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| author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2013-03-17 16:13:28 +0000 |
|---|---|---|
| committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2013-03-17 16:13:28 +0000 |
| commit | 2b2bbf6433f7271abce9c3e4cbdf2f456fcbeca3 (patch) | |
| tree | df9b3967acb62fff1190b1625cf373b8ed95f48a /nuttx/syscall | |
| parent | db8769c0dbd3a9c33b60863a62f33cc5158bf7bd (diff) | |
| download | nuttx-2b2bbf6433f7271abce9c3e4cbdf2f456fcbeca3.tar.gz nuttx-2b2bbf6433f7271abce9c3e4cbdf2f456fcbeca3.tar.bz2 nuttx-2b2bbf6433f7271abce9c3e4cbdf2f456fcbeca3.zip | |
Add support for nested system calls
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5752 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'nuttx/syscall')
| -rw-r--r-- | nuttx/syscall/Kconfig | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/nuttx/syscall/Kconfig b/nuttx/syscall/Kconfig index 6e047012a..0c5b74ab1 100644 --- a/nuttx/syscall/Kconfig +++ b/nuttx/syscall/Kconfig @@ -5,6 +5,8 @@ if NUTTX_KERNEL +comment "System call configuration" + config SYS_RESERVED int "Number of reserved system calls" default 0 @@ -16,4 +18,20 @@ config SYS_RESERVED architecture; number of the kernel system calls will begin with this number. +config SYS_NNEST + int "Number of nested system calls" + default 2 + ---help--- + This is architecture dependent. Most architectures allocate + resources to manage a fixed, maximum number of nested system calls. + A nested system call occurs in the following scenario: (1) A non- + privileged user thread executes a system call, (2) part of the + system call processing cause a call back into the user space code, + and (3) the user space code performs another system call. + + In the current design, this can happen only under one condition: + When the kernel calls back into user space in order to allocate user + space memory. So it is expected that the maximum nesting level will + be only 2. + endif |