[cip-dev] [PATCH 57/86] ARM: shmobile: Move shmobile_smp_{mpidr, fn, arg}[] from .text to .bss

Fabrizio Castro
2018-06-29T14:38:58Z

From: Geert Uytterhoeven <geert+renesas@glider.be>

If CONFIG_DEBUG_RODATA=y, the kernel crashes during system suspend:

Freezing user space processes ... (elapsed 0.004 seconds) done.
Freezing remaining freezable tasks ... (elapsed 0.002 seconds)
done.
PM: suspend of devices complete after 111.948 msecs
PM: late suspend of devices complete after 1.086 msecs
PM: noirq suspend of devices complete after 11.576 msecs
Disabling non-boot CPUs ...
Kernel panic - not syncing: Attempted to kill the idle task!
1014ec ---[ end Kernel panic - not syncing: Attempted to kill the idle task!
CPU0: stopping

This happens because the .text section is marked read-only, while the
arrays shmobile_smp_mpidr[], shmobile_smp_fn[], and shmobile_smp_arg[]
are being written to.

Fix this by moving these arrays from the .text to the .bss section.
This requires accessing them through PC-relative offsets.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
(cherry picked from commit 4e960f52fce16a3bf3261fa92c34cf2306059ba2)
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Biju Das <biju.das@bp.renesas.com>
---
arch/arm/mach-shmobile/headsmp.S | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/arch/arm/mach-shmobile/headsmp.S b/arch/arm/mach-shmobile/headsmp.S
index 330c1fc..94d86ed 100644
--- a/arch/arm/mach-shmobile/headsmp.S
+++ b/arch/arm/mach-shmobile/headsmp.S
@@ -50,9 +50,11 @@ ENTRY(shmobile_smp_boot)
mrc p15, 0, r1, c0, c0, 5 @ r1 = MPIDR
and r0, r1, r0 @ r0 = cpu_logical_map() value
mov r1, #0 @ r1 = CPU index
- adr r5, 1f @ array of per-cpu mpidr values
- adr r6, 2f @ array of per-cpu functions
- adr r7, 3f @ array of per-cpu arguments
+ adr r2, 1f
+ ldmia r2, {r5, r6, r7}
+ add r5, r5, r2 @ array of per-cpu mpidr values
+ add r6, r6, r2 @ array of per-cpu functions
+ add r7, r7, r2 @ array of per-cpu arguments

shmobile_smp_boot_find_mpidr:
ldr r8, [r5, r1, lsl #2]
@@ -80,12 +82,18 @@ ENTRY(shmobile_smp_sleep)
b shmobile_smp_boot
ENDPROC(shmobile_smp_sleep)

+ .align 2
+1: .long shmobile_smp_mpidr - .
+ .long shmobile_smp_fn - 1b
+ .long shmobile_smp_arg - 1b
+
+ .bss
.globl shmobile_smp_mpidr
shmobile_smp_mpidr:
-1: .space NR_CPUS * 4
+ .space NR_CPUS * 4
.globl shmobile_smp_fn
shmobile_smp_fn:
-2: .space NR_CPUS * 4
+ .space NR_CPUS * 4
.globl shmobile_smp_arg
shmobile_smp_arg:
-3: .space NR_CPUS * 4
+ .space NR_CPUS * 4
--
2.7.4