powerpc/kprobes/optprobes: Use patch_instruction()

So that we can implement STRICT_RWX, use patch_instruction() in
optprobes.

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 32 insertions, 21 deletions

diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c
index ec60ed0d4aad..6f8273f5e988 100644
--- a/arch/powerpc/kernel/optprobes.c
+++ b/arch/powerpc/kernel/optprobes.c
@@ -158,12 +158,13 @@ void arch_remove_optimized_kprobe(struct optimized_kprobe *op)
 void patch_imm32_load_insns(unsigned int val, kprobe_opcode_t *addr)
 {
         /* addis r4,0,(insn)@h */
-        *addr++ = PPC_INST_ADDIS | ___PPC_RT(4) |
-                  ((val >> 16) & 0xffff);
+        patch_instruction(addr, PPC_INST_ADDIS | ___PPC_RT(4) |
+                          ((val >> 16) & 0xffff));
+        addr++;
 
         /* ori r4,r4,(insn)@l */
-        *addr = PPC_INST_ORI | ___PPC_RA(4) | ___PPC_RS(4) |
-                (val & 0xffff);
+        patch_instruction(addr, PPC_INST_ORI | ___PPC_RA(4) |
+                          ___PPC_RS(4) | (val & 0xffff));
 }
 
 /*
@@ -173,24 +174,28 @@ void patch_imm32_load_insns(unsigned int val, kprobe_opcode_t *addr)
 void patch_imm64_load_insns(unsigned long val, kprobe_opcode_t *addr)
 {
         /* lis r3,(op)@highest */
-        *addr++ = PPC_INST_ADDIS | ___PPC_RT(3) |
-                  ((val >> 48) & 0xffff);
+        patch_instruction(addr, PPC_INST_ADDIS | ___PPC_RT(3) |
+                          ((val >> 48) & 0xffff));
+        addr++;
 
         /* ori r3,r3,(op)@higher */
-        *addr++ = PPC_INST_ORI | ___PPC_RA(3) | ___PPC_RS(3) |
-                  ((val >> 32) & 0xffff);
+        patch_instruction(addr, PPC_INST_ORI | ___PPC_RA(3) |
+                          ___PPC_RS(3) | ((val >> 32) & 0xffff));
+        addr++;
 
         /* rldicr r3,r3,32,31 */
-        *addr++ = PPC_INST_RLDICR | ___PPC_RA(3) | ___PPC_RS(3) |
-                  __PPC_SH64(32) | __PPC_ME64(31);
+        patch_instruction(addr, PPC_INST_RLDICR | ___PPC_RA(3) |
+                          ___PPC_RS(3) | __PPC_SH64(32) | __PPC_ME64(31));
+        addr++;
 
         /* oris r3,r3,(op)@h */
-        *addr++ = PPC_INST_ORIS | ___PPC_RA(3) | ___PPC_RS(3) |
-                  ((val >> 16) & 0xffff);
+        patch_instruction(addr, PPC_INST_ORIS | ___PPC_RA(3) |
+                          ___PPC_RS(3) | ((val >> 16) & 0xffff));
+        addr++;
 
         /* ori r3,r3,(op)@l */
-        *addr = PPC_INST_ORI | ___PPC_RA(3) | ___PPC_RS(3) |
-                (val & 0xffff);
+        patch_instruction(addr, PPC_INST_ORI | ___PPC_RA(3) |
+                          ___PPC_RS(3) | (val & 0xffff));
 }
 
 int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
@@ -198,7 +203,8 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
         kprobe_opcode_t *buff, branch_op_callback, branch_emulate_step;
         kprobe_opcode_t *op_callback_addr, *emulate_step_addr;
         long b_offset;
-        unsigned long nip;
+        unsigned long nip, size;
+        int rc, i;
 
         kprobe_ppc_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
 
@@ -231,8 +237,14 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
                 goto error;
 
         /* Setup template */
-        memcpy(buff, optprobe_template_entry,
-                        TMPL_END_IDX * sizeof(kprobe_opcode_t));
+        /* We can optimize this via patch_instruction_window later */
+        size = (TMPL_END_IDX * sizeof(kprobe_opcode_t)) / sizeof(int);
+        pr_devel("Copying template to %p, size %lu\n", buff, size);
+        for (i = 0; i < size; i++) {
+                rc = patch_instruction(buff + i, *(optprobe_template_entry + i));
+                if (rc < 0)
+                        goto error;
+        }
 
         /*
          * Fixup the template with instructions to:
@@ -261,8 +273,8 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
         if (!branch_op_callback || !branch_emulate_step)
                 goto error;
 
-        buff[TMPL_CALL_HDLR_IDX] = branch_op_callback;
-        buff[TMPL_EMULATE_IDX] = branch_emulate_step;
+        patch_instruction(buff + TMPL_CALL_HDLR_IDX, branch_op_callback);
+        patch_instruction(buff + TMPL_EMULATE_IDX, branch_emulate_step);
 
         /*
          * 3. load instruction to be emulated into relevant register, and
@@ -272,8 +284,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
         /*
          * 4. branch back from trampoline
          */
-        buff[TMPL_RET_IDX] = create_branch((unsigned int *)buff + TMPL_RET_IDX,
-                                (unsigned long)nip, 0);
+        patch_branch(buff + TMPL_RET_IDX, (unsigned long)nip, 0);
 
         flush_icache_range((unsigned long)buff,
                            (unsigned long)(&buff[TMPL_END_IDX]));