diff options
Diffstat (limited to 'src/vm/arm/ehhelpers.asm')
| -rw-r--r-- | src/vm/arm/ehhelpers.asm | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/src/vm/arm/ehhelpers.asm b/src/vm/arm/ehhelpers.asm new file mode 100644 index 0000000000..ac26c7eaf4 --- /dev/null +++ b/src/vm/arm/ehhelpers.asm @@ -0,0 +1,182 @@ +; Licensed to the .NET Foundation under one or more agreements. +; The .NET Foundation licenses this file to you under the MIT license. +; See the LICENSE file in the project root for more information. + +; ==++== +; + +; +; ==--== +#include "ksarm.h" + +#include "asmconstants.h" + +#include "asmmacros.h" + + IMPORT FixContextHandler + IMPORT LinkFrameAndThrow + IMPORT HijackHandler + IMPORT ThrowControlForThread + +; +; WARNING!! These functions immediately ruin thread unwindability. This is +; WARNING!! OK as long as there is a mechanism for saving the thread context +; WARNING!! prior to running these functions as well as a mechanism for +; WARNING!! restoring the context prior to any stackwalk. This means that +; WARNING!! we need to ensure that no GC can occur while the stack is +; WARNING!! unwalkable. This further means that we cannot allow any exception +; WARNING!! to occur when the stack is unwalkable +; + + TEXTAREA + + ; GSCookie, scratch area + GBLA OFFSET_OF_FRAME + + ; GSCookie + alignment padding +OFFSET_OF_FRAME SETA 4 + SIZEOF__GSCookie + + MACRO + GenerateRedirectedStubWithFrame $STUB, $TARGET + + ; + ; This is the primary function to which execution will be redirected to. + ; + NESTED_ENTRY $STUB + + ; + ; IN: lr: original IP before redirect + ; + + PROLOG_PUSH {r4,r7,lr} + PROLOG_STACK_ALLOC OFFSET_OF_FRAME + SIZEOF__FaultingExceptionFrame + + ; At this point, the stack maybe misaligned if the thread abort was asynchronously + ; triggered in the prolog or epilog of the managed method. For such a case, we must + ; align the stack before calling into the VM. + ; + ; Runtime check for 8-byte alignment. + PROLOG_STACK_SAVE r7 + and r0, r7, #4 + sub sp, sp, r0 + + ; Save pointer to FEF for GetFrameFromRedirectedStubStackFrame + add r4, sp, #OFFSET_OF_FRAME + + ; Prepare to initialize to NULL + mov r1,#0 + str r1, [r4] ; Initialize vtbl (it is not strictly necessary) + str r1, [r4, #FaultingExceptionFrame__m_fFilterExecuted] ; Initialize BOOL for personality routine + + mov r0, r4 ; move the ptr to FEF in R0 + + ; stack must be 8 byte aligned + CHECK_STACK_ALIGNMENT + + bl $TARGET + + ; Target should not return. + EMIT_BREAKPOINT + + NESTED_END $STUB + + MEND + +; ------------------------------------------------------------------ +; +; Helpers for async (NullRef, AccessViolation) exceptions +; + + NESTED_ENTRY NakedThrowHelper2,,FixContextHandler + PROLOG_PUSH {r0, lr} + + ; On entry: + ; + ; R0 = Address of FaultingExceptionFrame + bl LinkFrameAndThrow + + ; Target should not return. + EMIT_BREAKPOINT + + NESTED_END NakedThrowHelper2 + + + GenerateRedirectedStubWithFrame NakedThrowHelper, NakedThrowHelper2 + +; ------------------------------------------------------------------ +; +; Helpers for ThreadAbort exceptions +; + + NESTED_ENTRY RedirectForThreadAbort2,,HijackHandler + PROLOG_PUSH {r0, lr} + + ; stack must be 8 byte aligned + CHECK_STACK_ALIGNMENT + + ; On entry: + ; + ; R0 = Address of FaultingExceptionFrame. + ; + ; Invoke the helper to setup the FaultingExceptionFrame and raise the exception + bl ThrowControlForThread + + ; ThrowControlForThread doesn't return. + EMIT_BREAKPOINT + + NESTED_END RedirectForThreadAbort2 + + GenerateRedirectedStubWithFrame RedirectForThreadAbort, RedirectForThreadAbort2 + +; ------------------------------------------------------------------ + + ; This helper enables us to call into a funclet after applying the non-volatiles + NESTED_ENTRY CallEHFunclet + + PROLOG_PUSH {r4-r11, lr} + PROLOG_STACK_ALLOC 4 + + ; On entry: + ; + ; R0 = throwable + ; R1 = PC to invoke + ; R2 = address of R4 register in CONTEXT record; used to restore the non-volatile registers of CrawlFrame + ; R3 = address of the location where the SP of funclet's caller (i.e. this helper) should be saved. + ; + ; Save the SP of this function + str sp, [r3] + ; apply the non-volatiles corresponding to the CrawlFrame + ldm r2, {r4-r11} + ; Invoke the funclet + blx r1 + + EPILOG_STACK_FREE 4 + EPILOG_POP {r4-r11, pc} + + NESTED_END CallEHFunclet + + ; This helper enables us to call into a filter funclet by passing it the CallerSP to lookup the + ; frame pointer for accessing the locals in the parent method. + NESTED_ENTRY CallEHFilterFunclet + + PROLOG_PUSH {lr} + PROLOG_STACK_ALLOC 4 + + ; On entry: + ; + ; R0 = throwable + ; R1 = SP of the caller of the method/funclet containing the filter + ; R2 = PC to invoke + ; R3 = address of the location where the SP of funclet's caller (i.e. this helper) should be saved. + ; + ; Save the SP of this function + str sp, [r3] + ; Invoke the filter funclet + blx r2 + + EPILOG_STACK_FREE 4 + EPILOG_POP {pc} + + NESTED_END CallEHFilterFunclet + END + |