Add exception vector guards

This patch adds guards so that an exception vector exceeding 32
instructions will generate a compile-time error. This keeps the
exception handlers in check from spilling over.

Change-Id: I7aa56dd0071a333664e2814c656d3896032046fe

diff --git a/bl1/aarch64/early_exceptions.S b/bl1/aarch64/early_exceptions.S
index 84bdae162c6e7b525206318f7d751743f8d4ebd1..d06e85435ffbd6a2038323e09b43662212f72fb4 100644 (file)
--- a/bl1/aarch64/early_exceptions.S
+++ b/bl1/aarch64/early_exceptions.S
@@ -33,6 +33,7 @@
 #include <bl1.h>
 #include <platform.h>
 #include <runtime_svc.h>
+#include <asm_macros.S>
 
        .globl  early_exceptions
        .weak   display_boot_progress
@@ -55,24 +56,28 @@ SynchronousExceptionSP0:
        mov     x0, #SYNC_EXCEPTION_SP_EL0
        bl      plat_report_exception
        b       SynchronousExceptionSP0
+       check_vector_size SynchronousExceptionSP0
 
        .align  7
 IrqSP0:
        mov     x0, #IRQ_SP_EL0
        bl      plat_report_exception
        b       IrqSP0
+       check_vector_size IrqSP0
 
        .align  7
 FiqSP0:
        mov     x0, #FIQ_SP_EL0
        bl      plat_report_exception
        b       FiqSP0
+       check_vector_size FiqSP0
 
        .align  7
 SErrorSP0:
        mov     x0, #SERROR_SP_EL0
        bl      plat_report_exception
        b       SErrorSP0
+       check_vector_size SErrorSP0
 
        /* -----------------------------------------------------
         * Current EL with SPx: 0x200 - 0x380
@@ -83,24 +88,28 @@ SynchronousExceptionSPx:
        mov     x0, #SYNC_EXCEPTION_SP_ELX
        bl      plat_report_exception
        b       SynchronousExceptionSPx
+       check_vector_size SynchronousExceptionSPx
 
        .align  7
 IrqSPx:
        mov     x0, #IRQ_SP_ELX
        bl      plat_report_exception
        b       IrqSPx
+       check_vector_size IrqSPx
 
        .align  7
 FiqSPx:
        mov     x0, #FIQ_SP_ELX
        bl      plat_report_exception
        b       FiqSPx
+       check_vector_size FiqSPx
 
        .align  7
 SErrorSPx:
        mov     x0, #SERROR_SP_ELX
        bl      plat_report_exception
        b       SErrorSPx
+       check_vector_size SErrorSPx
 
        /* -----------------------------------------------------
         * Lower EL using AArch64 : 0x400 - 0x580
@@ -115,24 +124,28 @@ SynchronousExceptionA64:
         * ---------------------------------------------
         */
        b       process_exception
+       check_vector_size SynchronousExceptionA64
 
        .align  7
 IrqA64:
        mov     x0, #IRQ_AARCH64
        bl      plat_report_exception
        b       IrqA64
+       check_vector_size IrqA64
 
        .align  7
 FiqA64:
        mov     x0, #FIQ_AARCH64
        bl      plat_report_exception
        b       FiqA64
+       check_vector_size FiqA64
 
        .align  7
 SErrorA64:
        mov     x0, #SERROR_AARCH64
        bl      plat_report_exception
        b       SErrorA64
+       check_vector_size SErrorA64
 
        /* -----------------------------------------------------
         * Lower EL using AArch32 : 0x0 - 0x180
@@ -143,24 +156,28 @@ SynchronousExceptionA32:
        mov     x0, #SYNC_EXCEPTION_AARCH32
        bl      plat_report_exception
        b       SynchronousExceptionA32
+       check_vector_size SynchronousExceptionA32
 
        .align  7
 IrqA32:
        mov     x0, #IRQ_AARCH32
        bl      plat_report_exception
        b       IrqA32
+       check_vector_size IrqA32
 
        .align  7
 FiqA32:
        mov     x0, #FIQ_AARCH32
        bl      plat_report_exception
        b       FiqA32
+       check_vector_size FiqA32
 
        .align  7
 SErrorA32:
        mov     x0, #SERROR_AARCH32
        bl      plat_report_exception
        b       SErrorA32
+       check_vector_size SErrorA32
 
        .align  7
 

diff --git a/bl31/aarch64/runtime_exceptions.S b/bl31/aarch64/runtime_exceptions.S
index 10e65dc8b1441054093545d2b8a3a360bbb2f424..870c27427fc2986dfd3d826672ba658f5548f927 100644 (file)
--- a/bl31/aarch64/runtime_exceptions.S
+++ b/bl31/aarch64/runtime_exceptions.S
@@ -32,6 +32,7 @@
 #include <runtime_svc.h>
 #include <platform.h>
 #include <context.h>
+#include "asm_macros.S"
 #include "cm_macros.S"
 
        .globl  runtime_exceptions
@@ -53,6 +54,7 @@ sync_exception_sp_el0:
         */
        wfi
        b       sync_exception_sp_el0
+       check_vector_size sync_exception_sp_el0
 
        .align  7
        /* -----------------------------------------------------
@@ -63,16 +65,19 @@ sync_exception_sp_el0:
 irq_sp_el0:
        handle_async_exception IRQ_SP_EL0
        b       irq_sp_el0
+       check_vector_size irq_sp_el0
 
        .align  7
 fiq_sp_el0:
        handle_async_exception FIQ_SP_EL0
        b       fiq_sp_el0
+       check_vector_size fiq_sp_el0
 
        .align  7
 serror_sp_el0:
        handle_async_exception SERROR_SP_EL0
        b       serror_sp_el0
+       check_vector_size serror_sp_el0
 
        /* -----------------------------------------------------
         * Current EL with SPx: 0x200 - 0x380
@@ -93,6 +98,7 @@ sync_exception_sp_elx:
         */
        wfi
        b       sync_exception_sp_elx
+       check_vector_size sync_exception_sp_elx
 
        /* -----------------------------------------------------
         * As mentioned in the previous comment, all bets are
@@ -103,12 +109,17 @@ sync_exception_sp_elx:
        .align  7
 irq_sp_elx:
        b       irq_sp_elx
+       check_vector_size irq_sp_elx
+
        .align  7
 fiq_sp_elx:
        b       fiq_sp_elx
+       check_vector_size fiq_sp_elx
+
        .align  7
 serror_sp_elx:
        b       serror_sp_elx
+       check_vector_size serror_sp_elx
 
        /* -----------------------------------------------------
         * Lower EL using AArch64 : 0x400 - 0x580
@@ -125,6 +136,7 @@ sync_exception_aarch64:
         * -----------------------------------------------------
         */
        handle_sync_exception
+       check_vector_size sync_exception_aarch64
 
        .align  7
        /* -----------------------------------------------------
@@ -135,16 +147,19 @@ sync_exception_aarch64:
 irq_aarch64:
        handle_async_exception IRQ_AARCH64
        b       irq_aarch64
+       check_vector_size irq_aarch64
 
        .align  7
 fiq_aarch64:
        handle_async_exception FIQ_AARCH64
        b       fiq_aarch64
+       check_vector_size fiq_aarch64
 
        .align  7
 serror_aarch64:
        handle_async_exception SERROR_AARCH64
        b       serror_aarch64
+       check_vector_size serror_aarch64
 
        /* -----------------------------------------------------
         * Lower EL using AArch32 : 0x600 - 0x780
@@ -161,6 +176,7 @@ sync_exception_aarch32:
         * -----------------------------------------------------
         */
        handle_sync_exception
+       check_vector_size sync_exception_aarch32
 
        .align  7
        /* -----------------------------------------------------
@@ -171,16 +187,20 @@ sync_exception_aarch32:
 irq_aarch32:
        handle_async_exception IRQ_AARCH32
        b       irq_aarch32
+       check_vector_size irq_aarch32
 
        .align  7
 fiq_aarch32:
        handle_async_exception FIQ_AARCH32
        b       fiq_aarch32
+       check_vector_size fiq_aarch32
 
        .align  7
 serror_aarch32:
        handle_async_exception SERROR_AARCH32
        b       serror_aarch32
+       check_vector_size serror_aarch32
+
        .align  7
 
        .section        .text, "ax"

diff --git a/include/asm_macros.S b/include/asm_macros.S
index decef0b952d3e84c87e86a240169e8ccbe68dc1f..f94d75fe714bcf51d32f718cc6d2f4d4e79ecdc2 100644 (file)
--- a/include/asm_macros.S
+++ b/include/asm_macros.S
@@ -68,3 +68,15 @@
        ubfx    \end_level, \clidr, \shift, \fw
        lsl     \end_level, \end_level, \ls
        .endm
+
+       /*
+        * This macro verifies that the a given vector doesn't exceed the
+        * architectural limit of 32 instructions. This is meant to be placed
+        * immedately after the last instruction in the vector. It takes the
+        * vector entry as the parameter
+        */
+       .macro check_vector_size since
+         .if (. - \since) > (32 * 4)
+           .error "Vector exceeds 32 instructions"
+         .endif
+       .endm