From: Peter Zijlstra <peterz@infradead.org>
To: Sathvika Vasireddy <sv@linux.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, jpoimboe@redhat.com,
linux-kernel@vger.kernel.org, aik@ozlabs.ru, mpe@ellerman.id.au,
mingo@redhat.com, christophe.leroy@csgroup.eu,
rostedt@goodmis.org, mbenes@suse.cz, npiggin@gmail.com,
chenzhongjin@huawei.com, naveen.n.rao@linux.vnet.ibm.com
Subject: Re: [PATCH v3 02/16] powerpc: Override __ALIGN and __ALIGN_STR macros
Date: Tue, 13 Sep 2022 14:03:54 +0200 [thread overview]
Message-ID: <YyBxqjtC0DAhmQrT@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20220912082020.226755-3-sv@linux.ibm.com>
On Mon, Sep 12, 2022 at 01:50:06PM +0530, Sathvika Vasireddy wrote:
> In a subsequent patch, we would want to annotate powerpc assembly functions
> with SYM_FUNC_START_LOCAL macro. This macro depends on __ALIGN macro.
>
> The default expansion of __ALIGN macro is:
> #define __ALIGN .align 4,0x90
>
> So, override __ALIGN and __ALIGN_STR macros to use the same alignment as
> that of the existing _GLOBAL macro. Also, do not pad with 0x90, because
> repeated 0x90s are not a nop or trap on powerpc.
>
> Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
> ---
> arch/powerpc/include/asm/linkage.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/powerpc/include/asm/linkage.h b/arch/powerpc/include/asm/linkage.h
> index b71b9582e754..b88d1d2cf304 100644
> --- a/arch/powerpc/include/asm/linkage.h
> +++ b/arch/powerpc/include/asm/linkage.h
> @@ -4,6 +4,9 @@
>
> #include <asm/types.h>
>
> +#define __ALIGN .align 2
> +#define __ALIGN_STR ".align 2"
Like mentioned last time; I'm fixing this (but you're right to not wait
on that), that said, would it make sense to write it like:
#define __ALIGN .balign 4
#define __ALIGN_STR __stringify(__ALIGN)
That said; with power instructions being 4 bytes, the above alignment is
basically no-alignment, right?
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Sathvika Vasireddy <sv@linux.ibm.com>
Cc: aik@ozlabs.ru, chenzhongjin@huawei.com, npiggin@gmail.com,
linux-kernel@vger.kernel.org, mingo@redhat.com,
rostedt@goodmis.org, jpoimboe@redhat.com,
naveen.n.rao@linux.vnet.ibm.com, mbenes@suse.cz,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v3 02/16] powerpc: Override __ALIGN and __ALIGN_STR macros
Date: Tue, 13 Sep 2022 14:03:54 +0200 [thread overview]
Message-ID: <YyBxqjtC0DAhmQrT@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20220912082020.226755-3-sv@linux.ibm.com>
On Mon, Sep 12, 2022 at 01:50:06PM +0530, Sathvika Vasireddy wrote:
> In a subsequent patch, we would want to annotate powerpc assembly functions
> with SYM_FUNC_START_LOCAL macro. This macro depends on __ALIGN macro.
>
> The default expansion of __ALIGN macro is:
> #define __ALIGN .align 4,0x90
>
> So, override __ALIGN and __ALIGN_STR macros to use the same alignment as
> that of the existing _GLOBAL macro. Also, do not pad with 0x90, because
> repeated 0x90s are not a nop or trap on powerpc.
>
> Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
> ---
> arch/powerpc/include/asm/linkage.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/powerpc/include/asm/linkage.h b/arch/powerpc/include/asm/linkage.h
> index b71b9582e754..b88d1d2cf304 100644
> --- a/arch/powerpc/include/asm/linkage.h
> +++ b/arch/powerpc/include/asm/linkage.h
> @@ -4,6 +4,9 @@
>
> #include <asm/types.h>
>
> +#define __ALIGN .align 2
> +#define __ALIGN_STR ".align 2"
Like mentioned last time; I'm fixing this (but you're right to not wait
on that), that said, would it make sense to write it like:
#define __ALIGN .balign 4
#define __ALIGN_STR __stringify(__ALIGN)
That said; with power instructions being 4 bytes, the above alignment is
basically no-alignment, right?
next prev parent reply other threads:[~2022-09-13 12:04 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-12 8:20 [PATCH v3 00/16] objtool: Enable and implement --mcount option on powerpc Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 01/16] powerpc: Fix __WARN_FLAGS() for use with Objtool Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 02/16] powerpc: Override __ALIGN and __ALIGN_STR macros Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-13 12:03 ` Peter Zijlstra [this message]
2022-09-13 12:03 ` Peter Zijlstra
2022-09-13 12:21 ` Christophe Leroy
2022-09-13 12:21 ` Christophe Leroy
2022-09-13 13:15 ` Peter Zijlstra
2022-09-13 13:15 ` Peter Zijlstra
2022-09-12 8:20 ` [PATCH v3 03/16] powerpc: Fix objtool unannotated intra-function call warnings Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 04/16] powerpc: Curb objtool unannotated intra-function warnings Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 05/16] powerpc: Skip objtool from running on drivers/crypto/vmx/aesp8-ppc.o Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 06/16] powerpc: Fix objtool unannotated intra-function call warnings on PPC32 Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 07/16] powerpc: Skip objtool from running on VDSO files Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 08/16] objtool: Fix SEGFAULT Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 09/16] objtool: Use target file endianness instead of a compiled constant Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 10/16] objtool: Use target file class size " Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 11/16] objtool: Add --mnop as an option to --mcount Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 18:55 ` kernel test robot
2022-09-12 18:55 ` kernel test robot
2022-09-15 6:56 ` Naveen N. Rao
2022-09-15 6:56 ` Naveen N. Rao
2022-09-15 6:56 ` Naveen N. Rao
2022-09-17 19:12 ` kernel test robot
2022-09-17 19:12 ` kernel test robot
2022-09-28 0:48 ` [objtool] ca5e2b42c0: kernel_BUG_at_arch/x86/kernel/jump_label.c kernel test robot
2022-09-28 0:48 ` kernel test robot
2022-09-28 0:48 ` kernel test robot
2022-09-28 15:44 ` Nathan Chancellor
2022-09-28 15:44 ` Nathan Chancellor
2022-09-28 15:44 ` Nathan Chancellor
2022-09-28 19:13 ` Josh Poimboeuf
2022-09-28 19:13 ` Josh Poimboeuf
2022-09-28 19:13 ` Josh Poimboeuf
2022-09-28 20:45 ` Nathan Chancellor
2022-09-28 20:45 ` Nathan Chancellor
2022-09-28 20:45 ` Nathan Chancellor
2022-09-12 8:20 ` [PATCH v3 12/16] objtool: Read special sections with alts only when specific options are selected Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 13/16] objtool: Use macros to define arch specific reloc types Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 14/16] objtool: Add arch specific function arch_ftrace_match() Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 15/16] objtool/powerpc: Enable objtool to be built on ppc Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-12 8:20 ` [PATCH v3 16/16] objtool/powerpc: Add --mcount specific implementation Sathvika Vasireddy
2022-09-12 8:20 ` Sathvika Vasireddy
2022-09-13 10:00 ` Christophe Leroy
2022-09-13 10:00 ` Christophe Leroy
2022-09-13 14:13 ` [PATCH v3 00/16] objtool: Enable and implement --mcount option on powerpc Peter Zijlstra
2022-09-13 14:13 ` Peter Zijlstra
2022-09-14 0:15 ` Josh Poimboeuf
2022-09-14 0:15 ` Josh Poimboeuf
2022-09-21 9:10 ` Sathvika Vasireddy
2022-09-21 9:10 ` Sathvika Vasireddy
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