diff options
| author | Jisheng Zhang <jszhang@kernel.org> | 2023-01-29 01:28:52 +0800 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@rivosinc.com> | 2023-01-31 23:29:41 -0800 |
| commit | 8d23e94a443388e81c42ea7e476a5d79c1c795c9 (patch) | |
| tree | 2d6b984dc1e84a24f45256213efb52d4933b0937 /arch/riscv/kernel/cpufeature.c | |
| parent | 1bc400ffb52b460eedc51ebd9b7753b7f2314878 (diff) | |
riscv: switch to relative alternative entries
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>
Diffstat (limited to 'arch/riscv/kernel/cpufeature.c')
| -rw-r--r-- | arch/riscv/kernel/cpufeature.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 6193f401f0c5..18ea518f9e68 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -281,6 +281,7 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin, unsigned int stage) { struct alt_entry *alt; + void *oldptr, *altptr; if (stage == RISCV_ALTERNATIVES_EARLY_BOOT) return; @@ -297,9 +298,10 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin, if (!__riscv_isa_extension_available(NULL, alt->errata_id)) continue; - patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len); - riscv_alternative_fix_offsets(alt->old_ptr, alt->alt_len, - alt->old_ptr - alt->alt_ptr); + oldptr = ALT_OLD_PTR(alt); + altptr = ALT_ALT_PTR(alt); + patch_text_nosync(oldptr, altptr, alt->alt_len); + riscv_alternative_fix_offsets(oldptr, alt->alt_len, oldptr - altptr); } } #endif |