Re: [tip:x86/asm] debug: Fix __bug_table[] in arch linker scripts

From: hpa
Date: Mon Apr 03 2017 - 06:05:56 EST

On April 3, 2017 1:27:49 AM PDT, tip-bot for Peter Zijlstra <tipbot@xxxxxxxxx> wrote:
>Commit-ID: b5effd3815ccbe3df1a015a6d67d8a24a27813d5
>Gitweb:
>http://git.kernel.org/tip/b5effd3815ccbe3df1a015a6d67d8a24a27813d5
>Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
>AuthorDate: Thu, 30 Mar 2017 17:49:27 +0200
>Committer: Ingo Molnar <mingo@xxxxxxxxxx>
>CommitDate: Mon, 3 Apr 2017 10:22:40 +0200
>
>debug: Fix __bug_table[] in arch linker scripts
>
>The kbuild test robot reported this build failure on a number
>of architectures:
>
> > make.cross ARCH=arm
> > lib/lib.a(bug.o): In function `find_bug':
> > >> lib/bug.c:135: undefined reference to `__start___bug_table'
> > >> lib/bug.c:135: undefined reference to `__stop___bug_table'
>
>Caused by:
>
> 19d436268dde ("debug: Add _ONCE() logic to report_bug()")
>
>Which moved the BUG_TABLE from RO_DATA_SECTION() to RW_DATA_SECTION(),
>but a number of architectures don't use RW_DATA_SECTION(), so they
>ended up with no __bug_table[] ...
>
>Ideally all those would use RW_DATA_SECTION() in their linker scripts,
>but that's for another day.
>
>Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
>Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
>Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>Cc: kbuild test robot <fengguang.wu@xxxxxxxxx>
>Cc: kbuild-all@xxxxxx
>Cc: tipbuild@xxxxxxxxx
>Link:
>http://lkml.kernel.org/r/20170330154927.o6qmgfp4bdhrajbm@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
>---
> arch/arm/kernel/vmlinux-xip.lds.S | 2 ++
> arch/arm/kernel/vmlinux.lds.S | 2 ++
> arch/avr32/kernel/vmlinux.lds.S | 1 +
> arch/blackfin/kernel/vmlinux.lds.S | 2 ++
> arch/c6x/kernel/vmlinux.lds.S | 2 ++
> arch/cris/kernel/vmlinux.lds.S | 2 ++
> arch/frv/kernel/vmlinux.lds.S | 2 ++
> arch/ia64/kernel/vmlinux.lds.S | 2 ++
> arch/mips/kernel/vmlinux.lds.S | 1 +
> arch/powerpc/kernel/vmlinux.lds.S | 2 ++
> arch/x86/kernel/vmlinux.lds.S | 1 +
> 11 files changed, 19 insertions(+)
>
>diff --git a/arch/arm/kernel/vmlinux-xip.lds.S
>b/arch/arm/kernel/vmlinux-xip.lds.S
>index 37b2a11..8265b11 100644
>--- a/arch/arm/kernel/vmlinux-xip.lds.S
>+++ b/arch/arm/kernel/vmlinux-xip.lds.S
>@@ -242,6 +242,8 @@ SECTIONS
> }
> _edata_loc = __data_loc + SIZEOF(.data);
>
>+ BUG_TABLE
>+
> #ifdef CONFIG_HAVE_TCM
> /*
> * We align everything to a page boundary so we can
>diff --git a/arch/arm/kernel/vmlinux.lds.S
>b/arch/arm/kernel/vmlinux.lds.S
>index ce18007..c83a7ba 100644
>--- a/arch/arm/kernel/vmlinux.lds.S
>+++ b/arch/arm/kernel/vmlinux.lds.S
>@@ -262,6 +262,8 @@ SECTIONS
> }
> _edata_loc = __data_loc + SIZEOF(.data);
>
>+ BUG_TABLE
>+
> #ifdef CONFIG_HAVE_TCM
> /*
> * We align everything to a page boundary so we can
>diff --git a/arch/avr32/kernel/vmlinux.lds.S
>b/arch/avr32/kernel/vmlinux.lds.S
>index 17f2730..623d18d 100644
>--- a/arch/avr32/kernel/vmlinux.lds.S
>+++ b/arch/avr32/kernel/vmlinux.lds.S
>@@ -75,6 +75,7 @@ SECTIONS
>
> _edata = .;
> }
>+ BUG_TABLE
>
> BSS_SECTION(0, 8, 8)
> _end = .;
>diff --git a/arch/blackfin/kernel/vmlinux.lds.S
>b/arch/blackfin/kernel/vmlinux.lds.S
>index 68069a1..334ef81 100644
>--- a/arch/blackfin/kernel/vmlinux.lds.S
>+++ b/arch/blackfin/kernel/vmlinux.lds.S
>@@ -115,6 +115,8 @@ SECTIONS
> __data_lma = LOADADDR(.data);
> __data_len = SIZEOF(.data);
>
>+ BUG_TABLE
>+
> /* The init section should be last, so when we free it, it goes into
> * the general memory pool, and (hopefully) will decrease
>fragmentation
> * a tiny bit. The init section has a _requirement_ that it be
>diff --git a/arch/c6x/kernel/vmlinux.lds.S
>b/arch/c6x/kernel/vmlinux.lds.S
>index a1a5c16..29ebea4 100644
>--- a/arch/c6x/kernel/vmlinux.lds.S
>+++ b/arch/c6x/kernel/vmlinux.lds.S
>@@ -128,6 +128,8 @@ SECTIONS
> . = ALIGN(8);
> }
>
>+ BUG_TABLE
>+
> _edata = .;
>
> __bss_start = .;
>diff --git a/arch/cris/kernel/vmlinux.lds.S
>b/arch/cris/kernel/vmlinux.lds.S
>index 9795862..867f237 100644
>--- a/arch/cris/kernel/vmlinux.lds.S
>+++ b/arch/cris/kernel/vmlinux.lds.S
>@@ -68,6 +68,8 @@ SECTIONS
> __edata = . ; /* End of data section. */
> _edata = . ;
>
>+ BUG_TABLE
>+
> INIT_TASK_DATA_SECTION(PAGE_SIZE)
>
> . = ALIGN(PAGE_SIZE); /* Init code and data. */
>diff --git a/arch/frv/kernel/vmlinux.lds.S
>b/arch/frv/kernel/vmlinux.lds.S
>index aa6e573..3f44dcb 100644
>--- a/arch/frv/kernel/vmlinux.lds.S
>+++ b/arch/frv/kernel/vmlinux.lds.S
>@@ -102,6 +102,8 @@ SECTIONS
>
> _edata = .; /* End of data section */
>
>+ BUG_TABLE
>+
> /* GP section */
> . = ALIGN(L1_CACHE_BYTES);
> _gp = . + 2048;
>diff --git a/arch/ia64/kernel/vmlinux.lds.S
>b/arch/ia64/kernel/vmlinux.lds.S
>index f89d20c..798026d 100644
>--- a/arch/ia64/kernel/vmlinux.lds.S
>+++ b/arch/ia64/kernel/vmlinux.lds.S
>@@ -192,6 +192,8 @@ SECTIONS {
> CONSTRUCTORS
> }
>
>+ BUG_TABLE
>+
> . = ALIGN(16); /* gp must be 16-byte aligned for exc. table */
> .got : AT(ADDR(.got) - LOAD_OFFSET) {
> *(.got.plt)
>diff --git a/arch/mips/kernel/vmlinux.lds.S
>b/arch/mips/kernel/vmlinux.lds.S
>index f0a0e6d..8ca2371 100644
>--- a/arch/mips/kernel/vmlinux.lds.S
>+++ b/arch/mips/kernel/vmlinux.lds.S
>@@ -97,6 +97,7 @@ SECTIONS
> DATA_DATA
> CONSTRUCTORS
> }
>+ BUG_TABLE
> _gp = . + 0x8000;
> .lit8 : {
> *(.lit8)
>diff --git a/arch/powerpc/kernel/vmlinux.lds.S
>b/arch/powerpc/kernel/vmlinux.lds.S
>index 7394b77..1c24c89 100644
>--- a/arch/powerpc/kernel/vmlinux.lds.S
>+++ b/arch/powerpc/kernel/vmlinux.lds.S
>@@ -312,6 +312,8 @@ SECTIONS
> NOSAVE_DATA
> }
>
>+ BUG_TABLE
>+
> . = ALIGN(PAGE_SIZE);
> _edata = .;
> PROVIDE32 (edata = .);
>diff --git a/arch/x86/kernel/vmlinux.lds.S
>b/arch/x86/kernel/vmlinux.lds.S
>index c74ae9c..c8a3b61 100644
>--- a/arch/x86/kernel/vmlinux.lds.S
>+++ b/arch/x86/kernel/vmlinux.lds.S
>@@ -146,6 +146,7 @@ SECTIONS
> _edata = .;
> } :data
>
>+ BUG_TABLE
>
> . = ALIGN(PAGE_SIZE);
> __vvar_page = .;

Case in point why we want structured linker tables, btw...
--
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