diff options
Diffstat (limited to 'Documentation/powerpc')
| -rw-r--r-- | Documentation/powerpc/syscall64-abi.rst | 51 |
1 files changed, 32 insertions, 19 deletions
diff --git a/Documentation/powerpc/syscall64-abi.rst b/Documentation/powerpc/syscall64-abi.rst index cf9b2857c72a..dabee3729e5a 100644 --- a/Documentation/powerpc/syscall64-abi.rst +++ b/Documentation/powerpc/syscall64-abi.rst @@ -46,25 +46,38 @@ stack frame LR and CR save fields are not used. Register preservation rules --------------------------- -Register preservation rules match the ELF ABI calling sequence with the -following differences: - -+------------------------------------------------------------------------+ -| For the sc instruction, differences with the ELF ABI | -+--------------+--------------+------------------------------------------+ -| r0 | Volatile | (System call number.) | -| rr3 | Volatile | (Parameter 1, and return value.) | -| rr4-r8 | Volatile | (Parameters 2-6.) | -| rcr0 | Volatile | (cr0.SO is the return error condition.) | -| rcr1, cr5-7 | Nonvolatile | | -| rlr | Nonvolatile | | -+--------------+--------------+------------------------------------------+ -| For the scv 0 instruction, differences with the ELF ABI | -+--------------+--------------+------------------------------------------+ -| r0 | Volatile | (System call number.) | -| r3 | Volatile | (Parameter 1, and return value.) | -| r4-r8 | Volatile | (Parameters 2-6.) | -+--------------+--------------+------------------------------------------+ +Register preservation rules match the ELF ABI calling sequence with some +differences. + +For the sc instruction, the differences from the ELF ABI are as follows: + ++--------------+--------------------+-----------------------------------------+ +| Register | Preservation Rules | Purpose | ++==============+====================+=========================================+ +| r0 | Volatile | (System call number.) | ++--------------+--------------------+-----------------------------------------+ +| r3 | Volatile | (Parameter 1, and return value.) | ++--------------+--------------------+-----------------------------------------+ +| r4-r8 | Volatile | (Parameters 2-6.) | ++--------------+--------------------+-----------------------------------------+ +| cr0 | Volatile | (cr0.SO is the return error condition.) | ++--------------+--------------------+-----------------------------------------+ +| cr1, cr5-7 | Nonvolatile | | ++--------------+--------------------+-----------------------------------------+ +| lr | Nonvolatile | | ++--------------+--------------------+-----------------------------------------+ + +For the scv 0 instruction, the differences from the ELF ABI are as follows: + ++--------------+--------------------+-----------------------------------------+ +| Register | Preservation Rules | Purpose | ++==============+====================+=========================================+ +| r0 | Volatile | (System call number.) | ++--------------+--------------------+-----------------------------------------+ +| r3 | Volatile | (Parameter 1, and return value.) | ++--------------+--------------------+-----------------------------------------+ +| r4-r8 | Volatile | (Parameters 2-6.) | ++--------------+--------------------+-----------------------------------------+ All floating point and vector data registers as well as control and status registers are nonvolatile. |