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/bl31/aarch64/bl31_entrypoint.S b/bl31/aarch64/bl31_entrypoint.S
index cd0c023..1b8488d 100644
--- a/bl31/aarch64/bl31_entrypoint.S
+++ b/bl31/aarch64/bl31_entrypoint.S
@@ -31,6 +31,7 @@
#include <bl_common.h>
#include <platform.h>
#include <arch.h>
+#include "cm_macros.S"
.globl bl31_entrypoint
@@ -129,6 +130,12 @@
ldr x1, =__COHERENT_RAM_UNALIGNED_SIZE__
bl zeromem16
+ /* ---------------------------------------------
+ * Use SP_EL0 for the C runtime stack.
+ * ---------------------------------------------
+ */
+ msr spsel, #0
+
/* --------------------------------------------
* Give ourselves a small coherent stack to
* ease the pain of initializing the MMU
@@ -155,32 +162,26 @@
bl platform_set_stack
/* ---------------------------------------------
- * Use the more complex exception vectors now
- * the stacks are setup.
- * ---------------------------------------------
- */
- adr x1, runtime_exceptions
- msr vbar_el3, x1
-
- /* ---------------------------------------------
- * Use SP_EL0 to initialize BL31. It allows us
- * to jump to the next image without having to
- * come back here to ensure all of the stack's
- * been popped out. run_image() is not nice
- * enough to reset the stack pointer before
- * handing control to the next stage.
- * ---------------------------------------------
- */
- mov x0, sp
- msr sp_el0, x0
- msr spsel, #0
- isb
-
- /* ---------------------------------------------
* Jump to main function.
* ---------------------------------------------
*/
bl bl31_main
+ /* ---------------------------------------------
+ * Use the more complex exception vectors now
+ * that context management is setup. 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 x1, runtime_exceptions
+ msr vbar_el3, x1
+
+ zero_callee_saved_regs
+ b el3_exit
+
_panic:
+ wfi
b _panic
diff --git a/bl31/aarch64/exception_handlers.c b/bl31/aarch64/exception_handlers.c
deleted file mode 100644
index 3151294..0000000
--- a/bl31/aarch64/exception_handlers.c
+++ /dev/null
@@ -1,184 +0,0 @@
-/*
- * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * Redistributions of source code must retain the above copyright notice, this
- * list of conditions and the following disclaimer.
- *
- * Redistributions in binary form must reproduce the above copyright notice,
- * this list of conditions and the following disclaimer in the documentation
- * and/or other materials provided with the distribution.
- *
- * Neither the name of ARM nor the names of its contributors may be used
- * to endorse or promote products derived from this software without specific
- * prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include <arch_helpers.h>
-#include <platform.h>
-#include <bl_common.h>
-#include <bl31.h>
-#include <psci.h>
-#include <assert.h>
-#include <runtime_svc.h>
-
-/*******************************************************************************
- * This function checks whether this is a valid smc e.g.
- * the function id is correct, top word of args are zeroed
- * when aarch64 makes an aarch32 call etc.
- ******************************************************************************/
-int validate_smc(gp_regs *regs)
-{
- unsigned int rw = GET_RW(regs->spsr);
- unsigned int cc = GET_SMC_CC(regs->x0);
-
- /* Check if there is a difference in the caller RW and SMC CC */
- if (rw == cc) {
-
- /* Check whether the caller has chosen the right func. id */
- if (cc == SMC_64) {
- regs->x0 = SMC_UNK;
- return SMC_UNK;
- }
-
- /*
- * Paranoid check to zero the top word of passed args
- * irrespective of caller's register width.
- *
- * TODO: Check if this needed if the caller is aarch32
- */
- regs->x0 &= (unsigned int) 0xFFFFFFFF;
- regs->x1 &= (unsigned int) 0xFFFFFFFF;
- regs->x2 &= (unsigned int) 0xFFFFFFFF;
- regs->x3 &= (unsigned int) 0xFFFFFFFF;
- regs->x4 &= (unsigned int) 0xFFFFFFFF;
- regs->x5 &= (unsigned int) 0xFFFFFFFF;
- regs->x6 &= (unsigned int) 0xFFFFFFFF;
- }
-
- return 0;
-}
-
-/* TODO: Break down the SMC handler into fast and standard SMC handlers. */
-void smc_handler(unsigned type, unsigned long esr, gp_regs *regs)
-{
- /* Check if the SMC has been correctly called */
- if (validate_smc(regs) != 0)
- return;
-
- switch (regs->x0) {
- case PSCI_VERSION:
- regs->x0 = psci_version();
- break;
-
- case PSCI_CPU_OFF:
- regs->x0 = __psci_cpu_off();
- break;
-
- case PSCI_CPU_SUSPEND_AARCH64:
- case PSCI_CPU_SUSPEND_AARCH32:
- regs->x0 = __psci_cpu_suspend(regs->x1, regs->x2, regs->x3);
- break;
-
- case PSCI_CPU_ON_AARCH64:
- case PSCI_CPU_ON_AARCH32:
- regs->x0 = psci_cpu_on(regs->x1, regs->x2, regs->x3);
- break;
-
- case PSCI_AFFINITY_INFO_AARCH32:
- case PSCI_AFFINITY_INFO_AARCH64:
- regs->x0 = psci_affinity_info(regs->x1, regs->x2);
- break;
-
- default:
- regs->x0 = SMC_UNK;
- }
-
- return;
-}
-
-void irq_handler(unsigned type, unsigned long esr, gp_regs *regs)
-{
- plat_report_exception(type);
- assert(0);
-}
-
-void fiq_handler(unsigned type, unsigned long esr, gp_regs *regs)
-{
- plat_report_exception(type);
- assert(0);
-}
-
-void serror_handler(unsigned type, unsigned long esr, gp_regs *regs)
-{
- plat_report_exception(type);
- assert(0);
-}
-
-void sync_exception_handler(unsigned type, gp_regs *regs)
-{
- unsigned long esr = read_esr();
- unsigned int ec = EC_BITS(esr);
-
- switch (ec) {
-
- case EC_AARCH32_SMC:
- case EC_AARCH64_SMC:
- smc_handler(type, esr, regs);
- break;
-
- default:
- plat_report_exception(type);
- assert(0);
- }
- return;
-}
-
-void async_exception_handler(unsigned type, gp_regs *regs)
-{
- unsigned long esr = read_esr();
-
- switch (type) {
-
- case IRQ_SP_EL0:
- case IRQ_SP_ELX:
- case IRQ_AARCH64:
- case IRQ_AARCH32:
- irq_handler(type, esr, regs);
- break;
-
- case FIQ_SP_EL0:
- case FIQ_SP_ELX:
- case FIQ_AARCH64:
- case FIQ_AARCH32:
- fiq_handler(type, esr, regs);
- break;
-
- case SERROR_SP_EL0:
- case SERROR_SP_ELX:
- case SERROR_AARCH64:
- case SERROR_AARCH32:
- serror_handler(type, esr, regs);
- break;
-
- default:
- plat_report_exception(type);
- assert(0);
- }
-
- return;
-}
diff --git a/bl31/aarch64/runtime_exceptions.S b/bl31/aarch64/runtime_exceptions.S
index 92835dc..10e65dc 100644
--- a/bl31/aarch64/runtime_exceptions.S
+++ b/bl31/aarch64/runtime_exceptions.S
@@ -30,12 +30,13 @@
#include <arch.h>
#include <runtime_svc.h>
+#include <platform.h>
+#include <context.h>
+#include "cm_macros.S"
.globl runtime_exceptions
-
-
-#include <asm_macros.S>
-
+ .globl el3_exit
+ .globl get_exception_stack
.section .vectors, "ax"; .align 11
@@ -46,39 +47,32 @@
* -----------------------------------------------------
*/
sync_exception_sp_el0:
- exception_entry save_regs
- mov x0, #SYNC_EXCEPTION_SP_EL0
- mov x1, sp
- bl sync_exception_handler
- exception_exit restore_regs
- eret
+ /* -----------------------------------------------------
+ * We don't expect any synchronous exceptions from EL3
+ * -----------------------------------------------------
+ */
+ wfi
+ b sync_exception_sp_el0
.align 7
+ /* -----------------------------------------------------
+ * EL3 code is non-reentrant. Any asynchronous exception
+ * is a serious error. Loop infinitely.
+ * -----------------------------------------------------
+ */
irq_sp_el0:
- exception_entry save_regs
- mov x0, #IRQ_SP_EL0
- mov x1, sp
- bl async_exception_handler
- exception_exit restore_regs
- eret
+ handle_async_exception IRQ_SP_EL0
+ b irq_sp_el0
.align 7
fiq_sp_el0:
- exception_entry save_regs
- mov x0, #FIQ_SP_EL0
- mov x1, sp
- bl async_exception_handler
- exception_exit restore_regs
- eret
+ handle_async_exception FIQ_SP_EL0
+ b fiq_sp_el0
.align 7
serror_sp_el0:
- exception_entry save_regs
- mov x0, #SERROR_SP_EL0
- mov x1, sp
- bl async_exception_handler
- exception_exit restore_regs
- eret
+ handle_async_exception SERROR_SP_EL0
+ b serror_sp_el0
/* -----------------------------------------------------
* Current EL with SPx: 0x200 - 0x380
@@ -86,39 +80,35 @@
*/
.align 7
sync_exception_sp_elx:
- exception_entry save_regs
- mov x0, #SYNC_EXCEPTION_SP_ELX
- mov x1, sp
- bl sync_exception_handler
- exception_exit restore_regs
- eret
+ /* -----------------------------------------------------
+ * This exception will trigger if anything went wrong
+ * during a previous exception entry or exit or while
+ * handling an earlier unexpected synchronous exception.
+ * In any case we cannot rely on SP_EL3. Switching to a
+ * known safe area of memory will corrupt at least a
+ * single register. It is best to enter wfi in loop as
+ * that will preserve the system state for analysis
+ * through a debugger later.
+ * -----------------------------------------------------
+ */
+ wfi
+ b sync_exception_sp_elx
+ /* -----------------------------------------------------
+ * As mentioned in the previous comment, all bets are
+ * off if SP_EL3 cannot be relied upon. Report their
+ * occurrence.
+ * -----------------------------------------------------
+ */
.align 7
irq_sp_elx:
- exception_entry save_regs
- mov x0, #IRQ_SP_ELX
- mov x1, sp
- bl async_exception_handler
- exception_exit restore_regs
- eret
-
+ b irq_sp_elx
.align 7
fiq_sp_elx:
- exception_entry save_regs
- mov x0, #FIQ_SP_ELX
- mov x1, sp
- bl async_exception_handler
- exception_exit restore_regs
- eret
-
+ b fiq_sp_elx
.align 7
serror_sp_elx:
- exception_entry save_regs
- mov x0, #SERROR_SP_ELX
- mov x1, sp
- bl async_exception_handler
- exception_exit restore_regs
- eret
+ b serror_sp_elx
/* -----------------------------------------------------
* Lower EL using AArch64 : 0x400 - 0x580
@@ -126,39 +116,35 @@
*/
.align 7
sync_exception_aarch64:
- exception_entry save_regs
- mov x0, #SYNC_EXCEPTION_AARCH64
- mov x1, sp
- bl sync_exception_handler
- exception_exit restore_regs
- eret
+ /* -----------------------------------------------------
+ * This exception vector will be the entry point for
+ * SMCs and traps that are unhandled at lower ELs most
+ * commonly. SP_EL3 should point to a valid cpu context
+ * where the general purpose and system register state
+ * can be saved.
+ * -----------------------------------------------------
+ */
+ handle_sync_exception
.align 7
+ /* -----------------------------------------------------
+ * Asynchronous exceptions from lower ELs are not
+ * currently supported. Report their occurrence.
+ * -----------------------------------------------------
+ */
irq_aarch64:
- exception_entry save_regs
- mov x0, #IRQ_AARCH64
- mov x1, sp
- bl async_exception_handler
- exception_exit restore_regs
- eret
+ handle_async_exception IRQ_AARCH64
+ b irq_aarch64
.align 7
fiq_aarch64:
- exception_entry save_regs
- mov x0, #FIQ_AARCH64
- mov x1, sp
- bl async_exception_handler
- exception_exit restore_regs
- eret
+ handle_async_exception FIQ_AARCH64
+ b fiq_aarch64
.align 7
serror_aarch64:
- exception_entry save_regs
- mov x0, #IRQ_AARCH32
- mov x1, sp
- bl async_exception_handler
- exception_exit restore_regs
- eret
+ handle_async_exception SERROR_AARCH64
+ b serror_aarch64
/* -----------------------------------------------------
* Lower EL using AArch32 : 0x600 - 0x780
@@ -166,39 +152,281 @@
*/
.align 7
sync_exception_aarch32:
- exception_entry save_regs
- mov x0, #SYNC_EXCEPTION_AARCH32
- mov x1, sp
- bl sync_exception_handler
- exception_exit restore_regs
- eret
+ /* -----------------------------------------------------
+ * This exception vector will be the entry point for
+ * SMCs and traps that are unhandled at lower ELs most
+ * commonly. SP_EL3 should point to a valid cpu context
+ * where the general purpose and system register state
+ * can be saved.
+ * -----------------------------------------------------
+ */
+ handle_sync_exception
.align 7
+ /* -----------------------------------------------------
+ * Asynchronous exceptions from lower ELs are not
+ * currently supported. Report their occurrence.
+ * -----------------------------------------------------
+ */
irq_aarch32:
- exception_entry save_regs
- mov x0, #IRQ_AARCH32
- mov x1, sp
- bl async_exception_handler
- exception_exit restore_regs
- eret
+ handle_async_exception IRQ_AARCH32
+ b irq_aarch32
.align 7
fiq_aarch32:
- exception_entry save_regs
- mov x0, #FIQ_AARCH32
- mov x1, sp
- bl async_exception_handler
- exception_exit restore_regs
- eret
+ handle_async_exception FIQ_AARCH32
+ b fiq_aarch32
.align 7
serror_aarch32:
- exception_entry save_regs
- mov x0, #SERROR_AARCH32
- mov x1, sp
- bl async_exception_handler
- exception_exit restore_regs
+ handle_async_exception SERROR_AARCH32
+ b serror_aarch32
+ .align 7
+
+ .section .text, "ax"
+ /* -----------------------------------------------------
+ * 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 remaining tasks. They
+ * involve finding the runtime service handler that is
+ * the target of the SMC & switching to runtime stacks
+ * (SP_EL0) before calling the handler.
+ *
+ * Note that x30 has been explicitly saved and can be
+ * used here
+ * -----------------------------------------------------
+ */
+smc_handler32:
+ /* Check whether aarch32 issued an SMC64 */
+ tbnz x0, #FUNCID_CC_SHIFT, smc_prohibited
+
+ /* -----------------------------------------------------
+ * Since we're are coming from aarch32, x8-x18 need to
+ * be saved as per SMC32 calling convention. If a lower
+ * EL in aarch64 is making an SMC32 call then it must
+ * have saved x8-x17 already therein.
+ * -----------------------------------------------------
+ */
+ stp x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
+ stp x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
+ stp x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
+ stp x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
+ stp x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
+
+ /* x4-x7, x18, sp_el0 are saved below */
+
+smc_handler64:
+ /* -----------------------------------------------------
+ * Populate the parameters for the SMC handler. We
+ * already have x0-x4 in place. x5 will point to a
+ * cookie (not used now). x6 will point to the context
+ * structure (SP_EL3) and x7 will contain flags we need
+ * to pass to the handler Hence save x5-x7. Note that x4
+ * only needs to be preserved for AArch32 callers but we
+ * do it for AArch64 callers as well for convenience
+ * -----------------------------------------------------
+ */
+ stp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
+ stp x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
+
+ mov x5, xzr
+ mov x6, sp
+
+ /* 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 descriptor index from array of indices */
+ adr x14, rt_svc_descs_indices
+ ldrb w15, [x14, x16]
+
+ /* Save x18 and SP_EL0 */
+ mrs x17, sp_el0
+ stp x18, x17, [x6, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
+
+ /* -----------------------------------------------------
+ * Restore the saved C runtime stack value which will
+ * become the new SP_EL0 i.e. EL3 runtime stack. It was
+ * saved in the 'cpu_context' structure prior to the last
+ * ERET from EL3.
+ * -----------------------------------------------------
+ */
+ 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.
+ * -----------------------------------------------------
+ */
+ mrs x16, spsr_el3
+ mrs x17, elr_el3
+ mrs x18, scr_el3
+ stp x16, x17, [x6, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
+ stp x18, xzr, [x6, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
+
+ /* Copy SCR_EL3.NS bit to the flag to indicate caller's security */
+ bfi x7, x18, #0, #1
+
+ mov sp, x12
+
+ /* -----------------------------------------------------
+ * Call the Secure Monitor Call handler and then drop
+ * directly into el3_exit() which will program any
+ * remaining architectural state prior to issuing the
+ * ERET to the desired lower EL.
+ * -----------------------------------------------------
+ */
+#if DEBUG
+ cbz x15, rt_svc_fw_critical_error
+#endif
+ blr x15
+
+ /* -----------------------------------------------------
+ * This routine assumes that the SP_EL3 is pointing to
+ * a valid context structure from where the gp regs and
+ * other special registers can be retrieved.
+ * -----------------------------------------------------
+ */
+el3_exit: ; .type el3_exit, %function
+ /* -----------------------------------------------------
+ * Save the current SP_EL0 i.e. the EL3 runtime stack
+ * which will be used for handling the next SMC. Then
+ * switch to SP_EL3
+ * -----------------------------------------------------
+ */
+ mov x17, sp
+ msr spsel, #1
+ str x17, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]
+
+ /* -----------------------------------------------------
+ * Restore SPSR_EL3, ELR_EL3 and SCR_EL3 prior to ERET
+ * -----------------------------------------------------
+ */
+ ldp x18, xzr, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
+ ldp x16, x17, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
+ msr scr_el3, x18
+ msr spsr_el3, x16
+ msr elr_el3, x17
+
+ /* Restore saved general purpose registers and return */
+ bl restore_scratch_registers
+ ldp x30, xzr, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
eret
- .align 7
+smc_unknown:
+ /*
+ * Here we restore x4-x18 regardless of where we came from. AArch32
+ * callers will find the registers contents unchanged, but AArch64
+ * callers will find the registers modified (with stale earlier NS
+ * content). Either way, we aren't leaking any secure information
+ * through them
+ */
+ bl restore_scratch_registers_callee
+
+smc_prohibited:
+ ldp x30, xzr, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
+ mov w0, #SMC_UNK
+ eret
+
+rt_svc_fw_critical_error:
+ b rt_svc_fw_critical_error
+
+ /* -----------------------------------------------------
+ * The following functions are used to saved and restore
+ * all the caller saved registers as per the aapcs_64.
+ * These are not macros to ensure their invocation fits
+ * within the 32 instructions per exception vector.
+ * -----------------------------------------------------
+ */
+save_scratch_registers: ; .type save_scratch_registers, %function
+ stp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
+ stp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
+ stp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
+ stp x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
+ stp x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
+ stp x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
+ stp x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
+ stp x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
+ stp x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
+ mrs x17, sp_el0
+ stp x18, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
+ ret
+
+restore_scratch_registers: ; .type restore_scratch_registers, %function
+ ldp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
+ ldp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
+
+restore_scratch_registers_callee:
+ ldp x18, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
+
+ ldp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
+ ldp x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
+ ldp x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
+ ldp x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
+ ldp x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
+ ldp x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
+
+ msr sp_el0, x17
+ ldp x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
+ ret
+
+ /* -----------------------------------------------------
+ * 256 bytes of exception stack for each cpu
+ * -----------------------------------------------------
+ */
+#if DEBUG
+#define PCPU_EXCEPTION_STACK_SIZE 0x300
+#else
+#define PCPU_EXCEPTION_STACK_SIZE 0x100
+#endif
+ /* -----------------------------------------------------
+ * void get_exception_stack (uint64_t mpidr) : This
+ * function is used to allocate a small stack for
+ * reporting unhandled exceptions
+ * -----------------------------------------------------
+ */
+get_exception_stack: ; .type get_exception_stack, %function
+ mov x10, x30 // lr
+ bl platform_get_core_pos
+ add x0, x0, #1
+ mov x1, #PCPU_EXCEPTION_STACK_SIZE
+ mul x0, x0, x1
+ ldr x1, =pcpu_exception_stack
+ add x0, x1, x0
+ ret x10
+
+ /* -----------------------------------------------------
+ * Per-cpu exception stacks in normal memory.
+ * -----------------------------------------------------
+ */
+ .section data, "aw", %nobits; .align 6
+
+pcpu_exception_stack:
+ /* Zero fill */
+ .space (PLATFORM_CORE_COUNT * PCPU_EXCEPTION_STACK_SIZE), 0
diff --git a/bl31/aarch64/runtime_exceptions_next.S b/bl31/aarch64/runtime_exceptions_next.S
deleted file mode 100644
index 10e65dc..0000000
--- a/bl31/aarch64/runtime_exceptions_next.S
+++ /dev/null
@@ -1,432 +0,0 @@
-/*
- * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * Redistributions of source code must retain the above copyright notice, this
- * list of conditions and the following disclaimer.
- *
- * Redistributions in binary form must reproduce the above copyright notice,
- * this list of conditions and the following disclaimer in the documentation
- * and/or other materials provided with the distribution.
- *
- * Neither the name of ARM nor the names of its contributors may be used
- * to endorse or promote products derived from this software without specific
- * prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include <arch.h>
-#include <runtime_svc.h>
-#include <platform.h>
-#include <context.h>
-#include "cm_macros.S"
-
- .globl runtime_exceptions
- .globl el3_exit
- .globl get_exception_stack
-
- .section .vectors, "ax"; .align 11
-
- .align 7
-runtime_exceptions:
- /* -----------------------------------------------------
- * Current EL with _sp_el0 : 0x0 - 0x180
- * -----------------------------------------------------
- */
-sync_exception_sp_el0:
- /* -----------------------------------------------------
- * We don't expect any synchronous exceptions from EL3
- * -----------------------------------------------------
- */
- wfi
- b sync_exception_sp_el0
-
- .align 7
- /* -----------------------------------------------------
- * EL3 code is non-reentrant. Any asynchronous exception
- * is a serious error. Loop infinitely.
- * -----------------------------------------------------
- */
-irq_sp_el0:
- handle_async_exception IRQ_SP_EL0
- b irq_sp_el0
-
- .align 7
-fiq_sp_el0:
- handle_async_exception FIQ_SP_EL0
- b fiq_sp_el0
-
- .align 7
-serror_sp_el0:
- handle_async_exception SERROR_SP_EL0
- b serror_sp_el0
-
- /* -----------------------------------------------------
- * Current EL with SPx: 0x200 - 0x380
- * -----------------------------------------------------
- */
- .align 7
-sync_exception_sp_elx:
- /* -----------------------------------------------------
- * This exception will trigger if anything went wrong
- * during a previous exception entry or exit or while
- * handling an earlier unexpected synchronous exception.
- * In any case we cannot rely on SP_EL3. Switching to a
- * known safe area of memory will corrupt at least a
- * single register. It is best to enter wfi in loop as
- * that will preserve the system state for analysis
- * through a debugger later.
- * -----------------------------------------------------
- */
- wfi
- b sync_exception_sp_elx
-
- /* -----------------------------------------------------
- * As mentioned in the previous comment, all bets are
- * off if SP_EL3 cannot be relied upon. Report their
- * occurrence.
- * -----------------------------------------------------
- */
- .align 7
-irq_sp_elx:
- b irq_sp_elx
- .align 7
-fiq_sp_elx:
- b fiq_sp_elx
- .align 7
-serror_sp_elx:
- b serror_sp_elx
-
- /* -----------------------------------------------------
- * Lower EL using AArch64 : 0x400 - 0x580
- * -----------------------------------------------------
- */
- .align 7
-sync_exception_aarch64:
- /* -----------------------------------------------------
- * This exception vector will be the entry point for
- * SMCs and traps that are unhandled at lower ELs most
- * commonly. SP_EL3 should point to a valid cpu context
- * where the general purpose and system register state
- * can be saved.
- * -----------------------------------------------------
- */
- handle_sync_exception
-
- .align 7
- /* -----------------------------------------------------
- * Asynchronous exceptions from lower ELs are not
- * currently supported. Report their occurrence.
- * -----------------------------------------------------
- */
-irq_aarch64:
- handle_async_exception IRQ_AARCH64
- b irq_aarch64
-
- .align 7
-fiq_aarch64:
- handle_async_exception FIQ_AARCH64
- b fiq_aarch64
-
- .align 7
-serror_aarch64:
- handle_async_exception SERROR_AARCH64
- b serror_aarch64
-
- /* -----------------------------------------------------
- * Lower EL using AArch32 : 0x600 - 0x780
- * -----------------------------------------------------
- */
- .align 7
-sync_exception_aarch32:
- /* -----------------------------------------------------
- * This exception vector will be the entry point for
- * SMCs and traps that are unhandled at lower ELs most
- * commonly. SP_EL3 should point to a valid cpu context
- * where the general purpose and system register state
- * can be saved.
- * -----------------------------------------------------
- */
- handle_sync_exception
-
- .align 7
- /* -----------------------------------------------------
- * Asynchronous exceptions from lower ELs are not
- * currently supported. Report their occurrence.
- * -----------------------------------------------------
- */
-irq_aarch32:
- handle_async_exception IRQ_AARCH32
- b irq_aarch32
-
- .align 7
-fiq_aarch32:
- handle_async_exception FIQ_AARCH32
- b fiq_aarch32
-
- .align 7
-serror_aarch32:
- handle_async_exception SERROR_AARCH32
- b serror_aarch32
- .align 7
-
- .section .text, "ax"
- /* -----------------------------------------------------
- * 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 remaining tasks. They
- * involve finding the runtime service handler that is
- * the target of the SMC & switching to runtime stacks
- * (SP_EL0) before calling the handler.
- *
- * Note that x30 has been explicitly saved and can be
- * used here
- * -----------------------------------------------------
- */
-smc_handler32:
- /* Check whether aarch32 issued an SMC64 */
- tbnz x0, #FUNCID_CC_SHIFT, smc_prohibited
-
- /* -----------------------------------------------------
- * Since we're are coming from aarch32, x8-x18 need to
- * be saved as per SMC32 calling convention. If a lower
- * EL in aarch64 is making an SMC32 call then it must
- * have saved x8-x17 already therein.
- * -----------------------------------------------------
- */
- stp x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
- stp x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
- stp x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
- stp x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
- stp x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
-
- /* x4-x7, x18, sp_el0 are saved below */
-
-smc_handler64:
- /* -----------------------------------------------------
- * Populate the parameters for the SMC handler. We
- * already have x0-x4 in place. x5 will point to a
- * cookie (not used now). x6 will point to the context
- * structure (SP_EL3) and x7 will contain flags we need
- * to pass to the handler Hence save x5-x7. Note that x4
- * only needs to be preserved for AArch32 callers but we
- * do it for AArch64 callers as well for convenience
- * -----------------------------------------------------
- */
- stp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
- stp x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
-
- mov x5, xzr
- mov x6, sp
-
- /* 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 descriptor index from array of indices */
- adr x14, rt_svc_descs_indices
- ldrb w15, [x14, x16]
-
- /* Save x18 and SP_EL0 */
- mrs x17, sp_el0
- stp x18, x17, [x6, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
-
- /* -----------------------------------------------------
- * Restore the saved C runtime stack value which will
- * become the new SP_EL0 i.e. EL3 runtime stack. It was
- * saved in the 'cpu_context' structure prior to the last
- * ERET from EL3.
- * -----------------------------------------------------
- */
- 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.
- * -----------------------------------------------------
- */
- mrs x16, spsr_el3
- mrs x17, elr_el3
- mrs x18, scr_el3
- stp x16, x17, [x6, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
- stp x18, xzr, [x6, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
-
- /* Copy SCR_EL3.NS bit to the flag to indicate caller's security */
- bfi x7, x18, #0, #1
-
- mov sp, x12
-
- /* -----------------------------------------------------
- * Call the Secure Monitor Call handler and then drop
- * directly into el3_exit() which will program any
- * remaining architectural state prior to issuing the
- * ERET to the desired lower EL.
- * -----------------------------------------------------
- */
-#if DEBUG
- cbz x15, rt_svc_fw_critical_error
-#endif
- blr x15
-
- /* -----------------------------------------------------
- * This routine assumes that the SP_EL3 is pointing to
- * a valid context structure from where the gp regs and
- * other special registers can be retrieved.
- * -----------------------------------------------------
- */
-el3_exit: ; .type el3_exit, %function
- /* -----------------------------------------------------
- * Save the current SP_EL0 i.e. the EL3 runtime stack
- * which will be used for handling the next SMC. Then
- * switch to SP_EL3
- * -----------------------------------------------------
- */
- mov x17, sp
- msr spsel, #1
- str x17, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]
-
- /* -----------------------------------------------------
- * Restore SPSR_EL3, ELR_EL3 and SCR_EL3 prior to ERET
- * -----------------------------------------------------
- */
- ldp x18, xzr, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
- ldp x16, x17, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
- msr scr_el3, x18
- msr spsr_el3, x16
- msr elr_el3, x17
-
- /* Restore saved general purpose registers and return */
- bl restore_scratch_registers
- ldp x30, xzr, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
- eret
-
-smc_unknown:
- /*
- * Here we restore x4-x18 regardless of where we came from. AArch32
- * callers will find the registers contents unchanged, but AArch64
- * callers will find the registers modified (with stale earlier NS
- * content). Either way, we aren't leaking any secure information
- * through them
- */
- bl restore_scratch_registers_callee
-
-smc_prohibited:
- ldp x30, xzr, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
- mov w0, #SMC_UNK
- eret
-
-rt_svc_fw_critical_error:
- b rt_svc_fw_critical_error
-
- /* -----------------------------------------------------
- * The following functions are used to saved and restore
- * all the caller saved registers as per the aapcs_64.
- * These are not macros to ensure their invocation fits
- * within the 32 instructions per exception vector.
- * -----------------------------------------------------
- */
-save_scratch_registers: ; .type save_scratch_registers, %function
- stp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
- stp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
- stp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
- stp x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
- stp x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
- stp x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
- stp x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
- stp x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
- stp x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
- mrs x17, sp_el0
- stp x18, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
- ret
-
-restore_scratch_registers: ; .type restore_scratch_registers, %function
- ldp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
- ldp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
-
-restore_scratch_registers_callee:
- ldp x18, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
-
- ldp x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
- ldp x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
- ldp x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
- ldp x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
- ldp x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
- ldp x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
-
- msr sp_el0, x17
- ldp x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
- ret
-
- /* -----------------------------------------------------
- * 256 bytes of exception stack for each cpu
- * -----------------------------------------------------
- */
-#if DEBUG
-#define PCPU_EXCEPTION_STACK_SIZE 0x300
-#else
-#define PCPU_EXCEPTION_STACK_SIZE 0x100
-#endif
- /* -----------------------------------------------------
- * void get_exception_stack (uint64_t mpidr) : This
- * function is used to allocate a small stack for
- * reporting unhandled exceptions
- * -----------------------------------------------------
- */
-get_exception_stack: ; .type get_exception_stack, %function
- mov x10, x30 // lr
- bl platform_get_core_pos
- add x0, x0, #1
- mov x1, #PCPU_EXCEPTION_STACK_SIZE
- mul x0, x0, x1
- ldr x1, =pcpu_exception_stack
- add x0, x1, x0
- ret x10
-
- /* -----------------------------------------------------
- * Per-cpu exception stacks in normal memory.
- * -----------------------------------------------------
- */
- .section data, "aw", %nobits; .align 6
-
-pcpu_exception_stack:
- /* Zero fill */
- .space (PLATFORM_CORE_COUNT * PCPU_EXCEPTION_STACK_SIZE), 0
-
diff --git a/bl31/bl31.mk b/bl31/bl31.mk
index 280aa88..fec8ebe 100644
--- a/bl31/bl31.mk
+++ b/bl31/bl31.mk
@@ -49,7 +49,6 @@
BL31_OBJS += bl31_arch_setup.o \
bl31_entrypoint.o \
- exception_handlers.o \
runtime_exceptions.o \
bl31_main.o \
psci_entry.o \
diff --git a/bl31/bl31_main.c b/bl31/bl31_main.c
index dc65b60..9d2dc29 100644
--- a/bl31/bl31_main.c
+++ b/bl31/bl31_main.c
@@ -48,15 +48,18 @@
cm_init();
}
-void bl31_arch_next_el_setup(void);
-
/*******************************************************************************
* BL31 is responsible for setting up the runtime services for the primary cpu
- * before passing control to the bootloader (UEFI) or Linux.
+ * before passing control to the bootloader (UEFI) or Linux. This function calls
+ * runtime_svc_init() which initializes all registered runtime services. The run
+ * time services would setup enough context for the core to swtich to the next
+ * exception level. When this function returns, the core will switch to the
+ * programmed exception level via. an ERET.
******************************************************************************/
void bl31_main(void)
{
- el_change_info *image_info;
+ el_change_info *next_image_info;
+ uint32_t scr;
/* Perform remaining generic architectural setup from EL3 */
bl31_arch_setup();
@@ -76,10 +79,27 @@
/* Clean caches before re-entering normal world */
dcsw_op_all(DCCSW);
- image_info = bl31_get_next_image_info();
+ /*
+ * Setup minimal architectural state of the next highest EL to
+ * allow execution in it immediately upon entering it.
+ */
bl31_arch_next_el_setup();
- change_el(image_info);
- /* There is no valid reason for change_el() to return */
- assert(0);
+ /* Program EL3 registers to enable entry into the next EL */
+ next_image_info = bl31_get_next_image_info();
+ scr = read_scr();
+ if (next_image_info->security_state == NON_SECURE)
+ scr |= SCR_NS_BIT;
+
+ /*
+ * Tell the context mgmt. library to ensure that SP_EL3 points to
+ * the right context to exit from EL3 correctly.
+ */
+ cm_set_el3_eret_context(next_image_info->security_state,
+ next_image_info->entrypoint,
+ next_image_info->spsr,
+ scr);
+
+ /* Finally set the next context */
+ cm_set_next_eret_context(next_image_info->security_state);
}
diff --git a/bl31/context_mgmt.c b/bl31/context_mgmt.c
index bbdbad2..44ef0d9 100644
--- a/bl31/context_mgmt.c
+++ b/bl31/context_mgmt.c
@@ -143,11 +143,31 @@
}
/*******************************************************************************
- * This function is used to program SP_EL3 to point to the 'cpu_context'
- * structure which will be used for programming the EL3 architectural state to
- * enable an ERET into a lower EL e.g. general purpose registers and system
- * registers like SCR_EL3, SPSR_EL3, SCR_EL3 etc. The same structure will be
- * used to save the same registers after an exception entry from the lower EL.
+ * This function function populates 'cpu_context' pertaining to the given
+ * security state with the entrypoint, SPSR and SCR values so that an ERET from
+ * this securit state correctly restores corresponding values to drop the CPU to
+ * the next exception level
+ ******************************************************************************/
+void cm_set_el3_eret_context(uint32_t security_state, uint64_t entrypoint,
+ uint32_t spsr, uint32_t scr)
+{
+ cpu_context *ctx;
+ el3_state *state;
+
+ ctx = cm_get_context(read_mpidr(), security_state);
+ assert(ctx);
+
+ /* Populate EL3 state so that we've the right context before doing ERET */
+ state = get_el3state_ctx(ctx);
+ write_ctx_reg(state, CTX_SPSR_EL3, spsr);
+ write_ctx_reg(state, CTX_ELR_EL3, entrypoint);
+ write_ctx_reg(state, CTX_SCR_EL3, scr);
+}
+
+/*******************************************************************************
+ * This function is used to program the context that's used for exception
+ * return. This initializes the SP_EL3 to a pointer to a 'cpu_context' set for
+ * the required security state
******************************************************************************/
void cm_set_next_eret_context(uint32_t security_state)
{
@@ -155,6 +175,7 @@
#if DEBUG
uint64_t sp_mode;
#endif
+
ctx = cm_get_context(read_mpidr(), security_state);
assert(ctx);
@@ -174,3 +195,22 @@
"msr spsel, #0\n"
: : "r" (ctx));
}
+
+/*******************************************************************************
+ * This function is used to program exception stack in the 'cpu_context'
+ * structure. This is the initial stack used for taking and handling exceptions
+ * at EL3. This stack is expected to be initialized once by each security state
+ ******************************************************************************/
+void cm_init_exception_stack(uint64_t mpidr, uint32_t security_state)
+{
+ cpu_context *ctx;
+ el3_state *state;
+
+ ctx = cm_get_context(mpidr, security_state);
+ assert(ctx);
+
+ /* Set exception stack in the context */
+ state = get_el3state_ctx(ctx);
+
+ write_ctx_reg(state, CTX_EXCEPTION_SP, get_exception_stack(mpidr));
+}
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
);
diff --git a/common/runtime_svc.c b/common/runtime_svc.c
index 0ea1bf5..6e8a1bb 100644
--- a/common/runtime_svc.c
+++ b/common/runtime_svc.c
@@ -41,6 +41,7 @@
#include <runtime_svc.h>
#include <context.h>
#include <debug.h>
+#include <context_mgmt.h>
/*******************************************************************************
* The 'rt_svc_descs' array holds the runtime service descriptors exported by
@@ -146,7 +147,7 @@
void fault_handler(void *handle)
{
- gp_regs_next *gpregs_ctx = get_gpregs_ctx(handle);
+ gp_regs *gpregs_ctx = get_gpregs_ctx(handle);
ERROR("Unhandled synchronous fault. Register dump @ 0x%x \n",
gpregs_ctx);
panic();
diff --git a/include/aarch64/arch.h b/include/aarch64/arch.h
index e8773d9..69926a3 100644
--- a/include/aarch64/arch.h
+++ b/include/aarch64/arch.h
@@ -320,7 +320,7 @@
extern void bl1_arch_setup(void);
extern void bl2_arch_setup(void);
extern void bl31_arch_setup(void);
-
+extern void bl31_arch_next_el_setup(void);
#endif /*__ASSEMBLY__*/
#endif /* __ARCH_H__ */
diff --git a/include/asm_macros.S b/include/asm_macros.S
index 9de135c..decef0b 100644
--- a/include/asm_macros.S
+++ b/include/asm_macros.S
@@ -54,18 +54,6 @@
.endm
- .macro exception_entry func
- stp x29, x30, [sp, #-(SIZEOF_GPREGS - GPREGS_FP_OFF)]!
- bl \func
- .endm
-
-
- .macro exception_exit func
- bl \func
- ldp x29, x30, [sp], #(SIZEOF_GPREGS - GPREGS_FP_OFF)
- .endm
-
-
.macro smc_check label
bl read_esr
ubfx x0, x0, #ESR_EC_SHIFT, #ESR_EC_LENGTH
diff --git a/include/context.h b/include/context.h
index 1c1a3a2..082e511d 100644
--- a/include/context.h
+++ b/include/context.h
@@ -193,7 +193,7 @@
* callee saved registers if used by the C runtime and the assembler
* does not touch the remaining.
*/
-DEFINE_REG_STRUCT(gp_regs_next, CTX_GPREG_ALL);
+DEFINE_REG_STRUCT(gp_regs, CTX_GPREG_ALL);
/*
* AArch64 EL1 system register context structure for preserving the
@@ -233,7 +233,7 @@
* correspond to either the secure or the non-secure state.
*/
typedef struct {
- gp_regs_next gpregs_ctx;
+ gp_regs gpregs_ctx;
el3_state el3state_ctx;
el1_sys_regs sysregs_ctx;
fp_regs fpregs_ctx;
diff --git a/include/context_mgmt.h b/include/context_mgmt.h
index 2150a55..b8c8077 100644
--- a/include/context_mgmt.h
+++ b/include/context_mgmt.h
@@ -46,6 +46,9 @@
extern void cm_el3_sysregs_context_restore(uint32_t security_state);
extern void cm_el1_sysregs_context_save(uint32_t security_state);
extern void cm_el1_sysregs_context_restore(uint32_t security_state);
+extern void cm_set_el3_eret_context(uint32_t security_state, uint64_t entrypoint,
+ uint32_t spsr, uint32_t scr);
extern void cm_set_next_eret_context(uint32_t security_state);
+extern void cm_init_exception_stack(uint64_t mpidr, uint32_t security_state);
#endif /*__ASSEMBLY__*/
#endif /* __CM_H__ */
diff --git a/include/runtime_svc.h b/include/runtime_svc.h
index 3ee043e..ad202a9 100644
--- a/include/runtime_svc.h
+++ b/include/runtime_svc.h
@@ -101,43 +101,8 @@
#define SERROR_AARCH32 0xf
/*******************************************************************************
- * Constants that allow assembler code to access members of the 'gp_regs'
- * structure at their correct offsets.
+ * Structure definition, typedefs & constants for the runtime service framework
******************************************************************************/
-#define SIZEOF_GPREGS 0x110
-#define GPREGS_X0_OFF 0x0
-#define GPREGS_X1_OFF 0x8
-#define GPREGS_X2_OFF 0x10
-#define GPREGS_X3_OFF 0x18
-#define GPREGS_X4_OFF 0x20
-#define GPREGS_X5_OFF 0x28
-#define GPREGS_X6_OFF 0x30
-#define GPREGS_X7_OFF 0x38
-#define GPREGS_X8_OFF 0x40
-#define GPREGS_X9_OFF 0x48
-#define GPREGS_X10_OFF 0x50
-#define GPREGS_X11_OFF 0x58
-#define GPREGS_X12_OFF 0x60
-#define GPREGS_X13_OFF 0x68
-#define GPREGS_X14_OFF 0x70
-#define GPREGS_X15_OFF 0x78
-#define GPREGS_X16_OFF 0x80
-#define GPREGS_X17_OFF 0x88
-#define GPREGS_X18_OFF 0x90
-#define GPREGS_X19_OFF 0x98
-#define GPREGS_X20_OFF 0xA0
-#define GPREGS_X21_OFF 0xA8
-#define GPREGS_X22_OFF 0xB0
-#define GPREGS_X23_OFF 0xB8
-#define GPREGS_X24_OFF 0xC0
-#define GPREGS_X25_OFF 0xC8
-#define GPREGS_X26_OFF 0xD0
-#define GPREGS_X27_OFF 0xD8
-#define GPREGS_X28_OFF 0xE0
-#define GPREGS_SP_EL0_OFF 0xE8
-#define GPREGS_SPSR_OFF 0xF0
-#define GPREGS_FP_OFF 0x100
-#define GPREGS_LR_OFF 0x108
/*
* Constants to allow the assembler access a runtime service
@@ -219,46 +184,6 @@
void *handle,
uint64_t flags);
typedef struct {
- uint64_t x0;
- uint64_t x1;
- uint64_t x2;
- uint64_t x3;
- uint64_t x4;
- uint64_t x5;
- uint64_t x6;
- uint64_t x7;
- uint64_t x8;
- uint64_t x9;
- uint64_t x10;
- uint64_t x11;
- uint64_t x12;
- uint64_t x13;
- uint64_t x14;
- uint64_t x15;
- uint64_t x16;
- uint64_t x17;
- uint64_t x18;
- uint64_t x19;
- uint64_t x20;
- uint64_t x21;
- uint64_t x22;
- uint64_t x23;
- uint64_t x24;
- uint64_t x25;
- uint64_t x26;
- uint64_t x27;
- uint64_t x28;
- uint64_t sp_el0;
- uint32_t spsr;
- /*
- * Alignment constraint which allows save & restore of fp & lr on the
- * stack during exception handling
- */
- uint64_t fp __aligned(16);
- uint64_t lr;
-} __aligned(16) gp_regs;
-
-typedef struct {
uint8_t start_oen;
uint8_t end_oen;
uint8_t call_type;
@@ -280,16 +205,6 @@
_setup, \
_smch }
-/*******************************************************************************
- * Compile time assertions to ensure that:
- * 1) the assembler code's view of the size of the 'gp_regs' data structure is
- * the same as the actual size of this data structure.
- * 2) the assembler code's view of the offset of the frame pointer member of
- * the 'gp_regs' structure is the same as the actual offset of this member.
- ******************************************************************************/
-CASSERT((sizeof(gp_regs) == SIZEOF_GPREGS), assert_sizeof_gpregs_mismatch);
-CASSERT(GPREGS_FP_OFF == __builtin_offsetof(gp_regs, fp), \
- assert_gpregs_fp_offset_mismatch);
/*
* Compile time assertions related to the 'rt_svc_desc' structure to:
* 1. ensure that the assembler and the compiler view of the size
@@ -323,6 +238,7 @@
extern void runtime_svc_init();
extern uint64_t __RT_SVC_DESCS_START__;
extern uint64_t __RT_SVC_DESCS_END__;
-
+extern uint64_t get_exception_stack(uint64_t mpidr);
+extern void fault_handler(void *handle);
#endif /*__ASSEMBLY__*/
#endif /* __RUNTIME_SVC_H__ */
diff --git a/lib/arch/aarch64/misc_helpers.S b/lib/arch/aarch64/misc_helpers.S
index 37258e1..324be76 100644
--- a/lib/arch/aarch64/misc_helpers.S
+++ b/lib/arch/aarch64/misc_helpers.S
@@ -31,9 +31,6 @@
#include <arch_helpers.h>
#include <runtime_svc.h>
- .globl save_regs
- .globl restore_regs
-
.globl enable_irq
.globl disable_irq
@@ -84,51 +81,6 @@
.section .text, "ax"
-save_regs: ; .type save_regs, %function
- sub sp, sp, #GPREGS_FP_OFF
- stp x0, x1, [sp, #GPREGS_X0_OFF]
- stp x2, x3, [sp, #GPREGS_X2_OFF]
- stp x4, x5, [sp, #GPREGS_X4_OFF]
- stp x6, x7, [sp, #GPREGS_X6_OFF]
- stp x8, x9, [sp, #GPREGS_X8_OFF]
- stp x10, x11, [sp, #GPREGS_X10_OFF]
- stp x12, x13, [sp, #GPREGS_X12_OFF]
- stp x14, x15, [sp, #GPREGS_X14_OFF]
- stp x16, x17, [sp, #GPREGS_X16_OFF]
- stp x18, x19, [sp, #GPREGS_X18_OFF]
- stp x20, x21, [sp, #GPREGS_X20_OFF]
- stp x22, x23, [sp, #GPREGS_X22_OFF]
- stp x24, x25, [sp, #GPREGS_X24_OFF]
- stp x26, x27, [sp, #GPREGS_X26_OFF]
- mrs x0, sp_el0
- stp x28, x0, [sp, #GPREGS_X28_OFF]
- mrs x0, spsr_el3
- str w0, [sp, #GPREGS_SPSR_OFF]
- ret
-
-
-restore_regs: ; .type restore_regs, %function
- ldr w9, [sp, #GPREGS_SPSR_OFF]
- msr spsr_el3, x9
- ldp x28, x9, [sp, #GPREGS_X28_OFF]
- msr sp_el0, x9
- ldp x26, x27, [sp, #GPREGS_X26_OFF]
- ldp x24, x25, [sp, #GPREGS_X24_OFF]
- ldp x22, x23, [sp, #GPREGS_X22_OFF]
- ldp x20, x21, [sp, #GPREGS_X20_OFF]
- ldp x18, x19, [sp, #GPREGS_X18_OFF]
- ldp x16, x17, [sp, #GPREGS_X16_OFF]
- ldp x14, x15, [sp, #GPREGS_X14_OFF]
- ldp x12, x13, [sp, #GPREGS_X12_OFF]
- ldp x10, x11, [sp, #GPREGS_X10_OFF]
- ldp x8, x9, [sp, #GPREGS_X8_OFF]
- ldp x6, x7, [sp, #GPREGS_X6_OFF]
- ldp x4, x5, [sp, #GPREGS_X4_OFF]
- ldp x2, x3, [sp, #GPREGS_X2_OFF]
- ldp x0, x1, [sp, #GPREGS_X0_OFF]
- add sp, sp, #GPREGS_FP_OFF
- ret
-
get_afflvl_shift: ; .type get_afflvl_shift, %function
cmp x0, #3
cinc x0, x0, eq