From ca82be5f5cffc3b64e4c8d6d944b8a77bfce1a0e Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Fri, 3 Mar 2017 12:00:05 +0100 Subject: [PATCH] x86emul: assert no duplicate mappings of stub space Suggested-by: Andrew Cooper Signed-off-by: Jan Beulich Reviewed-by: Andrew Cooper --- tools/tests/x86_emulator/x86_emulate.c | 7 +++++-- xen/arch/x86/x86_emulate.c | 1 + 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/tools/tests/x86_emulator/x86_emulate.c b/tools/tests/x86_emulator/x86_emulate.c index cda0fd8ee1..bbfd03f9b3 100644 --- a/tools/tests/x86_emulator/x86_emulate.c +++ b/tools/tests/x86_emulator/x86_emulate.c @@ -19,8 +19,11 @@ # define __OP "r" /* Operand Prefix */ #endif -#define get_stub(stb) ((void *)((stb).addr = (uintptr_t)(stb).buf)) -#define put_stub(stb) +#define get_stub(stb) ({ \ + assert(!(stb).addr); \ + (void *)((stb).addr = (uintptr_t)(stb).buf); \ +}) +#define put_stub(stb) ((stb).addr = 0) bool emul_test_make_stack_executable(void) { diff --git a/xen/arch/x86/x86_emulate.c b/xen/arch/x86/x86_emulate.c index 653b5f8b31..51df3408a0 100644 --- a/xen/arch/x86/x86_emulate.c +++ b/xen/arch/x86/x86_emulate.c @@ -28,6 +28,7 @@ #define get_stub(stb) ({ \ BUILD_BUG_ON(STUB_BUF_SIZE / 2 < MAX_INST_LEN + 1); \ + ASSERT(!(stb).ptr); \ (stb).addr = this_cpu(stubs.addr) + STUB_BUF_SIZE / 2; \ ((stb).ptr = map_domain_page(_mfn(this_cpu(stubs.mfn)))) + \ ((stb).addr & ~PAGE_MASK); \ -- 2.39.5