[PATCH v7 0/9] ARM: VDSO

On 06/27/2014 04:46 AM, Russell King - ARM Linux wrote:

On Fri, Jun 27, 2014 at 11:41:46AM +0200, Ard Biesheuvel wrote:

quoted

It appears that the EF_ARM_ABI_FLOAT_[SOFT|HARD] defines are just renames of

#define EF_ARM_SOFT_FLOAT       0x200
#define EF_ARM_VFP_FLOAT        0x400

so perhaps use those instead?

Or maybe provide our own definitions so we're not reliant on the host
environment providing the correct definitions for these.

Right.

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This is what really concerns me about the VDSO.  It adds an additional
dependence on the C library in order to build the kernel.  What if you
don't have a C library in your cross-build setup (I don't.)

This is a host tool, so this is about the host libc not the target libc.

It still sounds pretty fragile.

Since removing -lgcc from the link (one of the changes from v6 to v7), I
believe the VDSO is not asking more of the toolchain or build
environment than the rest of the kernel does.  I have definitely built
it without a target libc.  Apart from the host program's use of
too-recent ELF constants (now fixed), I would appreciate help
identifying any remaining sources of fragility.