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arm64: probes: Move kprobes-specific fields

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We share struct arch_probe_insn between krpboes and uprobes, but most of
its fields aren't necessary for uprobes:

* The 'insn' field is only used by kprobes as a pointer to the XOL slot.

* The 'restore' field is only used by probes as the PC to restore after
  stepping an instruction in the XOL slot.

* The 'pstate_cc' field isn't used by kprobes or uprobes, and seems to
  only exist as a result of copy-pasting the 32-bit arm implementation
  of kprobes.

As these fields live in struct arch_probe_insn they cannot use
definitions that only exist when CONFIG_KPROBES=y, such as the
kprobe_opcode_t typedef, which we'd like to use in subsequent patches.

Clean this up by removing the 'pstate_cc' field, and moving the
kprobes-specific fields into the kprobes-specific struct
arch_specific_insn. To make it clear that the fields are related to
stepping instructions in the XOL slot, 'insn' is renamed to 'xol_insn'
and 'restore' is renamed to 'xol_restore'

At the same time, remove the misleading and useless comment above struct
arch_probe_insn.

The should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20241008155851.801546-5-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Rutland
2024-10-08 16:58:49 +01:00
committed by Catalin Marinas
parent 13f8f1e05f
commit 6105c5d46d
2 changed files with 18 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
arch/arm64/include/asm/probes.h
View File

@@ -12,18 +12,16 @@
typedef u32 probe_opcode_t;
typedef void (probes_handler_t) (u32 opcode, long addr, struct pt_regs *);
/* architecture specific copy of original instruction */
struct arch_probe_insn {
probe_opcode_t *insn;
pstate_check_t *pstate_cc;
probes_handler_t *handler;
/* restore address after step xol */
unsigned long restore;
};
#ifdef CONFIG_KPROBES
typedef u32 kprobe_opcode_t;
struct arch_specific_insn {
struct arch_probe_insn api;
probe_opcode_t *xol_insn;
/* restore address after step xol */
unsigned long xol_restore;
};
#endif

30
arch/arm64/kernel/probes/kprobes.c
View File

@@ -43,7 +43,7 @@ post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *);
static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
{
kprobe_opcode_t *addr = p->ainsn.api.insn;
kprobe_opcode_t *addr = p->ainsn.xol_insn;
/*
* Prepare insn slot, Mark Rutland points out it depends on a coupe of
@@ -70,14 +70,14 @@ static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
/*
* Needs restoring of return address after stepping xol.
*/
p->ainsn.api.restore = (unsigned long) p->addr +
p->ainsn.xol_restore = (unsigned long) p->addr +
sizeof(kprobe_opcode_t);
}
static void __kprobes arch_prepare_simulate(struct kprobe *p)
{
/* This instructions is not executed xol. No need to adjust the PC */
p->ainsn.api.restore = 0;
p->ainsn.xol_restore = 0;
}
static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs)
@@ -110,18 +110,18 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
return -EINVAL;
case INSN_GOOD_NO_SLOT: /* insn need simulation */
p->ainsn.api.insn = NULL;
p->ainsn.xol_insn = NULL;
break;
case INSN_GOOD: /* instruction uses slot */
p->ainsn.api.insn = get_insn_slot();
if (!p->ainsn.api.insn)
p->ainsn.xol_insn = get_insn_slot();
if (!p->ainsn.xol_insn)
return -ENOMEM;
break;
}
/* prepare the instruction */
if (p->ainsn.api.insn)
if (p->ainsn.xol_insn)
arch_prepare_ss_slot(p);
else
arch_prepare_simulate(p);
@@ -148,9 +148,9 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
if (p->ainsn.api.insn) {
free_insn_slot(p->ainsn.api.insn, 0);
p->ainsn.api.insn = NULL;
if (p->ainsn.xol_insn) {
free_insn_slot(p->ainsn.xol_insn, 0);
p->ainsn.xol_insn = NULL;
}
}
@@ -205,9 +205,9 @@ static void __kprobes setup_singlestep(struct kprobe *p,
}
if (p->ainsn.api.insn) {
if (p->ainsn.xol_insn) {
/* prepare for single stepping */
slot = (unsigned long)p->ainsn.api.insn;
slot = (unsigned long)p->ainsn.xol_insn;
kprobes_save_local_irqflag(kcb, regs);
instruction_pointer_set(regs, slot);
@@ -245,8 +245,8 @@ static void __kprobes
post_kprobe_handler(struct kprobe *cur, struct kprobe_ctlblk *kcb, struct pt_regs *regs)
{
/* return addr restore if non-branching insn */
if (cur->ainsn.api.restore != 0)
instruction_pointer_set(regs, cur->ainsn.api.restore);
if (cur->ainsn.xol_restore != 0)
instruction_pointer_set(regs, cur->ainsn.xol_restore);
/* restore back original saved kprobe variables and continue */
if (kcb->kprobe_status == KPROBE_REENTER) {
@@ -348,7 +348,7 @@ kprobe_breakpoint_ss_handler(struct pt_regs *regs, unsigned long esr)
struct kprobe *cur = kprobe_running();
if (cur && (kcb->kprobe_status & (KPROBE_HIT_SS | KPROBE_REENTER)) &&
((unsigned long)&cur->ainsn.api.insn[1] == addr)) {
((unsigned long)&cur->ainsn.xol_insn[1] == addr)) {
kprobes_restore_local_irqflag(kcb, regs);
post_kprobe_handler(cur, kcb, regs);