I was surprised that my user-mode applications ran successfully under
qemu-ppc64 2.10.1
running on Linux on x86_64, but crashed when run directly under Linux on 64-bit
PowerPC.
Investigation showed that qemu-ppc64 does not emulate system calls faithfully.
On real Linux on PowerPC64, a system
... this one is even smaller. Plus it uses the familiar strlen() function:
size_t strnlen(const char *string, size_t max_count)
{
return strlen(string) < max_count ? strlen(string) : max_count;
}
Please do not use that implementation.
The major goal of strnlen is to avoid looking beyond
"qemu-ppc -g 1234 foo" emulating the 32-bit PowerPC instruction 0x7c88
("tweq r0,r0") terminates with "fatal: Tried to call a TRAP".
Instead, when co-operating with gdbserver (-g ) then qemu-ppc
should generate a SIGTRAP, just like real execution under gdb.
The "tweq r0,r0" and others are
I don't really know why we use 0xf700 as our
reserved_va value here, though. Alex, you added that
years ago, can you remember why you used that value?
IIRC I wanted to map the full 32 bits of address space possibly in use by a
32bit application, but leave some room for something, but I
Thanks for your reply, Peter. [I fixed my typo in the Subject: field of the
header.]
[Moving here from https://bugzilla.redhat.com/show_bug.cgi?id=1493304 ]
qemu-arm from qemu-user-2.10.0-1.fc27.x86_64 (thus emulating 32-bit ARM on
x86_64)
generates SIGSEGV when code modifies a
[Moving here from https://bugzilla.redhat.com/show_bug.cgi?id=1493304 ]
qemu-arm from qemu-user-2.10.0-1.fc27.x86_64 (thus emulating 32-bit ARM on
x86_64)
generates SIGSEGV when code modifies a never-previously executed instruction
that is on a writable page and is 848 bytes ahead of pc.
A
to discover that the instruction stream is being modified.
Instead, there is direct notification of what is happening. If nothing
else, then under CONFIG_QEMU the implementation of sys_ptrace()
must notify the emulator to flush the appropriate translations.
--
John Reiser, [EMAIL PROTECTED]
/target-mips/helper.c 2007-05-07 13:24:50.0 -0700
@@ -358,6 +358,7 @@
goto set_EPC;
case EXCP_BREAK:
cause = 9;
+ tlb_flush_page(env, env-PC);
goto set_EPC;
case EXCP_RI:
cause = 10;
--
John Reiser, [EMAIL PROTECTED]
'.)
--
John Reiser, [EMAIL PROTECTED]
?) and shuts down.
It would be nice if qemu emulation detected such a situation,
then issued an informative message, in addition to
looping forever as an emulation of hardware shutdown.
--
John Reiser, [EMAIL PROTECTED]
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Qemu
directives for access to a few static 'const'
arrays) is easy.
--
John Reiser, [EMAIL PROTECTED]
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