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-rw-r--r--src/arch/arm/linux/process.cc12
1 files changed, 12 insertions, 0 deletions
diff --git a/src/arch/arm/linux/process.cc b/src/arch/arm/linux/process.cc
index 620bcf116..bc6388b73 100644
--- a/src/arch/arm/linux/process.cc
+++ b/src/arch/arm/linux/process.cc
@@ -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)]