Add support for the SMC Calling Convention 2.0
Due to differences in the bitfields of the SMC IDs, it is not possible
to support SMCCC 1.X and 2.0 at the same time.
The behaviour of `SMCCC_MAJOR_VERSION` has changed. Now, it is a build
option that specifies the major version of the SMCCC that the Trusted
Firmware supports. The only two allowed values are 1 and 2, and it
defaults to 1. The value of `SMCCC_MINOR_VERSION` is derived from it.
Note: Support for SMCCC v2.0 is an experimental feature to enable
prototyping of secure partition specifications. Support for this
convention is disabled by default and could be removed without notice.
Change-Id: I88abf9ccf08e9c66a13ce55c890edea54d9f16a7
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/bl31/aarch64/runtime_exceptions.S b/bl31/aarch64/runtime_exceptions.S
index 60be932..1c3ed3f 100644
--- a/bl31/aarch64/runtime_exceptions.S
+++ b/bl31/aarch64/runtime_exceptions.S
@@ -11,6 +11,7 @@
#include <interrupt_mgmt.h>
#include <platform_def.h>
#include <runtime_svc.h>
+#include <smccc.h>
.globl runtime_exceptions
@@ -289,6 +290,37 @@
/* ---------------------------------------------------------------------
+ * This macro takes an argument in x16 that is the index in the
+ * 'rt_svc_descs_indices' array, checks that the value in the array is
+ * valid, and loads in x15 the pointer to the handler of that service.
+ * ---------------------------------------------------------------------
+ */
+ .macro load_rt_svc_desc_pointer
+ /* Load descriptor index from array of indices */
+ adr x14, rt_svc_descs_indices
+ ldrb w15, [x14, x16]
+
+#if SMCCC_MAJOR_VERSION == 1
+ /* Any index greater than 127 is invalid. Check bit 7. */
+ tbnz w15, 7, smc_unknown
+#elif SMCCC_MAJOR_VERSION == 2
+ /* Verify that the top 3 bits of the loaded index are 0 (w15 <= 31) */
+ cmp w15, #31
+ b.hi smc_unknown
+#endif /* SMCCC_MAJOR_VERSION */
+
+ /*
+ * Get the descriptor using the index
+ * x11 = (base + off), w15 = index
+ *
+ * handler = (base + off) + (index << log2(size))
+ */
+ adr x11, (__RT_SVC_DESCS_START__ + RT_SVC_DESC_HANDLE)
+ lsl w10, w15, #RT_SVC_SIZE_LOG2
+ ldr x15, [x11, w10, uxtw]
+ .endm
+
+ /* ---------------------------------------------------------------------
* The following code handles secure monitor calls.
* Depending upon the execution state from where the SMC has been
* invoked, it frees some general purpose registers to perform the
@@ -311,23 +343,53 @@
* now). x6 will point to the context structure (SP_EL3) and x7 will
* contain flags we need to pass to the handler.
*
- * Save x4-x29 and sp_el0. Refer to SMCCC v1.1.
+ * Save x4-x29 and sp_el0.
*/
save_x4_to_x29_sp_el0
mov x5, xzr
mov x6, sp
+#if SMCCC_MAJOR_VERSION == 1
+
/* Get the unique owning entity number */
ubfx x16, x0, #FUNCID_OEN_SHIFT, #FUNCID_OEN_WIDTH
ubfx x15, x0, #FUNCID_TYPE_SHIFT, #FUNCID_TYPE_WIDTH
orr x16, x16, x15, lsl #FUNCID_OEN_WIDTH
- adr x11, (__RT_SVC_DESCS_START__ + RT_SVC_DESC_HANDLE)
+ load_rt_svc_desc_pointer
- /* Load descriptor index from array of indices */
- adr x14, rt_svc_descs_indices
- ldrb w15, [x14, x16]
+#elif SMCCC_MAJOR_VERSION == 2
+
+ /* Bit 31 must be set */
+ tbz x0, #FUNCID_TYPE_SHIFT, smc_unknown
+
+ /*
+ * Check MSB of namespace to decide between compatibility/vendor and
+ * SPCI/SPRT
+ */
+ tbz x0, #(FUNCID_NAMESPACE_SHIFT + 1), compat_or_vendor
+
+ /* Namespaces SPRT and SPCI currently unimplemented */
+ b smc_unknown
+
+compat_or_vendor:
+
+ /* Namespace is b'00 (compatibility) or b'01 (vendor) */
+
+ /*
+ * Add the LSB of the namespace (bit [28]) to the OEN [27:24] to create
+ * a 5-bit index into the rt_svc_descs_indices array.
+ *
+ * The low 16 entries of the rt_svc_descs_indices array correspond to
+ * OENs of the compatibility namespace and the top 16 entries of the
+ * array are assigned to the vendor namespace descriptor.
+ */
+ ubfx x16, x0, #FUNCID_OEN_SHIFT, #(FUNCID_OEN_WIDTH + 1)
+
+ load_rt_svc_desc_pointer
+
+#endif /* SMCCC_MAJOR_VERSION */
/*
* Restore the saved C runtime stack value which will become the new
@@ -336,25 +398,10 @@
*/
ldr x12, [x6, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]
- /*
- * Any index greater than 127 is invalid. Check bit 7 for
- * a valid index
- */
- tbnz w15, 7, smc_unknown
-
/* Switch to SP_EL0 */
msr spsel, #0
/*
- * Get the descriptor using the index
- * x11 = (base + off), x15 = index
- *
- * handler = (base + off) + (index << log2(size))
- */
- lsl w10, w15, #RT_SVC_SIZE_LOG2
- ldr x15, [x11, w10, uxtw]
-
- /*
* Save the SPSR_EL3, ELR_EL3, & SCR_EL3 in case there is a world
* switch during SMC handling.
* TODO: Revisit if all system registers can be saved later.