
 }
@@ -598,7 +600,7 @@ static void __init test_translate_branch(void)
 	patch_instruction(q, instr);
 	check(instr_is_branch_to_addr(p, addr));
 	check(instr_is_branch_to_addr(q, addr));
-	check(ppc_inst_equal(*q, ppc_inst(0x4a000000)));
+	check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x4a000000)));
 
 	/* Maximum positive case, move x to x - 32 MB + 4 */
 	p = buf + 0x2000000;
@@ -609,7 +611,7 @@ static void __init test_translate_branch(void)
 	patch_instruction(q, instr);
 	check(instr_is_branch_to_addr(p, addr));
 	check(instr_is_branch_to_addr(q, addr));
-	check(ppc_inst_equal(*q, ppc_inst(0x49fffffc)));
+	check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x49fffffc)));
 
 	/* Jump to x + 16 MB moved to x + 20 MB */
 	p = buf;
@@ -655,7 +657,7 @@ static void __init test_translate_branch(void)
 	patch_instruction(q, instr);
 	check(instr_is_branch_to_addr(p, addr));
 	check(instr_is_branch_to_addr(q, addr));
-	check(ppc_inst_equal(*q, ppc_inst(0x43ff8000)));
+	check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff8000)));
 
 	/* Maximum positive case, move x to x - 32 KB + 4 */
 	p = buf + 0x8000;
@@ -667,7 +669,7 @@ static void __init test_translate_branch(void)
 	patch_instruction(q, instr);
 	check(instr_is_branch_to_addr(p, addr));
 	check(instr_is_branch_to_addr(q, addr));
-	check(ppc_inst_equal(*q, ppc_inst(0x43ff7ffc)));
+	check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff7ffc)));
 
 	/* Jump to x + 12 KB moved to x + 20 KB */
 	p = buf;
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
index fb6e8e8abf4e..c0d3ed4efb7e 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -48,7 +48,7 @@ static int patch_alt_instruction(struct ppc_inst *src, struct ppc_inst *dest,
 	int err;
 	struct ppc_inst instr;
 
-	instr = *src;
+	instr = ppc_inst_read(src);
 
 	if (instr_is_relative_branch(*src)) {
 		struct ppc_inst *target = (struct ppc_inst *)branch_target(src);
@@ -403,7 +403,7 @@ static void do_final_fixups(void)
 	length = (__end_interrupts - _stext) / sizeof(struct ppc_inst);
 
 	while (length--) {
-		raw_patch_instruction(dest, *src);
+		raw_patch_instruction(dest, ppc_inst_read(src));
 		src++;
 		dest++;
 	}
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index e0132d6d24d0..68e0b05d9226 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -702,13 +702,13 @@ static int xmon_core(struct pt_regs *regs, int fromipi)
 	if ((regs->msr & (MSR_IR|MSR_PR|MSR_64BIT)) == (MSR_IR|MSR_64BIT)) {
 		bp = at_breakpoint(regs->nip);
 		if (bp != NULL) {
-			int stepped = emulate_step(regs, bp->instr[0]);
+			int stepped = emulate_step(regs, ppc_inst_read(bp->instr));
 			if (stepped == 0) {
 				regs->nip = (unsigned long) &bp->instr[0];
 				atomic_inc(&bp->ref_count);
 			} else if (stepped < 0) {
 				printf("Couldn't single-step %s instruction\n",
-				    (IS_RFID(bp->instr[0])? "rfid": "mtmsrd"));
+				    IS_RFID(ppc_inst_read(bp->instr))? "rfid": "mtmsrd");
 			}
 		}
 	}
@@ -949,7 +949,7 @@ static void remove_bpts(void)
 		if (mread(bp->address, &instr, 4) == 4
 		    && ppc_inst_equal(instr, ppc_inst(bpinstr))
 		    && patch_instruction(
-			(struct ppc_inst *)bp->address, bp->instr[0]) != 0)
+			(struct ppc_inst *)bp->address, ppc_inst_read(bp->instr)) != 0)
 			printf("Couldn't remove breakpoint at %lx\n",
 			       bp->address);
 	}
-- 
2.17.1


  parent reply	other threads:[~2020-05-06  4:06 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-06  3:40 [PATCH v8 00/30] Initial Prefixed Instruction support Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 01/30] powerpc/xmon: Remove store_inst() for patch_instruction() Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 02/30] powerpc/xmon: Move breakpoint instructions to own array Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 03/30] powerpc/xmon: Move breakpoints to text section Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 04/30] powerpc/xmon: Use bitwise calculations in_breakpoint_table() Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 05/30] powerpc: Change calling convention for create_branch() et. al Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 06/30] powerpc: Use a macro for creating instructions from u32s Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 07/30] powerpc: Use an accessor for instructions Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 08/30] powerpc: Use a function for getting the instruction op code Jordan Niethe
2020-05-15  7:48   ` Jordan Niethe
2020-05-16 11:08     ` Michael Ellerman
2020-05-17  7:41       ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 09/30] powerpc: Use a function for byte swapping instructions Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 10/30] powerpc: Introduce functions for instruction equality Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 11/30] powerpc: Use a datatype for instructions Jordan Niethe
2020-05-08  1:51   ` Jordan Niethe
2020-05-08  7:17     ` Christophe Leroy
2020-05-11  1:19       ` Jordan Niethe
2020-05-08  2:15   ` Jordan Niethe
2020-05-17 10:48   ` Jordan Niethe
2020-05-06  3:40 ` Jordan Niethe [this message]
2020-05-16 18:39   ` [PATCH v8 12/30] powerpc: Use a function for reading instructions Christophe Leroy
2020-05-17 10:44     ` Jordan Niethe
2020-05-19  4:05       ` Michael Ellerman
2020-05-19  5:03         ` Christophe Leroy
2020-05-20  4:16           ` Michael Ellerman
2020-05-06  3:40 ` [PATCH v8 13/30] powerpc: Add a probe_user_read_inst() function Jordan Niethe
2020-05-13 12:52   ` Michael Ellerman
2020-05-13 23:51     ` Jordan Niethe
2020-05-14  5:46   ` Christophe Leroy
2020-05-15  3:46     ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 14/30] powerpc: Add a probe_kernel_read_inst() function Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 15/30] powerpc/kprobes: Use patch_instruction() Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 16/30] powerpc: Define and use __get_user_instr{, inatomic}() Jordan Niethe
2020-05-13 14:18   ` Michael Ellerman
2020-05-13 23:54     ` Jordan Niethe
2020-05-14  1:43       ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 17/30] powerpc: Introduce a function for reporting instruction length Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 18/30] powerpc/xmon: Use a function for reading instructions Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 19/30] powerpc/xmon: Move insertion of breakpoint for xol'ing Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 20/30] powerpc: Make test_translate_branch() independent of instruction length Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 21/30] powerpc: Enable Prefixed Instructions Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 22/30] powerpc: Define new SRR1 bits for a future ISA version Jordan Niethe
2020-05-08  2:26   ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 23/30] powerpc: Add prefixed instructions to instruction data type Jordan Niethe
2020-05-14  1:40   ` Jordan Niethe
2020-05-14  6:11   ` Christophe Leroy
2020-05-14 12:06     ` Alistair Popple
2020-05-14 12:29       ` Jordan Niethe
2020-05-14 12:57       ` Christophe Leroy
2020-05-14 12:28     ` Jordan Niethe
2020-05-15  1:33     ` Michael Ellerman
2020-05-15  7:52       ` Jordan Niethe
2020-05-16 11:54   ` [PATCH v8 22.5/30] powerpc/optprobes: Add register argument to patch_imm64_load_insns() Michael Ellerman
2020-06-09  5:51     ` Michael Ellerman
2020-05-06  3:40 ` [PATCH v8 24/30] powerpc: Test prefixed code patching Jordan Niethe
2020-05-15  7:54   ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 25/30] powerpc: Test prefixed instructions in feature fixups Jordan Niethe
2020-05-15  7:57   ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 26/30] powerpc/xmon: Don't allow breakpoints on suffixes Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 27/30] powerpc/kprobes: " Jordan Niethe
2021-05-18 18:43   ` Christophe Leroy
2021-05-18 19:52     ` Gabriel Paubert
2021-05-19  8:11     ` Naveen N. Rao
2021-05-20  3:45       ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 28/30] powerpc: Support prefixed instructions in alignment handler Jordan Niethe
2020-05-14  6:14   ` Christophe Leroy
2020-05-14 12:15     ` Alistair Popple
2020-05-14 12:59       ` Christophe Leroy
2020-05-06  3:40 ` [PATCH v8 29/30] powerpc sstep: Add support for prefixed load/stores Jordan Niethe
2020-05-14  6:15   ` Christophe Leroy
2020-05-14 12:19     ` Alistair Popple
2020-05-14 13:00       ` Christophe Leroy
2020-05-15  7:59   ` Jordan Niethe
2020-05-06  3:40 ` [PATCH v8 30/30] powerpc sstep: Add support for prefixed fixed-point arithmetic Jordan Niethe
2020-05-14  6:15   ` Christophe Leroy
2020-05-15  8:02   ` Jordan Niethe
2020-05-14  5:31 ` [PATCH v8 00/30] Initial Prefixed Instruction support Christophe Leroy
2020-05-14 10:33   ` Jordan Niethe
2020-05-20 10:59 ` Michael Ellerman

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