[PATCH v6 12/28] powerpc: Use a function for reading instructions
Jordan Niethe
jniethe5 at gmail.com
Tue Apr 28 11:57:58 AEST 2020
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.
Signed-off-by: Jordan Niethe <jniethe5 at 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
---
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 | 23 +++++++++++------------
arch/powerpc/lib/feature-fixups.c | 4 ++--
arch/powerpc/xmon/xmon.c | 6 +++---
9 files changed, 30 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 9ed996cb0589..17ad844e24f5 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 7118b46a6543..859b602fa270 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 dfeb317a58ad..d704f9598f48 100644
--- a/arch/powerpc/kernel/optprobes.c
+++ b/arch/powerpc/kernel/optprobes.c
@@ -100,8 +100,8 @@ 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) &&
- analyse_instr(&op, ®s, *(struct ppc_inst *)p->ainsn.insn) == 1) {
+ if (!is_conditional_branch(ppc_inst_read((struct ppc_inst *)p->ainsn.insn)) &&
+ analyse_instr(&op, ®s, ppc_inst_read((struct ppc_inst *)p->ainsn.insn)) == 1) {
emulate_update_regs(®s, &op);
nip = regs.nip;
}
diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c
index 2c70d1854b5c..63228e0e8cfc 100644
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -846,7 +846,7 @@ 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);
@@ -854,7 +854,7 @@ 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 1cc5120c2c9d..85ad61aa0304 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -349,9 +349,9 @@ 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;
@@ -359,7 +359,7 @@ 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;
@@ -369,13 +369,12 @@ 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;
}
@@ -599,7 +598,7 @@ 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;
@@ -610,7 +609,7 @@ 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;
@@ -656,7 +655,7 @@ 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;
@@ -668,7 +667,7 @@ 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 05be435959fb..13ec3264a565 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);
@@ -401,7 +401,7 @@ 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 cb624fe789ec..65abae7a0103 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -701,13 +701,13 @@ 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");
}
}
}
@@ -948,7 +948,7 @@ 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
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