132 lines
3.4 KiB
ArmAsm
132 lines
3.4 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* The actual FRED entry points.
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*/
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#include <linux/export.h>
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#include <asm/asm.h>
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#include <asm/fred.h>
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#include <asm/segment.h>
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#include "calling.h"
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.code64
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.section .noinstr.text, "ax"
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.macro FRED_ENTER
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UNWIND_HINT_END_OF_STACK
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ENDBR
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PUSH_AND_CLEAR_REGS
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movq %rsp, %rdi /* %rdi -> pt_regs */
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.endm
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.macro FRED_EXIT
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UNWIND_HINT_REGS
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POP_REGS
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.endm
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/*
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* The new RIP value that FRED event delivery establishes is
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* IA32_FRED_CONFIG & ~FFFH for events that occur in ring 3.
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* Thus the FRED ring 3 entry point must be 4K page aligned.
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*/
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.align 4096
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SYM_CODE_START_NOALIGN(asm_fred_entrypoint_user)
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FRED_ENTER
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call fred_entry_from_user
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SYM_INNER_LABEL(asm_fred_exit_user, SYM_L_GLOBAL)
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FRED_EXIT
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1: ERETU
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_ASM_EXTABLE_TYPE(1b, asm_fred_entrypoint_user, EX_TYPE_ERETU)
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SYM_CODE_END(asm_fred_entrypoint_user)
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/*
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* The new RIP value that FRED event delivery establishes is
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* (IA32_FRED_CONFIG & ~FFFH) + 256 for events that occur in
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* ring 0, i.e., asm_fred_entrypoint_user + 256.
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*/
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.org asm_fred_entrypoint_user + 256, 0xcc
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SYM_CODE_START_NOALIGN(asm_fred_entrypoint_kernel)
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FRED_ENTER
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call fred_entry_from_kernel
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FRED_EXIT
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ERETS
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SYM_CODE_END(asm_fred_entrypoint_kernel)
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#if IS_ENABLED(CONFIG_KVM_INTEL)
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SYM_FUNC_START(asm_fred_entry_from_kvm)
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push %rbp
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mov %rsp, %rbp
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UNWIND_HINT_SAVE
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/*
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* Both IRQ and NMI from VMX can be handled on current task stack
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* because there is no need to protect from reentrancy and the call
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* stack leading to this helper is effectively constant and shallow
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* (relatively speaking). Do the same when FRED is active, i.e., no
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* need to check current stack level for a stack switch.
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*
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* Emulate the FRED-defined redzone and stack alignment.
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*/
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sub $(FRED_CONFIG_REDZONE_AMOUNT << 6), %rsp
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and $FRED_STACK_FRAME_RSP_MASK, %rsp
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/*
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* Start to push a FRED stack frame, which is always 64 bytes:
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*
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* +--------+-----------------+
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* | Bytes | Usage |
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* +--------+-----------------+
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* | 63:56 | Reserved |
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* | 55:48 | Event Data |
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* | 47:40 | SS + Event Info |
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* | 39:32 | RSP |
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* | 31:24 | RFLAGS |
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* | 23:16 | CS + Aux Info |
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* | 15:8 | RIP |
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* | 7:0 | Error Code |
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* +--------+-----------------+
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*/
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push $0 /* Reserved, must be 0 */
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push $0 /* Event data, 0 for IRQ/NMI */
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push %rdi /* fred_ss handed in by the caller */
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push %rbp
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pushf
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mov $__KERNEL_CS, %rax
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push %rax
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/*
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* Unlike the IDT event delivery, FRED _always_ pushes an error code
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* after pushing the return RIP, thus the CALL instruction CANNOT be
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* used here to push the return RIP, otherwise there is no chance to
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* push an error code before invoking the IRQ/NMI handler.
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*
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* Use LEA to get the return RIP and push it, then push an error code.
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*/
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lea 1f(%rip), %rax
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push %rax /* Return RIP */
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push $0 /* Error code, 0 for IRQ/NMI */
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PUSH_AND_CLEAR_REGS clear_bp=0 unwind_hint=0
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movq %rsp, %rdi /* %rdi -> pt_regs */
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call __fred_entry_from_kvm /* Call the C entry point */
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POP_REGS
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ERETS
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1:
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/*
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* Objtool doesn't understand what ERETS does, this hint tells it that
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* yes, we'll reach here and with what stack state. A save/restore pair
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* isn't strictly needed, but it's the simplest form.
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*/
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UNWIND_HINT_RESTORE
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pop %rbp
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RET
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SYM_FUNC_END(asm_fred_entry_from_kvm)
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EXPORT_SYMBOL_GPL(asm_fred_entry_from_kvm);
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#endif
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