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/* SPDX-License-Identifier: GPL-2.0 */
#include <asm/asm-offsets.h>
#include <asm/tdx.h>
/*
* TDCALL and SEAMCALL are supported in Binutils >= 2.36.
*/
#define tdcall .byte 0x66,0x0f,0x01,0xcc
#define seamcall .byte 0x66,0x0f,0x01,0xcf
/*
* TDX_MODULE_CALL - common helper macro for both
* TDCALL and SEAMCALL instructions.
*
* TDCALL - used by TDX guests to make requests to the
* TDX module and hypercalls to the VMM.
* SEAMCALL - used by TDX hosts to make requests to the
* TDX module.
*/
.macro TDX_MODULE_CALL host:req
/*
* R12 will be used as temporary storage for struct tdx_module_output
* pointer. Since R12-R15 registers are not used by TDCALL/SEAMCALL
* services supported by this function, it can be reused.
*/
/* Callee saved, so preserve it */
push %r12
/*
* Push output pointer to stack.
* After the operation, it will be fetched into R12 register.
*/
push %r9
/* Mangle function call ABI into TDCALL/SEAMCALL ABI: */
/* Move Leaf ID to RAX */
mov %rdi, %rax
/* Move input 4 to R9 */
mov %r8, %r9
/* Move input 3 to R8 */
mov %rcx, %r8
/* Move input 1 to RCX */
mov %rsi, %rcx
/* Leave input param 2 in RDX */
.if \host
seamcall
/*
* SEAMCALL instruction is essentially a VMExit from VMX root
* mode to SEAM VMX root mode. VMfailInvalid (CF=1) indicates
* that the targeted SEAM firmware is not loaded or disabled,
* or P-SEAMLDR is busy with another SEAMCALL. %rax is not
* changed in this case.
*
* Set %rax to TDX_SEAMCALL_VMFAILINVALID for VMfailInvalid.
* This value will never be used as actual SEAMCALL error code as
* it is from the Reserved status code class.
*/
jnc .Lno_vmfailinvalid
mov $TDX_SEAMCALL_VMFAILINVALID, %rax
.Lno_vmfailinvalid:
.else
tdcall
.endif
/*
* Fetch output pointer from stack to R12 (It is used
* as temporary storage)
*/
pop %r12
/*
* Since this macro can be invoked with NULL as an output pointer,
* check if caller provided an output struct before storing output
* registers.
*
* Update output registers, even if the call failed (RAX != 0).
* Other registers may contain details of the failure.
*/
test %r12, %r12
jz .Lno_output_struct
/* Copy result registers to output struct: */
movq %rcx, TDX_MODULE_rcx(%r12)
movq %rdx, TDX_MODULE_rdx(%r12)
movq %r8, TDX_MODULE_r8(%r12)
movq %r9, TDX_MODULE_r9(%r12)
movq %r10, TDX_MODULE_r10(%r12)
movq %r11, TDX_MODULE_r11(%r12)
.Lno_output_struct:
/* Restore the state of R12 register */
pop %r12
.endm
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