Merge tag 'mmc-v4.9' of git://git.linaro.org/people/ulf.hansson/mmc

[cascardo/linux.git] / arch / arm64 / kernel / alternative.c

diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c
index d2ee1b2..06d650f 100644 (file)
--- a/arch/arm64/kernel/alternative.c
+++ b/arch/arm64/kernel/alternative.c
@@ -25,14 +25,13 @@
 #include <asm/alternative.h>
 #include <asm/cpufeature.h>
 #include <asm/insn.h>
+#include <asm/sections.h>
 #include <linux/stop_machine.h>
 
 #define __ALT_PTR(a,f)         (u32 *)((void *)&(a)->f + (a)->f)
 #define ALT_ORIG_PTR(a)                __ALT_PTR(a, orig_offset)
 #define ALT_REPL_PTR(a)                __ALT_PTR(a, alt_offset)
 
-extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
-
 struct alt_region {
        struct alt_instr *begin;
        struct alt_instr *end;
@@ -59,6 +58,8 @@ static bool branch_insn_requires_update(struct alt_instr *alt, unsigned long pc)
        BUG();
 }
 
+#define align_down(x, a)       ((unsigned long)(x) & ~(((unsigned long)(a)) - 1))
+
 static u32 get_alt_insn(struct alt_instr *alt, u32 *insnptr, u32 *altinsnptr)
 {
        u32 insn;
@@ -80,6 +81,25 @@ static u32 get_alt_insn(struct alt_instr *alt, u32 *insnptr, u32 *altinsnptr)
                        offset = target - (unsigned long)insnptr;
                        insn = aarch64_set_branch_offset(insn, offset);
                }
+       } else if (aarch64_insn_is_adrp(insn)) {
+               s32 orig_offset, new_offset;
+               unsigned long target;
+
+               /*
+                * If we're replacing an adrp instruction, which uses PC-relative
+                * immediate addressing, adjust the offset to reflect the new
+                * PC. adrp operates on 4K aligned addresses.
+                */
+               orig_offset  = aarch64_insn_adrp_get_offset(insn);
+               target = align_down(altinsnptr, SZ_4K) + orig_offset;
+               new_offset = target - align_down(insnptr, SZ_4K);
+               insn = aarch64_insn_adrp_set_offset(insn, new_offset);
+       } else if (aarch64_insn_uses_literal(insn)) {
+               /*
+                * Disallow patching unhandled instructions using PC relative
+                * literal addresses
+                */
+               BUG();
        }
 
        return insn;
@@ -124,8 +144,8 @@ static int __apply_alternatives_multi_stop(void *unused)
 {
        static int patched = 0;
        struct alt_region region = {
-               .begin  = __alt_instructions,
-               .end    = __alt_instructions_end,
+               .begin  = (struct alt_instr *)__alt_instructions,
+               .end    = (struct alt_instr *)__alt_instructions_end,
        };
 
        /* We always have a CPU 0 at this point (__init) */