/*
 * llvm C frontend for perf. Support dynamically compile C file
 *
 * Inspired by clang example code:
 * http://llvm.org/svn/llvm-project/cfe/trunk/examples/clang-interpreter/main.cpp
 *
 * Copyright (C) 2016 Wang Nan <wangnan0@huawei.com>
 * Copyright (C) 2016 Huawei Inc.
 */

#include "clang/CodeGen/CodeGenAction.h"
#include "clang/Frontend/CompilerInvocation.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/TextDiagnosticPrinter.h"
#include "clang/Tooling/Tooling.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Module.h"
#include "llvm/Option/Option.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include <memory>

#include "clang.h"
#include "clang-c.h"

namespace perf {

static std::unique_ptr<llvm::LLVMContext> LLVMCtx;

using namespace clang;

static CompilerInvocation *
createCompilerInvocation(llvm::opt::ArgStringList CFlags, StringRef& Path,
			 DiagnosticsEngine& Diags)
{
	llvm::opt::ArgStringList CCArgs {
		"-cc1",
		"-triple", "bpf-pc-linux",
		"-fsyntax-only",
		"-ferror-limit", "19",
		"-fmessage-length", "127",
		"-O2",
		"-nostdsysteminc",
		"-nobuiltininc",
		"-vectorize-loops",
		"-vectorize-slp",
		"-Wno-unused-value",
		"-Wno-pointer-sign",
		"-x", "c"};

	CCArgs.append(CFlags.begin(), CFlags.end());
	CompilerInvocation *CI = tooling::newInvocation(&Diags, CCArgs);

	FrontendOptions& Opts = CI->getFrontendOpts();
	Opts.Inputs.clear();
	Opts.Inputs.emplace_back(Path, IK_C);
	return CI;
}

static std::unique_ptr<llvm::Module>
getModuleFromSource(llvm::opt::ArgStringList CFlags,
		    StringRef Path, IntrusiveRefCntPtr<vfs::FileSystem> VFS)
{
	CompilerInstance Clang;
	Clang.createDiagnostics();

	Clang.setVirtualFileSystem(&*VFS);

	IntrusiveRefCntPtr<CompilerInvocation> CI =
		createCompilerInvocation(std::move(CFlags), Path,
					 Clang.getDiagnostics());
	Clang.setInvocation(&*CI);

	std::unique_ptr<CodeGenAction> Act(new EmitLLVMOnlyAction(&*LLVMCtx));
	if (!Clang.ExecuteAction(*Act))
		return std::unique_ptr<llvm::Module>(nullptr);

	return Act->takeModule();
}

std::unique_ptr<llvm::Module>
getModuleFromSource(llvm::opt::ArgStringList CFlags,
		    StringRef Name, StringRef Content)
{
	using namespace vfs;

	llvm::IntrusiveRefCntPtr<OverlayFileSystem> OverlayFS(
			new OverlayFileSystem(getRealFileSystem()));
	llvm::IntrusiveRefCntPtr<InMemoryFileSystem> MemFS(
			new InMemoryFileSystem(true));

	/*
	 * pushOverlay helps setting working dir for MemFS. Must call
	 * before addFile.
	 */
	OverlayFS->pushOverlay(MemFS);
	MemFS->addFile(Twine(Name), 0, llvm::MemoryBuffer::getMemBuffer(Content));

	return getModuleFromSource(std::move(CFlags), Name, OverlayFS);
}

std::unique_ptr<llvm::Module>
getModuleFromSource(llvm::opt::ArgStringList CFlags, StringRef Path)
{
	IntrusiveRefCntPtr<vfs::FileSystem> VFS(vfs::getRealFileSystem());
	return getModuleFromSource(std::move(CFlags), Path, VFS);
}

std::unique_ptr<llvm::SmallVectorImpl<char>>
getBPFObjectFromModule(llvm::Module *Module)
{
	using namespace llvm;

	std::string TargetTriple("bpf-pc-linux");
	std::string Error;
	const Target* Target = TargetRegistry::lookupTarget(TargetTriple, Error);
	if (!Target) {
		llvm::errs() << Error;
		return std::unique_ptr<llvm::SmallVectorImpl<char>>(nullptr);
	}

	llvm::TargetOptions Opt;
	TargetMachine *TargetMachine =
		Target->createTargetMachine(TargetTriple,
					    "generic", "",
					    Opt, Reloc::Static);

	Module->setDataLayout(TargetMachine->createDataLayout());
	Module->setTargetTriple(TargetTriple);

	std::unique_ptr<SmallVectorImpl<char>> Buffer(new SmallVector<char, 0>());
	raw_svector_ostream ostream(*Buffer);

	legacy::PassManager PM;
	if (TargetMachine->addPassesToEmitFile(PM, ostream,
					       TargetMachine::CGFT_ObjectFile)) {
		llvm::errs() << "TargetMachine can't emit a file of this type\n";
		return std::unique_ptr<llvm::SmallVectorImpl<char>>(nullptr);;
	}
	PM.run(*Module);

	return std::move(Buffer);
}

}

extern "C" {
void perf_clang__init(void)
{
	perf::LLVMCtx.reset(new llvm::LLVMContext());
	LLVMInitializeBPFTargetInfo();
	LLVMInitializeBPFTarget();
	LLVMInitializeBPFTargetMC();
	LLVMInitializeBPFAsmPrinter();
}

void perf_clang__cleanup(void)
{
	perf::LLVMCtx.reset(nullptr);
	llvm::llvm_shutdown();
}

int perf_clang__compile_bpf(const char *filename,
			    void **p_obj_buf,
			    size_t *p_obj_buf_sz)
{
	using namespace perf;

	if (!p_obj_buf || !p_obj_buf_sz)
		return -EINVAL;

	llvm::opt::ArgStringList CFlags;
	auto M = getModuleFromSource(std::move(CFlags), filename);
	if (!M)
		return  -EINVAL;
	auto O = getBPFObjectFromModule(&*M);
	if (!O)
		return -EINVAL;

	size_t size = O->size_in_bytes();
	void *buffer;

	buffer = malloc(size);
	if (!buffer)
		return -ENOMEM;
	memcpy(buffer, O->data(), size);
	*p_obj_buf = buffer;
	*p_obj_buf_sz = size;
	return 0;
}
}
/tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;</td><td class='right'>2017-02-03 17:10:28 +1100</td></tr>
<tr><th>committer</th><td>Michael Ellerman &lt;mpe@ellerman.id.au&gt;</td><td class='right'>2017-02-08 23:36:29 +1100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/arch/tile/include?h=nds-private-remove&amp;id=d7df2443cd5f67fc6ee7c05a88e4996e8177f91b'>d7df2443cd5f67fc6ee7c05a88e4996e8177f91b</a> (<a href='/cgit.cgi/linux/net-next.git/patch/tools/arch/tile/include?id=d7df2443cd5f67fc6ee7c05a88e4996e8177f91b'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=d7df2443cd5f67fc6ee7c05a88e4996e8177f91b'>098a7c0ca4fceb8a65cb1f693c9d71990388933d</a> /<a href='/cgit.cgi/linux/net-next.git/tree/tools/arch/tile/include?h=nds-private-remove&amp;id=d7df2443cd5f67fc6ee7c05a88e4996e8177f91b'>tools/arch/tile/include</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/arch/tile/include?h=nds-private-remove&amp;id=a0615a16f7d0ceb5804d295203c302d496d8ee91'>a0615a16f7d0ceb5804d295203c302d496d8ee91</a> (<a href='/cgit.cgi/linux/net-next.git/diff/tools/arch/tile/include?h=nds-private-remove&amp;id=d7df2443cd5f67fc6ee7c05a88e4996e8177f91b&amp;id2=a0615a16f7d0ceb5804d295203c302d496d8ee91'>diff</a>)</td></tr></table>
<div class='commit-subject'>powerpc/mm: Fix spurrious segfaults on radix with autonuma</div><div class='commit-msg'>When autonuma (Automatic NUMA balancing) marks a PTE inaccessible it
clears all the protection bits but leave the PTE valid.

With the Radix MMU, an attempt at executing from such a PTE will
take a fault with bit 35 of SRR1 set "SRR1_ISI_N_OR_G".

It is thus incorrect to treat all such faults as errors. We should
pass them to handle_mm_fault() for autonuma to deal with. The case
of pages that are really not executable is handled by the existing
test for VM_EXEC further down.

That leaves us with catching the kernel attempts at executing user
pages. We can catch that earlier, even before we do find_vma.

It is never valid on powerpc for the kernel to take an exec fault
to begin with. So fold that test with the existing test for the
kernel faulting on kernel addresses to bail out early.

Fixes: 1d18ad026844 ("powerpc/mm: Detect instruction fetch denied and report")
Signed-off-by: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Reviewed-by: Aneesh Kumar K.V &lt;aneesh.kumar@linux.vnet.ibm.com&gt;
Acked-by: Balbir Singh &lt;bsingharora@gmail.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=d7df2443cd5f67fc6ee7c05a88e4996e8177f91b'>Diffstat</a> (limited to 'tools/arch/tile/include')</div><table summary='diffstat' class='diffstat'>