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From: Paul Burton <paul.burton@mips.com>
To: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
	"linux-kselftest@vger.kernel.org"
	<linux-kselftest@vger.kernel.org>,
	"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
	"will@kernel.org" <will@kernel.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"salyzyn@android.com" <salyzyn@android.com>,
	"0x7f454c46@gmail.com" <0x7f454c46@gmail.com>,
	"luto@kernel.org" <luto@kernel.org>
Subject: Re: [PATCH v2 3/8] mips: compat: vdso: Use legacy syscalls as fallback
Date: Tue, 3 Sep 2019 13:52:19 +0000
Message-ID: <20190903134335.uxxf5kvp3afe7rfr@pburton-laptop> (raw)
In-Reply-To: <20190830135902.20861-4-vincenzo.frascino@arm.com>

Hi Vincenzo,

On Fri, Aug 30, 2019 at 02:58:57PM +0100, Vincenzo Frascino wrote:
> The generic VDSO implementation uses the Y2038 safe clock_gettime64() and
> clock_getres_time64() syscalls as fallback for 32bit VDSO. This breaks
> seccomp setups because these syscalls might be not (yet) allowed.
> 
> Implement the 32bit variants which use the legacy syscalls and select the
> variant in the core library.
> 
> The 64bit time variants are not removed because they are required for the
> time64 based vdso accessors.
> 
> Cc: Paul Burton <paul.burton@mips.com>
> Fixes: 00b26474c2f1 ("lib/vdso: Provide generic VDSO implementation")
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

How would you like this to be applied? I'd be happy to apply this one to
mips-next, where commit 24640f233b46 ("mips: Add support for generic
vDSO") added the file being modified here. Otherwise:

    Acked-by: Paul Burton <paul.burton@mips.com>

Thanks,
    Paul

> ---
>  arch/mips/include/asm/vdso/gettimeofday.h | 45 +++++++++++++++++++++++
>  arch/mips/vdso/config-n32-o32-env.c       |  1 +
>  2 files changed, 46 insertions(+)
> 
> diff --git a/arch/mips/include/asm/vdso/gettimeofday.h b/arch/mips/include/asm/vdso/gettimeofday.h
> index c59fe08b0347..e78462e8ca2e 100644
> --- a/arch/mips/include/asm/vdso/gettimeofday.h
> +++ b/arch/mips/include/asm/vdso/gettimeofday.h
> @@ -105,6 +105,51 @@ static __always_inline int clock_getres_fallback(
>  	return error ? -ret : ret;
>  }
>  
> +#if _MIPS_SIM != _MIPS_SIM_ABI64
> +
> +#define VDSO_HAS_32BIT_FALLBACK	1
> +
> +static __always_inline long clock_gettime32_fallback(
> +					clockid_t _clkid,
> +					struct old_timespec32 *_ts)
> +{
> +	register struct old_timespec32 *ts asm("a1") = _ts;
> +	register clockid_t clkid asm("a0") = _clkid;
> +	register long ret asm("v0");
> +	register long nr asm("v0") = __NR_clock_gettime;
> +	register long error asm("a3");
> +
> +	asm volatile(
> +	"       syscall\n"
> +	: "=r" (ret), "=r" (error)
> +	: "r" (clkid), "r" (ts), "r" (nr)
> +	: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
> +	  "$14", "$15", "$24", "$25", "hi", "lo", "memory");
> +
> +	return error ? -ret : ret;
> +}
> +
> +static __always_inline int clock_getres32_fallback(
> +					clockid_t _clkid,
> +					struct old_timespec32 *_ts)
> +{
> +	register struct old_timespec32 *ts asm("a1") = _ts;
> +	register clockid_t clkid asm("a0") = _clkid;
> +	register long ret asm("v0");
> +	register long nr asm("v0") = __NR_clock_getres;
> +	register long error asm("a3");
> +
> +	asm volatile(
> +	"       syscall\n"
> +	: "=r" (ret), "=r" (error)
> +	: "r" (clkid), "r" (ts), "r" (nr)
> +	: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
> +	  "$14", "$15", "$24", "$25", "hi", "lo", "memory");
> +
> +	return error ? -ret : ret;
> +}
> +#endif
> +
>  #ifdef CONFIG_CSRC_R4K
>  
>  static __always_inline u64 read_r4k_count(void)
> diff --git a/arch/mips/vdso/config-n32-o32-env.c b/arch/mips/vdso/config-n32-o32-env.c
> index 7f8d957abd4a..0011a632aef2 100644
> --- a/arch/mips/vdso/config-n32-o32-env.c
> +++ b/arch/mips/vdso/config-n32-o32-env.c
> @@ -10,6 +10,7 @@
>   */
>  #undef CONFIG_64BIT
>  
> +#define BUILD_VDSO32
>  #define CONFIG_32BIT 1
>  #define CONFIG_GENERIC_ATOMIC64 1
>  #define BUILD_VDSO32_64
> -- 
> 2.23.0
> 

  reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-30 13:58 [PATCH v2 0/8] vdso: Complete the conversion to 32bit syscalls Vincenzo Frascino
2019-08-30 13:58 ` [PATCH v2 1/8] arm64: compat: vdso: Expose BUILD_VDSO32 Vincenzo Frascino
2019-09-03 14:36   ` Vincenzo Frascino
2019-09-03 14:38     ` Will Deacon
2019-08-30 13:58 ` [PATCH v2 2/8] lib: vdso: Build 32 bit specific functions in the right context Vincenzo Frascino
2019-08-30 13:58 ` [PATCH v2 3/8] mips: compat: vdso: Use legacy syscalls as fallback Vincenzo Frascino
2019-09-03 13:52   ` Paul Burton [this message]
2019-09-03 14:20     ` Vincenzo Frascino
2019-09-03 21:00   ` Paul Burton
2019-08-30 13:58 ` [PATCH v2 4/8] lib: vdso: Remove VDSO_HAS_32BIT_FALLBACK Vincenzo Frascino
2019-08-30 13:58 ` [PATCH v2 5/8] lib: vdso: Remove checks on return value for 32 bit vDSO Vincenzo Frascino
2019-08-30 14:16   ` Vincenzo Frascino
2019-08-30 13:59 ` [PATCH v2 6/8] arm64: compat: vdso: Remove unused VDSO_HAS_32BIT_FALLBACK Vincenzo Frascino
2019-08-30 13:59 ` [PATCH v2 7/8] mips: " Vincenzo Frascino
2019-09-03 14:46   ` Paul Burton
2019-09-03 14:51     ` Vincenzo Frascino
2019-08-30 13:59 ` [PATCH v2 8/8] x86: " Vincenzo Frascino

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