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From: "Arnd Bergmann" <arnd@arndb.de>
To: "Yuntao Liu" <liuyuntao12@huawei.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Cc: "Russell King" <linux@armlinux.org.uk>,
	"Andrew Davis" <afd@ti.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	"Geert Uytterhoeven" <geert+renesas@glider.be>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Mike Rapoport" <rppt@kernel.org>,
	"Eric DeVolder" <eric.devolder@oracle.com>,
	"Rob Herring" <robh@kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Linus Walleij" <linus.walleij@linaro.org>
Subject: Re: [PATCH -next] arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION
Date: Thu, 22 Feb 2024 10:52:10 +0100	[thread overview]
Message-ID: <f5326293-b446-49e5-9cc0-78c9009af136@app.fastmail.com> (raw)
In-Reply-To: <30b01c65-12f2-4ee0-81d5-c7a2da2c36b4@app.fastmail.com>

On Wed, Feb 21, 2024, at 16:51, Arnd Bergmann wrote:
> I have given your patch some build testing with random
> configurations in my build setup and it seems to work
> fine with gcc/binutils, but unfortunately I came across
> a link failure using clang/lld:

I ran into another bug now, this time with CONFIG_XIP_KERNEL=y:

no __ex_table in file: vmlinux
Failed to sort kernel tables
make[4]: *** [scripts/Makefile.vmlinux:37: vmlinux] Error 1

Essentially you have to modify arch/arm/kernel/vmlinux-xip.lds.S
the same way as vmlinux.lds.S:

--- a/arch/arm/kernel/vmlinux-xip.lds.S
+++ b/arch/arm/kernel/vmlinux-xip.lds.S
@@ -63,7 +63,7 @@ SECTIONS
        . = ALIGN(4);
        __ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) {
                __start___ex_table = .;
-               ARM_MMU_KEEP(*(__ex_table))
+               ARM_MMU_KEEP(KEEP(*(__ex_table)))
                __stop___ex_table = .;
        }
 
@@ -83,7 +83,7 @@ SECTIONS
        }
        .init.arch.info : {
                __arch_info_begin = .;
-               *(.arch.info.init)
+               KEEP(*(.arch.info.init))
                __arch_info_end = .;
        }
        .init.tagtable : {


The pv_table is not needed for XIP_KERNEL=y because that
requires not patching the kernel.

    Arnd

WARNING: multiple messages have this Message-ID (diff)
From: "Arnd Bergmann" <arnd@arndb.de>
To: "Yuntao Liu" <liuyuntao12@huawei.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Cc: "Russell King" <linux@armlinux.org.uk>,
	"Andrew Davis" <afd@ti.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	"Geert Uytterhoeven" <geert+renesas@glider.be>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Mike Rapoport" <rppt@kernel.org>,
	"Eric DeVolder" <eric.devolder@oracle.com>,
	"Rob Herring" <robh@kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Linus Walleij" <linus.walleij@linaro.org>
Subject: Re: [PATCH -next] arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION
Date: Thu, 22 Feb 2024 10:52:10 +0100	[thread overview]
Message-ID: <f5326293-b446-49e5-9cc0-78c9009af136@app.fastmail.com> (raw)
In-Reply-To: <30b01c65-12f2-4ee0-81d5-c7a2da2c36b4@app.fastmail.com>

On Wed, Feb 21, 2024, at 16:51, Arnd Bergmann wrote:
> I have given your patch some build testing with random
> configurations in my build setup and it seems to work
> fine with gcc/binutils, but unfortunately I came across
> a link failure using clang/lld:

I ran into another bug now, this time with CONFIG_XIP_KERNEL=y:

no __ex_table in file: vmlinux
Failed to sort kernel tables
make[4]: *** [scripts/Makefile.vmlinux:37: vmlinux] Error 1

Essentially you have to modify arch/arm/kernel/vmlinux-xip.lds.S
the same way as vmlinux.lds.S:

--- a/arch/arm/kernel/vmlinux-xip.lds.S
+++ b/arch/arm/kernel/vmlinux-xip.lds.S
@@ -63,7 +63,7 @@ SECTIONS
        . = ALIGN(4);
        __ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) {
                __start___ex_table = .;
-               ARM_MMU_KEEP(*(__ex_table))
+               ARM_MMU_KEEP(KEEP(*(__ex_table)))
                __stop___ex_table = .;
        }
 
@@ -83,7 +83,7 @@ SECTIONS
        }
        .init.arch.info : {
                __arch_info_begin = .;
-               *(.arch.info.init)
+               KEEP(*(.arch.info.init))
                __arch_info_end = .;
        }
        .init.tagtable : {


The pv_table is not needed for XIP_KERNEL=y because that
requires not patching the kernel.

    Arnd

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2024-02-22  9:52 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-20  8:15 [PATCH -next] arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION Yuntao Liu
2024-02-20  8:15 ` Yuntao Liu
2024-02-20  8:40 ` Arnd Bergmann
2024-02-20  8:40   ` Arnd Bergmann
2024-02-20  9:53   ` liuyuntao (F)
2024-02-20  9:53     ` liuyuntao (F)
2024-02-21 15:51     ` Arnd Bergmann
2024-02-21 15:51       ` Arnd Bergmann
2024-02-22  9:52       ` Arnd Bergmann [this message]
2024-02-22  9:52         ` Arnd Bergmann
2024-02-22 11:32         ` liuyuntao (F)
2024-02-22 11:32           ` liuyuntao (F)
2024-02-22 11:24       ` liuyuntao (F)
2024-02-22 11:24         ` liuyuntao (F)
2024-02-22 16:04         ` Arnd Bergmann
2024-02-22 16:04           ` Arnd Bergmann
2024-02-23  1:39           ` liuyuntao (F)
2024-02-23  1:39             ` liuyuntao (F)
2024-02-23  6:32             ` Arnd Bergmann
2024-02-23  6:32               ` Arnd Bergmann
2024-02-27  8:06           ` liuyuntao (F)
2024-02-27  8:06             ` liuyuntao (F)
2024-03-07  3:09             ` liuyuntao (F)
2024-03-07  3:09               ` liuyuntao (F)
2024-03-07  7:29               ` Arnd Bergmann
2024-03-07  7:29                 ` Arnd Bergmann

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