| Message ID | 20210809012509.4983c1d6@xhacker (mailing list archive) |
|---|---|
| Headers | show |
| Series | riscv: improve __ex_table section handling | expand |
On Sun, 08 Aug 2021 10:25:09 PDT (-0700), jszhang3@mail.ustc.edu.cn wrote: > From: Jisheng Zhang <jszhang@kernel.org> > > Enable BUILDTIME_TABLE_SORT to sort the exception table at build time > then move exception table to RO_DATA segment. > > Jisheng Zhang (2): > riscv: Enable BUILDTIME_TABLE_SORT > riscv: Move EXCEPTION_TABLE to RO_DATA segment > > arch/riscv/Kconfig | 1 + > arch/riscv/kernel/vmlinux-xip.lds.S | 1 - > arch/riscv/kernel/vmlinux.lds.S | 4 ++-- > scripts/sorttable.c | 1 + > 4 files changed, 4 insertions(+), 3 deletions(-) This seems reasonable, but it's failing for some configurations (at least tinyconfig) saying there is no __ex_table. I'm not entirely sure how that comes about, as we've got them for futexes and uaccess. Maybe the right thing to do here is to fix scripts/sorttable.c so it can handle files with nothing to sort? I think it's just as simple as a successful early out like this diff --git a/scripts/sorttable.h b/scripts/sorttable.h index a2baa2fefb13..207ddeddb506 100644 --- a/scripts/sorttable.h +++ b/scripts/sorttable.h @@ -294,8 +294,9 @@ static int do_sort(Elf_Ehdr *ehdr, goto out; } #endif + /* If there is no __ex_table section there is no work do to. */ if (!extab_sec) { - fprintf(stderr, "no __ex_table in file: %s\n", fname); + rc = 0; goto out; } I'm not entirely sure though -- my logic is essentially just "there's no __ex_table, so there's nothing to sort, so just don't try". All the configurations I can actually boot have an __ex_table, so I'm not sure how to test that.
On Wed, 25 Aug 2021 23:47:02 -0700 (PDT) Palmer Dabbelt <palmer@dabbelt.com> wrote: > On Sun, 08 Aug 2021 10:25:09 PDT (-0700), jszhang3@mail.ustc.edu.cn wrote: > > From: Jisheng Zhang <jszhang@kernel.org> > > > > Enable BUILDTIME_TABLE_SORT to sort the exception table at build time > > then move exception table to RO_DATA segment. > > > > Jisheng Zhang (2): > > riscv: Enable BUILDTIME_TABLE_SORT > > riscv: Move EXCEPTION_TABLE to RO_DATA segment > > > > arch/riscv/Kconfig | 1 + > > arch/riscv/kernel/vmlinux-xip.lds.S | 1 - > > arch/riscv/kernel/vmlinux.lds.S | 4 ++-- > > scripts/sorttable.c | 1 + > > 4 files changed, 4 insertions(+), 3 deletions(-) > > This seems reasonable, but it's failing for some configurations (at > least tinyconfig) saying there is no __ex_table. I'm not entirely sure Nice catch! tinyconfig in riscv means NOMMU which indicates no __ex_table at all. It seems we have to only enable BUILDTIME_TABLE_SORT for MMU case. will send out V2 soon. Thanks > how that comes about, as we've got them for futexes and uaccess. > > Maybe the right thing to do here is to fix scripts/sorttable.c so it can > handle files with nothing to sort? I think it's just as simple as a > successful early out like this > > diff --git a/scripts/sorttable.h b/scripts/sorttable.h > index a2baa2fefb13..207ddeddb506 100644 > --- a/scripts/sorttable.h > +++ b/scripts/sorttable.h > @@ -294,8 +294,9 @@ static int do_sort(Elf_Ehdr *ehdr, > goto out; > } > #endif > + /* If there is no __ex_table section there is no work do to. */ > if (!extab_sec) { > - fprintf(stderr, "no __ex_table in file: %s\n", fname); > + rc = 0; > goto out; > } > > I'm not entirely sure though -- my logic is essentially just "there's no > __ex_table, so there's nothing to sort, so just don't try". > > All the configurations I can actually boot have an __ex_table, so I'm > not sure how to test that. > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv
From: Jisheng Zhang <jszhang@kernel.org> Enable BUILDTIME_TABLE_SORT to sort the exception table at build time then move exception table to RO_DATA segment. Jisheng Zhang (2): riscv: Enable BUILDTIME_TABLE_SORT riscv: Move EXCEPTION_TABLE to RO_DATA segment arch/riscv/Kconfig | 1 + arch/riscv/kernel/vmlinux-xip.lds.S | 1 - arch/riscv/kernel/vmlinux.lds.S | 4 ++-- scripts/sorttable.c | 1 + 4 files changed, 4 insertions(+), 3 deletions(-)