AArch32: Add `TRUSTED_BOARD_BOOT` support
This patch adds `TRUSTED_BOARD_BOOT` support for AArch32 mode.
To build this patch the "mbedtls/include/mbedtls/bignum.h"
needs to be modified to remove `#define MBEDTLS_HAVE_UDBL`
when `MBEDTLS_HAVE_INT32` is defined. This is a workaround
for "https://github.com/ARMmbed/mbedtls/issues/708"
NOTE: TBBR support on Juno AArch32 is not currently supported.
Change-Id: I86d80e30b9139adc4d9663f112801ece42deafcf
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>
Co-Authored-By: Yatharth Kochar <yatharth.kochar@arm.com>
diff --git a/bl1/aarch32/bl1_exceptions.S b/bl1/aarch32/bl1_exceptions.S
index de7ddc5..f73db40 100644
--- a/bl1/aarch32/bl1_exceptions.S
+++ b/bl1/aarch32/bl1_exceptions.S
@@ -8,11 +8,18 @@
#include <asm_macros.S>
#include <bl1.h>
#include <bl_common.h>
+#include <context.h>
+#include <smcc_helpers.h>
+#include <smcc_macros.S>
+#include <xlat_tables.h>
.globl bl1_aarch32_smc_handler
func bl1_aarch32_smc_handler
+ /* On SMC entry, `sp` points to `smc_ctx_t`. Save `lr`. */
+ str lr, [sp, #SMC_CTX_LR_MON]
+
/* ------------------------------------------------
* SMC in BL1 is handled assuming that the MMU is
* turned off by BL2.
@@ -20,12 +27,12 @@
*/
/* ----------------------------------------------
- * Only RUN_IMAGE SMC is supported.
+ * Detect if this is a RUN_IMAGE or other SMC.
* ----------------------------------------------
*/
- mov r8, #BL1_SMC_RUN_IMAGE
- cmp r8, r0
- blne report_exception
+ mov lr, #BL1_SMC_RUN_IMAGE
+ cmp lr, r0
+ bne smc_handler
/* ------------------------------------------------
* Make sure only Secure world reaches here.
@@ -70,3 +77,76 @@
ldm r8, {r0, r1, r2, r3}
eret
endfunc bl1_aarch32_smc_handler
+
+ /* -----------------------------------------------------
+ * Save Secure/Normal world context and jump to
+ * BL1 SMC handler.
+ * -----------------------------------------------------
+ */
+func smc_handler
+ /* -----------------------------------------------------
+ * Save the GP registers.
+ * -----------------------------------------------------
+ */
+ smcc_save_gp_mode_regs
+
+ /*
+ * `sp` still points to `smc_ctx_t`. Save it to a register
+ * and restore the C runtime stack pointer to `sp`.
+ */
+ mov r6, sp
+ ldr sp, [r6, #SMC_CTX_SP_MON]
+
+ ldr r0, [r6, #SMC_CTX_SCR]
+ and r7, r0, #SCR_NS_BIT /* flags */
+
+ /* Switch to Secure Mode */
+ bic r0, #SCR_NS_BIT
+ stcopr r0, SCR
+ isb
+
+ /* If caller is from Secure world then turn on the MMU */
+ tst r7, #SCR_NS_BIT
+ bne skip_mmu_on
+
+ /* Turn on the MMU */
+ mov r0, #DISABLE_DCACHE
+ bl enable_mmu_secure
+
+ /* Enable the data cache. */
+ ldcopr r9, SCTLR
+ orr r9, r9, #SCTLR_C_BIT
+ stcopr r9, SCTLR
+ isb
+
+skip_mmu_on:
+ /* Prepare arguments for BL1 SMC wrapper. */
+ ldr r0, [r6, #SMC_CTX_GPREG_R0] /* smc_fid */
+ mov r1, #0 /* cookie */
+ mov r2, r6 /* handle */
+ mov r3, r7 /* flags */
+ bl bl1_smc_wrapper
+
+ /* Get the smc_context for next BL image */
+ bl smc_get_next_ctx
+ mov r4, r0
+
+ /* Only turn-off MMU if going to secure world */
+ ldr r5, [r4, #SMC_CTX_SCR]
+ tst r5, #SCR_NS_BIT
+ bne skip_mmu_off
+
+ /* Disable the MMU */
+ bl disable_mmu_icache_secure
+ stcopr r0, TLBIALL
+ dsb sy
+ isb
+
+skip_mmu_off:
+ /* -----------------------------------------------------
+ * Do the transition to next BL image.
+ * -----------------------------------------------------
+ */
+ mov r0, r4
+ monitor_exit
+endfunc smc_handler