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x86/kprobes: Refactor can_{probe,boost} return type to bool

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Both can_probe and can_boost have int return type but are using int as
boolean in their context.

Refactor both functions to make them actually return boolean.

Link: https://lore.kernel.org/all/20240204031300.830475-2-jinghao7@illinois.edu/

Signed-off-by: Jinghao Jia <jinghao7@illinois.edu>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
This commit is contained in:
Jinghao Jia 2024-03-07 00:26:01 +09:00 committed by Masami Hiramatsu (Google)
parent 90d35da658
commit e4778a0ef3
2 changed files with 16 additions and 19 deletions
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2
arch/x86/kernel/kprobes/common.h
View File

@ -78,7 +78,7 @@
#endif
/* Ensure if the instruction can be boostable */
extern int can_boost(struct insn *insn, void *orig_addr);
extern bool can_boost(struct insn *insn, void *orig_addr);
/* Recover instruction if given address is probed */
extern unsigned long recover_probed_instruction(kprobe_opcode_t *buf,
unsigned long addr);

33
arch/x86/kernel/kprobes/core.c
View File

@ -137,14 +137,14 @@ NOKPROBE_SYMBOL(synthesize_relcall);
* Returns non-zero if INSN is boostable.
* RIP relative instructions are adjusted at copying time in 64 bits mode
*/
int can_boost(struct insn *insn, void *addr)
bool can_boost(struct insn *insn, void *addr)
{
kprobe_opcode_t opcode;
insn_byte_t prefix;
int i;
if (search_exception_tables((unsigned long)addr))
return 0; /* Page fault may occur on this address. */
return false; /* Page fault may occur on this address. */
/* 2nd-byte opcode */
if (insn->opcode.nbytes == 2)
@ -152,7 +152,7 @@ int can_boost(struct insn *insn, void *addr)
(unsigned long *)twobyte_is_boostable);
if (insn->opcode.nbytes != 1)
return 0;
return false;
for_each_insn_prefix(insn, i, prefix) {
insn_attr_t attr;
@ -160,7 +160,7 @@ int can_boost(struct insn *insn, void *addr)
attr = inat_get_opcode_attribute(prefix);
/* Can't boost Address-size override prefix and CS override prefix */
if (prefix == 0x2e || inat_is_address_size_prefix(attr))
return 0;
return false;
}
opcode = insn->opcode.bytes[0];
@ -181,12 +181,12 @@ int can_boost(struct insn *insn, void *addr)
case 0xf6 ... 0xf7: /* Grp3 */
case 0xfe: /* Grp4 */
/* ... are not boostable */
return 0;
return false;
case 0xff: /* Grp5 */
/* Only indirect jmp is boostable */
return X86_MODRM_REG(insn->modrm.bytes[0]) == 4;
default:
return 1;
return true;
}
}
@ -253,20 +253,18 @@ unsigned long recover_probed_instruction(kprobe_opcode_t *buf, unsigned long add
}
/* Check if paddr is at an instruction boundary */
static int can_probe(unsigned long paddr)
static bool can_probe(unsigned long paddr)
{
unsigned long addr, __addr, offset = 0;
struct insn insn;
kprobe_opcode_t buf[MAX_INSN_SIZE];
if (!kallsyms_lookup_size_offset(paddr, NULL, &offset))
return 0;
return false;
/* Decode instructions */
addr = paddr - offset;
while (addr < paddr) {
int ret;
/*
* Check if the instruction has been modified by another
* kprobe, in which case we replace the breakpoint by the
@ -277,11 +275,10 @@ static int can_probe(unsigned long paddr)
*/
__addr = recover_probed_instruction(buf, addr);
if (!__addr)
return 0;
return false;
ret = insn_decode_kernel(&insn, (void *)__addr);
if (ret < 0)
return 0;
if (insn_decode_kernel(&insn, (void *)__addr) < 0)
return false;
#ifdef CONFIG_KGDB
/*
@ -290,7 +287,7 @@ static int can_probe(unsigned long paddr)
*/
if (insn.opcode.bytes[0] == INT3_INSN_OPCODE &&
kgdb_has_hit_break(addr))
return 0;
return false;
#endif
addr += insn.length;
}
@ -310,10 +307,10 @@ static int can_probe(unsigned long paddr)
*/
__addr = recover_probed_instruction(buf, addr);
if (!__addr)
return 0;
return false;
if (insn_decode_kernel(&insn, (void *)__addr) < 0)
return 0;
return false;
if (insn.opcode.value == 0xBA)
offset = 12;
@ -324,7 +321,7 @@ static int can_probe(unsigned long paddr)
/* This movl/addl is used for decoding CFI. */
if (is_cfi_trap(addr + offset))
return 0;
return false;
}
out: