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-rw-r--r--arch/arm64/include/asm/insn.h1
-rw-r--r--arch/arm64/kernel/insn.c81
2 files changed, 66 insertions, 16 deletions
diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
index d2f49423c5dc..f81b328d9cf4 100644
--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -285,6 +285,7 @@ bool aarch64_insn_is_nop(u32 insn);
int aarch64_insn_read(void *addr, u32 *insnp);
int aarch64_insn_write(void *addr, u32 insn);
enum aarch64_insn_encoding_class aarch64_get_insn_class(u32 insn);
+u64 aarch64_insn_decode_immediate(enum aarch64_insn_imm_type type, u32 insn);
u32 aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
u32 insn, u64 imm);
u32 aarch64_insn_gen_branch_imm(unsigned long pc, unsigned long addr,
diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c
index c8eca88f12e6..924902083e47 100644
--- a/arch/arm64/kernel/insn.c
+++ b/arch/arm64/kernel/insn.c
@@ -265,23 +265,13 @@ int __kprobes aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt)
return aarch64_insn_patch_text_sync(addrs, insns, cnt);
}
-u32 __kprobes aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
- u32 insn, u64 imm)
+static int __kprobes aarch64_get_imm_shift_mask(enum aarch64_insn_imm_type type,
+ u32 *maskp, int *shiftp)
{
- u32 immlo, immhi, lomask, himask, mask;
+ u32 mask;
int shift;
switch (type) {
- case AARCH64_INSN_IMM_ADR:
- lomask = 0x3;
- himask = 0x7ffff;
- immlo = imm & lomask;
- imm >>= 2;
- immhi = imm & himask;
- imm = (immlo << 24) | (immhi);
- mask = (lomask << 24) | (himask);
- shift = 5;
- break;
case AARCH64_INSN_IMM_26:
mask = BIT(26) - 1;
shift = 0;
@@ -320,9 +310,68 @@ u32 __kprobes aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
shift = 16;
break;
default:
- pr_err("aarch64_insn_encode_immediate: unknown immediate encoding %d\n",
- type);
- return 0;
+ return -EINVAL;
+ }
+
+ *maskp = mask;
+ *shiftp = shift;
+
+ return 0;
+}
+
+#define ADR_IMM_HILOSPLIT 2
+#define ADR_IMM_SIZE SZ_2M
+#define ADR_IMM_LOMASK ((1 << ADR_IMM_HILOSPLIT) - 1)
+#define ADR_IMM_HIMASK ((ADR_IMM_SIZE >> ADR_IMM_HILOSPLIT) - 1)
+#define ADR_IMM_LOSHIFT 29
+#define ADR_IMM_HISHIFT 5
+
+u64 aarch64_insn_decode_immediate(enum aarch64_insn_imm_type type, u32 insn)
+{
+ u32 immlo, immhi, mask;
+ int shift;
+
+ switch (type) {
+ case AARCH64_INSN_IMM_ADR:
+ shift = 0;
+ immlo = (insn >> ADR_IMM_LOSHIFT) & ADR_IMM_LOMASK;
+ immhi = (insn >> ADR_IMM_HISHIFT) & ADR_IMM_HIMASK;
+ insn = (immhi << ADR_IMM_HILOSPLIT) | immlo;
+ mask = ADR_IMM_SIZE - 1;
+ break;
+ default:
+ if (aarch64_get_imm_shift_mask(type, &mask, &shift) < 0) {
+ pr_err("aarch64_insn_decode_immediate: unknown immediate encoding %d\n",
+ type);
+ return 0;
+ }
+ }
+
+ return (insn >> shift) & mask;
+}
+
+u32 __kprobes aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
+ u32 insn, u64 imm)
+{
+ u32 immlo, immhi, mask;
+ int shift;
+
+ switch (type) {
+ case AARCH64_INSN_IMM_ADR:
+ shift = 0;
+ immlo = (imm & ADR_IMM_LOMASK) << ADR_IMM_LOSHIFT;
+ imm >>= ADR_IMM_HILOSPLIT;
+ immhi = (imm & ADR_IMM_HIMASK) << ADR_IMM_HISHIFT;
+ imm = immlo | immhi;
+ mask = ((ADR_IMM_LOMASK << ADR_IMM_LOSHIFT) |
+ (ADR_IMM_HIMASK << ADR_IMM_HISHIFT));
+ break;
+ default:
+ if (aarch64_get_imm_shift_mask(type, &mask, &shift) < 0) {
+ pr_err("aarch64_insn_encode_immediate: unknown immediate encoding %d\n",
+ type);
+ return 0;
+ }
}
/* Update the immediate field. */