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6716785: implicit null checks not triggering with CompressedOops

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Allocate alignment-sized page(s) below java heap so that memory accesses at heap_base+1page give signal and cause an implicit null check

Reviewed-by: kvn, jmasa, phh, jcoomes
This commit is contained in:
Coleen Phillimore 2008-07-19 17:38:22 -04:00
parent 575988272e
commit 20dba03e99
23 changed files with 197 additions and 133 deletions
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17
hotspot/src/os/solaris/vm/os_solaris.cpp
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@ -2965,10 +2965,21 @@ static bool solaris_mprotect(char* addr, size_t bytes, int prot) {
return retVal == 0;
}
// Protect memory (make it read-only. (Used to pass readonly pages through
// Protect memory (Used to pass readonly pages through
// JNI GetArray<type>Elements with empty arrays.)
bool os::protect_memory(char* addr, size_t bytes) {
return solaris_mprotect(addr, bytes, PROT_READ);
bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
bool is_committed) {
unsigned int p = 0;
switch (prot) {
case MEM_PROT_NONE: p = PROT_NONE; break;
case MEM_PROT_READ: p = PROT_READ; break;
case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
default:
ShouldNotReachHere();
}
// is_committed is unused.
return solaris_mprotect(addr, bytes, p);
}
// guard_memory and unguard_memory only happens within stack guard pages.