powerpc/pseries: Remove unnecessary syscall trampoline
When we originally added the ability to split the exception vectors from the kernel (commit 1f6a93e4 ("powerpc: Make it possible to move the interrupt handlers away from the kernel" 2008-09-15)), the LOAD_HANDLER() macro used an addi instruction to compute the offset of the common handler from the kernel base address. Using addi meant the handler had to be within 32K of the kernel base address, due to the addi instruction taking a signed immediate value. That necessitated creating a trampoline for the system call handler, because system_call_common (in entry64.S) is not linked within 32K of the kernel base address. Later in commit 61e2390e ("powerpc: Make load_hander handle upto 64k offset" 2012-11-15) we changed LOAD_HANDLER to take a 64K offset, by changing it to use ori. Although system_call_common is not in head_64.S or exceptions-64s.S, it is included in head-y, which causes it to be linked early in the kernel text, so in practice it ends up below 64K. Additionally if it can't be placed below 64K the linker will fail to build with a "relocation truncated to fit" error. So remove the trampoline. Newer toolchains are able to work out that the ori in LOAD_HANDLER only takes a 16 bit offset, and so they generate a 16 bit relocation. Older toolchains (binutils 2.22 at least) are not so smart, so we have to add the @l annotation to tell the assembler to generate a 16 bit relocation. Signed-off-by:Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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