lib: Fix __sbi_hfence_gvma_vmid_gpa() and __sbi_hfence_vvma_asid_va()

The arguments/parameters of __sbi_hfence_gvma_vmid_gpa() and
__sbi_hfence_vvma_asid_va() functions are swapped so we fix it.

Currently, we did not face any issues because QEMU does a full
TLB flush for all HFENCE instructions.

We also improve documentation of HFENCE.GVMA and HFENCE.VVMA
instruction encoding.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

2 files changed, 74 insertions, 14 deletions

diff --git a/lib/sbi/sbi_hfence.S b/lib/sbi/sbi_hfence.S
index 30a6e9f..d05becb 100644
--- a/lib/sbi/sbi_hfence.S
+++ b/lib/sbi/sbi_hfence.S
@@ -9,67 +9,127 @@
  */
 
 	/*
-	 * Instruction encoding of hfence.gvma is:
+	 * HFENCE.GVMA rs1, rs2
+	 * HFENCE.GVMA zero, rs2
+	 * HFENCE.GVMA rs1
+	 * HFENCE.GVMA
+	 *
+	 * rs1!=zero and rs2!=zero ==> HFENCE.GVMA rs1, rs2
+	 * rs1==zero and rs2!=zero ==> HFENCE.GVMA zero, rs2
+	 * rs1!=zero and rs2==zero ==> HFENCE.GVMA rs1
+	 * rs1==zero and rs2==zero ==> HFENCE.GVMA
+	 *
+	 * Instruction encoding of HFENCE.GVMA is:
 	 * 0110001 rs2(5) rs1(5) 000 00000 1110011
 	 */
 
 	.align 3
 	.global __sbi_hfence_gvma_vmid_gpa
 __sbi_hfence_gvma_vmid_gpa:
-	/* hfence.gvma a1, a0 */
-	.word 0x62a60073
+	/*
+	 * rs1 = a0 (GPA)
+	 * rs2 = a1 (VMID)
+	 * HFENCE.GVMA a0, a1
+	 * 0110001 01011 01010 000 00000 1110011
+	 */
+	.word 0x62b50073
 	ret
 
 	.align 3
 	.global __sbi_hfence_gvma_vmid
 __sbi_hfence_gvma_vmid:
-	/* hfence.gvma zero, a0 */
+	/*
+	 * rs1 = zero
+	 * rs2 = a0 (VMID)
+	 * HFENCE.GVMA zero, a0
+	 * 0110001 01010 00000 000 00000 1110011
+	 */
 	.word 0x62a00073
 	ret
 
 	.align 3
 	.global __sbi_hfence_gvma_gpa
 __sbi_hfence_gvma_gpa:
-	/* hfence.gvma a0 */
+	/*
+	 * rs1 = a0 (GPA)
+	 * rs2 = zero
+	 * HFENCE.GVMA a0
+	 * 0110001 00000 01010 000 00000 1110011
+	 */
 	.word 0x62050073
 	ret
 
 	.align 3
 	.global __sbi_hfence_gvma_all
 __sbi_hfence_gvma_all:
-	/* hfence.gvma */
+	/*
+	 * rs1 = zero
+	 * rs2 = zero
+	 * HFENCE.GVMA
+	 * 0110001 00000 00000 000 00000 1110011
+	 */
 	.word 0x62000073
 	ret
 
 	/*
-	 * Instruction encoding of hfence.bvma is:
+	 * HFENCE.VVMA rs1, rs2
+	 * HFENCE.VVMA zero, rs2
+	 * HFENCE.VVMA rs1
+	 * HFENCE.VVMA
+	 *
+	 * rs1!=zero and rs2!=zero ==> HFENCE.VVMA rs1, rs2
+	 * rs1==zero and rs2!=zero ==> HFENCE.VVMA zero, rs2
+	 * rs1!=zero and rs2==zero ==> HFENCE.VVMA rs1
+	 * rs1==zero and rs2==zero ==> HFENCE.vVMA
+	 *
+	 * Instruction encoding of HFENCE.VVMA is:
 	 * 0010001 rs2(5) rs1(5) 000 00000 1110011
 	 */
 
 	.align 3
 	.global __sbi_hfence_vvma_asid_va
 __sbi_hfence_vvma_asid_va:
-	/* hfence.bvma a1, a0 */
-	.word 0x22a60073
+	/*
+	 * rs1 = a0 (VA)
+	 * rs2 = a1 (ASID)
+	 * HFENCE.VVMA a0, a1
+	 * 0010001 01011 01010 000 00000 1110011
+	 */
+	.word 0x22b50073
 	ret
 
 	.align 3
 	.global __sbi_hfence_vvma_asid
 __sbi_hfence_vvma_asid:
-	/* hfence.bvma zero, a0 */
+	/*
+	 * rs1 = zero
+	 * rs2 = a0 (ASID)
+	 * HFENCE.VVMA zero, a0
+	 * 0010001 01010 00000 000 00000 1110011
+	 */
 	.word 0x22a00073
 	ret
 
 	.align 3
 	.global __sbi_hfence_vvma_va
 __sbi_hfence_vvma_va:
-	/* hfence.bvma a0 */
+	/*
+	 * rs1 = a0 (VA)
+	 * rs2 = zero
+	 * HFENCE.VVMA zero, a0
+	 * 0010001 00000 01010 000 00000 1110011
+	 */
 	.word 0x22050073
 	ret
 
 	.align 3
 	.global __sbi_hfence_vvma_all
 __sbi_hfence_vvma_all:
-	/* hfence.bvma */
+	/*
+	 * rs1 = zero
+	 * rs2 = zero
+	 * HFENCE.VVMA
+	 * 0010001 00000 00000 000 00000 1110011
+	 */
 	.word 0x22000073
 	ret
diff --git a/lib/sbi/sbi_tlb.c b/lib/sbi/sbi_tlb.c
index c6ca7b1..c8e62cd 100644
--- a/lib/sbi/sbi_tlb.c
+++ b/lib/sbi/sbi_tlb.c
@@ -112,7 +112,7 @@ static void sbi_tlb_hfence_vvma_asid(struct sbi_tlb_info *tinfo)
 	}
 
 	for (i = 0; i < size; i += PAGE_SIZE) {
-		__sbi_hfence_vvma_asid_va(asid, start + i);
+		__sbi_hfence_vvma_asid_va(start + i, asid);
 	}
 
 done:
@@ -137,7 +137,7 @@ static void sbi_tlb_hfence_gvma_vmid(struct sbi_tlb_info *tinfo)
 	}
 
 	for (i = 0; i < size; i += PAGE_SIZE) {
-		__sbi_hfence_gvma_vmid_gpa(vmid, start+i);
+		__sbi_hfence_gvma_vmid_gpa(start + i, vmid);
 	}
 }