powerpc/code-patching: Reorganise do_patch_instruction() to ease error handling

Split do_patch_instruction() in two functions, the caller doing the
spin locking and the callee doing everything else.

And remove a few unnecessary initialisations and intermediate
variables.

This allows the callee to return from anywhere in the function.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/dbc85980a0d2a935731b272e8907e8bb1d8fc8c5.1638446239.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 740ba0d..3da7224 100644 (file)
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -129,13 +129,30 @@ static void unmap_patch_area(unsigned long addr)
        flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
 }
 
+static int __do_patch_instruction(u32 *addr, ppc_inst_t instr)
+{
+       int err;
+       u32 *patch_addr;
+       unsigned long text_poke_addr;
+
+       text_poke_addr = (unsigned long)__this_cpu_read(text_poke_area)->addr;
+       patch_addr = (u32 *)(text_poke_addr + offset_in_page(addr));
+
+       err = map_patch_area(addr, text_poke_addr);
+       if (err)
+               return err;
+
+       err = __patch_instruction(addr, instr, patch_addr);
+
+       unmap_patch_area(text_poke_addr);
+
+       return err;
+}
+
 static int do_patch_instruction(u32 *addr, ppc_inst_t instr)
 {
        int err;
-       u32 *patch_addr = NULL;
        unsigned long flags;
-       unsigned long text_poke_addr;
-       unsigned long kaddr = (unsigned long)addr;
 
        /*
         * During early early boot patch_instruction is called
@@ -146,19 +163,7 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t instr)
                return raw_patch_instruction(addr, instr);
 
        local_irq_save(flags);
-
-       text_poke_addr = (unsigned long)__this_cpu_read(text_poke_area)->addr;
-       err = map_patch_area(addr, text_poke_addr);
-       if (err)
-               goto out;
-
-       patch_addr = (u32 *)(text_poke_addr + (kaddr & ~PAGE_MASK));
-
-       err = __patch_instruction(addr, instr, patch_addr);
-
-       unmap_patch_area(text_poke_addr);
-
-out:
+       err = __do_patch_instruction(addr, instr);
        local_irq_restore(flags);
 
        return err;