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-rw-r--r--bl1/aarch32/bl1_exceptions.S165
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diff --git a/bl1/aarch32/bl1_exceptions.S b/bl1/aarch32/bl1_exceptions.S
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+/*
+ * Copyright (c) 2016-2022, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <bl1/bl1.h>
+#include <common/bl_common.h>
+#include <context.h>
+#include <lib/xlat_tables/xlat_tables.h>
+#include <smccc_helpers.h>
+#include <smccc_macros.S>
+
+ .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.
+ * ------------------------------------------------
+ */
+
+ /* ----------------------------------------------
+ * Detect if this is a RUN_IMAGE or other SMC.
+ * ----------------------------------------------
+ */
+ mov lr, #BL1_SMC_RUN_IMAGE
+ cmp lr, r0
+ bne smc_handler
+
+ /* ------------------------------------------------
+ * Make sure only Secure world reaches here.
+ * ------------------------------------------------
+ */
+ ldcopr r8, SCR
+ tst r8, #SCR_NS_BIT
+ blne report_exception
+
+ /* ---------------------------------------------------------------------
+ * Pass control to next secure image.
+ * Here it expects r1 to contain the address of a entry_point_info_t
+ * structure describing the BL entrypoint.
+ * ---------------------------------------------------------------------
+ */
+ mov r8, r1
+ mov r0, r1
+ bl bl1_print_next_bl_ep_info
+
+#if SPIN_ON_BL1_EXIT
+ bl print_debug_loop_message
+debug_loop:
+ b debug_loop
+#endif
+
+ mov r0, r8
+ bl bl1_plat_prepare_exit
+
+ stcopr r0, TLBIALL
+ dsb sy
+ isb
+
+ /*
+ * Extract PC and SPSR based on struct `entry_point_info_t`
+ * and load it in LR and SPSR registers respectively.
+ */
+ ldr lr, [r8, #ENTRY_POINT_INFO_PC_OFFSET]
+ ldr r1, [r8, #(ENTRY_POINT_INFO_PC_OFFSET + 4)]
+ msr spsr_xc, r1
+
+ /* Some BL32 stages expect lr_svc to provide the BL33 entry address */
+ cps #MODE32_svc
+ ldr lr, [r8, #ENTRY_POINT_INFO_LR_SVC_OFFSET]
+ cps #MODE32_mon
+
+ add r8, r8, #ENTRY_POINT_INFO_ARGS_OFFSET
+ ldm r8, {r0, r1, r2, r3}
+ exception_return
+endfunc bl1_aarch32_smc_handler
+
+ /* -----------------------------------------------------
+ * Save Secure/Normal world context and jump to
+ * BL1 SMC handler.
+ * -----------------------------------------------------
+ */
+func smc_handler
+ /* -----------------------------------------------------
+ * Save the GP registers.
+ * -----------------------------------------------------
+ */
+ smccc_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_svc_mon
+
+ /*
+ * Invalidate `smc_ctx_t` in data cache to prevent dirty data being
+ * used.
+ */
+ mov r0, r6
+ mov r1, #SMC_CTX_SIZE
+ bl inv_dcache_range
+
+ /* 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