PIE: make call to GDT relocation fixup generalized
When a Firmware is complied as Position Independent Executable it needs
to request GDT fixup by passing size of the memory region to
el3_entrypoint_common macro.
The Global descriptor table fixup will be done early on during cold boot
process of primary core.
Currently only BL31 supports PIE, but in future when BL2_AT_EL3 will be
compiled as PIE, it can simply pass fixup size to the common el3
entrypoint macro to fixup GDT.
The reason for this patch was to overcome the bug introduced by SHA
330ead806 which called fixup routine for each core causing
re-initializing of global pointers thus overwriting any changes
done by the previous core.
Change-Id: I55c792cc3ea9e7eef34c2e4653afd04572c4f055
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
diff --git a/bl1/aarch64/bl1_entrypoint.S b/bl1/aarch64/bl1_entrypoint.S
index 855add3..00f2718 100644
--- a/bl1/aarch64/bl1_entrypoint.S
+++ b/bl1/aarch64/bl1_entrypoint.S
@@ -30,7 +30,8 @@
_secondary_cold_boot=!COLD_BOOT_SINGLE_CPU \
_init_memory=1 \
_init_c_runtime=1 \
- _exception_vectors=bl1_exceptions
+ _exception_vectors=bl1_exceptions \
+ _pie_fixup_size=0
/* --------------------------------------------------------------------
* Perform BL1 setup
diff --git a/bl2/aarch64/bl2_el3_entrypoint.S b/bl2/aarch64/bl2_el3_entrypoint.S
index 6fe2dd9..f97121e 100644
--- a/bl2/aarch64/bl2_el3_entrypoint.S
+++ b/bl2/aarch64/bl2_el3_entrypoint.S
@@ -26,7 +26,8 @@
_secondary_cold_boot=!COLD_BOOT_SINGLE_CPU \
_init_memory=1 \
_init_c_runtime=1 \
- _exception_vectors=bl2_el3_exceptions
+ _exception_vectors=bl2_el3_exceptions \
+ _pie_fixup_size=0
/* ---------------------------------------------
* Restore parameters of boot rom
diff --git a/bl31/aarch64/bl31_entrypoint.S b/bl31/aarch64/bl31_entrypoint.S
index 1ad26e4..74b0993 100644
--- a/bl31/aarch64/bl31_entrypoint.S
+++ b/bl31/aarch64/bl31_entrypoint.S
@@ -32,17 +32,6 @@
mov x22, x2
mov x23, x3
- /* --------------------------------------------------------------------
- * If PIE is enabled, fixup the Global descriptor Table and dynamic
- * relocations
- * --------------------------------------------------------------------
- */
-#if ENABLE_PIE
- mov_imm x0, BL31_BASE
- mov_imm x1, BL31_LIMIT
- bl fixup_gdt_reloc
-#endif /* ENABLE_PIE */
-
#if !RESET_TO_BL31
/* ---------------------------------------------------------------------
* For !RESET_TO_BL31 systems, only the primary CPU ever reaches
@@ -59,7 +48,8 @@
_secondary_cold_boot=0 \
_init_memory=0 \
_init_c_runtime=1 \
- _exception_vectors=runtime_exceptions
+ _exception_vectors=runtime_exceptions \
+ _pie_fixup_size=BL31_LIMIT - BL31_BASE
#else
/* ---------------------------------------------------------------------
@@ -74,7 +64,8 @@
_secondary_cold_boot=!COLD_BOOT_SINGLE_CPU \
_init_memory=1 \
_init_c_runtime=1 \
- _exception_vectors=runtime_exceptions
+ _exception_vectors=runtime_exceptions \
+ _pie_fixup_size=BL31_LIMIT - BL31_BASE
/* ---------------------------------------------------------------------
* For RESET_TO_BL31 systems, BL31 is the first bootloader to run so
@@ -174,7 +165,8 @@
_secondary_cold_boot=0 \
_init_memory=0 \
_init_c_runtime=0 \
- _exception_vectors=runtime_exceptions
+ _exception_vectors=runtime_exceptions \
+ _pie_fixup_size=0
/*
* We're about to enable MMU and participate in PSCI state coordination.
diff --git a/include/arch/aarch64/el3_common_macros.S b/include/arch/aarch64/el3_common_macros.S
index 378e827..b14b7b6 100644
--- a/include/arch/aarch64/el3_common_macros.S
+++ b/include/arch/aarch64/el3_common_macros.S
@@ -232,11 +232,18 @@
*
* _exception_vectors:
* Address of the exception vectors to program in the VBAR_EL3 register.
+ *
+ * _pie_fixup_size:
+ * Size of memory region to fixup Global Descriptor Table (GDT).
+ *
+ * A non-zero value is expected when firmware needs GDT to be fixed-up.
+ *
* -----------------------------------------------------------------------------
*/
.macro el3_entrypoint_common \
_init_sctlr, _warm_boot_mailbox, _secondary_cold_boot, \
- _init_memory, _init_c_runtime, _exception_vectors
+ _init_memory, _init_c_runtime, _exception_vectors, \
+ _pie_fixup_size
.if \_init_sctlr
/* -------------------------------------------------------------
@@ -283,6 +290,26 @@
do_cold_boot:
.endif /* _warm_boot_mailbox */
+ .if \_pie_fixup_size
+#if ENABLE_PIE
+ /*
+ * ------------------------------------------------------------
+ * If PIE is enabled fixup the Global descriptor Table only
+ * once during primary core cold boot path.
+ *
+ * Compile time base address, required for fixup, is calculated
+ * using "pie_fixup" label present within first page.
+ * ------------------------------------------------------------
+ */
+ pie_fixup:
+ ldr x0, =pie_fixup
+ and x0, x0, #~(PAGE_SIZE - 1)
+ mov_imm x1, \_pie_fixup_size
+ add x1, x1, x0
+ bl fixup_gdt_reloc
+#endif /* ENABLE_PIE */
+ .endif /* _pie_fixup_size */
+
/* ---------------------------------------------------------------------
* Set the exception vectors.
* ---------------------------------------------------------------------