On 01/13/2015 12:45 PM, Ian Campbell wrote:
The secure world code is relocated to the MB just below the top of 4G, we
reserve it in the FDT (by setting CONFIG_ARMV7_SECURE_RESERVE_SIZE) but it is
not protected in h/w. See next patch.
diff --git a/include/configs/jetson-tk1.h b/include/configs/jetson-tk1.h
+#define CONFIG_ARMV7_PSCI 1
+/* Reserve top 1M for secure RAM */
+#define CONFIG_ARMV7_SECURE_BASE 0xfff00000
+#define CONFIG_ARMV7_SECURE_RESERVE_SIZE 0x00100000
I /think/ the assumption in the existing code is that
CONFIG_ARMV7_SECURE_BASE is the base of some out-of-DRAM secure memory,
and hence that's why arch/arm/cpu/armv7/virt-dt.c() only reserves memory
if that symbol is *not* set? That seems like rather a confusing semantic
given the variable name. Introducing a new define that looks like it's
simply the size of that region but actually changes the reservation
semantics makes the situation worse for me.
Wouldn't it be better to have:
CONFIG_ARMV7_SECURE_BASE defines where the secure code is copied to.
CONFIG_ARMV7_SECURE_BASE_IS_IN_DRAM defines the obvious; whether the
secure base is in DRAM or not.
That define would default to unset and you'd get the current behaviour.
If that define was set, then CONFIG_ARMV7_SECURE_BASE through
CONFIG_ARMV7_SECURE_BASE + (__secure_end - __secure_start) would be
reserved in RAM?
That way, armv7_update_dt would be more like:
int armv7_update_dt(void *fdt)
{
#if defined(CONFIG_ARMV7_SECURE_BASE_IS_IN_DRAM) || \
!defined(CONFIG_ARMV7_SECURE_BASE)
/* secure code lives in RAM, keep it alive */
#if defined(CONFIG_ARMV7_SECURE_BASE)
base = CONFIG_ARMV7_SECURE_BASE;
#else
base = __secure_start;
#endif
fdt_add_mem_rsv(fdt, base, __secure_end - __secure_start);
#endif
return fdt_psci(fdt);
}
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