arm64: entry: Add macro for reading symbol addresses from the trampoline
authorJames Morse <james.morse@arm.com>
Thu, 25 Nov 2021 14:25:34 +0000 (14:25 +0000)
committerJames Morse <james.morse@arm.com>
Wed, 16 Feb 2022 13:16:27 +0000 (13:16 +0000)
commitb28a8eebe81c186fdb1a0078263b30576c8e1f42
tree1ed8e379c63bc0b06b082c983d31557b56811fef
parentba2689234be92024e5635d30fe744f4853ad97db
arm64: entry: Add macro for reading symbol addresses from the trampoline

The trampoline code needs to use the address of symbols in the wider
kernel, e.g. vectors. PC-relative addressing wouldn't work as the
trampoline code doesn't run at the address the linker expected.

tramp_ventry uses a literal pool, unless CONFIG_RANDOMIZE_BASE is
set, in which case it uses the data page as a literal pool because
the data page can be unmapped when running in user-space, which is
required for CPUs vulnerable to meltdown.

Pull this logic out as a macro, instead of adding a third copy
of it.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
arch/arm64/kernel/entry.S