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-rw-r--r--pkg/sentry/platform/ring0/entry_arm64.s73
-rw-r--r--pkg/sentry/platform/ring0/kernel_arm64.go8
2 files changed, 70 insertions, 11 deletions
diff --git a/pkg/sentry/platform/ring0/entry_arm64.s b/pkg/sentry/platform/ring0/entry_arm64.s
index baa6c4910..d42eda37b 100644
--- a/pkg/sentry/platform/ring0/entry_arm64.s
+++ b/pkg/sentry/platform/ring0/entry_arm64.s
@@ -25,10 +25,14 @@
// not available for calls.
//
+// ERET returns using the ELR and SPSR for the current exception level.
#define ERET() \
WORD $0xd69f03e0
+// RSV_REG is a register that holds el1 information temporarily.
#define RSV_REG R18_PLATFORM
+
+// RSV_REG_APP is a register that holds el0 information temporarily.
#define RSV_REG_APP R9
#define FPEN_NOTRAP 0x3
@@ -36,6 +40,12 @@
#define FPEN_ENABLE (FPEN_NOTRAP << FPEN_SHIFT)
+// Saves a register set.
+//
+// This is a macro because it may need to executed in contents where a stack is
+// not available for calls.
+//
+// The following registers are not saved: R9, R18.
#define REGISTERS_SAVE(reg, offset) \
MOVD R0, offset+PTRACE_R0(reg); \
MOVD R1, offset+PTRACE_R1(reg); \
@@ -67,6 +77,12 @@
MOVD R29, offset+PTRACE_R29(reg); \
MOVD R30, offset+PTRACE_R30(reg);
+// Loads a register set.
+//
+// This is a macro because it may need to executed in contents where a stack is
+// not available for calls.
+//
+// The following registers are not loaded: R9, R18.
#define REGISTERS_LOAD(reg, offset) \
MOVD offset+PTRACE_R0(reg), R0; \
MOVD offset+PTRACE_R1(reg), R1; \
@@ -98,7 +114,7 @@
MOVD offset+PTRACE_R29(reg), R29; \
MOVD offset+PTRACE_R30(reg), R30;
-//NOP
+// NOP-s
#define nop31Instructions() \
WORD $0xd503201f; \
WORD $0xd503201f; \
@@ -254,6 +270,7 @@
#define ESR_ELx_WFx_ISS_WFE (UL(1) << 0)
#define ESR_ELx_xVC_IMM_MASK ((1UL << 16) - 1)
+// LOAD_KERNEL_ADDRESS loads a kernel address.
#define LOAD_KERNEL_ADDRESS(from, to) \
MOVD from, to; \
ORR $0xffff000000000000, to, to;
@@ -263,15 +280,18 @@
LOAD_KERNEL_ADDRESS(CPU_SELF(from), RSV_REG); \
MOVD $CPU_STACK_TOP(RSV_REG), RSV_REG; \
MOVD RSV_REG, RSP; \
+ WORD $0xd538d092; \ //MRS TPIDR_EL1, R18
ISB $15; \
DSB $15;
+// SWITCH_TO_APP_PAGETABLE sets a new pagetable for a container application.
#define SWITCH_TO_APP_PAGETABLE(from) \
MOVD CPU_TTBR0_APP(from), RSV_REG; \
WORD $0xd5182012; \ // MSR R18, TTBR0_EL1
ISB $15; \
DSB $15;
+// SWITCH_TO_KVM_PAGETABLE sets the kvm pagetable.
#define SWITCH_TO_KVM_PAGETABLE(from) \
MOVD CPU_TTBR0_KVM(from), RSV_REG; \
WORD $0xd5182012; \ // MSR R18, TTBR0_EL1
@@ -294,6 +314,7 @@
WORD $0xd5181040; \ //MSR R0, CPACR_EL1
ISB $15;
+// KERNEL_ENTRY_FROM_EL0 is the entry code of the vcpu from el0 to el1.
#define KERNEL_ENTRY_FROM_EL0 \
SUB $16, RSP, RSP; \ // step1, save r18, r9 into kernel temporary stack.
STP (RSV_REG, RSV_REG_APP), 16*0(RSP); \
@@ -315,19 +336,22 @@
WORD $0xd5384103; \ // MRS SP_EL0, R3
MOVD R3, PTRACE_SP(RSV_REG_APP);
+// KERNEL_ENTRY_FROM_EL1 is the entry code of the vcpu from el1 to el1.
#define KERNEL_ENTRY_FROM_EL1 \
WORD $0xd538d092; \ //MRS TPIDR_EL1, R18
- REGISTERS_SAVE(RSV_REG, CPU_REGISTERS); \ // save sentry context
+ REGISTERS_SAVE(RSV_REG, CPU_REGISTERS); \ // Save sentry context.
MOVD RSV_REG_APP, CPU_REGISTERS+PTRACE_R9(RSV_REG); \
WORD $0xd5384004; \ // MRS SPSR_EL1, R4
MOVD R4, CPU_REGISTERS+PTRACE_PSTATE(RSV_REG); \
MRS ELR_EL1, R4; \
MOVD R4, CPU_REGISTERS+PTRACE_PC(RSV_REG); \
MOVD RSP, R4; \
- MOVD R4, CPU_REGISTERS+PTRACE_SP(RSV_REG);
+ MOVD R4, CPU_REGISTERS+PTRACE_SP(RSV_REG); \
+ LOAD_KERNEL_STACK(RSV_REG); // Load the temporary stack.
+// Halt halts execution.
TEXT ·Halt(SB),NOSPLIT,$0
- // clear bluepill.
+ // Clear bluepill.
WORD $0xd538d092 //MRS TPIDR_EL1, R18
CMP RSV_REG, R9
BNE mmio_exit
@@ -341,8 +365,22 @@ mmio_exit:
// MMIO_EXIT.
MOVD $0, R9
MOVD R0, 0xffff000000001000(R9)
- B ·kernelExitToEl1(SB)
+ RET
+
+// HaltAndResume halts execution and point the pointer to the resume function.
+TEXT ·HaltAndResume(SB),NOSPLIT,$0
+ BL ·Halt(SB)
+ B ·kernelExitToEl1(SB) // Resume.
+// HaltEl1SvcAndResume calls Hooks.KernelSyscall and resume.
+TEXT ·HaltEl1SvcAndResume(SB),NOSPLIT,$0
+ WORD $0xd538d092 // MRS TPIDR_EL1, R18
+ MOVD CPU_SELF(RSV_REG), R3 // Load vCPU.
+ MOVD R3, 8(RSP) // First argument (vCPU).
+ CALL ·kernelSyscall(SB) // Call the trampoline.
+ B ·kernelExitToEl1(SB) // Resume.
+
+// Shutdown stops the guest.
TEXT ·Shutdown(SB),NOSPLIT,$0
// PSCI EVENT.
MOVD $0x84000009, R0
@@ -429,6 +467,7 @@ TEXT ·kernelExitToEl0(SB),NOSPLIT,$0
TEXT ·kernelExitToEl1(SB),NOSPLIT,$0
ERET()
+// Start is the CPU entrypoint.
TEXT ·Start(SB),NOSPLIT,$0
IRQ_DISABLE
MOVD R8, RSV_REG
@@ -437,18 +476,23 @@ TEXT ·Start(SB),NOSPLIT,$0
B ·kernelExitToEl1(SB)
+// El1_sync_invalid is the handler for an invalid EL1_sync.
TEXT ·El1_sync_invalid(SB),NOSPLIT,$0
B ·Shutdown(SB)
+// El1_irq_invalid is the handler for an invalid El1_irq.
TEXT ·El1_irq_invalid(SB),NOSPLIT,$0
B ·Shutdown(SB)
+// El1_fiq_invalid is the handler for an invalid El1_fiq.
TEXT ·El1_fiq_invalid(SB),NOSPLIT,$0
B ·Shutdown(SB)
+// El1_error_invalid is the handler for an invalid El1_error.
TEXT ·El1_error_invalid(SB),NOSPLIT,$0
B ·Shutdown(SB)
+// El1_sync is the handler for El1_sync.
TEXT ·El1_sync(SB),NOSPLIT,$0
KERNEL_ENTRY_FROM_EL1
WORD $0xd5385219 // MRS ESR_EL1, R25
@@ -484,10 +528,10 @@ el1_da:
MOVD $PageFault, R3
MOVD R3, CPU_VECTOR_CODE(RSV_REG)
- B ·Halt(SB)
+ B ·HaltAndResume(SB)
el1_ia:
- B ·Halt(SB)
+ B ·HaltAndResume(SB)
el1_sp_pc:
B ·Shutdown(SB)
@@ -496,7 +540,9 @@ el1_undef:
B ·Shutdown(SB)
el1_svc:
- B ·Halt(SB)
+ MOVD $0, CPU_ERROR_CODE(RSV_REG)
+ MOVD $0, CPU_ERROR_TYPE(RSV_REG)
+ B ·HaltEl1SvcAndResume(SB)
el1_dbg:
B ·Shutdown(SB)
@@ -508,15 +554,19 @@ el1_fpsimd_acc:
el1_invalid:
B ·Shutdown(SB)
+// El1_irq is the handler for El1_irq.
TEXT ·El1_irq(SB),NOSPLIT,$0
B ·Shutdown(SB)
+// El1_fiq is the handler for El1_fiq.
TEXT ·El1_fiq(SB),NOSPLIT,$0
B ·Shutdown(SB)
+// El1_error is the handler for El1_error.
TEXT ·El1_error(SB),NOSPLIT,$0
B ·Shutdown(SB)
+// El0_sync is the handler for El0_sync.
TEXT ·El0_sync(SB),NOSPLIT,$0
KERNEL_ENTRY_FROM_EL0
WORD $0xd5385219 // MRS ESR_EL1, R25
@@ -554,7 +604,7 @@ el0_svc:
MOVD $Syscall, R3
MOVD R3, CPU_VECTOR_CODE(RSV_REG)
- B ·Halt(SB)
+ B ·HaltAndResume(SB)
el0_da:
WORD $0xd538d092 //MRS TPIDR_EL1, R18
@@ -568,7 +618,7 @@ el0_da:
MOVD $PageFault, R3
MOVD R3, CPU_VECTOR_CODE(RSV_REG)
- B ·Halt(SB)
+ B ·HaltAndResume(SB)
el0_ia:
B ·Shutdown(SB)
@@ -613,7 +663,7 @@ TEXT ·El0_error(SB),NOSPLIT,$0
MOVD $VirtualizationException, R3
MOVD R3, CPU_VECTOR_CODE(RSV_REG)
- B ·Halt(SB)
+ B ·HaltAndResume(SB)
TEXT ·El0_sync_invalid(SB),NOSPLIT,$0
B ·Shutdown(SB)
@@ -627,6 +677,7 @@ TEXT ·El0_fiq_invalid(SB),NOSPLIT,$0
TEXT ·El0_error_invalid(SB),NOSPLIT,$0
B ·Shutdown(SB)
+// Vectors implements exception vector table.
TEXT ·Vectors(SB),NOSPLIT,$0
B ·El1_sync_invalid(SB)
nop31Instructions()
diff --git a/pkg/sentry/platform/ring0/kernel_arm64.go b/pkg/sentry/platform/ring0/kernel_arm64.go
index c3d341998..ccacaea6b 100644
--- a/pkg/sentry/platform/ring0/kernel_arm64.go
+++ b/pkg/sentry/platform/ring0/kernel_arm64.go
@@ -16,6 +16,14 @@
package ring0
+// HaltAndResume halts execution and point the pointer to the resume function.
+//go:nosplit
+func HaltAndResume()
+
+// HaltEl1SvcAndResume calls Hooks.KernelSyscall and resume.
+//go:nosplit
+func HaltEl1SvcAndResume()
+
// init initializes architecture-specific state.
func (k *Kernel) init(opts KernelOpts) {
// Save the root page tables.