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| author | Jeremy Fitzhardinge | 2009-03-17 01:24:34 +0100 |
|---|---|---|
| committer | H. Peter Anvin | 2009-03-17 02:36:31 +0100 |
| commit | 42854dc0a6320ff36722749acafa0697522d9556 (patch) | |
| tree | d85b34e78479e5b726cbe7f5632033dfc8b269a2 /Documentation | |
| parent | VM, x86, PAT: add a new vm flag to track full pfnmap at mmap (diff) | |
| download | kernel-qcow2-linux-42854dc0a6320ff36722749acafa0697522d9556.tar.gz kernel-qcow2-linux-42854dc0a6320ff36722749acafa0697522d9556.tar.xz kernel-qcow2-linux-42854dc0a6320ff36722749acafa0697522d9556.zip | |
x86, paravirt: prevent gcc from generating the wrong addressing mode
Impact: fix crash on VMI (VMware)
When we generate a call sequence for calling a paravirtualized
function, we presume that the generated code is "call *0xXXXXX",
which is a 6 byte opcode; this is larger than a normal
direct call, and so we can patch a direct call over it.
At the moment, however we give gcc enough rope to hang us by
putting the address in a register and generating a two byte
indirect-via-register call. Prevent this by explicitly
dereferencing the function pointer and passing it into the
asm as a constant.
This prevents crashes in VMI, as it cannot handle unpatchable
callsites.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Alok Kataria <akataria@vmware.com>
LKML-Reference: <49BEEDC2.2070809@goop.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'Documentation')
0 files changed, 0 insertions, 0 deletions