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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] x86emul: correct stub invocation constraints
On 04/25/2017 05:04 AM, Jan Beulich wrote:
> Stub invocations need to have the space the stub occupies as an input,
> to prevent the compiler from re-ordering (or omitting) writes to it.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> --- a/xen/arch/x86/x86_emulate/x86_emulate.c
> +++ b/xen/arch/x86/x86_emulate/x86_emulate.c
> @@ -837,7 +837,8 @@ do{ asm volatile (
> ".popsection\n\t" \
> _ASM_EXTABLE(.Lret%=, .Lfix%=) \
> : [exn] "+g" (res_), constraints, \
> - [stub] "rm" (stub.func) ); \
> + [stub] "rm" (stub.func), \
> + "m" (*(uint8_t(*)[MAX_INST_LEN + 1])stub.ptr) ); \
> if ( unlikely(~res_.raw) ) \
> { \
> gprintk(XENLOG_WARNING, \
> @@ -853,7 +854,8 @@ do{ asm volatile (
> #else
> # define invoke_stub(pre, post, constraints...) \
> asm volatile ( pre "\n\tcall *%[stub]\n\t" post \
> - : constraints, [stub] "rm" (stub.func) )
> + : constraints, [stub] "rm" (stub.func), \
> + "m" (*(uint8_t(*)[MAX_INST_LEN + 1])stub.buf) )
> #endif
>
> #define emulate_stub(dst, src...) do { \
>
This breaks on old compilers:
FC-64
<build@build-mk2:~/xtt-x86_64/bootstrap/xen.git/tools/fuzz/x86_instruction_emulator>
gcc --version
gcc (GCC) 4.4.4 20100503 (Red Hat 4.4.4-2)
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
FC-64
<build@build-mk2:~/xtt-x86_64/bootstrap/xen.git/tools/fuzz/x86_instruction_emulator>
pwd
/home/build/xtt-x86_64/bootstrap/xen.git/tools/fuzz/x86_instruction_emulator
FC-64
<build@build-mk2:~/xtt-x86_64/bootstrap/xen.git/tools/fuzz/x86_instruction_emulator>
gcc -m64 -DBUILD_ID -fno-strict-aliasing -std=gnu99 -Wall
-Wstrict-prototypes -Wdeclaration-after-statement
-Wno-unused-but-set-variable -g3 -O0 -fno-omit-frame-pointer
-D__XEN_INTERFACE_VERSION__=__XEN_LATEST_INTERFACE_VERSION__ -MMD -MF
.x86_emulate.o.d -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
-I/home/build/xtt-x86_64/bootstrap/xen.git/tools/fuzz/x86_instruction_emulator/../../../tools/include
-D__XEN_TOOLS__ -I. -c -o x86_emulate.o x86_emulate.c
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c: In function ‘x86_emulate’:
x86_emulate/x86_emulate.c:4085: error: memory input 3 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:4161: error: memory input 3 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:4226: error: memory input 5 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:4229: error: memory input 3 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:4279: error: memory input 5 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:4288: error: memory input 3 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:4353: error: memory input 3 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:4402: error: memory input 3 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:4465: error: memory input 3 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:4516: error: memory input 5 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:4522: error: memory input 3 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:5632: error: memory input 5 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:5679: error: memory input 8 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:5863: error: memory input 3 is not directly
addressable
x86_emulate/x86_emulate.c:6069: error: memory input 4 is not directly
addressable
x86_emulate/x86_emulate.c:6213: error: memory input 3 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:7029: error: memory input 3 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:7178: error: memory input 6 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:7328: error: memory input 7 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:7362: error: memory input 6 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:7482: error: memory input 3 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:7603: error: memory input 9 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:7607: error: memory input 9 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:7676: error: memory input 6 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:7715: error: memory input 6 is not directly
addressable
In file included from x86_emulate.c:157:
x86_emulate/x86_emulate.c:7795: error: memory input 4 is not directly
addressable
x86_emulate/x86_emulate.c:7798: error: memory input 3 is not directly
addressable
FC-64
<build@build-mk2:~/xtt-x86_64/bootstrap/xen.git/tools/fuzz/x86_instruction_emulator>
-boris
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