[08/23] arm64: ilp32: add documentation on the ILP32 ABI for ARM64

Commit Message

Yury Norov May 24, 2016, 12:04 a.m. UTC

Based on Andrew Pinski's patch-series.

Signed-off-by: Yury Norov <[e-mail]>
---
 Documentation/arm64/ilp32.txt | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 Documentation/arm64/ilp32.txt

Patch

diff --git a/Documentation/arm64/ilp32.txt b/Documentation/arm64/ilp32.txt
new file mode 100644
index 0000000..8e74d67
--- /dev/null
+++ b/Documentation/arm64/ilp32.txt
@@ -0,0 +1,25 @@ 
+ILP32 AARCH64 SYSCALL ABI
+=========================
+
+This document describes the ILP32 syscall ABI and where it differs
+from the generic compat linux syscall interface.
+
+Syscalls which normally would pass 64bit values as two arguments;
+now pass the 64bit value as one argument. Next syscalls are affected:
+fadvise64_64,
+fallocate,
+ftruncate,
+lookup_dcookie,
+pread64,
+pwrite64,
+readahead,
+shmat,
+sync_file_range,
+truncate,
+lseek,
+mmap
+
+struct rt_sigframe is redefined and contains struct compat_siginfo,
+as compat syscalls expects, and struct ilp32_sigframe, to handle
+AARCH64 register set and 32-bit userspace register representation.
+