On 12/23/2015 11:51 AM, Tony Lindgren wrote:
* Kees Cook <keescook@xxxxxxxxxxxx> [151202 12:31]:
The use of CONFIG_DEBUG_RODATA is generally seen as an essential part of
kernel self-protection:
http://www.openwall.com/lists/kernel-hardening/2015/11/30/13
Additionally, its name has grown to mean things beyond just rodata. To
get ARM closer to this, we ought to rearrange the names of the configs
that control how the kernel protects its memory. What was called
CONFIG_ARM_KERNMEM_PERMS is really doing the work that other architectures
call CONFIG_DEBUG_RODATA.
This redefines CONFIG_DEBUG_RODATA to actually do the bulk of the
ROing (and NXing). In the place of the old CONFIG_DEBUG_RODATA, use
CONFIG_DEBUG_ALIGN_RODATA, since that's what the option does: adds
section alignment for making rodata explicitly NX, as arm does not split
the page tables like arm64 does without _ALIGN_RODATA.
Also all omap3 boards are now oopsing in Linux next if PM is enabled:
[ 18.549865] Unable to handle kernel paging request at virtual address c01237dc
[ 18.557830] pgd = cf704000
[ 18.560974] [c01237dc] *pgd=8000041e(bad)
[ 18.565765] Internal error: Oops: 80d [#1] SMP ARM
[ 18.571105] Modules linked in: ledtrig_default_on leds_gpio led_class rtc_twl twl4030_wdt
[ 18.581024] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc6-00003-g1bb2057 #2973
[ 18.589508] Hardware name: Generic OMAP36xx (Flattened Device Tree)
[ 18.596466] task: c0c06638 ti: c0c00000 task.ti: c0c00000
[ 18.602539] PC is at wait_dll_lock_timed+0x8/0x14
[ 18.607849] LR is at save_context_wfi+0x24/0x28
[ 18.612976] pc : [<c0123750>] lr : [<c01236b0>] psr: 600e0093
[ 18.612976] sp : c0c01ea0 ip : c0c028d4 fp : 00000002
[ 18.625549] r10: 00000000 r9 : ffffffff r8 : 00000000
[ 18.631378] r7 : c01237d8 r6 : 00000003 r5 : 0000000a r4 : 00000001
[ 18.638610] r3 : 00000004 r2 : 00000006 r1 : f03fe03a r0 : 0a000023
[ 18.645843] Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment none
[ 18.653839] Control: 10c53879 Table: 8f704019 DAC: 00000051
[ 18.660217] Process swapper/0 (pid: 0, stack limit = 0xc0c00218)
[ 18.666900] Stack: (0xc0c01ea0 to 0xc0c02000)
[ 18.671936] 1ea0: 00000030 c0c01efc 00000003 00000001 00000000 c0c0a0a0 c0c028d4 00000000
[ 18.681060] 1ec0: c0122ef8 00000000 c010d210 8f0b0000 c0c01efc 80119dc0 00000000 00000000
[ 18.690185] 1ee0: 00000000 00000051 80004019 10c5387d 000000e2 00f00000 00000000 c0c06638
[ 18.699279] 1f00: cf6a4e00 00000003 00000001 00000000 c0c0a0a0 00000000 00000000 c010d3bc
[ 18.708404] 1f20: c0cbd460 c0cbdd14 00000003 c012308c 00000003 c0c09f90 c0cbdd54 00000000
[ 18.717529] 1f40: 00000001 c0124584 51b8dc60 00000004 c0cb8a9c c0c09fa0 cfb3ba58 c05a8e14
[ 18.726654] 1f60: 008a43a0 00000000 51b8dc60 00000004 51b8dc60 00000004 c0c029ec c0c00000
[ 18.735778] 1f80: c0c029ec 00000000 c0cb8a9c cfb3ba58 c0c09fa0 c0c0298c c0b6ea50 c017bbb4
[ 18.744934] 1fa0: c0740760 c0b6a4e4 c0cbd000 ffffffff cfb473c0 c0b00c34 ffffffff ffffffff
[ 18.754058] 1fc0: 00000000 c0b0066c 00000000 c0b4fa48 00000000 c0cbd214 c0c0296c c0b4fa44
[ 18.763183] 1fe0: c0c08208 80004059 413fc082 00000000 00000000 8000807c 00000000 00000000
[ 18.772308] [<c0123750>] (wait_dll_lock_timed) from [<c0c0a0a0>] (omap3_idle_driver+0x100/0x33c)
[ 18.782043] Code: 1a000019 e28f708c e59f408c e2844001 (e5874004)
Reverting the $subject patch fixes the issue.
Regards,
Tony
Looks like a case similar to Geert's
adr r7, kick_counter
wait_dll_lock_timed:
ldr r4, wait_dll_lock_counter
add r4, r4, #1
str r4, [r7, #wait_dll_lock_counter - kick_counter]
ldr r4, sdrc_dlla_status
/* Wait 20uS for lock */
mov r6, #8
kick_counter and wait_dll_lock_counter are in the text section which is marked read only.
They need to be moved to the data section along with a few other variables from what I
can tell (maybe those are read only?).
I suspect this is going to be a common issue with suspend/resume code paths since those
are hand written assembly.
Thanks,
Laura
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>