Add support for handling runtime service requests
This patch uses the reworked exception handling support to handle
runtime service requests through SMCs following the SMC calling
convention. This is a giant commit since all the changes are
inter-related. It does the following:
1. Replace the old exception handling mechanism with the new one
2. Enforce that SP_EL0 is used C runtime stacks.
3. Ensures that the cold and warm boot paths use the 'cpu_context'
structure to program an ERET into the next lower EL.
4. Ensures that SP_EL3 always points to the next 'cpu_context'
structure prior to an ERET into the next lower EL
5. Introduces a PSCI SMC handler which completes the use of PSCI as a
runtime service
Change-Id: I661797f834c0803d2c674d20f504df1b04c2b852
Co-authored-by: Achin Gupta <achin.gupta@arm.com>
diff --git a/common/psci/psci_common.c b/common/psci/psci_common.c
index 193655d..214db78 100644
--- a/common/psci/psci_common.c
+++ b/common/psci/psci_common.c
@@ -36,6 +36,7 @@
#include <platform.h>
#include <psci.h>
#include <psci_private.h>
+#include <context_mgmt.h>
#include <runtime_svc.h>
#include "debug.h"
@@ -86,7 +87,8 @@
unsigned int state;
/* Retrieve our node from the topology tree */
- node = psci_get_aff_map_node(mpidr & MPIDR_AFFINITY_MASK, MPIDR_AFFLVL0);
+ node = psci_get_aff_map_node(mpidr & MPIDR_AFFINITY_MASK,
+ MPIDR_AFFLVL0);
assert(node);
/*
@@ -222,13 +224,12 @@
void psci_get_ns_entry_info(unsigned int index)
{
unsigned long sctlr = 0, scr, el_status, id_aa64pfr0;
- gp_regs *ns_gp_regs;
+ uint64_t mpidr = read_mpidr();
+ cpu_context *ns_entry_context;
+ gp_regs *ns_entry_gpregs;
scr = read_scr();
- /* Switch to the non-secure view of the registers */
- write_scr(scr | SCR_NS_BIT);
-
/* Find out which EL we are going to */
id_aa64pfr0 = read_id_aa64pfr0_el1();
el_status = (id_aa64pfr0 >> ID_AA64PFR0_EL2_SHIFT) &
@@ -257,23 +258,29 @@
write_sctlr_el1(sctlr);
/* Fulfill the cpu_on entry reqs. as per the psci spec */
- write_scr(scr);
- write_elr(psci_ns_entry_info[index].eret_info.entrypoint);
+ ns_entry_context = (cpu_context *) cm_get_context(mpidr, NON_SECURE);
+ assert(ns_entry_context);
/*
- * Set the general purpose registers to ~0 upon entry into the
- * non-secure world except for x0 which should contain the
- * context id & spsr. This is done directly on the "would be"
- * stack pointer. Prior to entry into the non-secure world, an
- * offset equivalent to the size of the 'gp_regs' structure is
- * added to the sp. This general purpose register context is
- * retrieved then.
+ * Setup general purpose registers to return the context id and
+ * prevent leakage of secure information into the normal world.
*/
- ns_gp_regs = (gp_regs *) platform_get_stack(read_mpidr());
- ns_gp_regs--;
- memset(ns_gp_regs, ~0, sizeof(*ns_gp_regs));
- ns_gp_regs->x0 = psci_ns_entry_info[index].context_id;
- ns_gp_regs->spsr = psci_ns_entry_info[index].eret_info.spsr;
+ ns_entry_gpregs = get_gpregs_ctx(ns_entry_context);
+ write_ctx_reg(ns_entry_gpregs,
+ CTX_GPREG_X0,
+ psci_ns_entry_info[index].context_id);
+
+ /*
+ * Tell the context management library to setup EL3 system registers to
+ * be able to ERET into the ns state, and SP_EL3 points to the right
+ * context to exit from EL3 correctly.
+ */
+ cm_set_el3_eret_context(NON_SECURE,
+ psci_ns_entry_info[index].eret_info.entrypoint,
+ psci_ns_entry_info[index].eret_info.spsr,
+ scr);
+
+ cm_set_next_eret_context(NON_SECURE);
}
/*******************************************************************************
@@ -344,7 +351,7 @@
*/
spsr |= DAIF_ABT_BIT | DAIF_IRQ_BIT | DAIF_FIQ_BIT;
spsr <<= PSR_DAIF_SHIFT;
- if(ee)
+ if (ee)
spsr |= SPSR32_EE_BIT;
spsr |= mode;
@@ -500,7 +507,7 @@
mpidr_aff_map_nodes mpidr_nodes;
int rc;
- mpidr &= MPIDR_AFFINITY_MASK;;
+ mpidr &= MPIDR_AFFINITY_MASK;
/*
* Collect the pointers to the nodes in the topology tree for
diff --git a/common/psci/psci_entry.S b/common/psci/psci_entry.S
index 28a4143..15e074c 100644
--- a/common/psci/psci_entry.S
+++ b/common/psci/psci_entry.S
@@ -34,6 +34,7 @@
#include <psci_private.h>
#include <runtime_svc.h>
#include <asm_macros.S>
+#include <cm_macros.S>
.globl psci_aff_on_finish_entry
.globl psci_aff_suspend_finish_entry
@@ -74,6 +75,13 @@
msr vbar_el3, x0
isb
+ /* ---------------------------------------------
+ * Use SP_EL0 for the C runtime stack.
+ * ---------------------------------------------
+ */
+ msr spsel, #0
+ isb
+
bl read_mpidr
mov x19, x0
bl platform_set_coherent_stack
@@ -102,31 +110,19 @@
bl platform_set_stack
/* ---------------------------------------------
- * Now that the execution stack has been set
+ * Now that the context management has been set
* up, enable full runtime exception handling.
- * Since we're just about to leave this EL with
- * ERET, we don't need an ISB here
+ * SP_EL3 is pointing to a 'cpu_context'
+ * structure which has an exception stack
+ * allocated. Since we're just about to leave
+ * this EL with ERET, we don't need an ISB here
* ---------------------------------------------
*/
adr x0, runtime_exceptions
msr vbar_el3, x0
- /* --------------------------------------------
- * Use the size of the general purpose register
- * context to restore the register state
- * stashed by earlier code
- * --------------------------------------------
- */
- sub sp, sp, #SIZEOF_GPREGS
- exception_exit restore_regs
-
- /* --------------------------------------------
- * Jump back to the non-secure world assuming
- * that the elr and spsr setup has been done
- * by the finishers
- * --------------------------------------------
- */
- eret
+ zero_callee_saved_regs
+ b el3_exit
_panic:
b _panic
diff --git a/common/psci/psci_main.c b/common/psci/psci_main.c
index a70a21a..67f189d 100644
--- a/common/psci/psci_main.c
+++ b/common/psci/psci_main.c
@@ -35,6 +35,9 @@
#include <console.h>
#include <platform.h>
#include <psci_private.h>
+#include <runtime_svc.h>
+#include <debug.h>
+#include <context_mgmt.h>
/*******************************************************************************
* PSCI frontend api for servicing SMCs. Described in the PSCI spec.
@@ -199,3 +202,70 @@
assert(0);
}
+/*******************************************************************************
+ * PSCI top level handler for servicing SMCs.
+ ******************************************************************************/
+uint64_t psci_smc_handler(uint32_t smc_fid,
+ uint64_t x1,
+ uint64_t x2,
+ uint64_t x3,
+ uint64_t x4,
+ void *cookie,
+ void *handle,
+ uint64_t flags)
+{
+ uint64_t rc;
+
+ switch (smc_fid) {
+ case PSCI_VERSION:
+ rc = psci_version();
+ break;
+
+ case PSCI_CPU_OFF:
+ rc = __psci_cpu_off();
+ break;
+
+ case PSCI_CPU_SUSPEND_AARCH64:
+ case PSCI_CPU_SUSPEND_AARCH32:
+ rc = __psci_cpu_suspend(x1, x2, x3);
+ break;
+
+ case PSCI_CPU_ON_AARCH64:
+ case PSCI_CPU_ON_AARCH32:
+ rc = psci_cpu_on(x1, x2, x3);
+ break;
+
+ case PSCI_AFFINITY_INFO_AARCH32:
+ case PSCI_AFFINITY_INFO_AARCH64:
+ rc = psci_affinity_info(x1, x2);
+ break;
+
+ case PSCI_MIG_AARCH32:
+ case PSCI_MIG_AARCH64:
+ rc = psci_migrate(x1);
+ break;
+
+ case PSCI_MIG_INFO_TYPE:
+ rc = psci_migrate_info_type();
+ break;
+
+ case PSCI_MIG_INFO_UP_CPU_AARCH32:
+ case PSCI_MIG_INFO_UP_CPU_AARCH64:
+ rc = psci_migrate_info_up_cpu();
+ break;
+
+ case PSCI_SYSTEM_OFF:
+ psci_system_off();
+ assert(0);
+
+ case PSCI_SYSTEM_RESET:
+ psci_system_reset();
+ assert(0);
+
+ default:
+ rc = SMC_UNK;
+ WARN("Unimplemented psci call -> 0x%x \n", smc_fid);
+ }
+
+ SMC_RET1(handle, rc);
+}
diff --git a/common/psci/psci_private.h b/common/psci/psci_private.h
index de9c291..3d7ae74 100644
--- a/common/psci/psci_private.h
+++ b/common/psci/psci_private.h
@@ -151,6 +151,16 @@
int,
int);
extern unsigned int psci_afflvl_suspend_finish(unsigned long, int, int);
+
+/* Private exported functions from psci_main.c */
+extern uint64_t psci_smc_handler(uint32_t smc_fid,
+ uint64_t x1,
+ uint64_t x2,
+ uint64_t x3,
+ uint64_t x4,
+ void *cookie,
+ void *handle,
+ uint64_t flags);
#endif /*__ASSEMBLY__*/
#endif /* __PSCI_PRIVATE_H__ */
diff --git a/common/psci/psci_setup.c b/common/psci/psci_setup.c
index c471d1f..8d7903c 100644
--- a/common/psci/psci_setup.c
+++ b/common/psci/psci_setup.c
@@ -195,6 +195,9 @@
cm_set_context(mpidr,
(void *) &psci_ns_context[linear_id],
NON_SECURE);
+
+ /* Initialize exception stack in the context */
+ cm_init_exception_stack(mpidr, NON_SECURE);
}
return;
@@ -348,5 +351,5 @@
OEN_STD_END,
SMC_TYPE_FAST,
psci_setup,
- NULL
+ psci_smc_handler
);