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PIE: make call to GDT relocation fixup generalized

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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>
This commit is contained in:
Manish Pandey 2019-11-26 11:34:17 +00:00
parent b3257a3d39
commit da90359b78
4 changed files with 38 additions and 17 deletions
bl1/aarch64
bl1_entrypoint.S
bl2/aarch64
bl2_el3_entrypoint.S
bl31/aarch64
bl31_entrypoint.S
include/arch/aarch64
el3_common_macros.S

3
bl1/aarch64/bl1_entrypoint.S
View file

@ -30,7 +30,8 @@ func bl1_entrypoint
_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

3
bl2/aarch64/bl2_el3_entrypoint.S
View file

@ -26,7 +26,8 @@ func bl2_entrypoint
_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

20
bl31/aarch64/bl31_entrypoint.S
View file

@ -32,17 +32,6 @@ func bl31_entrypoint
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 @@ func bl31_entrypoint
_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 @@ func bl31_entrypoint
_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 @@ func bl31_warm_entrypoint
_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.

29
include/arch/aarch64/el3_common_macros.S
View file

@ -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.
* ---------------------------------------------------------------------