Messages in this thread | | | Subject | Re: [PATCH V2] arm64/cpufeature: Add get_arm64_ftr_reg_nowarn() | From | Anshuman Khandual <> | Date | Wed, 27 May 2020 07:56:30 +0530 |
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On 05/27/2020 01:16 AM, Will Deacon wrote: > On Tue, May 26, 2020 at 04:01:35PM +0100, Catalin Marinas wrote: >> On Tue, May 26, 2020 at 07:09:13PM +0530, Anshuman Khandual wrote: >>> @@ -632,8 +654,6 @@ static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new) >>> const struct arm64_ftr_bits *ftrp; >>> struct arm64_ftr_reg *reg = get_arm64_ftr_reg(sys_reg); >>> >>> - BUG_ON(!reg); >>> - >>> for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) { >>> u64 ftr_mask = arm64_ftr_mask(ftrp); >>> s64 ftr_new = arm64_ftr_value(ftrp, new); >>> @@ -762,7 +782,6 @@ static int check_update_ftr_reg(u32 sys_id, int cpu, u64 val, u64 boot) >>> { >>> struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id); >>> >>> - BUG_ON(!regp); >>> update_cpu_ftr_reg(regp, val); >>> if ((boot & regp->strict_mask) == (val & regp->strict_mask)) >>> return 0; >>> @@ -776,9 +795,6 @@ static void relax_cpu_ftr_reg(u32 sys_id, int field) >>> const struct arm64_ftr_bits *ftrp; >>> struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id); >>> >>> - if (WARN_ON(!regp)) >>> - return; >> >> I think Will wanted an early return in all these functions not just >> removing the BUG_ON(). I'll let him clarify. > > Yes, the callers need to check the pointer and return early.
Sure, will do. But for check_update_ftr_reg(), a feature register search failure should be treated as a success (0) or a failure (1). What should it return ? Seems bit tricky, as there are good reasons to go either way.
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