[PATCH v6 17/28] powerpc: Introduce a function for reporting instruction length
From: Jordan Niethe <hidden>
Date: 2020-04-28 02:35:59
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest, uprobes · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds, Masami Hiramatsu, Oleg Nesterov, Peter Zijlstra
Currently all instructions have the same length, but in preparation for
prefixed instructions introduce a function for returning instruction
length.
Signed-off-by: Jordan Niethe <redacted>
---
v6: - feature-fixups.c: do_final_fixups(): use here
- ppc_inst_len(): change return type from bool to int
- uprobes: Use ppc_inst_read() before calling ppc_inst_len()
---
arch/powerpc/include/asm/inst.h | 5 +++++
arch/powerpc/kernel/kprobes.c | 6 ++++--
arch/powerpc/kernel/uprobes.c | 2 +-
arch/powerpc/lib/feature-fixups.c | 14 +++++++-------
4 files changed, 17 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/include/asm/inst.h b/arch/powerpc/include/asm/inst.h
index 0d581b332c20..2f3c9d5bcf7c 100644
--- a/arch/powerpc/include/asm/inst.h
+++ b/arch/powerpc/include/asm/inst.h@@ -17,6 +17,11 @@ static inline u32 ppc_inst_val(struct ppc_inst x) return x.val; } +static inline int ppc_inst_len(struct ppc_inst x) +{ + return sizeof(struct ppc_inst); +} + static inline int ppc_inst_primary_opcode(struct ppc_inst x) { return ppc_inst_val(x) >> 26;
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index ff53e5ef7e40..8d17cfdcdc54 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c@@ -474,14 +474,16 @@ NOKPROBE_SYMBOL(trampoline_probe_handler); */ int kprobe_post_handler(struct pt_regs *regs) { + int len; struct kprobe *cur = kprobe_running(); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); if (!cur || user_mode(regs)) return 0; + len = ppc_inst_len(ppc_inst_read((struct ppc_inst *)cur->ainsn.insn)); /* make sure we got here for instruction we have a kprobe on */ - if (((unsigned long)cur->ainsn.insn + 4) != regs->nip) + if (((unsigned long)cur->ainsn.insn + len) != regs->nip) return 0; if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
@@ -490,7 +492,7 @@ int kprobe_post_handler(struct pt_regs *regs) } /* Adjust nip to after the single-stepped instruction */ - regs->nip = (unsigned long)cur->addr + 4; + regs->nip = (unsigned long)cur->addr + len; regs->msr |= kcb->kprobe_saved_msr; /*Restore back the original saved kprobes variables and continue. */
diff --git a/arch/powerpc/kernel/uprobes.c b/arch/powerpc/kernel/uprobes.c
index 6893d40a48c5..83e883e1a42d 100644
--- a/arch/powerpc/kernel/uprobes.c
+++ b/arch/powerpc/kernel/uprobes.c@@ -112,7 +112,7 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) * support doesn't exist and have to fix-up the next instruction * to be executed. */ - regs->nip = utask->vaddr + MAX_UINSN_BYTES; + regs->nip = utask->vaddr + ppc_inst_len(ppc_inst_read(&auprobe->insn)); user_disable_single_step(current); return 0;
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
index 13ec3264a565..f4845e740338 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c@@ -390,20 +390,20 @@ void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end) static void do_final_fixups(void) { #if defined(CONFIG_PPC64) && defined(CONFIG_RELOCATABLE) - struct ppc_inst *src, *dest; - unsigned long length; + struct ppc_inst inst, *src, *dest, *end; if (PHYSICAL_START == 0) return; src = (struct ppc_inst *)(KERNELBASE + PHYSICAL_START); dest = (struct ppc_inst *)KERNELBASE; - length = (__end_interrupts - _stext) / sizeof(struct ppc_inst); + end = (void *)src + (__end_interrupts - _stext); - while (length--) { - raw_patch_instruction(dest, ppc_inst_read(src)); - src++; - dest++; + while (src < end) { + inst = ppc_inst_read(src); + raw_patch_instruction(dest, inst); + src = (void *)src + ppc_inst_len(inst); + dest = (void *)dest + ppc_inst_len(inst); } #endif }
--
2.17.1