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ARM: Add a cmpxchg implementation to the "comm page".

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This implementation does what it's supposed to (I think), but it's not atomic
and doesn't have memory barriers like the kernel's version.
This commit is contained in:
Gabe Black 2009-06-09 23:41:03 -07:00
parent 37ac2871d5
commit 3ff1e922c2
1 changed files with 12 additions and 0 deletions
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12
src/arch/arm/linux/process.cc
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@ -482,6 +482,18 @@ ArmLinuxProcess::startup()
swiNeg1, sizeof(swiNeg1));
}
// This -should- be atomic, but I don't think all the support that we'd
// need is implemented. There should also be memory barriers around it.
uint8_t cmpxchg[] =
{
0x00, 0x30, 0x92, 0xe5, //ldr r3, [r2]
0x00, 0x30, 0x53, 0xe0, //subs r3, r3, r0
0x00, 0x10, 0x92, 0x05, //streq r1, [r2]
0x03, 0x00, 0xa0, 0xe1, //mov r0, r3
0x0e, 0xf0, 0xa0, 0xe1 //usr_ret lr
};
tc->getMemPort()->writeBlob(commPage + 0x0fc0, cmpxchg, sizeof(cmpxchg));
uint8_t get_tls[] =
{
0x08, 0x00, 0x9f, 0xe5, //ldr r0, [pc, #(16 - 8)]