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From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: Paul Burton <paul.burton@mips.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 15:20:42 +0100
Message-ID: <aef6a427-12af-a77e-994f-37c7a618377c@arm.com> (raw)
In-Reply-To: <20190903134335.uxxf5kvp3afe7rfr@pburton-laptop>

Hi Paul,

thank you for your review.

On 9/3/19 2:52 PM, Paul Burton wrote:
> 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>
> 

Please feel free to apply this to mips-next.

Thanks,
Vincenzo

> 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: 25+ 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
2020-01-13 22:28   ` Thomas Gleixner
2020-01-14  9:33     ` Thomas Gleixner
2020-01-14 10:15       ` Vincenzo Frascino
2020-01-14 10:37         ` Thomas Gleixner
2020-01-14 10:41           ` Vincenzo Frascino
2020-01-14 11:15           ` Vincenzo Frascino
2020-01-16 19:43   ` [PATCH] MIPS: vdso: Define BUILD_VDSO32 when building a 32bit kernel Thomas Gleixner
2020-01-16 20:11     ` Paul Burton
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
2019-09-03 14:20     ` Vincenzo Frascino [this message]
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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