2021-08-26 14:18:39

by Jisheng Zhang

Subject: [PATCH v2 0/2] riscv: improve __ex_table section handling

From: Jisheng Zhang <[email protected]>

Enable BUILDTIME_TABLE_SORT to sort the exception table at build time
then move exception table to RO_DATA segment.

Since v1:
- Only enable BUILDTIME_TABLE_SORT for MMU. Thank Palmer for catching
tinyconfig case.

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(-)

--
2.32.0

2021-08-26 14:20:32

by Jisheng Zhang

Subject: [PATCH v2 2/2] riscv: Move EXCEPTION_TABLE to RO_DATA segment

From: Jisheng Zhang <[email protected]>

_ex_table section is read-only, so move it to RO_DATA.

Signed-off-by: Jisheng Zhang <[email protected]>
---
arch/riscv/kernel/vmlinux-xip.lds.S | 1 -
arch/riscv/kernel/vmlinux.lds.S | 4 ++--
2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/vmlinux-xip.lds.S b/arch/riscv/kernel/vmlinux-xip.lds.S
index af776555ded9..9c9f35091ef0 100644
--- a/arch/riscv/kernel/vmlinux-xip.lds.S
+++ b/arch/riscv/kernel/vmlinux-xip.lds.S
@@ -121,7 +121,6 @@ SECTIONS
}

BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0)
- EXCEPTION_TABLE(0x10)

.rel.dyn : AT(ADDR(.rel.dyn) - LOAD_OFFSET) {
*(.rel.dyn*)
diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S
index 502d0826ecb1..5104f3a871e3 100644
--- a/arch/riscv/kernel/vmlinux.lds.S
+++ b/arch/riscv/kernel/vmlinux.lds.S
@@ -4,6 +4,8 @@
* Copyright (C) 2017 SiFive
*/

+#define RO_EXCEPTION_TABLE_ALIGN 16
+
#ifdef CONFIG_XIP_KERNEL
#include "vmlinux-xip.lds.S"
#else
@@ -112,8 +114,6 @@ SECTIONS
*(.srodata*)
}

- EXCEPTION_TABLE(0x10)
-
. = ALIGN(SECTION_ALIGN);
_data = .;

--
2.32.0

2021-08-26 14:25:18

by Jisheng Zhang

Subject: [PATCH v2 1/2] riscv: Enable BUILDTIME_TABLE_SORT

From: Jisheng Zhang <[email protected]>

Enable BUILDTIME_TABLE_SORT to sort the exception table at build time
rather than during boot.

Signed-off-by: Jisheng Zhang <[email protected]>
---
arch/riscv/Kconfig | 1 +
scripts/sorttable.c | 1 +
2 files changed, 2 insertions(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 80a7aa9f74de..570689d3889b 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -40,6 +40,7 @@ config RISCV
select ARCH_WANT_FRAME_POINTERS
select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU
+ select BUILDTIME_TABLE_SORT if MMU
select CLONE_BACKWARDS
select CLINT_TIMER if !MMU
select COMMON_CLK
diff --git a/scripts/sorttable.c b/scripts/sorttable.c
index 0ef3abfc4a51..f355869c65cd 100644
--- a/scripts/sorttable.c
+++ b/scripts/sorttable.c
@@ -349,6 +349,7 @@ static int do_file(char const *const fname, void *addr)
case EM_ARM:
case EM_MICROBLAZE:
case EM_MIPS:
+ case EM_RISCV:
case EM_XTENSA:
break;
default:
--
2.32.0

2021-09-11 07:12:24

by Palmer Dabbelt

Subject: Re: [PATCH v2 0/2] riscv: improve __ex_table section handling

On Thu, 26 Aug 2021 07:09:52 PDT (-0700), [email protected] wrote:
> From: Jisheng Zhang <[email protected]>
>
> Enable BUILDTIME_TABLE_SORT to sort the exception table at build time
> then move exception table to RO_DATA segment.
>
> Since v1:
> - Only enable BUILDTIME_TABLE_SORT for MMU. Thank Palmer for catching
> tinyconfig case.
>
> 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(-)

Thanks, this is on for-next.