[PATCH -tip v11 10/27] kprobes: treewide: Use 'kprobe_opcode_t *' for the code address in get_optimi

Masami Hiramatsu
2021-09-14T14:40:07Z

Since get_optimized_kprobe() is only used inside kprobes,
it doesn't need to use 'unsigned long' type for 'addr' parameter.
Make it use 'kprobe_opcode_t *' for the 'addr' parameter and
subsequent call of arch_within_optimized_kprobe() also should use
'kprobe_opcode_t *'.

Note that MAX_OPTIMIZED_LENGTH and RELATIVEJUMP_SIZE are defined
by byte-size, but the size of 'kprobe_opcode_t' depends on the
architecture. Therefore, we must be careful when calculating
addresses using those macros.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
arch/arm/probes/kprobes/opt-arm.c | 7 ++++---
arch/powerpc/kernel/optprobes.c | 6 +++---
arch/x86/kernel/kprobes/opt.c | 6 +++---
include/linux/kprobes.h | 2 +-
kernel/kprobes.c | 10 +++++-----
5 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/arch/arm/probes/kprobes/opt-arm.c b/arch/arm/probes/kprobes/opt-arm.c
index c78180172120..dbef34ed933f 100644
--- a/arch/arm/probes/kprobes/opt-arm.c
+++ b/arch/arm/probes/kprobes/opt-arm.c
@@ -347,10 +347,11 @@ void arch_unoptimize_kprobes(struct list_head *oplist,
}

int arch_within_optimized_kprobe(struct optimized_kprobe *op,
- unsigned long addr)
+ kprobe_opcode_t *addr)
{
- return ((unsigned long)op->kp.addr <= addr &&
- (unsigned long)op->kp.addr + RELATIVEJUMP_SIZE > addr);
+ return (op->kp.addr <= addr &&
+ op->kp.addr + (RELATIVEJUMP_SIZE / sizeof(kprobe_opcode_t)) > addr);
+
}

void arch_remove_optimized_kprobe(struct optimized_kprobe *op)
diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c
index c79899abcec8..325ba544883c 100644
--- a/arch/powerpc/kernel/optprobes.c
+++ b/arch/powerpc/kernel/optprobes.c
@@ -301,8 +301,8 @@ void arch_unoptimize_kprobes(struct list_head *oplist, struct list_head *done_li
}
}

-int arch_within_optimized_kprobe(struct optimized_kprobe *op, unsigned long addr)
+int arch_within_optimized_kprobe(struct optimized_kprobe *op, kprobe_opcode_t *addr)
{
- return ((unsigned long)op->kp.addr <= addr &&
- (unsigned long)op->kp.addr + RELATIVEJUMP_SIZE > addr);
+ return (op->kp.addr <= addr &&
+ op->kp.addr + (RELATIVEJUMP_SIZE / sizeof(kprobe_opcode_t)) > addr);
}
diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index 71425ebba98a..b4a54a52aa59 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -367,10 +367,10 @@ int arch_check_optimized_kprobe(struct optimized_kprobe *op)

/* Check the addr is within the optimized instructions. */
int arch_within_optimized_kprobe(struct optimized_kprobe *op,
- unsigned long addr)
+ kprobe_opcode_t *addr)
{
- return ((unsigned long)op->kp.addr <= addr &&
- (unsigned long)op->kp.addr + op->optinsn.size > addr);
+ return (op->kp.addr <= addr &&
+ op->kp.addr + op->optinsn.size > addr);
}

/* Free optimized instruction slot */
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 9c28fbb18e74..6a5995f334a0 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -329,7 +329,7 @@ extern void arch_unoptimize_kprobes(struct list_head *oplist,
struct list_head *done_list);
extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
- unsigned long addr);
+ kprobe_opcode_t *addr);

extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index ec3d97fd8c6b..b6f1dcf4bff3 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -485,15 +485,15 @@ static int kprobe_queued(struct kprobe *p)
* Return an optimized kprobe whose optimizing code replaces
* instructions including 'addr' (exclude breakpoint).
*/
-static struct kprobe *get_optimized_kprobe(unsigned long addr)
+static struct kprobe *get_optimized_kprobe(kprobe_opcode_t *addr)
{
int i;
struct kprobe *p = NULL;
struct optimized_kprobe *op;

/* Don't check i = 0, since that is a breakpoint case. */
- for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
- p = get_kprobe((void *)(addr - i));
+ for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH / sizeof(kprobe_opcode_t); i++)
+ p = get_kprobe(addr - i);

if (p && kprobe_optready(p)) {
op = container_of(p, struct optimized_kprobe, kp);
@@ -967,7 +967,7 @@ static void __arm_kprobe(struct kprobe *p)
lockdep_assert_held(&text_mutex);

/* Find the overlapping optimized kprobes. */
- _p = get_optimized_kprobe((unsigned long)p->addr);
+ _p = get_optimized_kprobe(p->addr);
if (unlikely(_p))
/* Fallback to unoptimized kprobe */
unoptimize_kprobe(_p, true);
@@ -989,7 +989,7 @@ static void __disarm_kprobe(struct kprobe *p, bool reopt)
if (!kprobe_queued(p)) {
arch_disarm_kprobe(p);
/* If another kprobe was blocked, re-optimize it. */
- _p = get_optimized_kprobe((unsigned long)p->addr);
+ _p = get_optimized_kprobe(p->addr);
if (unlikely(_p) && reopt)
optimize_kprobe(_p);
}