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Subject[PATCH v15 02/10] arm64: Add more test functions to insn.c
Date
From: "David A. Long" <dave.long@linaro.org>

Certain instructions are hard to execute correctly out-of-line (as in
kprobes). Test functions are added to insn.[hc] to identify these. The
instructions include any that use PC-relative addressing, change the PC,
or change interrupt masking. For efficiency and simplicity test
functions are also added for small collections of related instructions.

Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
---
arch/arm64/include/asm/insn.h | 36 ++++++++++++++++++++++++++++++++++++
arch/arm64/kernel/insn.c | 34 ++++++++++++++++++++++++++++++++++
2 files changed, 70 insertions(+)

diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
index 30e50eb..497f7a2 100644
--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -120,6 +120,29 @@ enum aarch64_insn_register {
AARCH64_INSN_REG_SP = 31 /* Stack pointer: as load/store base reg */
};

+enum aarch64_insn_special_register {
+ AARCH64_INSN_SPCLREG_SPSR_EL1 = 0xC200,
+ AARCH64_INSN_SPCLREG_ELR_EL1 = 0xC201,
+ AARCH64_INSN_SPCLREG_SP_EL0 = 0xC208,
+ AARCH64_INSN_SPCLREG_SPSEL = 0xC210,
+ AARCH64_INSN_SPCLREG_CURRENTEL = 0xC212,
+ AARCH64_INSN_SPCLREG_DAIF = 0xDA11,
+ AARCH64_INSN_SPCLREG_NZCV = 0xDA10,
+ AARCH64_INSN_SPCLREG_FPCR = 0xDA20,
+ AARCH64_INSN_SPCLREG_DSPSR_EL0 = 0xDA28,
+ AARCH64_INSN_SPCLREG_DLR_EL0 = 0xDA29,
+ AARCH64_INSN_SPCLREG_SPSR_EL2 = 0xE200,
+ AARCH64_INSN_SPCLREG_ELR_EL2 = 0xE201,
+ AARCH64_INSN_SPCLREG_SP_EL1 = 0xE208,
+ AARCH64_INSN_SPCLREG_SPSR_INQ = 0xE218,
+ AARCH64_INSN_SPCLREG_SPSR_ABT = 0xE219,
+ AARCH64_INSN_SPCLREG_SPSR_UND = 0xE21A,
+ AARCH64_INSN_SPCLREG_SPSR_FIQ = 0xE21B,
+ AARCH64_INSN_SPCLREG_SPSR_EL3 = 0xF200,
+ AARCH64_INSN_SPCLREG_ELR_EL3 = 0xF201,
+ AARCH64_INSN_SPCLREG_SP_EL2 = 0xF210
+};
+
enum aarch64_insn_variant {
AARCH64_INSN_VARIANT_32BIT,
AARCH64_INSN_VARIANT_64BIT
@@ -223,8 +246,13 @@ static __always_inline bool aarch64_insn_is_##abbr(u32 code) \
static __always_inline u32 aarch64_insn_get_##abbr##_value(void) \
{ return (val); }

+__AARCH64_INSN_FUNCS(adr_adrp, 0x1F000000, 0x10000000)
+__AARCH64_INSN_FUNCS(prfm_lit, 0xFF000000, 0xD8000000)
__AARCH64_INSN_FUNCS(str_reg, 0x3FE0EC00, 0x38206800)
__AARCH64_INSN_FUNCS(ldr_reg, 0x3FE0EC00, 0x38606800)
+__AARCH64_INSN_FUNCS(ldr_lit, 0xBF000000, 0x18000000)
+__AARCH64_INSN_FUNCS(ldrsw_lit, 0xFF000000, 0x98000000)
+__AARCH64_INSN_FUNCS(exclusive, 0x3F800000, 0x08000000)
__AARCH64_INSN_FUNCS(stp_post, 0x7FC00000, 0x28800000)
__AARCH64_INSN_FUNCS(ldp_post, 0x7FC00000, 0x28C00000)
__AARCH64_INSN_FUNCS(stp_pre, 0x7FC00000, 0x29800000)
@@ -273,10 +301,15 @@ __AARCH64_INSN_FUNCS(svc, 0xFFE0001F, 0xD4000001)
__AARCH64_INSN_FUNCS(hvc, 0xFFE0001F, 0xD4000002)
__AARCH64_INSN_FUNCS(smc, 0xFFE0001F, 0xD4000003)
__AARCH64_INSN_FUNCS(brk, 0xFFE0001F, 0xD4200000)
+__AARCH64_INSN_FUNCS(exception, 0xFF000000, 0xD4000000)
__AARCH64_INSN_FUNCS(hint, 0xFFFFF01F, 0xD503201F)
__AARCH64_INSN_FUNCS(br, 0xFFFFFC1F, 0xD61F0000)
__AARCH64_INSN_FUNCS(blr, 0xFFFFFC1F, 0xD63F0000)
__AARCH64_INSN_FUNCS(ret, 0xFFFFFC1F, 0xD65F0000)
+__AARCH64_INSN_FUNCS(eret, 0xFFFFFFFF, 0xD69F03E0)
+__AARCH64_INSN_FUNCS(mrs, 0xFFF00000, 0xD5300000)
+__AARCH64_INSN_FUNCS(msr_imm, 0xFFF8F01F, 0xD500401F)
+__AARCH64_INSN_FUNCS(msr_reg, 0xFFF00000, 0xD5100000)

#undef __AARCH64_INSN_FUNCS

@@ -286,6 +319,8 @@ bool aarch64_insn_is_branch_imm(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);
+bool aarch64_insn_uses_literal(u32 insn);
+bool aarch64_insn_is_branch(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);
@@ -367,6 +402,7 @@ bool aarch32_insn_is_wide(u32 insn);
#define A32_RT_OFFSET 12
#define A32_RT2_OFFSET 0

+u32 aarch64_insn_extract_system_reg(u32 insn);
u32 aarch32_insn_extract_reg_num(u32 insn, int offset);
u32 aarch32_insn_mcr_extract_opc2(u32 insn);
u32 aarch32_insn_mcr_extract_crm(u32 insn);
diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c
index 368c082..28c6110f 100644
--- a/arch/arm64/kernel/insn.c
+++ b/arch/arm64/kernel/insn.c
@@ -162,6 +162,32 @@ static bool __kprobes __aarch64_insn_hotpatch_safe(u32 insn)
aarch64_insn_is_nop(insn);
}

+bool __kprobes aarch64_insn_uses_literal(u32 insn)
+{
+ /* ldr/ldrsw (literal), prfm */
+
+ return aarch64_insn_is_ldr_lit(insn) ||
+ aarch64_insn_is_ldrsw_lit(insn) ||
+ aarch64_insn_is_adr_adrp(insn) ||
+ aarch64_insn_is_prfm_lit(insn);
+}
+
+bool __kprobes aarch64_insn_is_branch(u32 insn)
+{
+ /* b, bl, cb*, tb*, b.cond, br, blr */
+
+ return aarch64_insn_is_b(insn) ||
+ aarch64_insn_is_bl(insn) ||
+ aarch64_insn_is_cbz(insn) ||
+ aarch64_insn_is_cbnz(insn) ||
+ aarch64_insn_is_tbz(insn) ||
+ aarch64_insn_is_tbnz(insn) ||
+ aarch64_insn_is_ret(insn) ||
+ aarch64_insn_is_br(insn) ||
+ aarch64_insn_is_blr(insn) ||
+ aarch64_insn_is_bcond(insn);
+}
+
/*
* ARM Architecture Reference Manual for ARMv8 Profile-A, Issue A.a
* Section B2.6.5 "Concurrent modification and execution of instructions":
@@ -1175,6 +1201,14 @@ u32 aarch64_set_branch_offset(u32 insn, s32 offset)
BUG();
}

+/*
+ * Extract the Op/CR data from a msr/mrs instruction.
+ */
+u32 aarch64_insn_extract_system_reg(u32 insn)
+{
+ return (insn & 0x1FFFE0) >> 5;
+}
+
bool aarch32_insn_is_wide(u32 insn)
{
return insn >= 0xe800;
--
2.5.0
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