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From: Damien Le Moal <damien.lemoal@wdc.com>
To: uclinux-dev@uclinux.org, ugerg@linux-m68k.org,
	Palmer Dabbelt <palmer@dabbelt.com>,
	linux-riscv@lists.infradead.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-kernel@vger.kernel.org
Cc: Max Filippov <jcmvbkbc@gmail.com>,
	Greg Ungerer <gerg@linux-m68k.org>,
	Anup Patel <anup.patel@wdc.com>, Christoph Hellwig <hch@lst.de>
Subject: [PATCH v3 2/2] riscv: Disable text-data gap in flat binaries
Date: Thu, 15 Apr 2021 15:15:02 +0900	[thread overview]
Message-ID: <20210415061502.7248-3-damien.lemoal@wdc.com> (raw)
In-Reply-To: <20210415061502.7248-1-damien.lemoal@wdc.com>

uclibc/gcc combined with elf2flt riscv linker file fully resolve the
PC relative __global_pointer$ value at compile time and do not generate
a relocation entry to set a runtime gp value. As a result, if the
flatbin loader introduces a gap between the text and data sections, the
gp value becomes incorrect and prevent correct execution of a flatbin
executable.

Avoid this problem by enabling CONFIG_BINFMT_FLAT_NO_TEXT_DATA_GAP
automatically when CONFIG_RISCV is enabled and CONFIG_MMU disabled.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
 arch/riscv/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 0d0cf67359cb..6a85fbbd056e 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -33,6 +33,7 @@ config RISCV
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
 	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
+	select BINFMT_FLAT_NO_TEXT_DATA_GAP if !MMU
 	select CLONE_BACKWARDS
 	select CLINT_TIMER if !MMU
 	select COMMON_CLK
-- 
2.30.2


WARNING: multiple messages have this Message-ID (diff)
From: Damien Le Moal <damien.lemoal@wdc.com>
To: uclinux-dev@uclinux.org, ugerg@linux-m68k.org,
	Palmer Dabbelt <palmer@dabbelt.com>,
	linux-riscv@lists.infradead.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-kernel@vger.kernel.org
Cc: Max Filippov <jcmvbkbc@gmail.com>,
	Greg Ungerer <gerg@linux-m68k.org>,
	Anup Patel <anup.patel@wdc.com>, Christoph Hellwig <hch@lst.de>
Subject: [PATCH v3 2/2] riscv: Disable text-data gap in flat binaries
Date: Thu, 15 Apr 2021 15:15:02 +0900	[thread overview]
Message-ID: <20210415061502.7248-3-damien.lemoal@wdc.com> (raw)
In-Reply-To: <20210415061502.7248-1-damien.lemoal@wdc.com>

uclibc/gcc combined with elf2flt riscv linker file fully resolve the
PC relative __global_pointer$ value at compile time and do not generate
a relocation entry to set a runtime gp value. As a result, if the
flatbin loader introduces a gap between the text and data sections, the
gp value becomes incorrect and prevent correct execution of a flatbin
executable.

Avoid this problem by enabling CONFIG_BINFMT_FLAT_NO_TEXT_DATA_GAP
automatically when CONFIG_RISCV is enabled and CONFIG_MMU disabled.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
 arch/riscv/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 0d0cf67359cb..6a85fbbd056e 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -33,6 +33,7 @@ config RISCV
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
 	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
+	select BINFMT_FLAT_NO_TEXT_DATA_GAP if !MMU
 	select CLONE_BACKWARDS
 	select CLINT_TIMER if !MMU
 	select COMMON_CLK
-- 
2.30.2


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http://lists.infradead.org/mailman/listinfo/linux-riscv

  parent reply	other threads:[~2021-04-15  6:15 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-15  6:15 [PATCH v3 0/2] Fix binfmt_flat loader for RISC-V Damien Le Moal
2021-04-15  6:15 ` Damien Le Moal
2021-04-15  6:15 ` [PATCH v3 1/2] binfmt_flat: allow not offsetting data start Damien Le Moal
2021-04-15  6:15   ` Damien Le Moal
2021-04-15 14:04   ` Greg Ungerer
2021-04-15 14:04     ` Greg Ungerer
2021-04-15 23:22     ` Damien Le Moal
2021-04-15 23:22       ` Damien Le Moal
2021-04-16  7:24       ` Greg Ungerer
2021-04-16  7:24         ` Greg Ungerer
2021-04-16  7:35         ` Damien Le Moal
2021-04-16  7:35           ` Damien Le Moal
2021-04-15  6:15 ` Damien Le Moal [this message]
2021-04-15  6:15   ` [PATCH v3 2/2] riscv: Disable text-data gap in flat binaries Damien Le Moal

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