Merge pull request #4840 from lubinszARM:pr_fpsimd_1

PiperOrigin-RevId: 343000335

4 files changed, 60 insertions, 70 deletions

diff --git a/pkg/sentry/platform/ring0/entry_arm64.s b/pkg/sentry/platform/ring0/entry_arm64.s
index 3e94e37a6..5f4b2105a 100644
--- a/pkg/sentry/platform/ring0/entry_arm64.s
+++ b/pkg/sentry/platform/ring0/entry_arm64.s
@@ -324,6 +324,18 @@
 	MOVD CPU_TTBR0_KVM(from), RSV_REG; \
 	MSR RSV_REG, TTBR0_EL1;
 
+TEXT ·EnableVFP(SB),NOSPLIT,$0
+	MOVD $FPEN_ENABLE, R0
+	WORD $0xd5181040 //MSR R0, CPACR_EL1
+	ISB $15
+	RET
+
+TEXT ·DisableVFP(SB),NOSPLIT,$0
+	MOVD $0, R0
+	WORD $0xd5181040 //MSR R0, CPACR_EL1
+	ISB $15
+	RET
+
 #define VFP_ENABLE \
 	MOVD $FPEN_ENABLE, R0; \
 	WORD $0xd5181040; \ //MSR R0, CPACR_EL1
diff --git a/pkg/sentry/platform/ring0/kernel_arm64.go b/pkg/sentry/platform/ring0/kernel_arm64.go
index 20cc65312..90a7b8392 100644
--- a/pkg/sentry/platform/ring0/kernel_arm64.go
+++ b/pkg/sentry/platform/ring0/kernel_arm64.go
@@ -65,11 +65,13 @@ func (c *CPU) SwitchToUser(switchOpts SwitchOpts) (vector Vector) {
 	regs.Pstate &= ^uint64(PsrFlagsClear)
 	regs.Pstate |= UserFlagsSet
 
+	EnableVFP()
 	LoadFloatingPoint(switchOpts.FloatingPointState)
 
 	kernelExitToEl0()
 
 	SaveFloatingPoint(switchOpts.FloatingPointState)
+	DisableVFP()
 
 	vector = c.vecCode
 
diff --git a/pkg/sentry/platform/ring0/lib_arm64.go b/pkg/sentry/platform/ring0/lib_arm64.go
index d91a09de1..0dffd33a3 100644
--- a/pkg/sentry/platform/ring0/lib_arm64.go
+++ b/pkg/sentry/platform/ring0/lib_arm64.go
@@ -53,6 +53,12 @@ func LoadFloatingPoint(*byte)
 // SaveFloatingPoint saves floating point state.
 func SaveFloatingPoint(*byte)
 
+// EnableVFP enables fpsimd.
+func EnableVFP()
+
+// DisableVFP disables fpsimd.
+func DisableVFP()
+
 // Init sets function pointers based on architectural features.
 //
 // This must be called prior to using ring0.
diff --git a/pkg/sentry/platform/ring0/lib_arm64.s b/pkg/sentry/platform/ring0/lib_arm64.s
index 19c1fca8b..6f4923539 100644
--- a/pkg/sentry/platform/ring0/lib_arm64.s
+++ b/pkg/sentry/platform/ring0/lib_arm64.s
@@ -35,62 +35,47 @@ TEXT ·CPACREL1(SB),NOSPLIT,$0-8
 	RET
 
 TEXT ·GetFPCR(SB),NOSPLIT,$0-8
-	WORD $0xd53b4201    	// MRS NZCV, R1
+	MOVD FPCR, R1
 	MOVD R1, ret+0(FP)
 	RET
 
 TEXT ·GetFPSR(SB),NOSPLIT,$0-8
-	WORD $0xd53b4421   	// MRS FPSR, R1
+	MOVD FPSR, R1
 	MOVD R1, ret+0(FP)
 	RET
 
 TEXT ·SetFPCR(SB),NOSPLIT,$0-8
 	MOVD addr+0(FP), R1
-	WORD $0xd51b4201  	// MSR R1, NZCV
+	MOVD R1, FPCR
 	RET
 
 TEXT ·SetFPSR(SB),NOSPLIT,$0-8
 	MOVD addr+0(FP), R1
-	WORD $0xd51b4421   	// MSR R1, FPSR
+	MOVD R1, FPSR
 	RET
 
 TEXT ·SaveVRegs(SB),NOSPLIT,$0-8
 	MOVD addr+0(FP), R0
 
 	// Skip aarch64_ctx, fpsr, fpcr.
-	FMOVD F0, 16*1(R0)
-	FMOVD F1, 16*2(R0)
-	FMOVD F2, 16*3(R0)
-	FMOVD F3, 16*4(R0)
-	FMOVD F4, 16*5(R0)
-	FMOVD F5, 16*6(R0)
-	FMOVD F6, 16*7(R0)
-	FMOVD F7, 16*8(R0)
-	FMOVD F8, 16*9(R0)
-	FMOVD F9, 16*10(R0)
-	FMOVD F10, 16*11(R0)
-	FMOVD F11, 16*12(R0)
-	FMOVD F12, 16*13(R0)
-	FMOVD F13, 16*14(R0)
-	FMOVD F14, 16*15(R0)
-	FMOVD F15, 16*16(R0)
-	FMOVD F16, 16*17(R0)
-	FMOVD F17, 16*18(R0)
-	FMOVD F18, 16*19(R0)
-	FMOVD F19, 16*20(R0)
-	FMOVD F20, 16*21(R0)
-	FMOVD F21, 16*22(R0)
-	FMOVD F22, 16*23(R0)
-	FMOVD F23, 16*24(R0)
-	FMOVD F24, 16*25(R0)
-	FMOVD F25, 16*26(R0)
-	FMOVD F26, 16*27(R0)
-	FMOVD F27, 16*28(R0)
-	FMOVD F28, 16*29(R0)
-	FMOVD F29, 16*30(R0)
-	FMOVD F30, 16*31(R0)
-	FMOVD F31, 16*32(R0)
-	ISB $15
+	ADD $16, R0, R0
+
+	WORD $0xad000400       //  stp  q0, q1, [x0]
+	WORD $0xad010c02       //  stp  q2, q3, [x0, #32]
+	WORD $0xad021404       //  stp  q4, q5, [x0, #64]
+	WORD $0xad031c06       //  stp  q6, q7, [x0, #96]
+	WORD $0xad042408       //  stp  q8, q9, [x0, #128]
+	WORD $0xad052c0a       //  stp  q10, q11, [x0, #160]
+	WORD $0xad06340c       //  stp  q12, q13, [x0, #192]
+	WORD $0xad073c0e       //  stp  q14, q15, [x0, #224]
+	WORD $0xad084410       //  stp  q16, q17, [x0, #256]
+	WORD $0xad094c12       //  stp  q18, q19, [x0, #288]
+	WORD $0xad0a5414       //  stp  q20, q21, [x0, #320]
+	WORD $0xad0b5c16       //  stp  q22, q23, [x0, #352]
+	WORD $0xad0c6418       //  stp  q24, q25, [x0, #384]
+	WORD $0xad0d6c1a       //  stp  q26, q27, [x0, #416]
+	WORD $0xad0e741c       //  stp  q28, q29, [x0, #448]
+	WORD $0xad0f7c1e       //  stp  q30, q31, [x0, #480]
 
 	RET
 
@@ -98,39 +83,24 @@ TEXT ·LoadVRegs(SB),NOSPLIT,$0-8
 	MOVD addr+0(FP), R0
 
 	// Skip aarch64_ctx, fpsr, fpcr.
-	FMOVD 16*1(R0), F0
-	FMOVD 16*2(R0), F1
-	FMOVD 16*3(R0), F2
-	FMOVD 16*4(R0), F3
-	FMOVD 16*5(R0), F4
-	FMOVD 16*6(R0), F5
-	FMOVD 16*7(R0), F6
-	FMOVD 16*8(R0), F7
-	FMOVD 16*9(R0), F8
-	FMOVD 16*10(R0), F9
-	FMOVD 16*11(R0), F10
-	FMOVD 16*12(R0), F11
-	FMOVD 16*13(R0), F12
-	FMOVD 16*14(R0), F13
-	FMOVD 16*15(R0), F14
-	FMOVD 16*16(R0), F15
-	FMOVD 16*17(R0), F16
-	FMOVD 16*18(R0), F17
-	FMOVD 16*19(R0), F18
-	FMOVD 16*20(R0), F19
-	FMOVD 16*21(R0), F20
-	FMOVD 16*22(R0), F21
-	FMOVD 16*23(R0), F22
-	FMOVD 16*24(R0), F23
-	FMOVD 16*25(R0), F24
-	FMOVD 16*26(R0), F25
-	FMOVD 16*27(R0), F26
-	FMOVD 16*28(R0), F27
-	FMOVD 16*29(R0), F28
-	FMOVD 16*30(R0), F29
-	FMOVD 16*31(R0), F30
-	FMOVD 16*32(R0), F31
-	ISB $15
+	ADD $16, R0, R0
+
+	WORD $0xad400400    // ldp  q0, q1, [x0]
+	WORD $0xad410c02    // ldp  q2, q3, [x0, #32]
+	WORD $0xad421404    // ldp  q4, q5, [x0, #64]
+	WORD $0xad431c06    // ldp  q6, q7, [x0, #96]
+	WORD $0xad442408    // ldp  q8, q9, [x0, #128]
+	WORD $0xad452c0a    // ldp  q10, q11, [x0, #160]
+	WORD $0xad46340c    // ldp  q12, q13, [x0, #192]
+	WORD $0xad473c0e    // ldp  q14, q15, [x0, #224]
+	WORD $0xad484410    // ldp  q16, q17, [x0, #256]
+	WORD $0xad494c12    // ldp  q18, q19, [x0, #288]
+	WORD $0xad4a5414    // ldp  q20, q21, [x0, #320]
+	WORD $0xad4b5c16    // ldp  q22, q23, [x0, #352]
+	WORD $0xad4c6418    // ldp  q24, q25, [x0, #384]
+	WORD $0xad4d6c1a    // ldp  q26, q27, [x0, #416]
+	WORD $0xad4e741c    // ldp  q28, q29, [x0, #448]
+	WORD $0xad4f7c1e    // ldp  q30, q31, [x0, #480]
 
 	RET