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Diffstat (limited to 'arch/arm64/kernel/alternative.c')
-rw-r--r--arch/arm64/kernel/alternative.c28
1 files changed, 24 insertions, 4 deletions
diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c
index d2ee1b21a10d..06d650f61da7 100644
--- 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) */