From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v4 5/5] arm64/kernel: enable A53 erratum #8434319 handling at runtime
Date: Thu, 8 Mar 2018 13:59:35 +0000 [thread overview]
Message-ID: <20180308135935.GA9573@arm.com> (raw)
In-Reply-To: <CAKv+Gu9a8pWdhN4PjN2t0dSpiocQfWhvr_jioxmhU2iJRSfV7g@mail.gmail.com>
On Thu, Mar 08, 2018 at 01:54:26PM +0000, Ard Biesheuvel wrote:
> On 8 March 2018 at 13:49, Mark Rutland <mark.rutland@arm•com> wrote:
> > On Thu, Mar 08, 2018 at 01:46:34PM +0000, Ard Biesheuvel wrote:
> >> On 8 March 2018 at 13:45, Will Deacon <will.deacon@arm•com> wrote:
> >> > On Tue, Mar 06, 2018 at 05:15:35PM +0000, Ard Biesheuvel wrote:
> >> >> Omit patching of ADRP instruction at module load time if the current
> >> >> CPUs are not susceptible to the erratum.
> >> >
> >> > [...]
> >> >
> >> >> diff --git a/arch/arm64/kernel/module-plts.c b/arch/arm64/kernel/module-plts.c
> >> >> index 534bf1d47119..1a583ccace00 100644
> >> >> --- a/arch/arm64/kernel/module-plts.c
> >> >> +++ b/arch/arm64/kernel/module-plts.c
> >> >> @@ -158,7 +158,8 @@ static unsigned int count_plts(Elf64_Sym *syms, Elf64_Rela *rela, int num,
> >> >> break;
> >> >> case R_AARCH64_ADR_PREL_PG_HI21_NC:
> >> >> case R_AARCH64_ADR_PREL_PG_HI21:
> >> >> - if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_843419))
> >> >> + if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_843419) ||
> >> >> + !cpus_have_const_cap(ARM64_WORKAROUND_843419))
> >> >> break;
> >> >>
> >> >> /*
> >> >> diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c
> >> >> index 89217704944e..47b40aaa1a5d 100644
> >> >> --- a/arch/arm64/kernel/module.c
> >> >> +++ b/arch/arm64/kernel/module.c
> >> >> @@ -201,6 +201,7 @@ static int reloc_insn_imm(enum aarch64_reloc_op op, __le32 *place, u64 val,
> >> >> static int reloc_insn_adrp(struct module *mod, __le32 *place, u64 val)
> >> >> {
> >> >> if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_843419) ||
> >> >> + !cpus_have_const_cap(ARM64_WORKAROUND_843419) ||
> >> >
> >> > Mind if I drop the IS_ENABLED check here and in the hunk above? The
> >> > const_cap check along should be sufficient, no?
> >> >
> >>
> >> Without the IS_ENABLED() check, the code will always be present in the
> >> object file.
> >>
> >> I have no strong preference either way, though.
> >
> > As with other case, perhaps fold this into a helper in
> > <asm/cpufeature.h> ?
> >
> > static inline bool system_needs_arm64_workaround_843419()
> > {
> > return (IS_ENABLED(CONFIG_ARM64_ERRATUM_843419) &&
> > cpus_have_const_cap(ARM64_WORKAROUND_843419))
> > }
> >
> > ... then use the inverse in the cases above.
> >
>
> I'm fine with adding a helper, but
> 'system_needs_arm64_workaround_843419' is a bit misleading, given that
> it returns false if the system needs it but support is compiled out.
FWIW, I'm fine with the code as it is.
Will
prev parent reply other threads:[~2018-03-08 13:59 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-06 17:15 [PATCH v4 0/5] arm64/kernel: get rid of GCC large model code Ard Biesheuvel
2018-03-06 17:15 ` [PATCH v4 1/5] arm64: module: don't BUG when exceeding preallocated PLT count Ard Biesheuvel
2018-03-06 17:15 ` [PATCH v4 2/5] arm64/kernel: kaslr: reduce module randomization range to 4 GB Ard Biesheuvel
2018-03-06 17:15 ` [PATCH v4 3/5] arm64/kernel: don't ban ADRP to work around Cortex-A53 erratum #843419 Ard Biesheuvel
2018-03-06 17:15 ` [PATCH v4 4/5] arm64/errata: add REVIDR handling to framework Ard Biesheuvel
2018-03-06 17:15 ` [PATCH v4 5/5] arm64/kernel: enable A53 erratum #8434319 handling at runtime Ard Biesheuvel
2018-03-08 13:45 ` Will Deacon
2018-03-08 13:46 ` Ard Biesheuvel
2018-03-08 13:47 ` Ard Biesheuvel
2018-03-08 13:48 ` Will Deacon
2018-03-08 13:49 ` Mark Rutland
2018-03-08 13:54 ` Ard Biesheuvel
2018-03-08 13:59 ` Will Deacon [this message]
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