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From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH 1/7] powerpc/build: put sys_call_table in .data.rel.ro if RELOCATABLE
Date: Thu, 15 Sep 2022 01:47:40 +1000	[thread overview]
Message-ID: <20220914154746.1122482-2-npiggin@gmail.com> (raw)
In-Reply-To: <20220914154746.1122482-1-npiggin@gmail.com>

Const function pointers live in .data.rel.ro rather than .rodata because
they must be relocated. This change prevents powerpc/32 from generating
R_PPC_UADDR32 relocations (which are not handled). The sys_call_table is
moved to writeable memory, but a later change will move it back.

After this patch, 44x_defconfig + CONFIG_RELOCATABLE boots to busybox.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/kernel/systbl.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/kernel/systbl.S b/arch/powerpc/kernel/systbl.S
index cb3358886203..0bec33e86f50 100644
--- a/arch/powerpc/kernel/systbl.S
+++ b/arch/powerpc/kernel/systbl.S
@@ -12,7 +12,11 @@
 
 #include <asm/ppc_asm.h>
 
+#ifdef CONFIG_RELOCATABLE
+.section .data.rel.ro,"aw"
+#else
 .section .rodata,"a"
+#endif
 
 #ifdef CONFIG_PPC64
 	.p2align	3
-- 
2.37.2


  reply	other threads:[~2022-09-14 15:49 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-14 15:47 [PATCH 0/7] powerpc: build / linker improvements Nicholas Piggin
2022-09-14 15:47 ` Nicholas Piggin [this message]
2022-09-15  5:53   ` [PATCH 1/7] powerpc/build: put sys_call_table in .data.rel.ro if RELOCATABLE Christophe Leroy
2022-09-15 12:51     ` Michael Ellerman
2022-09-16  0:30       ` Nicholas Piggin
2022-09-14 15:47 ` [PATCH 2/7] powerpc: move __end_rodata to cover arch read-only sections Nicholas Piggin
2022-09-15  5:50   ` Christophe Leroy
2022-09-15 12:47   ` Michael Ellerman
2022-09-16  0:28     ` Nicholas Piggin
2022-09-16  6:35       ` Michael Ellerman
2022-09-14 15:47 ` [PATCH 3/7] powerpc/32/build: move got1/got2 sections out of text Nicholas Piggin
2022-09-14 15:47 ` [PATCH 4/7] powerpc/build: move got, toc, plt, branch_lt sections to read-only Nicholas Piggin
2022-09-14 15:47 ` [PATCH 5/7] powerpc/build: move .data.rel.ro, .sdata2 " Nicholas Piggin
2022-09-14 15:47 ` [PATCH 6/7] powerpc/64/build: only include .opd with ELFv1 Nicholas Piggin
2022-09-14 15:47 ` [PATCH 7/7] powerpc/64/build: merge .got and .toc input sections Nicholas Piggin

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