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Diffstat (limited to 'arch/arm/kernel/entry-header.S')
| -rw-r--r-- | arch/arm/kernel/entry-header.S | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S index ae24dd54e9ef..81df2a3561ca 100644 --- a/arch/arm/kernel/entry-header.S +++ b/arch/arm/kernel/entry-header.S @@ -423,3 +423,40 @@ scno .req r7 @ syscall number tbl .req r8 @ syscall table pointer why .req r8 @ Linux syscall (!= 0) tsk .req r9 @ current thread_info + + .macro do_overflow_check, frame_size:req +#ifdef CONFIG_VMAP_STACK + @ + @ Test whether the SP has overflowed. Task and IRQ stacks are aligned + @ so that SP & BIT(THREAD_SIZE_ORDER + PAGE_SHIFT) should always be + @ zero. + @ +ARM( tst sp, #1 << (THREAD_SIZE_ORDER + PAGE_SHIFT) ) +THUMB( tst r1, #1 << (THREAD_SIZE_ORDER + PAGE_SHIFT) ) +THUMB( it ne ) + bne .Lstack_overflow_check\@ + + .pushsection .text +.Lstack_overflow_check\@: + @ + @ The stack pointer is not pointing to a valid vmap'ed stack, but it + @ may be pointing into the linear map instead, which may happen if we + @ are already running from the overflow stack. We cannot detect overflow + @ in such cases so just carry on. + @ + str ip, [r0, #12] @ Stash IP on the mode stack + ldr_l ip, high_memory @ Start of VMALLOC space +ARM( cmp sp, ip ) @ SP in vmalloc space? +THUMB( cmp r1, ip ) +THUMB( itt lo ) + ldrlo ip, [r0, #12] @ Restore IP + blo .Lout\@ @ Carry on + +THUMB( sub r1, sp, r1 ) @ Restore original R1 +THUMB( sub sp, r1 ) @ Restore original SP + add sp, sp, #\frame_size @ Undo svc_entry's SP change + b __bad_stack @ Handle VMAP stack overflow + .popsection +.Lout\@: +#endif + .endm |