arm64: add conditional instruction simulation support

Cease using the arm32 arm_check_condition() function and replace it with
a local version for use in deprecated instruction support on arm64. Also
make the function table used by this available for future use by kprobes
and/or uprobes.

This function is derived from code written by Sandeepa Prabhu.

Signed-off-by: Sandeepa Prabhu <sandeepa.s.prabhu@gmail.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
index 497f7a2c5f68a8d6956bf2d96eea79959abc1819..a44abbd61382ee365656fb91d8a26b5311d0cbdf 100644 (file)
--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -406,6 +406,9 @@ 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);
+
+typedef bool (pstate_check_t)(unsigned long);
+extern pstate_check_t * const aarch32_opcode_cond_checks[16];
 #endif /* __ASSEMBLY__ */
 
 #endif /* __ASM_INSN_H */

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 2173149d8954c6bfe15e562f3d014fa2a00a5ba4..4653aca9bb611b1fc7a7eb89b81456c42ecb55a2 100644 (file)
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -26,8 +26,7 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE
        $(call if_changed,objcopy)
 
 arm64-obj-$(CONFIG_COMPAT)             += sys32.o kuser32.o signal32.o         \
-                                          sys_compat.o entry32.o               \
-                                          ../../arm/kernel/opcodes.o
+                                          sys_compat.o entry32.o
 arm64-obj-$(CONFIG_FUNCTION_TRACER)    += ftrace.o entry-ftrace.o
 arm64-obj-$(CONFIG_MODULES)            += arm64ksyms.o module.o
 arm64-obj-$(CONFIG_ARM64_MODULE_PLTS)  += module-plts.o

diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c
index c37202c0c838d01a71d56b05d114cd0b419ff480..29348947652985e1556e4c7225cbfd17774a4d87 100644 (file)
--- a/arch/arm64/kernel/armv8_deprecated.c
+++ b/arch/arm64/kernel/armv8_deprecated.c
@@ -366,6 +366,21 @@ static int emulate_swpX(unsigned int address, unsigned int *data,
        return res;
 }
 
+#define        ARM_OPCODE_CONDITION_UNCOND     0xf
+
+static unsigned int __kprobes aarch32_check_condition(u32 opcode, u32 psr)
+{
+       u32 cc_bits  = opcode >> 28;
+
+       if (cc_bits != ARM_OPCODE_CONDITION_UNCOND) {
+               if ((*aarch32_opcode_cond_checks[cc_bits])(psr))
+                       return ARM_OPCODE_CONDTEST_PASS;
+               else
+                       return ARM_OPCODE_CONDTEST_FAIL;
+       }
+       return ARM_OPCODE_CONDTEST_UNCOND;
+}
+
 /*
  * swp_handler logs the id of calling process, dissects the instruction, sanity
  * checks the memory location, calls emulate_swpX for the actual operation and
@@ -380,7 +395,7 @@ static int swp_handler(struct pt_regs *regs, u32 instr)
 
        type = instr & TYPE_SWPB;
 
-       switch (arm_check_condition(instr, regs->pstate)) {
+       switch (aarch32_check_condition(instr, regs->pstate)) {
        case ARM_OPCODE_CONDTEST_PASS:
                break;
        case ARM_OPCODE_CONDTEST_FAIL:
@@ -461,7 +476,7 @@ static int cp15barrier_handler(struct pt_regs *regs, u32 instr)
 {
        perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc);
 
-       switch (arm_check_condition(instr, regs->pstate)) {
+       switch (aarch32_check_condition(instr, regs->pstate)) {
        case ARM_OPCODE_CONDTEST_PASS:
                break;
        case ARM_OPCODE_CONDTEST_FAIL:

diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c
index 28c6110ffcbb2173ac5bfbe967a31e8f304bb514..5cb2f3db3da5106552c56521e34015e23ca18ede 100644 (file)
--- a/arch/arm64/kernel/insn.c
+++ b/arch/arm64/kernel/insn.c
@@ -1234,3 +1234,101 @@ u32 aarch32_insn_mcr_extract_crm(u32 insn)
 {
        return insn & CRM_MASK;
 }
+
+static bool __kprobes __check_eq(unsigned long pstate)
+{
+       return (pstate & PSR_Z_BIT) != 0;
+}
+
+static bool __kprobes __check_ne(unsigned long pstate)
+{
+       return (pstate & PSR_Z_BIT) == 0;
+}
+
+static bool __kprobes __check_cs(unsigned long pstate)
+{
+       return (pstate & PSR_C_BIT) != 0;
+}
+
+static bool __kprobes __check_cc(unsigned long pstate)
+{
+       return (pstate & PSR_C_BIT) == 0;
+}
+
+static bool __kprobes __check_mi(unsigned long pstate)
+{
+       return (pstate & PSR_N_BIT) != 0;
+}
+
+static bool __kprobes __check_pl(unsigned long pstate)
+{
+       return (pstate & PSR_N_BIT) == 0;
+}
+
+static bool __kprobes __check_vs(unsigned long pstate)
+{
+       return (pstate & PSR_V_BIT) != 0;
+}
+
+static bool __kprobes __check_vc(unsigned long pstate)
+{
+       return (pstate & PSR_V_BIT) == 0;
+}
+
+static bool __kprobes __check_hi(unsigned long pstate)
+{
+       pstate &= ~(pstate >> 1);       /* PSR_C_BIT &= ~PSR_Z_BIT */
+       return (pstate & PSR_C_BIT) != 0;
+}
+
+static bool __kprobes __check_ls(unsigned long pstate)
+{
+       pstate &= ~(pstate >> 1);       /* PSR_C_BIT &= ~PSR_Z_BIT */
+       return (pstate & PSR_C_BIT) == 0;
+}
+
+static bool __kprobes __check_ge(unsigned long pstate)
+{
+       pstate ^= (pstate << 3);        /* PSR_N_BIT ^= PSR_V_BIT */
+       return (pstate & PSR_N_BIT) == 0;
+}
+
+static bool __kprobes __check_lt(unsigned long pstate)
+{
+       pstate ^= (pstate << 3);        /* PSR_N_BIT ^= PSR_V_BIT */
+       return (pstate & PSR_N_BIT) != 0;
+}
+
+static bool __kprobes __check_gt(unsigned long pstate)
+{
+       /*PSR_N_BIT ^= PSR_V_BIT */
+       unsigned long temp = pstate ^ (pstate << 3);
+
+       temp |= (pstate << 1);  /*PSR_N_BIT |= PSR_Z_BIT */
+       return (temp & PSR_N_BIT) == 0;
+}
+
+static bool __kprobes __check_le(unsigned long pstate)
+{
+       /*PSR_N_BIT ^= PSR_V_BIT */
+       unsigned long temp = pstate ^ (pstate << 3);
+
+       temp |= (pstate << 1);  /*PSR_N_BIT |= PSR_Z_BIT */
+       return (temp & PSR_N_BIT) != 0;
+}
+
+static bool __kprobes __check_al(unsigned long pstate)
+{
+       return true;
+}
+
+/*
+ * Note that the ARMv8 ARM calls condition code 0b1111 "nv", but states that
+ * it behaves identically to 0b1110 ("al").
+ */
+pstate_check_t * const aarch32_opcode_cond_checks[16] = {
+       __check_eq, __check_ne, __check_cs, __check_cc,
+       __check_mi, __check_pl, __check_vs, __check_vc,
+       __check_hi, __check_ls, __check_ge, __check_lt,
+       __check_gt, __check_le, __check_al, __check_al
+};