Re: [PATCH 04/11] Define the virtual space of KASan's shadow region

From: Liuwenliang (Lamb)
Date: Tue Oct 17 2017 - 09:04:07 EST


On 10/17/2017 8:45 PM, Abbott Liu wrote:
>What I said was
>
>'if the value of TASK_SIZE fits its 12-bit immediate field'
>
>and your value of TASK_SIZE is 0xb6e00000, which cannot be decomposed in the right way.
>
>If you build with KASAN disabled, it will generate a mov instruction instead.

Thanks for your explain. I understand now. I has tested and the testing result proves that what
you said is right.

Here is test log:
c010e9e0 <__irq_svc>:
c010e9e0: e24dd04c sub sp, sp, #76 ; 0x4c
c010e9e4: e31d0004 tst sp, #4
c010e9e8: 024dd004 subeq sp, sp, #4
c010e9ec: e88d1ffe stm sp, {r1, r2, r3, r4, r5, r6, r7, r8, r9, sl, fp, ip}
c010e9f0: e8900038 ldm r0, {r3, r4, r5}
c010e9f4: e28d7030 add r7, sp, #48 ; 0x30
c010e9f8: e3e06000 mvn r6, #0
c010e9fc: e28d204c add r2, sp, #76 ; 0x4c
c010ea00: 02822004 addeq r2, r2, #4
c010ea04: e52d3004 push {r3} ; (str r3, [sp, #-4]!)
c010ea08: e1a0300e mov r3, lr
c010ea0c: e887007c stm r7, {r2, r3, r4, r5, r6}
c010ea10: e1a0972d lsr r9, sp, #14
c010ea14: e1a09709 lsl r9, r9, #14
c010ea18: e5990008 ldr r0, [r9, #8]
c010ea1c: e3a014bf mov r1, #-1090519040 ; 0xbf000000 // ldr r1,=0xbf000000