arm中的Hypervisor模式是什么？
What is the Hypervisor mode in arm?
arch/arm/kernel/head.S中的宏safe_svcmode_maskall定义在arch/arm/include/assembler.h中，即
.macro safe_svcmode_maskall reg:req
#if __LINUX_ARM_ARCH__ >= 6 && !defined(CONFIG_CPU_V7M)
mrs \reg , cpsr
eor \reg, \reg, #HYP_MODE
tst \reg, #MODE_MASK
bic \reg , \reg , #MODE_MASK
......
我发现有一个HYP_MODE，通过一些简单的介绍得知它是hypervisormode.But我在armv7架构参考中没有得到它的详细介绍manual.Actually
没发现manual.It里面的词cannot equal to svc mode，因为svc mode在代码的上下文中也有提到。
此外，我注意到 'reg' 后面有一个 ':req'，这是一个 parameter.I 我知道 ':req' 意味着 'reg' 不能 empty.But 我在 gnu arm 汇编器手册中找不到 ':req' 的定义。
可能很简单question.But我想学习如何在官方手册中找到这些答案。（我仍然相信答案在这些manual.Maybe我没有选择相应的版本）
最后一题
But I can't find the definition of ':req' in gnu arm assembler manual.
You can qualify the macro argument to indicate whether all invocations must specify a non-blank value (through ‘:req’), or whether it takes all of the remaining arguments (through ‘:vararg’). You can supply a default value for any macro argument by following the name with ‘=deflt’.
以及示例，
.macro m p1:req, p2=0, p3:vararg
Begin the definition of a macro called m, with at least three arguments. The first argument must always have a value specified, but not the second, which instead has a default value. The third formal will get assigned all remaining arguments specified at invocation time.
第一题
I found there is a HYP_MODE and learned through some brief introduction that it is hypervisor mode.But I failed to get its detailed introduction in armv7 architecture reference manual.Actually I did't find the word in the manual.It can't be equal to svc mode,because svc mode is also mentioned in the context of the code.
在某些 CPU 上有 ARMV7A（不是 ARM7M）的管理程序模式，但不是全部。
参见：Hypervisor mode and ARM Virtualization extensions。
如果扩展名不存在，在ARM7A上修改这个位还是可以的。
arch/arm/kernel/head.S中的宏safe_svcmode_maskall定义在arch/arm/include/assembler.h中，即
.macro safe_svcmode_maskall reg:req
#if __LINUX_ARM_ARCH__ >= 6 && !defined(CONFIG_CPU_V7M)
mrs \reg , cpsr
eor \reg, \reg, #HYP_MODE
tst \reg, #MODE_MASK
bic \reg , \reg , #MODE_MASK
......
我发现有一个HYP_MODE，通过一些简单的介绍得知它是hypervisormode.But我在armv7架构参考中没有得到它的详细介绍manual.Actually 没发现manual.It里面的词cannot equal to svc mode，因为svc mode在代码的上下文中也有提到。
此外，我注意到 'reg' 后面有一个 ':req'，这是一个 parameter.I 我知道 ':req' 意味着 'reg' 不能 empty.But 我在 gnu arm 汇编器手册中找不到 ':req' 的定义。
可能很简单question.But我想学习如何在官方手册中找到这些答案。（我仍然相信答案在这些manual.Maybe我没有选择相应的版本）
最后一题
But I can't find the definition of ':req' in gnu arm assembler manual.
You can qualify the macro argument to indicate whether all invocations must specify a non-blank value (through ‘:req’), or whether it takes all of the remaining arguments (through ‘:vararg’). You can supply a default value for any macro argument by following the name with ‘=deflt’.
以及示例，
.macro m p1:req, p2=0, p3:vararg
Begin the definition of a macro called m, with at least three arguments. The first argument must always have a value specified, but not the second, which instead has a default value. The third formal will get assigned all remaining arguments specified at invocation time.
第一题
I found there is a HYP_MODE and learned through some brief introduction that it is hypervisor mode.But I failed to get its detailed introduction in armv7 architecture reference manual.Actually I did't find the word in the manual.It can't be equal to svc mode,because svc mode is also mentioned in the context of the code.
在某些 CPU 上有 ARMV7A（不是 ARM7M）的管理程序模式，但不是全部。
参见：Hypervisor mode and ARM Virtualization extensions。
如果扩展名不存在，在ARM7A上修改这个位还是可以的。