From: Samuel Holland samuel.holland@sifive.com
[ Upstream commit 51781ce8f4486c3738a6c85175b599ad1be71f89 ]
patch_text_nosync() already handles an arbitrary length of code, so this removes a superfluous loop and reduces the number of icache flushes.
Reviewed-by: Björn Töpel bjorn@rivosinc.com Signed-off-by: Samuel Holland samuel.holland@sifive.com Reviewed-by: Conor Dooley conor.dooley@microchip.com Link: https://lore.kernel.org/r/20240327160520.791322-6-samuel.holland@sifive.com Signed-off-by: Palmer Dabbelt palmer@rivosinc.com [apply to v6.6] Signed-off-by: Nam Cao namcao@linutronix.de --- this patch fixes a bug introduced by commit b1756750a397 ("riscv: kprobes: Use patch_text_nosync() for insn slots"), which replaced patch_text() with patch_text_nosync(). That is broken, because patch_text() and patch_text_nosync() takes different parameters (number of instruction vs patched length in bytes).
This bug was reported in: https://lore.kernel.org/stable/c7e463c0-8cad-4f4e-addd-195c06b7b6de@iscas.ac... --- arch/riscv/include/asm/patch.h | 2 +- arch/riscv/kernel/patch.c | 14 +++++--------- arch/riscv/kernel/probes/kprobes.c | 18 ++++++++++-------- arch/riscv/net/bpf_jit_comp64.c | 7 ++++--- 4 files changed, 20 insertions(+), 21 deletions(-)
diff --git a/arch/riscv/include/asm/patch.h b/arch/riscv/include/asm/patch.h index 9f5d6e14c405..7228e266b9a1 100644 --- a/arch/riscv/include/asm/patch.h +++ b/arch/riscv/include/asm/patch.h @@ -9,7 +9,7 @@ int patch_insn_write(void *addr, const void *insn, size_t len); int patch_text_nosync(void *addr, const void *insns, size_t len); int patch_text_set_nosync(void *addr, u8 c, size_t len); -int patch_text(void *addr, u32 *insns, int ninsns); +int patch_text(void *addr, u32 *insns, size_t len);
extern int riscv_patch_in_stop_machine;
diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c index 78387d843aa5..aeda87240dbc 100644 --- a/arch/riscv/kernel/patch.c +++ b/arch/riscv/kernel/patch.c @@ -19,7 +19,7 @@ struct patch_insn { void *addr; u32 *insns; - int ninsns; + size_t len; atomic_t cpu_count; };
@@ -234,14 +234,10 @@ NOKPROBE_SYMBOL(patch_text_nosync); static int patch_text_cb(void *data) { struct patch_insn *patch = data; - unsigned long len; - int i, ret = 0; + int ret = 0;
if (atomic_inc_return(&patch->cpu_count) == num_online_cpus()) { - for (i = 0; ret == 0 && i < patch->ninsns; i++) { - len = GET_INSN_LENGTH(patch->insns[i]); - ret = patch_insn_write(patch->addr + i * len, &patch->insns[i], len); - } + ret = patch_insn_write(patch->addr, patch->insns, patch->len); /* * Make sure the patching store is effective *before* we * increment the counter which releases all waiting CPUs @@ -262,13 +258,13 @@ static int patch_text_cb(void *data) } NOKPROBE_SYMBOL(patch_text_cb);
-int patch_text(void *addr, u32 *insns, int ninsns) +int patch_text(void *addr, u32 *insns, size_t len) { int ret; struct patch_insn patch = { .addr = addr, .insns = insns, - .ninsns = ninsns, + .len = len, .cpu_count = ATOMIC_INIT(0), };
diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c index 4fbc70e823f0..297427ffc4e0 100644 --- a/arch/riscv/kernel/probes/kprobes.c +++ b/arch/riscv/kernel/probes/kprobes.c @@ -23,13 +23,13 @@ post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *);
static void __kprobes arch_prepare_ss_slot(struct kprobe *p) { + size_t len = GET_INSN_LENGTH(p->opcode); u32 insn = __BUG_INSN_32; - unsigned long offset = GET_INSN_LENGTH(p->opcode);
- p->ainsn.api.restore = (unsigned long)p->addr + offset; + p->ainsn.api.restore = (unsigned long)p->addr + len;
- patch_text_nosync(p->ainsn.api.insn, &p->opcode, 1); - patch_text_nosync((void *)p->ainsn.api.insn + offset, &insn, 1); + patch_text_nosync(p->ainsn.api.insn, &p->opcode, len); + patch_text_nosync((void *)p->ainsn.api.insn + len, &insn, GET_INSN_LENGTH(insn)); }
static void __kprobes arch_prepare_simulate(struct kprobe *p) @@ -116,16 +116,18 @@ void *alloc_insn_page(void) /* install breakpoint in text */ void __kprobes arch_arm_kprobe(struct kprobe *p) { - u32 insn = (p->opcode & __INSN_LENGTH_MASK) == __INSN_LENGTH_32 ? - __BUG_INSN_32 : __BUG_INSN_16; + size_t len = GET_INSN_LENGTH(p->opcode); + u32 insn = len == 4 ? __BUG_INSN_32 : __BUG_INSN_16;
- patch_text(p->addr, &insn, 1); + patch_text(p->addr, &insn, len); }
/* remove breakpoint from text */ void __kprobes arch_disarm_kprobe(struct kprobe *p) { - patch_text(p->addr, &p->opcode, 1); + size_t len = GET_INSN_LENGTH(p->opcode); + + patch_text(p->addr, &p->opcode, len); }
void __kprobes arch_remove_kprobe(struct kprobe *p) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 26eeb3973631..16eb4cd11cbd 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -14,6 +14,7 @@ #include "bpf_jit.h"
#define RV_FENTRY_NINSNS 2 +#define RV_FENTRY_NBYTES (RV_FENTRY_NINSNS * 4)
#define RV_REG_TCC RV_REG_A6 #define RV_REG_TCC_SAVED RV_REG_S6 /* Store A6 in S6 if program do calls */ @@ -681,7 +682,7 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type poke_type, if (ret) return ret;
- if (memcmp(ip, old_insns, RV_FENTRY_NINSNS * 4)) + if (memcmp(ip, old_insns, RV_FENTRY_NBYTES)) return -EFAULT;
ret = gen_jump_or_nops(new_addr, ip, new_insns, is_call); @@ -690,8 +691,8 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type poke_type,
cpus_read_lock(); mutex_lock(&text_mutex); - if (memcmp(ip, new_insns, RV_FENTRY_NINSNS * 4)) - ret = patch_text(ip, new_insns, RV_FENTRY_NINSNS); + if (memcmp(ip, new_insns, RV_FENTRY_NBYTES)) + ret = patch_text(ip, new_insns, RV_FENTRY_NBYTES); mutex_unlock(&text_mutex); cpus_read_unlock();