Alec Roelke has submitted this change and it was merged. (
https://gem5-review.googlesource.com/6681 )
Change subject: arch-riscv: Define AT_RANDOM properly
......................................................................
arch-riscv: Define AT_RANDOM properly
According to the getauxval(3) man page, the AT_RANDOM aux value should
be a pointer to 16 random bytes. In the initial implementation of
RISC-V, this was based on spike's program stack setup, which copied the
program header table there instead. This patch changes the
implementation to use the proper 16 random bytes, making it compatible
with some RISC-V programs that use custom linker scripts.
Change-Id: Idaae7f19bf3ed3fd06d293e5e9c0b6f778270eb2
Reviewed-on: https://gem5-review.googlesource.com/6681
Reviewed-by: Jason Lowe-Power <[email protected]>
Maintainer: Alec Roelke <[email protected]>
---
M src/arch/riscv/process.cc
1 file changed, 11 insertions(+), 10 deletions(-)
Approvals:
Jason Lowe-Power: Looks good to me, approved
Alec Roelke: Looks good to me, approved
diff --git a/src/arch/riscv/process.cc b/src/arch/riscv/process.cc
index 371a8e4..6fe935c 100644
--- a/src/arch/riscv/process.cc
+++ b/src/arch/riscv/process.cc
@@ -36,6 +36,7 @@
#include <algorithm>
#include <cstddef>
#include <iostream>
+#include <iterator>
#include <map>
#include <string>
#include <vector>
@@ -44,6 +45,7 @@
#include "base/loader/elf_object.hh"
#include "base/loader/object_file.hh"
#include "base/logging.hh"
+#include "base/random.hh"
#include "cpu/thread_context.hh"
#include "debug/Stack.hh"
#include "mem/page_table.hh"
@@ -81,6 +83,8 @@
template<class IntType> void
RiscvProcess::argsInit(int pageSize)
{
+ const int RandomBytes = 16;
+
updateBias();
objFile->loadSections(initVirtMem);
ElfObject* elfObject = dynamic_cast<ElfObject*>(objFile);
@@ -88,7 +92,7 @@
// Determine stack size and populate auxv
Addr stack_top = memState->getStackMin();
- stack_top -= elfObject->programHeaderSize();
+ stack_top -= RandomBytes;
for (const string& arg: argv)
stack_top -= arg.size() + 1;
for (const string& env: envp)
@@ -114,15 +118,12 @@
allocateMem(roundDown(stack_top, pageSize),
roundUp(memState->getStackSize(), pageSize));
- // Copy program headers to stack
- memState->setStackMin(memState->getStackMin() -
- elfObject->programHeaderSize());
- uint8_t* phdr = new uint8_t[elfObject->programHeaderSize()];
- initVirtMem.readBlob(elfObject->programHeaderTable(), phdr,
- elfObject->programHeaderSize());
- initVirtMem.writeBlob(memState->getStackMin(), phdr,
- elfObject->programHeaderSize());
- delete phdr;
+ // Copy random bytes (for AT_RANDOM) to stack
+ memState->setStackMin(memState->getStackMin() - RandomBytes);
+ uint8_t at_random[RandomBytes];
+ generate(begin(at_random), end(at_random),
+ [&]{ return random_mt.random(0, 0xFF); });
+ initVirtMem.writeBlob(memState->getStackMin(), at_random, RandomBytes);
// Copy argv to stack
vector<Addr> argPointers;
--
To view, visit https://gem5-review.googlesource.com/6681
To unsubscribe, or for help writing mail filters, visit
https://gem5-review.googlesource.com/settings
Gerrit-Project: public/gem5
Gerrit-Branch: master
Gerrit-MessageType: merged
Gerrit-Change-Id: Idaae7f19bf3ed3fd06d293e5e9c0b6f778270eb2
Gerrit-Change-Number: 6681
Gerrit-PatchSet: 3
Gerrit-Owner: Alec Roelke <[email protected]>
Gerrit-Reviewer: Alec Roelke <[email protected]>
Gerrit-Reviewer: Jason Lowe-Power <[email protected]>
_______________________________________________
gem5-dev mailing list
[email protected]
http://m5sim.org/mailman/listinfo/gem5-dev
