Mercurial > hg > graal-jvmci-8
diff src/os/linux/vm/os_linux.cpp @ 237:1fdb98a17101
6716785: implicit null checks not triggering with CompressedOops
Summary: 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
| author | coleenp |
|---|---|
| date | Sat, 19 Jul 2008 17:38:22 -0400 |
| parents | 9c2ecc2ffb12 |
| children | d95b224e9f17 850fdf70db2b |
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--- a/src/os/linux/vm/os_linux.cpp Fri Jul 11 01:14:44 2008 -0700 +++ b/src/os/linux/vm/os_linux.cpp Sat Jul 19 17:38:22 2008 -0400 @@ -2414,8 +2414,20 @@ return ::mprotect(bottom, size, prot) == 0; } -bool os::protect_memory(char* addr, size_t size) { - return linux_mprotect(addr, size, PROT_READ); +// Set protections specified +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 linux_mprotect(addr, bytes, p); } bool os::guard_memory(char* addr, size_t size) { @@ -3704,8 +3716,9 @@ // Mark the polling page as readable void os::make_polling_page_readable(void) { - if( !protect_memory((char *)_polling_page, Linux::page_size()) ) + if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { fatal("Could not enable polling page"); + } }; int os::active_processor_count() {