lib: cpus: sanity check pointers before use
The cpu_ops structure contains a lot of function pointers. It
is a good idea to verify that the function pointer is not NULL
before executing it.
This patch sanity checks each pointer before use to prevent any
unforeseen crashes. These checks have been enabled for debug
builds only.
Change-Id: Ib208331c20e60f0c7c582a20eb3d8cc40fb99d21
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
diff --git a/lib/cpus/aarch64/cpu_helpers.S b/lib/cpus/aarch64/cpu_helpers.S
index 808c7f8..da663be 100644
--- a/lib/cpus/aarch64/cpu_helpers.S
+++ b/lib/cpus/aarch64/cpu_helpers.S
@@ -78,6 +78,10 @@
mov x1, #CPU_PWR_DWN_OPS
add x1, x1, x2, lsl #3
ldr x1, [x0, x1]
+#if ENABLE_ASSERTIONS
+ cmp x1, #0
+ ASM_ASSERT(ne)
+#endif
br x1
endfunc prepare_cpu_pwr_dwn
@@ -171,6 +175,10 @@
/* Subtract the increment and offset to get the cpu-ops pointer */
sub x0, x4, #(CPU_OPS_SIZE + CPU_MIDR)
+#if ENABLE_ASSERTIONS
+ cmp x0, #0
+ ASM_ASSERT(ne)
+#endif
error_exit:
ret
endfunc get_cpu_ops_ptr
@@ -276,7 +284,15 @@
* turn.
*/
mrs x0, tpidr_el3
+#if ENABLE_ASSERTIONS
+ cmp x0, #0
+ ASM_ASSERT(ne)
+#endif
ldr x1, [x0, #CPU_DATA_CPU_OPS_PTR]
+#if ENABLE_ASSERTIONS
+ cmp x1, #0
+ ASM_ASSERT(ne)
+#endif
ldr x0, [x1, #CPU_ERRATA_FUNC]
cbz x0, .Lnoprint
@@ -326,6 +342,10 @@
ASM_ASSERT(ne)
#endif
ldr x0, [x0, #CPU_DATA_CPU_OPS_PTR]
+#if ENABLE_ASSERTIONS
+ cmp x0, #0
+ ASM_ASSERT(ne)
+#endif
ldr x0, [x0, #CPU_EXTRA1_FUNC]
/*
* If the reserved function pointer is NULL, this CPU
@@ -359,6 +379,10 @@
ASM_ASSERT(ne)
#endif
ldr x0, [x0, #CPU_DATA_CPU_OPS_PTR]
+#if ENABLE_ASSERTIONS
+ cmp x0, #0
+ ASM_ASSERT(ne)
+#endif
ldr x0, [x0, #CPU_EXTRA2_FUNC]
ret
endfunc wa_cve_2018_3639_get_disable_ptr