diff options
| author | Vaibhav Jain <vaibhav@linux.ibm.com> | 2019-08-28 13:57:29 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-01-29 21:30:50 +1100 |
| commit | 58b278f568f0509497e2df7310bfd719156a60d1 (patch) | |
| tree | c8750848d83a468fc0c81441991245412a25fc02 /arch/powerpc/kernel | |
| parent | 9933819099c4600b41a042f27a074470a43cf6b9 (diff) | |
powerpc: Provide initial documentation for PAPR hcalls
This doc patch provides an initial description of the hcall op-codes
that are used by Linux kernel running as a guest (LPAR) on top of
PowerVM or any other sPAPR compliant hyper-visor (e.g qemu).
Apart from documenting the hcalls the doc-patch also provides a
rudimentary overview of how hcall ABI, how they are issued with the
Linux kernel and how information/control flows between the guest and
hypervisor.
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add SPDX tag, add it to index.rst]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190828082729.16695-1-vaibhav@linux.ibm.com
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 19 |
1 files changed, 3 insertions, 16 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index b049c0bfa883..ffc15f4f079d 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -1408,22 +1408,9 @@ EXC_VIRT_NONE(0x4b00, 0x100) * * Call convention: * - * syscall register convention is in Documentation/powerpc/syscall64-abi.rst - * - * For hypercalls, the register convention is as follows: - * r0 volatile - * r1-2 nonvolatile - * r3 volatile parameter and return value for status - * r4-r10 volatile input and output value - * r11 volatile hypercall number and output value - * r12 volatile input and output value - * r13-r31 nonvolatile - * LR nonvolatile - * CTR volatile - * XER volatile - * CR0-1 CR5-7 volatile - * CR2-4 nonvolatile - * Other registers nonvolatile + * syscall and hypercalls register conventions are documented in + * Documentation/powerpc/syscall64-abi.rst and + * Documentation/powerpc/papr_hcalls.rst respectively. * * The intersection of volatile registers that don't contain possible * inputs is: cr0, xer, ctr. We may use these as scratch regs upon entry |