powerpc: Introduce a function for reporting instruction length

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 <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-18-jniethe5@gmail.com

diff --git a/arch/powerpc/include/asm/inst.h b/arch/powerpc/include/asm/inst.h
index e7e779805090cec93a73edce63c8270f58f3134e..c7ea70e730737025e801d38afce7b7b6168854bf 100644 (file)
--- 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 a72c8e1a42ad75996d8257e81df9083d4de106fc..33d54b091c701cd3dc0f20dc9feb38fe28f4d737 100644 (file)
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -462,14 +462,16 @@ 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) {
@@ -478,7 +480,7 @@ 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 6893d40a48c5d772732fd881901e60266cf6abdf..83e883e1a42db2b0059983a0baeaf46875f610a6 100644 (file)
--- 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 3c55097d406db3033abcb3de47933958c538dbb3..0c9ffdef8096556101af103d4ece3efba8d01178 100644 (file)
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -392,20 +392,20 @@ 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
 }