From: Al Viro <viro@ZenIV.linux.org.uk>
To: Richard Henderson <rth@twiddle.net>
Cc: linux-arch@vger.kernel.org, arnd@arndb.de,
y2038@lists.linaro.org, linux-kernel@vger.kernel.org,
ink@jurassic.park.msu.ru, deepa.kernel@gmail.com,
linux-alpha@vger.kernel.org, Firoz Khan <firoz.khan@linaro.org>,
mattst88@gmail.com
Subject: Re: [PATCH 3/6] alpha: Unify the not-implemented system call entry name
Date: Sat, 11 Aug 2018 03:45:53 +0100 [thread overview]
Message-ID: <20180811024553.GF6515@ZenIV.linux.org.uk> (raw)
In-Reply-To: <98937991-cefa-b7f3-11c3-12727b3159b1@twiddle.net>
On Fri, Aug 10, 2018 at 07:31:55PM -0700, Richard Henderson wrote:
> > +++ b/arch/alpha/kernel/entry.S
> > @@ -473,7 +473,7 @@ entSys:
> > bne $3, strace
> > beq $4, 1f
> > ldq $27, 0($5)
> > -1: jsr $26, ($27), alpha_ni_syscall
> > +1: jsr $26, ($27), sys_ni_syscall
> > ldgp $gp, 0($26)
> > blt $0, $syscall_error /* the call failed */
> > stq $0, 0($sp)
>
> Once upon a time I had a patch to make the hint
> be sys_gettimeofday, as the most common syscall.
> Dunno what happened to that.
Might as well... ptraced case has it, non-ptraced doesn't.
BTW, seeing that it's your code - why was unop used in
alpha_ni_syscall? I don't remember the rules re pipeline
stalls; is it that some earlier variants prefer unop to
nop in such places? It's not that microoptimizing that
one makes any difference, but just out of curiosity -
would something like
lda $0, -ENOSYS
stq $sp, 0($sp) /* sp != 0 */
ret
do just as well there?
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WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Richard Henderson <rth@twiddle.net>
Cc: Firoz Khan <firoz.khan@linaro.org>,
linux-alpha@vger.kernel.org, ink@jurassic.park.msu.ru,
mattst88@gmail.com, y2038@lists.linaro.org,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
arnd@arndb.de, deepa.kernel@gmail.com
Subject: Re: [PATCH 3/6] alpha: Unify the not-implemented system call entry name
Date: Sat, 11 Aug 2018 03:45:53 +0100 [thread overview]
Message-ID: <20180811024553.GF6515@ZenIV.linux.org.uk> (raw)
Message-ID: <20180811024553.5acOzirfish4JoC0I8nyO1RgMCpnRJduyKc_92DMlEQ@z> (raw)
In-Reply-To: <98937991-cefa-b7f3-11c3-12727b3159b1@twiddle.net>
On Fri, Aug 10, 2018 at 07:31:55PM -0700, Richard Henderson wrote:
> > +++ b/arch/alpha/kernel/entry.S
> > @@ -473,7 +473,7 @@ entSys:
> > bne $3, strace
> > beq $4, 1f
> > ldq $27, 0($5)
> > -1: jsr $26, ($27), alpha_ni_syscall
> > +1: jsr $26, ($27), sys_ni_syscall
> > ldgp $gp, 0($26)
> > blt $0, $syscall_error /* the call failed */
> > stq $0, 0($sp)
>
> Once upon a time I had a patch to make the hint
> be sys_gettimeofday, as the most common syscall.
> Dunno what happened to that.
Might as well... ptraced case has it, non-ptraced doesn't.
BTW, seeing that it's your code - why was unop used in
alpha_ni_syscall? I don't remember the rules re pipeline
stalls; is it that some earlier variants prefer unop to
nop in such places? It's not that microoptimizing that
one makes any difference, but just out of curiosity -
would something like
lda $0, -ENOSYS
stq $sp, 0($sp) /* sp != 0 */
ret
do just as well there?
next prev parent reply other threads:[~2018-08-11 2:45 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-16 10:23 [PATCH 0/6] System call table generation support Firoz Khan
2018-07-16 10:23 ` Firoz Khan
2018-07-16 10:23 ` [PATCH 1/6] alpha: Move __IGNORE* entries to non uapi header Firoz Khan
2018-07-16 10:23 ` Firoz Khan
2018-08-11 19:28 ` Al Viro
2018-08-11 19:28 ` Al Viro
2018-08-11 20:59 ` Michael Cree
2018-08-11 20:59 ` Michael Cree
2018-08-11 22:27 ` Arnd Bergmann
2018-08-11 22:27 ` Arnd Bergmann
2018-07-16 10:23 ` [PATCH 2/6] alpha: Add CONFIG_OSF4_COMPAT for compat syscall support Firoz Khan
2018-07-16 10:23 ` Firoz Khan
2018-07-16 10:23 ` [PATCH 3/6] alpha: Unify the not-implemented system call entry name Firoz Khan
2018-07-16 10:23 ` Firoz Khan
2018-08-11 0:04 ` Al Viro
2018-08-11 0:04 ` Al Viro
2018-08-11 2:31 ` Richard Henderson
2018-08-11 2:31 ` Richard Henderson
2018-08-11 2:45 ` Al Viro [this message]
2018-08-11 2:45 ` Al Viro
2018-08-11 4:10 ` Richard Henderson
2018-08-11 4:10 ` Richard Henderson
2018-08-11 15:07 ` Al Viro
2018-08-11 15:07 ` Al Viro
2018-08-11 15:24 ` Richard Henderson
2018-08-11 15:24 ` Richard Henderson
2018-07-16 10:23 ` [PATCH 4/6] alpha: Replace NR_SYSCALLS macro from asm/unistd.h Firoz Khan
2018-07-16 10:23 ` Firoz Khan
2018-07-16 10:23 ` [PATCH 5/6] alpha: Add system call table generation support Firoz Khan
2018-07-16 10:23 ` Firoz Khan
2018-07-16 10:23 ` [PATCH 6/6] alpha: uapi header and system call table file generation Firoz Khan
2018-07-16 10:23 ` Firoz Khan
2018-07-16 16:23 ` kbuild test robot
2018-07-16 16:23 ` kbuild test robot
2018-07-16 14:09 ` [PATCH 0/6] System call table generation support Arnd Bergmann
2018-07-16 14:09 ` Arnd Bergmann
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