Messages in this thread Patch in this message | | | From | "Kirill A. Shutemov" <> | Subject | [PATCH] x86/selftests: Add test for mapping placement for 5-level paging | Date | Wed, 8 Nov 2017 13:22:50 +0300 |
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With 5-level paging, we have 56-bit virtual address space available for userspace. But we don't want to expose userspace to addresses above 47-bits, unless it asked specifically for it.
We use mmap(2) hint address as a way for kernel to know if it's okay to allocate virtual memory above 47-bit.
Let's add a self-test that covers few corner cases of the interface.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> --- tools/testing/selftests/x86/5lvl.c | 53 ++++++++++++++++++++++++++++++++++++ tools/testing/selftests/x86/Makefile | 2 +- 2 files changed, 54 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/x86/5lvl.c
diff --git a/tools/testing/selftests/x86/5lvl.c b/tools/testing/selftests/x86/5lvl.c new file mode 100644 index 000000000000..94610fd13ba2 --- /dev/null +++ b/tools/testing/selftests/x86/5lvl.c @@ -0,0 +1,53 @@ +#include <stdio.h> +#include <sys/mman.h> + +#define PAGE_SIZE 4096 +#define SIZE (2 * PAGE_SIZE) +#define LOW_ADDR ((void *) (1UL << 30)) +#define HIGH_ADDR ((void *) (1UL << 50)) +#define TASK_SIZE ((void *) (1UL << 47)) + +int main(int argc, char **argv) +{ + void *p; + + p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + printf("mmap(NULL): %p %s\n", p, p > TASK_SIZE ? "FAILED!" : ""); + + p = mmap(LOW_ADDR, SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + printf("mmap(%p): %p %s\n", LOW_ADDR, p, + p > TASK_SIZE ? "FAILED!" : ""); + + p = mmap(HIGH_ADDR, SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + printf("mmap(%p): %p\n", HIGH_ADDR, p); + + p = mmap(HIGH_ADDR, SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + printf("mmap(%p) again: %p\n", HIGH_ADDR, p); + + p = mmap(HIGH_ADDR, SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0); + printf("mmap(%p, MAP_FIXED): %p\n", HIGH_ADDR, p); + + p = mmap((void *)-1, SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + printf("mmap(-1): %p\n", p); + + p = mmap((void *)-1, SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + printf("mmap(-1) again: %p\n", p); + + p = mmap(TASK_SIZE - PAGE_SIZE, SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + printf("mmap(%p, %d): %p %s\n", TASK_SIZE - PAGE_SIZE, SIZE, p, + p > TASK_SIZE ? "FAILED!" : ""); + + p = mmap(TASK_SIZE - PAGE_SIZE, SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0); + printf("mmap(TASK_SIZE - PAGE_SIZE, MAP_FIXED): %p\n", p); + + return 0; +} diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index 0a74a20ca32b..1f5d6565fbef 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -10,7 +10,7 @@ TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt ptrace_sysc TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault test_syscall_vdso unwind_vdso \ test_FCMOV test_FCOMI test_FISTTP \ vdso_restorer -TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip +TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip 5lvl TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY) TARGETS_C_64BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_64BIT_ONLY) -- 2.14.2
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