BL31 arg0 potentially clobbered by init_c_runtime?

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Issue tracking for the ARM Trusted Firmware project

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BL31 arg0 potentially clobbered by init_c_runtime? #626

Closed GrqPnegre closed 5 years ago

GrqPnegre commented 6 years ago

In arm_bl31_early_plaform_setup for LOAD_IMAGE_V2, a portion of the BL2 address space is copied into BL31's: /*

Copy BL33 and BL32 (if present), entry point information.
They are stored in Secure RAM, in BL2's address space. */ As I understand, BL31 NOBITS is overlapping part or all BL2. Are there any guarantees that this memory won't be clobbered when BL31 performs init_c_runtime near its cold boot entry-point?

soby-mathew commented 6 years ago

Hi @grqpnegre,

The commit c099cd3 allowed BL31 to overlay BL2 for ARM platforms to enable more space for BL31. Currently the bl_params list in BL2 data section does not get corrupted by BL31 overlay, but there needs to be assertion check that BL31 will not clobber this region.

Thanks for bringing this to notice.

soby-mathew commented 6 years ago

Internal ref: https://jira.arm.com/browse/GENFW-2661