lib: sbi: Replace args with trap registers in ecall handler

We had added args pointer in ecall handler to ensure that ecall
handler only implements functionality and does not deal with
SBI calling convention. This also helped us to keep SBI calling
convention related code in one place at sbi_ecall_handler().

The Keystone Enclavce project needs access to the trap regsiters
in their ecall handler so that they can context switch enclaves
in custom SBI calls. To help the Keystone Enclave project, we
replace the args pointer in ecall handler parameter with a const
pointer to trap registers.

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

1 files changed, 32 insertions, 27 deletions

diff --git a/lib/sbi/sbi_ecall_replace.c b/lib/sbi/sbi_ecall_replace.c
index d06dfa2..a95821b 100644
--- a/lib/sbi/sbi_ecall_replace.c
+++ b/lib/sbi/sbi_ecall_replace.c
@@ -17,18 +17,20 @@
 #include <sbi/sbi_system.h>
 #include <sbi/sbi_timer.h>
 #include <sbi/sbi_tlb.h>
+#include <sbi/sbi_trap.h>
 
 static int sbi_ecall_time_handler(unsigned long extid, unsigned long funcid,
-				  unsigned long *args, unsigned long *out_val,
+				  const struct sbi_trap_regs *regs,
+				  unsigned long *out_val,
 				  struct sbi_trap_info *out_trap)
 {
 	int ret = 0;
 
 	if (funcid == SBI_EXT_TIME_SET_TIMER) {
 #if __riscv_xlen == 32
-		sbi_timer_event_start((((u64)args[1] << 32) | (u64)args[0]));
+		sbi_timer_event_start((((u64)regs->a1 << 32) | (u64)regs->a0));
 #else
-		sbi_timer_event_start((u64)args[0]);
+		sbi_timer_event_start((u64)regs->a0);
 #endif
 	} else
 		ret = SBI_ENOTSUPP;
@@ -43,7 +45,8 @@ struct sbi_ecall_extension ecall_time = {
 };
 
 static int sbi_ecall_rfence_handler(unsigned long extid, unsigned long funcid,
-				    unsigned long *args, unsigned long *out_val,
+				    const struct sbi_trap_regs *regs,
+				    unsigned long *out_val,
 				    struct sbi_trap_info *out_trap)
 {
 	int ret = 0;
@@ -60,41 +63,41 @@ static int sbi_ecall_rfence_handler(unsigned long extid, unsigned long funcid,
 	case SBI_EXT_RFENCE_REMOTE_FENCE_I:
 		SBI_TLB_INFO_INIT(&tlb_info, 0, 0, 0, 0,
 				  SBI_ITLB_FLUSH, source_hart);
-		ret = sbi_tlb_request(args[0], args[1], &tlb_info);
+		ret = sbi_tlb_request(regs->a0, regs->a1, &tlb_info);
 		break;
 	case SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA:
-		SBI_TLB_INFO_INIT(&tlb_info, args[2], args[3], 0, 0,
+		SBI_TLB_INFO_INIT(&tlb_info, regs->a2, regs->a3, 0, 0,
 				  SBI_TLB_FLUSH_GVMA, source_hart);
-		ret = sbi_tlb_request(args[0], args[1], &tlb_info);
+		ret = sbi_tlb_request(regs->a0, regs->a1, &tlb_info);
 		break;
 	case SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA_VMID:
-		SBI_TLB_INFO_INIT(&tlb_info, args[2], args[3], 0, args[4],
+		SBI_TLB_INFO_INIT(&tlb_info, regs->a2, regs->a3, 0, regs->a4,
 				  SBI_TLB_FLUSH_GVMA_VMID, source_hart);
-		ret = sbi_tlb_request(args[0], args[1], &tlb_info);
+		ret = sbi_tlb_request(regs->a0, regs->a1, &tlb_info);
 		break;
 	case SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA:
 		vmid = (csr_read(CSR_HGATP) & HGATP_VMID_MASK);
 		vmid = vmid >> HGATP_VMID_SHIFT;
-		SBI_TLB_INFO_INIT(&tlb_info, args[2], args[3], 0, vmid,
+		SBI_TLB_INFO_INIT(&tlb_info, regs->a2, regs->a3, 0, vmid,
 				  SBI_TLB_FLUSH_VVMA, source_hart);
-		ret = sbi_tlb_request(args[0], args[1], &tlb_info);
+		ret = sbi_tlb_request(regs->a0, regs->a1, &tlb_info);
 		break;
 	case SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID:
 		vmid = (csr_read(CSR_HGATP) & HGATP_VMID_MASK);
 		vmid = vmid >> HGATP_VMID_SHIFT;
-		SBI_TLB_INFO_INIT(&tlb_info, args[2], args[3], args[4], vmid,
-				  SBI_TLB_FLUSH_VVMA_ASID, source_hart);
-		ret = sbi_tlb_request(args[0], args[1], &tlb_info);
+		SBI_TLB_INFO_INIT(&tlb_info, regs->a2, regs->a3, regs->a4,
+				  vmid, SBI_TLB_FLUSH_VVMA_ASID, source_hart);
+		ret = sbi_tlb_request(regs->a0, regs->a1, &tlb_info);
 		break;
 	case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA:
-		SBI_TLB_INFO_INIT(&tlb_info, args[2], args[3], 0, 0,
+		SBI_TLB_INFO_INIT(&tlb_info, regs->a2, regs->a3, 0, 0,
 				  SBI_TLB_FLUSH_VMA, source_hart);
-		ret = sbi_tlb_request(args[0], args[1], &tlb_info);
+		ret = sbi_tlb_request(regs->a0, regs->a1, &tlb_info);
 		break;
 	case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID:
-		SBI_TLB_INFO_INIT(&tlb_info, args[2], args[3], args[4], 0,
+		SBI_TLB_INFO_INIT(&tlb_info, regs->a2, regs->a3, regs->a4, 0,
 				  SBI_TLB_FLUSH_VMA_ASID, source_hart);
-		ret = sbi_tlb_request(args[0], args[1], &tlb_info);
+		ret = sbi_tlb_request(regs->a0, regs->a1, &tlb_info);
 		break;
 	default:
 		ret = SBI_ENOTSUPP;
@@ -110,13 +113,14 @@ struct sbi_ecall_extension ecall_rfence = {
 };
 
 static int sbi_ecall_ipi_handler(unsigned long extid, unsigned long funcid,
-				 unsigned long *args, unsigned long *out_val,
+				 const struct sbi_trap_regs *regs,
+				 unsigned long *out_val,
 				 struct sbi_trap_info *out_trap)
 {
 	int ret = 0;
 
 	if (funcid == SBI_EXT_IPI_SEND_IPI)
-		ret = sbi_ipi_send_smode(args[0], args[1]);
+		ret = sbi_ipi_send_smode(regs->a0, regs->a1);
 	else
 		ret = SBI_ENOTSUPP;
 
@@ -130,15 +134,16 @@ struct sbi_ecall_extension ecall_ipi = {
 };
 
 static int sbi_ecall_srst_handler(unsigned long extid, unsigned long funcid,
-				  unsigned long *args, unsigned long *out_val,
+				  const struct sbi_trap_regs *regs,
+				  unsigned long *out_val,
 				  struct sbi_trap_info *out_trap)
 {
 	if (funcid == SBI_EXT_SRST_RESET) {
-		if ((((u32)-1U) <= ((u64)args[0])) ||
-		    (((u32)-1U) <= ((u64)args[1])))
+		if ((((u32)-1U) <= ((u64)regs->a0)) ||
+		    (((u32)-1U) <= ((u64)regs->a1)))
 			return SBI_EINVAL;
 
-		switch (args[0]) {
+		switch (regs->a0) {
 		case SBI_SRST_RESET_TYPE_SHUTDOWN:
 		case SBI_SRST_RESET_TYPE_COLD_REBOOT:
 		case SBI_SRST_RESET_TYPE_WARM_REBOOT:
@@ -147,7 +152,7 @@ static int sbi_ecall_srst_handler(unsigned long extid, unsigned long funcid,
 			return SBI_ENOTSUPP;
 		}
 
-		switch (args[1]) {
+		switch (regs->a1) {
 		case SBI_SRST_RESET_REASON_NONE:
 		case SBI_SRST_RESET_REASON_SYSFAIL:
 			break;
@@ -155,8 +160,8 @@ static int sbi_ecall_srst_handler(unsigned long extid, unsigned long funcid,
 			return SBI_ENOTSUPP;
 		}
 
-		if (sbi_system_reset_supported(args[0], args[1]))
-			sbi_system_reset(args[0], args[1]);
+		if (sbi_system_reset_supported(regs->a0, regs->a1))
+			sbi_system_reset(regs->a0, regs->a1);
 	}
 
 	return SBI_ENOTSUPP;