Messages in this thread | | | Subject | Re: [PATCH V2] arm64/cpufeature: Add get_arm64_ftr_reg_nowarn() | From | Suzuki K Poulose <> | Date | Tue, 26 May 2020 15:04:14 +0100 |
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On 05/26/2020 02:39 PM, Anshuman Khandual wrote: > There is no way to proceed when requested register could not be searched in > arm64_ftr_reg[]. Requesting for a non present register would be an error as > well. Hence lets just WARN_ON() when search fails in get_arm64_ftr_reg() > rather than checking for return value and doing a BUG_ON() instead in some > individual callers. But there are also caller instances that dont error out > when register search fails. Add a new helper get_arm64_ftr_reg_nowarn() for > such cases. > > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > Cc: Mark Brown <broonie@kernel.org> > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> > --- > Changes in V2: > > - Added get_arm64_ftr_reg_nowarn() per Will > - read_sanitised_ftr_reg() returns 0 when register search fails per Catalin > > Changes in V1: (https://patchwork.kernel.org/patch/11559083/) > > arch/arm64/kernel/cpufeature.c | 42 +++++++++++++++++++++++----------- > 1 file changed, 29 insertions(+), 13 deletions(-) > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index bc5048f152c1..f4555b9d145c 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -548,16 +548,16 @@ static int search_cmp_ftr_reg(const void *id, const void *regp) > } >
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> static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg, > s64 ftr_val) > { > @@ -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; > -
You need to return here, on !regp. Rest looks fine to me.
Suzuki
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