riscv: switch to relative alternative entries

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Instead of using absolute addresses for both the old instrucions and
the alternative instructions, use offsets relative to the alt_entry
values. So this not only cuts the size of the alternative entry, but
also meets the prerequisite for patching alternatives in the vDSO,
since absolute alternative entries are subject to dynamic relocation,
which is incompatible with the vDSO building.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230128172856.3814-10-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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Jisheng Zhang 2023-01-29 01:28:52 +08:00 • committed by Palmer Dabbelt

parent 1bc400ffb5

commit 8d23e94a44

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5 changed files with 36 additions and 23 deletions

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3

arch/riscv/errata/sifive/errata.c

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arch/riscv/errata/thead/errata.c

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arch/riscv/include/asm/alternative-macros.h

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arch/riscv/include/asm/alternative.h

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arch/riscv/kernel/cpufeature.c

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