lkml.org 
[lkml]   [2016]   [Jun]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH v13 03/10] arm64: add conditional instruction simulation support
Date
On 06/03/2016 11:53 PM, Masami Hiramatsu wrote:
> On Thu, 2 Jun 2016 23:26:17 -0400
> David Long <dave.long@linaro.org> wrote:
>
>> From: "David A. Long" <dave.long@linaro.org>
>>
>> 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 dervied from code written by Sandeepa Prabhu.
>>
>
> Basically looks good to me. I have some comments;
>
>> Signed-off-by: Sandeepa Prabhu <sandeepa.s.prabhu@gmail.com>
>> Signed-off-by: David A. Long <dave.long@linaro.org>
>> ---
>> arch/arm64/include/asm/insn.h | 3 ++
>> arch/arm64/kernel/Makefile | 3 +-
>> arch/arm64/kernel/armv8_deprecated.c | 19 ++++++-
>> arch/arm64/kernel/insn.c | 98 ++++++++++++++++++++++++++++++++++++
>> 4 files changed, 119 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
>> index 9785d10..98e4edd 100644
>> --- a/arch/arm64/include/asm/insn.h
>> +++ b/arch/arm64/include/asm/insn.h
>> @@ -406,6 +406,9 @@ u32 aarch64_extract_system_register(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 opcode_condition_checks[16];
>
> Are those condition checkers only for aarch32 opcode? or
> general for aarch64 too? If it is only for aarch32, we'd better
> add aarch32 prefix.
>

I have this vague recollection there once was a reason for this but I
can't for the life of me remember why. I altered the symbol name to
something that begins with aarch32.

>> #endif /* __ASSEMBLY__ */
>>
>> #endif /* __ASM_INSN_H */
>> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
>> index 2173149..4653aca 100644
>> --- 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 c37202c..88b9165 100644
>> --- 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 arm32_check_condition(u32 opcode, u32 psr)
>
> Would you be OK for using arm32 instead of aarch32 prefix?

I think you meant the opposite of that? I guess that would make sense,
and would be simple enough since it's an internal function. I will
change arm32 to aarch32.

>
>> +{
>> + u32 cc_bits = opcode >> 28;
>> +
>> + if (cc_bits != ARM_OPCODE_CONDITION_UNCOND) {
>> + if ((*opcode_condition_checks[cc_bits])(psr))
>> + return ARM_OPCODE_CONDTEST_PASS;
>> + else
>> + return ARM_OPCODE_CONDTEST_FAIL;
>> + }
>> + return ARM_OPCODE_CONDTEST_UNCOND;
>> +}
>
> Thank you,
>

Thanks,
-dl

\
 
 \ /
  Last update: 2016-06-13 07:01    [W:0.157 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site