Setup VBAR_EL3 incrementally
This patch ensures that VBAR_EL3 points to the simple stack-less
'early_exceptions' when the C runtime stack is not correctly setup to
use the more complex 'runtime_exceptions'. It is initialised to
'runtime_exceptions' once this is done.
This patch also moves all exception vectors into a '.vectors' section
and modifies linker scripts to place all such sections together. This
will minimize space wastage from alignment restrictions.
Change-Id: I8c3e596ea3412c8bd582af9e8d622bb1cb2e049d
diff --git a/bl1/aarch64/early_exceptions.S b/bl1/aarch64/early_exceptions.S
index ef47f9e..84bdae1 100644
--- a/bl1/aarch64/early_exceptions.S
+++ b/bl1/aarch64/early_exceptions.S
@@ -37,12 +37,12 @@
.globl early_exceptions
.weak display_boot_progress
- .section .text, "ax"; .align 11
+ .section .vectors, "ax"; .align 11
/* -----------------------------------------------------
- * Very simple exception handlers used by BL1 and BL2.
- * Apart from one SMC exception all other traps loop
- * endlessly.
+ * Very simple stackless exception handlers used by all
+ * bootloader stages. BL31 uses them before stacks are
+ * setup. BL1/BL2 use them throughout.
* -----------------------------------------------------
*/
.align 7
@@ -164,6 +164,7 @@
.align 7
+ .section .text, "ax"
process_exception:
sub sp, sp, #0x40
stp x0, x1, [sp, #0x0]
diff --git a/bl1/bl1.ld.S b/bl1/bl1.ld.S
index 969b8c2..ac52e52 100644
--- a/bl1/bl1.ld.S
+++ b/bl1/bl1.ld.S
@@ -45,6 +45,7 @@
*bl1_entrypoint.o(.text)
*(.text)
*(.rodata*)
+ *(.vectors)
__RO_END__ = .;
} >ROM
diff --git a/bl2/bl2.ld.S b/bl2/bl2.ld.S
index 849297a..77eb201 100644
--- a/bl2/bl2.ld.S
+++ b/bl2/bl2.ld.S
@@ -49,6 +49,7 @@
*bl2_entrypoint.o(.text)
*(.text)
*(.rodata*)
+ *(.vectors)
__RO_END_UNALIGNED__ = .;
/*
* Memory page(s) mapped to this section will be marked as
diff --git a/bl31/aarch64/bl31_entrypoint.S b/bl31/aarch64/bl31_entrypoint.S
index 57f6551..cd0c023 100644
--- a/bl31/aarch64/bl31_entrypoint.S
+++ b/bl31/aarch64/bl31_entrypoint.S
@@ -58,7 +58,7 @@
* Set the exception vector to something sane.
* ---------------------------------------------
*/
- adr x1, runtime_exceptions
+ adr x1, early_exceptions
msr vbar_el3, x1
/* ---------------------------------------------------------------------
@@ -155,6 +155,14 @@
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
diff --git a/bl31/aarch64/runtime_exceptions.S b/bl31/aarch64/runtime_exceptions.S
index ce0af74..92835dc 100644
--- a/bl31/aarch64/runtime_exceptions.S
+++ b/bl31/aarch64/runtime_exceptions.S
@@ -37,8 +37,8 @@
#include <asm_macros.S>
- .section .text, "ax"; .align 11
-
+ .section .vectors, "ax"; .align 11
+
.align 7
runtime_exceptions:
/* -----------------------------------------------------
diff --git a/bl31/bl31.ld.S b/bl31/bl31.ld.S
index 7cc8527..2583c9a 100644
--- a/bl31/bl31.ld.S
+++ b/bl31/bl31.ld.S
@@ -50,6 +50,7 @@
*bl31_entrypoint.o(.text)
*(.text)
*(.rodata*)
+ *(.vectors)
__RO_END_UNALIGNED__ = .;
/*
* Memory page(s) mapped to this section will be marked as read-only,
diff --git a/bl31/bl31.mk b/bl31/bl31.mk
index 5c374aa..f7c2168 100644
--- a/bl31/bl31.mk
+++ b/bl31/bl31.mk
@@ -62,7 +62,8 @@
spinlock.o \
gic_v3_sysregs.o \
bakery_lock.o \
- runtime_svc.o
+ runtime_svc.o \
+ early_exceptions.o
BL31_ENTRY_POINT := bl31_entrypoint
BL31_MAPFILE := bl31.map
diff --git a/common/psci/psci_afflvl_on.c b/common/psci/psci_afflvl_on.c
index 83d47d5..14f524c 100644
--- a/common/psci/psci_afflvl_on.c
+++ b/common/psci/psci_afflvl_on.c
@@ -353,7 +353,6 @@
/*
* Arch. management: Turn on mmu & restore architectural state
*/
- write_vbar((unsigned long) runtime_exceptions);
enable_mmu();
/*
diff --git a/common/psci/psci_afflvl_suspend.c b/common/psci/psci_afflvl_suspend.c
index 2abcafb..f374840 100644
--- a/common/psci/psci_afflvl_suspend.c
+++ b/common/psci/psci_afflvl_suspend.c
@@ -115,7 +115,6 @@
psci_suspend_context[index].sec_sysregs.mair = read_mair();
psci_suspend_context[index].sec_sysregs.tcr = read_tcr();
psci_suspend_context[index].sec_sysregs.ttbr = read_ttbr0();
- psci_suspend_context[index].sec_sysregs.vbar = read_vbar();
psci_suspend_context[index].sec_sysregs.pstate =
read_daif() & (DAIF_ABT_BIT | DAIF_DBG_BIT);
@@ -424,7 +423,6 @@
* Arch. management: Restore the stashed secure architectural
* context in the right order.
*/
- write_vbar(psci_suspend_context[index].sec_sysregs.vbar);
write_daif(read_daif() | psci_suspend_context[index].sec_sysregs.pstate);
write_mair(psci_suspend_context[index].sec_sysregs.mair);
write_tcr(psci_suspend_context[index].sec_sysregs.tcr);
diff --git a/common/psci/psci_entry.S b/common/psci/psci_entry.S
index a6a1a6f..28a4143 100644
--- a/common/psci/psci_entry.S
+++ b/common/psci/psci_entry.S
@@ -63,6 +63,17 @@
psci_aff_common_finish_entry:
adr x22, psci_afflvl_power_on_finish
+
+ /* ---------------------------------------------
+ * Exceptions should not occur at this point.
+ * Set VBAR in order to handle and report any
+ * that do occur
+ * ---------------------------------------------
+ */
+ adr x0, early_exceptions
+ msr vbar_el3, x0
+ isb
+
bl read_mpidr
mov x19, x0
bl platform_set_coherent_stack
@@ -90,6 +101,16 @@
mov x0, x19
bl platform_set_stack
+ /* ---------------------------------------------
+ * Now that the execution stack 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
+ * ---------------------------------------------
+ */
+ adr x0, runtime_exceptions
+ msr vbar_el3, x0
+
/* --------------------------------------------
* Use the size of the general purpose register
* context to restore the register state
diff --git a/include/aarch64/arch.h b/include/aarch64/arch.h
index 10d2adb..f40e148 100644
--- a/include/aarch64/arch.h
+++ b/include/aarch64/arch.h
@@ -326,7 +326,6 @@
unsigned long mair;
unsigned long tcr;
unsigned long ttbr;
- unsigned long vbar;
unsigned long pstate;
} sysregs_context;